JP2020174072A - Organic electroluminescence device and electronic device - Google Patents

Abstract

To provide an organic EL element capable of extending the life.SOLUTION: In an organic EL element, a light emitting layer includes a first compound M1 represented by a general formula (1), and a second compound M2 represented by a general formula (20A) or a general formula (20B), and one of D21 and D22 is represented by a general formula (21), and the other of D21 and D22 is represented by a general formula (22), and in the singlet energy, M2 is larger than M1.SELECTED DRAWING: Figure 5

Description

The present invention relates to organic electroluminescence devices and electronic devices.

When a voltage is applied to an organic electroluminescence device (hereinafter, may be referred to as an “organic EL device”), holes are injected into the light emitting layer from the anode, and electrons are injected into the light emitting layer from the cathode. Then, in the light emitting layer, the injected holes and electrons are recombined to form excitons. At this time, according to the statistical law of electron spin, singlet excitons are generated at a rate of 25%, and triplet excitons are generated at a rate of 75%.
Fluorescent organic EL devices that use light emitted from singlet excitons are being applied to full-color displays such as mobile phones and televisions, but are said to have an internal quantum efficiency of 25% as a limit. Therefore, studies are being conducted to improve the performance of the organic EL element.

For example, it is expected that an organic EL device can emit light more efficiently by using triplet excitons in addition to singlet excitons. Against this background, high-efficiency fluorescent organic EL devices using thermally activated delayed fluorescence (hereinafter, may be simply referred to as “delayed fluorescence”) have been proposed and studied.
The TADF (Thermally Activated Fluorescence) mechanism (mechanism) is from triplet excitons to singlet when a material with a small energy difference (ΔST) between the singlet level and the triplet level is used. It is a mechanism that utilizes the phenomenon that the inverse intersystem crossing to the term exciter occurs thermally. Thermal activation delayed fluorescence is described, for example, in "Chihaya Adachi," Device Properties of Organic Semiconductors, "Kodansha, published on April 1, 2012, pp. 261-268".
As a compound exhibiting thermal activation delayed fluorescence (TADF property) (hereinafter, also referred to as a TADF property compound), for example, a compound in which a donor site and an acceptor site are bonded in a molecule is known.

Documents 1 and 2 are examples of documents relating to organic EL devices.

International Publication No. 2014/208698 International Publication No. 2016/056559

In order to improve the performance of electronic devices such as displays, further improvement in the performance of organic EL elements is required.

An object of the present invention is to provide an organic electroluminescence device capable of improving performance, particularly a long life, and an electronic device provided with the organic electroluminescence device.

According to one aspect of the present invention, the light emitting layer has an anode, a cathode, and a light emitting layer contained between the anode and the cathode, and the light emitting layer has a first compound M1 and a second compound. The first compound M1 including M2 is represented by the following general formula (1), and the second compound M2 is represented by the following general formula (20A) or general formula (20B). a second compound singlet energy _S 1 of M2 (Mat2), the singlet energy _S 1 of the first compound M1 (Mat1) and but satisfies the following equation (equation 1), providing an organic electroluminescence device Will be done.
S ₁ (Mat 2)> S ₁ (Mat ₁ ) ... (Equation 1)

(In the general formula (1),
X is a nitrogen atom or a carbon atom bonded to Y,
Y is a hydrogen atom or a substituent,
R _{21 to} R ₂₆ are independently hydrogen atoms or substituents, or R ₂₁ and R ₂₂ pairs, R ₂₂ and R ₂₃ pairs, R ₂₄ and R ₂₅ pairs, and R ₂₅ and R. Any one or more of the ₂₆ pairs combine with each other to form a ring.
Y and R _{21 to} R ₂₆ as substituents are independent of each other.
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkoxy group having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylthio groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituted or unsubstituted ring-forming arylthio groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkenyl groups having 2 to 30 carbon atoms,
Substituentally substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Halogen atom,
Carboxylic acid group,
Substituted or unsubstituted ester groups,
Substituted or unsubstituted carbamoyl groups,
Substituted or unsubstituted amino groups,
Nitro group,
Cyano group,
Selected from the group consisting of substituted or unsubstituted silyl groups and substituted or unsubstituted siloxanyl groups.
Z ₂₁ and Z ₂₂ are independent substituents, or Z ₂₁ and Z ₂₂ are bonded to each other to form a ring.
Z ₂₁ and Z ₂₂ as substituents are independent of each other.
Halogen atom,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
It is selected from the group consisting of substituted or unsubstituted alkyl halide groups having 1 to 30 carbon atoms and substituted or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms. )

(In the general formula (20A) and the general formula (20B),
One of D ₂₁ and D ₂₂ is represented by the following general formula (21), and the other of D ₂₁ and D ₂₂ is represented by the following general formula (22).

(In the general formula (21),
R _{1 to} R ₈ are independent hydrogen atoms or substituents, respectively.
R _{1 to} R ₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
It is a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). )
(In the general formula (22),
X ₁ is a sulfur atom or an oxygen atom,
R ₁₉ and R ₂₀ are independent hydrogen atoms or substituents, respectively.
R _{31 to} R ₃₈ are independent hydrogen atoms or substituents, respectively.
R ₁₉ , R ₂₀ , and R _{31 to} R ₃₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). )

According to one aspect of the present invention, there is provided an electronic device equipped with the organic electroluminescence device according to the above-described aspect of the present invention.

According to one aspect of the present invention, it is possible to provide an organic electroluminescence device capable of improving performance, particularly a long life, and an electronic device including the organic electroluminescence device.

It is a figure which shows the schematic structure of an example of the organic electroluminescence device which concerns on 1st Embodiment of this invention. It is the schematic of the apparatus which measures a transient PL. It is a figure which shows an example of the attenuation curve of transient PL. It is a figure which shows the relationship between the energy level of the 1st compound and the 2nd compound, and the energy transfer in the light emitting layer of an example of the organic electroluminescence element which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between the energy level of the 1st compound, the 2nd compound and the 3rd compound, and the energy transfer in the light emitting layer of an example of the organic electroluminescence element which concerns on 2nd Embodiment of this invention.

[First Embodiment]
(Organic electroluminescence element)
The organic EL element according to this embodiment will be described.
The organic EL element according to the present embodiment includes an organic layer between both electrodes of the anode and the cathode. This organic layer contains at least one layer composed of an organic compound. Alternatively, this organic layer is formed by laminating a plurality of layers composed of organic compounds. The organic layer may further contain an inorganic compound.

The organic EL device according to the present embodiment has a first organic layer as an organic layer.

In the organic EL device of the present embodiment, at least one of the organic layers is a light emitting layer. The organic layer may be composed of, for example, one light emitting layer, or may include a layer that can be adopted for an organic EL element. The layer that can be adopted for the organic EL device is not particularly limited, but is at least one selected from the group consisting of, for example, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and a barrier layer. Layers are mentioned.

In the present embodiment, the first organic layer is a light emitting layer. The first organic layer as the light emitting layer contains the first compound M1 and the second compound M2.

In the present embodiment, the first organic layer as the light emitting layer may contain a metal complex.
It is also preferable that the light emitting layer does not contain a metal complex.
The light emitting layer preferably does not contain a phosphorescent material (dopant material).
The light emitting layer preferably does not contain a heavy metal complex and a phosphorescent rare earth metal complex. Examples of the heavy metal complex include an iridium complex, an osmium complex, a platinum complex and the like.

FIG. 1 shows a schematic configuration of an example of an organic EL device according to the present embodiment.
The organic EL element 1 includes a translucent substrate 2, an anode 3, a cathode 4, and an organic layer 10 arranged between the anode 3 and the cathode 4. The organic layer 10 is composed of a hole injection layer 6, a hole transport layer 7, a light emitting layer 5, an electron transport layer 8 and an electron injection layer 9 laminated in this order from the anode 3 side.

<First compound>
In the present embodiment, the first compound M1 is represented by the following general formula (1).
The first compound M1 is preferably a compound having fluorescence luminescence.

In the general formula (1)
X is a nitrogen atom or a carbon atom bonded to Y,
Y is a hydrogen atom or a substituent,
R _{21 to} R ₂₆ are independently hydrogen atoms or substituents, or R ₂₁ and R ₂₂ pairs, R ₂₂ and R ₂₃ pairs, R ₂₄ and R ₂₅ pairs, and R ₂₅ and R. Any one or more of the ₂₆ pairs combine with each other to form a ring.
Y and R _{21 to} R ₂₆ as substituents are independent of each other.
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkoxy group having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylthio groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituted or unsubstituted ring-forming arylthio groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkenyl groups having 2 to 30 carbon atoms,
Substituentally substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Halogen atom,
Carboxylic acid group,
Substituted or unsubstituted ester groups,
Substituted or unsubstituted carbamoyl groups,
Substituted or unsubstituted amino groups,
Nitro group,
Cyano group,
Selected from the group consisting of substituted or unsubstituted silyl groups and substituted or unsubstituted siloxanyl groups.
Z ₂₁ and Z ₂₂ are independent substituents, or Z ₂₁ and Z ₂₂ are bonded to each other to form a ring.
Z ₂₁ and Z ₂₂ as substituents are independent of each other.
Halogen atom,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
It is selected from the group consisting of substituted or unsubstituted alkyl halide groups having 1 to 30 carbon atoms and substituted or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms.

In the general formula (1), for example, when the pair of R ₂₅ and R ₂₆ are bonded to each other to form a ring, the first compound M1 is represented by the following general formula (11).

In the general formula _{(11), X, Y,} R 21 ~R 24, Z 21, and _{Z 22} are each the _X in the general formula _{(1), Y, R 21} ~R 24, Z 21, and Z Synonymous with ₂₂ , R _{27 to} R ₃₀ are independent hydrogen atoms or substituents, and R _{21 to} R ₂₄ are listed as substituents when R _{27 to} R ₃₀ are substituents. Synonymous with substituent.

In the general formula (1), when Z ₂₁ and Z ₂₂ are bonded to each other to form a ring, the first compound M1 is, for example, the following general formula (1A) or the following general formula (1B). expressed. However, the first compound M1 is not limited to the following structure.

In the general formula (1A), X, Y, and R _{21 to} R ₂₆ are synonymous with X, Y, and R _{21 to} R ₂₆ in the general formula (1), respectively, and R _1A is independent of each other. In addition, when it is a hydrogen atom or a substituent and R _1A is a substituent, the substituent is synonymous with the substituents listed for R _{21 to} R ₂₆ , and n3 is 4.
In the general formula (1B), X, Y, and R _{21 to} R ₂₆ are synonymous with X, Y, and R _{21 to} R ₂₆ in the general formula (1), respectively, and R _1B are independent of each other. In addition, when it is a hydrogen atom or a substituent and R _1B is a substituent, the substituent is synonymous with the substituents listed for R _{21 to} R ₂₆ , and n4 is 4.

At least one of Z ₂₁ and _{Z 22} (preferably _{Z 21} and _{Z 22)} is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted halogenated alkyl group having 1 to 30 carbon atoms , Substituted or unsubstituted ring-forming aryl group having 6 to 30 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, and substituted or unsubstituted. It is preferably a group selected from the group consisting of an unsubstituted ring-forming aryloxy group having 6 to 30 carbon atoms.
At least one of Z ₂₁ and Z ₂₂ has an alkoxy group having 1 to 30 carbon atoms substituted with a fluorine atom, an aryloxy group having 6 to 30 carbon atoms substituted with a fluorine atom, and 1 to 1 carbon atoms. More preferably, it is a group selected from the group consisting of an aryloxy group having 6 to 30 ring-forming carbon atoms substituted with 30 fluoroalkyl groups.
It is more preferable that at least one of Z ₂₁ and Z ₂₂ is an alkoxy group having 1 to 30 carbon atoms substituted with a fluorine atom, and Z ₂₁ and Z ₂₂ have 1 to 30 carbon atoms substituted with a fluorine atom. It is even more preferable that it is an alkoxy group of.

It is also preferable that Z ₂₁ and Z ₂₂ are the same.

On the other hand, it is also preferably at least one is a fluorine atom in the Z ₂₁ and the Z _22, it is also more preferred that the Z ₂₁ and the Z ₂₂ is a fluorine atom.

It is also preferable that at least one of the Z ₂₁ and the Z ₂₂ is a group represented by the following general formula (1a).

In the general formula (1a), A is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, or a substituted or unsubstituted ring-forming carbon. It is an aryl group of number 6 to 12, L ₂ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, or a substituted or unsubstituted ring-forming aryl group having 6 to 12 carbon atoms, and m is a substituted or unsubstituted arylene group. 0,1,2,3,4,5,6, or 7, when m is 3, 4, 5, 6, or 7, a plurality of _{L 2} may be the same or different from each other. m is preferably 0, 1, or 2. When m is 0, A directly bonds to O (oxygen atom).

In the general formula (1), when Z ₂₁ and Z ₂₂ are the groups represented by the general formula (1a), the first compound M1 is a compound represented by the following general formula (10).
The first compound M1 is also preferably a compound represented by the following general formula (10).

In the general formula (10), Y, R _{21 to} R ₂₆ when X and X are carbon atoms bonded to Y are X, Y, R _{21 to} R ₂₆ in the general formula (1), respectively. It is synonymous. A ₂₁ and A ₂₂ have the same meaning as A in the general formula (1a), and may be the same as or different from each other. L ₂₁ and L ₂₂ have the same meaning as L ₂ in the general formula (1a), and may be the same as or different from each other. m1 and m2 are 0, 1, 2, 3, 4, 5, 6 or 7, respectively, and are preferably 0, 1, or 2. When m1 is 2, 3, 4, 5, 6, or 7, the plurality of L _21s are the same or different from each other, and when m2 is 2, 3, 4, 5, 6, or 7, the plurality of L _21s are the same or different. ₂₂ are the same or different from each other. When m1 is 0, A ₂₁ is directly bonded to O (oxygen atom), and when m2 is 0, A ₂₂ is directly bonded to O (oxygen atom).

At least one of A and L ₂ in the general formula (1a) is preferably substituted with a halogen atom, and more preferably substituted with a fluorine atom.

A in the general formula (1a) is more preferably a perfluoroalkyl group having 1 to 6 carbon atoms or a perfluoroaryl group having 6 to 12 carbon atoms forming a ring, and a perfluoroalkyl group having 1 to 6 carbon atoms. It is more preferably a group.

L ₂ in the general formula (1a) is more preferably a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroarylene group having 6 to 12 ring-forming carbon atoms, and more preferably a perfluoroarylene group having 1 to 6 carbon atoms. It is more preferably an alkylene group.

That is, the first compound M1 is preferably a compound represented by the following general formula (10a).

In the general formula (10a),
X is synonymous with X in the general formula (1), and Y when X is a carbon atom bonded to Y is synonymous with Y in the general formula (1).
R _{21 to} R ₂₆ are independently synonymous with R _{21 to} R ₂₆ in the general formula (1).
m3 is 0 or more and 4 or less,
m4 is 0 or more and 4 or less,
m3 and m4 are the same as or different from each other.

In the general formulas (1), (11), (10), and (10a),
X is a carbon atom that bonds with Y,
Y is a hydrogen atom or a substituent,
Y as a substituent is an alkyl group having 1 to 30 carbon atoms substituted or unsubstituted, an alkyl halide group having 1 to 30 carbon atoms substituted or unsubstituted, and a ring-forming alkyl group having 6 to 30 substituted or unsubstituted carbon atoms. It is preferably a substituent selected from the group consisting of aryl groups, and more preferably a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms.

In the general formulas (1), (11), (10), and (10a),
In a more preferred embodiment
X is a carbon atom that bonds with Y,
Y is a hydrogen atom or a substituent,
Y as a substituent is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.
When Y as a substituent is an aryl group having a ring-forming carbon number of 6 to 30 having a substituent, the substituent is
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Examples thereof include a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 30 carbon atoms.

In the first compound M1, the Z ₂₁ and the Z ₂₂ may be bonded to each other to form a ring, but it is preferable that the Z ₂₁ and the Z ₂₂ are not bonded to each other to form a ring.

In the general formulas (1), (10), and (10a), at least one of R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or It is preferably a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms.
In the general formulas (1), (10), and (10a), R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, or substituted or unsubstituted. It is more preferably an alkyl halide group having 1 to 30 carbon atoms. In this case, it is preferable that R ₂₂ and R ₂₅ are hydrogen atoms.

In the general formulas (1), (10), and (10a), at least one of R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. Is preferable.
In the general formulas (1), (10), and (10a), R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ are substituted or unsubstituted aryl groups having 6 to 30 carbon atoms. preferable. In this case, it is preferable that R ₂₂ and R ₂₅ are hydrogen atoms.

In the general formulas (1), (10), and (10a),
In a more preferred embodiment
R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ are independent of each other.
Substituentally substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms),
A ring-forming alkyl group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms) substituted or unsubstituted, or a ring-forming alkyl group having 1 to 30 carbon atoms substituted with 6 to 30 carbon atoms (preferably ring forming). It is an aryl group having 6 to 12 carbon atoms).
An embodiment in which R ₂₂ and R ₂₅ are hydrogen atoms can be mentioned.

In the general formula (11), at least one of R ₂₁ , R ₂₃ , and R ₂₄ is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted halogen having 1 to 30 carbon atoms. It is preferably an alkylated group.

In the general formula (11), R ₂₁ , R ₂₃ , and R ₂₄ are substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, or substituted or unsubstituted alkyl halide groups having 1 to 30 carbon atoms. Is more preferable. In this case, R ₂₂ is preferably a hydrogen atom.

In the general formula (11), it is preferable that at least one of R ₂₁ , R ₂₃ , and R ₂₄ is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.

In the general formula (11), it is more preferable that R ₂₁ , R ₂₃ , and R ₂₄ are substituted or unsubstituted aryl groups having 6 to 30 carbon atoms. In this case, R ₂₂ is preferably a hydrogen atom.

In the general formula (11),
In a more preferred embodiment
R ₂₁ , R ₂₃ , and R ₂₄ are independent of each other.
Substituentally substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms),
A ring-forming alkyl group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms) substituted or unsubstituted, or a ring-forming alkyl group having 1 to 30 carbon atoms substituted with 6 to 30 carbon atoms (preferably ring forming). It is an aryl group having 6 to 12 carbon atoms).
An embodiment in which R ₂₂ is a hydrogen atom can be mentioned.

In the first compound M1, examples of the alkoxy group substituted with a fluorine atom include 2,2,2-trifluoroethoxy group, 2,2-difluorooloethoxy group, 2,2,3,3. 3-Pentafluoro-1-propoxy group, 2,2,3,3-tetrafluoro-1-propoxy group, 1,1,1,3,3,3-hexafluoro-2-propoxy group, 2,2 3,3,4,5,4-Heptafluoro-1-butyloxy group, 2,2,3,3,4,4-hexafluoro-1-butyloxy group, nonafluoroterriary butyloxy group, 2,2 3,3,4,4,5,5,5-nonafluoropentanoxy group, 2,2,3,3,4,5,5,6,6,6-undecafluorohexanoxy group , 2,3-bis (trifluoromethyl) -2,3-butandioxy group, 1,1,2,2-tetra (trifluoromethyl) ethyleneglycoxy group, 4,4,5,5,6,6 6-Heptafluorohexane-1,2-dioxy group, and 4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononane-1,2-dioxy The group etc. can be mentioned.

In the first compound M1, examples of the aryloxy group substituted with a fluorine atom or the aryloxy group substituted with a fluoroalkyl group include a pentafluorophenoxy group, a 3,4,5-trifluorophenoxy group, and 4 -Trifluoromethylphenoxy group, 3,5-bistrifluoromethylphenoxy group, 3-fluoro-4-trifluoromethylphenoxy group, 2,3,5,6-tetrafluoro-4-trifluoromethylphenoxy group, 4- Examples thereof include a fluorocatecholate group, a 4-trifluoromethylcatecholate group, a 3,5-bistrifluoromethylcatecholate group and the like.

When the first compound M1 is a fluorescent compound, it is preferable that the first compound M1 exhibits light emission having a main peak wavelength of 400 nm or more and 700 nm or less.
In the present specification, the main peak wavelength means that the emission intensity in the measured fluorescence spectrum is the maximum for a toluene solution in which the compound to be measured is dissolved at a concentration of ^10-6 mol / liter or more and ^10-5 mol / liter or less. Refers to the peak wavelength of the fluorescence spectrum. A spectrofluorometer (F-7000 manufactured by Hitachi High-Tech Science Corporation) is used as the measuring device.

The first compound M1 preferably emits red or green light.
In the present specification, the red emission means the emission in which the main peak wavelength of the fluorescence spectrum is in the range of 600 nm or more and 660 nm or less.
When the first compound M1 is a red fluorescent compound, the main peak wavelength of the first compound M1 is preferably 600 nm or more and 660 nm or less, more preferably 600 nm or more and 640 nm or less, and further preferably 610 nm or more and 630 nm or less. Is.
In the present specification, the green emission means the emission in which the main peak wavelength of the fluorescence spectrum is in the range of 500 nm or more and 560 nm or less.
When the first compound M1 is a green fluorescent compound, the main peak wavelength of the first compound M1 is preferably 500 nm or more and 560 nm or less, more preferably 500 nm or more and 540 nm or less, and further preferably 510 nm or more and 530 nm or less. Is.
In the present specification, the blue emission means the emission in which the main peak wavelength of the fluorescence spectrum is in the range of 430 nm or more and 480 nm or less.
When the first compound M1 is a blue fluorescent compound, the main peak wavelength of the first compound M1 is preferably 430 nm or more and 480 nm or less, more preferably 445 nm or more and 480 nm or less.

-Method for producing the first compound M1 The first compound M1 can be produced by a known method.

Specific examples of the first compound M1 according to this embodiment are shown below. The first compound M1 in the present invention is not limited to these specific examples.
The coordination bond between the boron atom and the nitrogen atom in the pyrromethene skeleton has various notations such as a solid line, a broken line, an arrow, or an omission. In the present specification, it is represented by a solid line, a broken line, or the description thereof is omitted.

<Second compound>
In the present embodiment, the second compound M2 is represented by the following general formula (20A) or general formula (20B).

(In the general formula (20A) and the general formula (20B),
One of D ₂₁ and D ₂₂ is represented by the following general formula (21), and the other of D ₂₁ and D ₂₂ is represented by the following general formula (22). )

(In the general formula (21),
R _{1 to} R ₈ are independent hydrogen atoms or substituents, respectively.
R _{1 to} R ₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
It is a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). )

(In the general formula (22),
X ₁ is a sulfur atom or an oxygen atom,
R ₁₉ and R ₂₀ are independent hydrogen atoms or substituents, respectively.
R _{31 to} R ₃₈ are independent hydrogen atoms or substituents, respectively.
R ₁₉ , R ₂₀ , and R _{31 to} R ₃₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). )

The R ₁ and R ₂ pairs, the R ₂ and R ₃ pairs, the R ₃ and R ₄ pairs, the R ₅ and R ₆ pairs, the R ₆ and R ₇ pairs, and the R ₇ and R ₈ pairs are Neither bind to each other.

R ₁₉ and R ₂₀ pairs, R ₃₁ and R ₃₂ pairs, R ₃₂ and R ₃₃ pairs, R ₃₃ and R ₃₄ pairs, R ₃₅ and R ₃₆ pairs, R ₃₆ and R ₃₇ pairs, and R Neither of the ₃₇ and R ₃₈ pairs bind to each other.

The second compound M2 is also preferably represented by the following general formula (23).

(In the general formula (23), R _{1 to} R ₈ , R ₁₉ , R ₂₀ , R _{31 to} R _38, and X ₁ are R _{1 to} R in the general formula (21) and the general formula (22), respectively. ₈ , R ₁₉ , R ₂₀ , R _{31 to} R ₃₈ and X ₁ are synonymous with)

The second compound M2 is also preferably represented by the following general formula (24).

(In the general formula (24), R _{1 to} R ₈ , R ₁₉ , R ₂₀ , R _{31 to} R _38, and X ₁ are R _{1 to} R in the general formula (21) and the general formula (22), respectively. ₈ , R ₁₉ , R ₂₀ , R _{31 to} R ₃₈ and X ₁ are synonymous with)

In the second compound M2, R _{1 to} R ₈ as substituents are independently
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
It is preferably an alkyl group having 1 to 30 carbon atoms substituted or unsubstituted, or an arylamino group having 6 to 60 carbon atoms substituted or unsubstituted.

In the second compound M2, R _{1 to} R ₈ as substituents are independently
Substituent or unsubstituted ring-forming aryl groups having 6 to 12 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 14 ring-forming atoms,
More preferably, it is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted ring-forming alkyl group having 6 to 24 carbon atoms.

In the second compound M2, R _{31 to} R ₃₈ as substituents are independently, respectively.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
It is preferably an alkyl group having 1 to 30 carbon atoms substituted or unsubstituted, or an arylamino group having 6 to 60 carbon atoms substituted or unsubstituted.

In the second compound M2, R _{31 to} R ₃₈ as substituents are independently, respectively.
Substituent or unsubstituted ring-forming aryl groups having 6 to 12 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 14 ring-forming atoms,
More preferably, it is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted ring-forming alkyl group having 6 to 24 carbon atoms.

In the second compound M2, R ₁₉ , R ₂₀ and R _{31 to} R ₃₈ are also preferably hydrogen atoms.

In the second compound M2, R _{1 to} R ₈ are also preferably hydrogen atoms.

In the second compound M2, R _{1 to} R ₈ , R ₁₉ , R ₂₀ and R _{31 to} R ₃₈ are also preferably hydrogen atoms.

In the second compound M2, X ₁ is preferably a sulfur atom.

The second compound M2 is preferably a delayed fluorescent compound.

-Delayed fluorescence Delayed fluorescence is explained on pages 261 to 268 of "Device Physical Properties of Organic Semiconductors" (edited by Chihaya Adachi, published by Kodansha). In that document, if the energy difference ΔE ₁₃ between the excited singlet state and the excited triplet state of the fluorescent light emitting material can be reduced, the reverse energy from the excited triplet state to the excited singlet state, which usually has a low transition probability, can be reduced. Transfer occurs with high efficiency, and thermal activated delayed fluorescence (Thermally Activated Fluore)
It is explained that (sense, TADF) is expressed. Further, FIG. 10.38 in the document describes the mechanism of delayed fluorescence generation. The second compound in the present embodiment is preferably a compound exhibiting thermally activated delayed fluorescence generated by such a mechanism.

In general, the emission of delayed fluorescence can be confirmed by transient PL (Photoluminescence) measurement.

It is also possible to analyze the behavior of delayed fluorescence based on the attenuation curve obtained from the transient PL measurement. Transient PL measurement is a method of irradiating a sample with a pulse laser to excite it and measuring the attenuation behavior (transient characteristics) of PL light emission after the irradiation is stopped. PL light emission in TADF materials is classified into a light emitting component from a singlet exciton generated by the first PL excitation and a light emitting component from a singlet exciton generated via a triplet exciton. The lifetime of singlet excitons generated by the first PL excitation is on the nanosecond order and is very short. Therefore, the light emission from the singlet exciton is rapidly attenuated after irradiation with the pulse laser.
On the other hand, delayed fluorescence is slowly attenuated due to light emission from singlet excitons generated via triplet excitons having a long lifetime. As described above, there is a large time difference between the light emission from the singlet exciton generated by the first PL excitation and the light emission from the singlet exciton generated via the triplet exciton. Therefore, the emission intensity derived from delayed fluorescence can be obtained.

FIG. 2 shows a schematic diagram of an exemplary device for measuring transient PL. An example of a transient PL measurement method and delayed fluorescence behavior analysis using FIG. 2 will be described.

The transient PL measuring device 100 of FIG. 2 includes a pulse laser unit 101 capable of irradiating light having a predetermined wavelength, a sample chamber 102 accommodating a measurement sample, a spectroscope 103 that disperses light emitted from the measurement sample, and 2 It includes a streak camera 104 for forming a dimensional image and a personal computer 105 for capturing and analyzing a two-dimensional image. The measurement of transient PL is not limited to the apparatus shown in FIG.

The sample accommodated in the sample chamber 102 is obtained by forming a thin film on a quartz substrate in which a doping material is doped at a concentration of 12% by mass with respect to the matrix material.

The thin film sample housed in the sample chamber 102 is irradiated with a pulse laser from the pulse laser unit 101 to excite the doping material. Light is emitted in a direction of 90 degrees with respect to the irradiation direction of the excitation light, the extracted light is separated by the spectroscope 103, and a two-dimensional image is formed in the streak camera 104. As a result, it is possible to obtain a two-dimensional image in which the vertical axis corresponds to time, the horizontal axis corresponds to wavelength, and the bright spot corresponds to emission intensity. When this two-dimensional image is cut out on a predetermined time axis, it is possible to obtain an emission spectrum in which the vertical axis is the emission intensity and the horizontal axis is the wavelength. Further, when the two-dimensional image is cut out on the wavelength axis, an attenuation curve (transient PL) in which the vertical axis is the logarithm of the emission intensity and the horizontal axis is the time can be obtained.

For example, the following reference compound H1 was used as the matrix material, and the following reference compound D1 was used as the doping material to prepare a thin film sample A as described above, and transient PL measurement was performed.

Here, the attenuation curves were analyzed using the above-mentioned thin film sample A and thin film sample B. For the thin film sample B, the following reference compound H2 was used as the matrix material, and the reference compound D1 was used as the doping material to prepare a thin film sample as described above.

FIG. 3 shows the attenuation curves obtained from the transient PLs measured for the thin film sample A and the thin film sample B.

By transient PL measurement as described above, it is possible to obtain an emission attenuation curve in which the vertical axis is the emission intensity and the horizontal axis is the time. Based on this emission attenuation curve, the fluorescence intensity of fluorescence emitted from the singlet excited state generated by photoexcitation and delayed fluorescence emitted from the singlet excited state generated by reverse energy transfer via the triplet excited state. The ratio can be estimated. In the delayed fluorescence material, the ratio of the intensity of the slowly decaying fluorescence to the intensity of the rapidly decaying fluorescence is large to some extent.

Specifically, as the light emission from the delayed fluorescent material, there are Prompt light emission (immediate light emission) and Delay light emission (delayed light emission). Prompt emission (immediate emission) is emission that is immediately observed from the excited state after being excited by pulsed light (light emitted from a pulse laser) having a wavelength absorbed by the delayed fluorescent material. Delay light emission (delayed light emission) is light emission that is not immediately observed after being excited by the pulsed light but is observed thereafter.

The amounts of Prompt emission and Delay emission and their ratios can be determined by the same method as described in "Nature 492, 234-238, 2012" (Reference 1). The device used to calculate the amounts of Prompt emission and Delay emission is not limited to the apparatus described in Reference 1 or the apparatus shown in FIG.

Further, in the present embodiment, a sample prepared by the following method is used for measuring the delayed fluorescence of the second compound. For example, the second compound is dissolved in toluene to prepare a dilute solution with an absorbance of 0.05 or less at the excitation wavelength to remove the contribution of self-absorption. Further, in order to prevent quenching by oxygen, the sample solution is frozen and degassed and then sealed in a cell with a lid under an argon atmosphere to obtain an oxygen-free sample solution saturated with argon.
The fluorescence spectrum of the sample solution is measured with a spectrofluorometer FP-8600 (manufactured by Nippon Kogaku Co., Ltd.), and the fluorescence spectrum of an ethanol solution of 9,10-diphenylanthracene is measured under the same conditions. Using the fluorescence area intensities of both spectra, Morris et al. J. Phys. Chem. The total fluorescence quantum yield is calculated by the equation (1) in 80 (1976) 969.

The amounts of Prompt emission and Delay emission and their ratios can be determined by the same method as described in "Nature 492, 234-238, 2012" (Reference 1). The device used to calculate the amounts of Prompt emission and Delay emission is not limited to the apparatus described in Reference 1 or the apparatus shown in FIG.
When in the present embodiment, the amount of Prompt luminescence measurement target compound (second compound) (Immediate emission) and _{X P,} the amount of Delay emission (delayed luminescence) was _{X D, X D} / _{X P} The value of is preferably 0.05 or more.
The measurement of the amount and ratio of Prompt emission and Delay emission of the compound other than the second compound in the present specification is the same as the measurement of the amount and ratio of Prompt emission and Delay emission of the second compound.

-Method for producing the second compound The second compound M2 can be produced according to a known synthesis method or by following the synthesis method and using a known alternative reaction and raw material suitable for the desired product.

Specific examples of the second compound M2 include the following compounds. However, the present invention is not limited to specific examples of these second compounds M2.

<Relationship between the first compound and the second compound in the light emitting layer>
In the organic EL device 1 of the present embodiment, the singlet energy _S 1 of the second compound M2 (Mat2), a singlet energy _S 1 of the first compound M1 (Mat1) but, following equation (Equation 1) It is preferable to satisfy the relationship.
S ₁ (Mat 2)> S ₁ (Mat ₁ ) ... (Equation 1)

The energy gap T _77K (Mat2) in 77 [K] of the second compound M2 is preferably larger than the energy gap T _77K (Mat1) in 77 [K] of the first compound M1. That is, it is preferable to satisfy the relationship of the following mathematical formula (Equation 3).
T _77K (Mat2)> T _77K (Mat1) ... (Number 3)

When the organic EL element 1 of the present embodiment is made to emit light, it is preferable that the first compound M1 mainly emits light in the light emitting layer 5.

-Relationship between triplet energy and energy gap at 77 [K] Here, the relationship between triplet energy and the energy gap at 77 [K] will be described. In this embodiment, the energy gap at 77 [K] differs from the normally defined triplet energy.
The triplet energy measurement is performed as follows. First, a sample in which a solution in which a compound to be measured is dissolved in an appropriate solvent is sealed in a quartz glass tube is prepared. For this sample, the phosphorescence spectrum (vertical axis: phosphorescence emission intensity, horizontal axis: wavelength) was measured at a low temperature (77 [K]), and a tangent line was drawn with respect to the rising edge of the phosphorescence spectrum on the short wavelength side. The triple term energy is calculated from a predetermined conversion formula based on the wavelength value at the intersection of the tangent line and the horizontal axis.
Here, among the compounds according to the present embodiment, the thermally active delayed fluorescence compound is preferably a compound having a small ΔST. When ΔST is small, intersystem crossing and inverse intersystem crossing are likely to occur even in a low temperature (77 [K]) state, and an excited singlet state and an excited triplet state coexist. As a result, the spectrum measured in the same manner as described above contains light emission from both the excited singlet state and the excited triplet state, and it is difficult to distinguish from which state the light is emitted. , Basically, the triplet energy value is considered to be dominant.
Therefore, in the present embodiment, the measurement method is the same as that of the normal triplet energy T, but in order to distinguish the difference in the strict sense, the value measured as follows is referred to as the energy gap T _77K. .. The compound to be measured is dissolved in EPA (diethyl ether: isopentane: ethanol = 5: 5: 2 (volume ratio)) so as to have a concentration of 10 μmol / L, and this solution is placed in a quartz cell for measurement. Use as a sample. For this measurement sample, the phosphorescence spectrum (vertical axis: phosphorescence emission intensity, horizontal axis: wavelength) is measured at a low temperature (77 [K]), and a tangent line is drawn with respect to the rising edge of the phosphorescence spectrum on the short wavelength side. Based on the wavelength value λ _edge [nm] at the intersection of the tangent line and the horizontal axis, the amount of energy calculated from the following conversion formula (F1) is defined as the energy gap T _77K at 77 [K].
Conversion formula (F1): T _77K [eV] = 1239.85 / λ _edge

The tangent to the rising edge of the phosphorescence spectrum on the short wavelength side is drawn as follows. When moving on the spectrum curve from the short wavelength side of the phosphorescent spectrum to the maximum value on the shortest wavelength side of the maximum values of the spectrum, consider the tangent lines at each point on the curve toward the long wavelength side. This tangent increases in slope as the curve rises (ie, as the vertical axis increases). The tangent line drawn at the point where the value of the slope takes the maximum value (that is, the tangent line at the inflection point) is the tangent line to the rising edge of the phosphorescent spectrum on the short wavelength side.
The maximum point having a peak intensity of 15% or less of the maximum peak intensity of the spectrum is not included in the maximum value on the shortest wavelength side described above, and the slope value closest to the maximum value on the shortest wavelength side is the maximum. The tangent line drawn at the point where the value is taken is taken as the tangent line to the rising edge of the phosphorescent spectrum on the short wavelength side.
For the measurement of phosphorescence, an F-4500 type spectrofluorometer main body manufactured by Hitachi High-Technology Co., Ltd. can be used. The measuring device is not limited to this, and may be measured by combining a cooling device, a low temperature container, an excitation light source, and a light receiving device.

・ Singlet energy S ₁
The method of measuring the solution using a singlet energy S ₁ (hereinafter sometimes referred to as solution method.), A method described below.
A 10 μmol / L toluene solution of the compound to be measured is prepared, placed in a quartz cell, and the absorption spectrum (vertical axis: absorption intensity, horizontal axis: wavelength) of this sample is measured at room temperature (300 K). A tangent line is drawn for the fall on the long wavelength side of this absorption spectrum, and the wavelength value λedge [nm] at the intersection of the tangent line and the horizontal axis is substituted into the conversion formula (F2) shown below to calculate the singlet energy. To do.
Conversion formula (F2): S ₁ [eV] = 1239.85 / λedge
Examples of the absorption spectrum measuring device include, but are not limited to, a spectrophotometer (device name: U3310) manufactured by Hitachi, Ltd.

The tangent to the fall on the long wavelength side of the absorption spectrum is drawn as follows. When moving on the spectrum curve from the maximum value on the longest wavelength side to the long wavelength direction among the maximum values of the absorption spectrum, consider the tangents at each point on the curve. This tangent repeats that the slope decreases and then increases as the curve descends (ie, as the value on the vertical axis decreases). The tangent line drawn at the point where the slope value takes the minimum value on the longest wavelength side (except when the absorbance is 0.1 or less) is defined as the tangent line to the fall of the long wavelength side of the absorption spectrum.
The maximum point having an absorbance value of 0.2 or less is not included in the maximum value on the longest wavelength side.

In this embodiment, defines a singlet energy _{S 1,} the difference between the energy gap _{T 77K} at 77 [K] and _{(S 1 -T 77K)} as .DELTA.St.

In this embodiment, the singlet energy _S 1 of the second compound M2 (Mat2), difference .DELTA.St (Mat2) of an energy gap _T 77K (Mat2) in 77 [K] of the second compound M2 is It is preferably less than 0.3 eV, more preferably less than 0.2 eV, and even more preferably less than 0.1 eV. That is, it is preferable that ΔST (Mat2) satisfies the relationship of the following mathematical formulas (Equation 1A) to (Equation 1D).
ΔST (Mat2) = S ₁ (Mat2) -T _77K (Mat2) <0.3eV ... (Equation 1A)
ΔST (Mat2) = S ₁ (Mat2) -T _77K (Mat2) <0.2eV ... (Equation 1B)
ΔST (Mat2) = S ₁ (Mat2) -T _77K (Mat2) <0.1 eV ... (Equation 1C)
ΔST (Mat2) = S ₁ (Mat2) -T _77K (Mat2) <0.01eV ... (Equation 1D)

The organic EL element 1 of the present embodiment preferably emits red light or green light.
When the organic EL element 1 of the present embodiment emits green light, the main peak wavelength of the light emitted from the organic EL element 1 is preferably 500 nm or more and 560 nm or less.
When the organic EL element 1 of the present embodiment emits red light, the main peak wavelength of the light emitted from the organic EL element 1 is preferably 600 nm or more and 660 nm or less.
When the organic EL element 1 of the present embodiment emits blue light, the main peak wavelength of the light emitted from the organic EL element 1 is preferably 430 nm or more and 480 nm or less.

The main peak wavelength of the light emitted from the organic EL element is measured as follows.
The spectral radiance spectrum when a voltage is applied to the organic EL element so that the current density is 10 mA / cm ² is measured with a spectral radiance meter CS-2000 (manufactured by Konica Minolta Co., Ltd.).
In the obtained spectral radiance spectrum, the peak wavelength of the emission spectrum having the maximum emission intensity is measured, and this is defined as the main peak wavelength (unit: nm).

-Film thickness of the light emitting layer The film thickness of the light emitting layer 5 in the organic EL element 1 of the present embodiment is preferably 5 nm or more and 50 nm or less, more preferably 7 nm or more and 50 nm or less, and most preferably 10 nm or more and 50 nm or less. When it is 5 nm or more, it is easy to form a light emitting layer and adjust the chromaticity, and when it is 50 nm or less, an increase in the driving voltage is likely to be suppressed.

-Compound content in the light emitting layer The content of the second compound M2 and the first compound M1 contained in the light emitting layer 5 is preferably in the following range, for example.
The content of the second compound M2 is preferably 10% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and 20% by mass or more and 60% by mass or less. Is even more preferable.
The content of the first compound M1 is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less, and 0.01% by mass or more and 1 It is more preferably mass% or less.
The present embodiment does not exclude that the light emitting layer 5 contains materials other than the second compound M2 and the first compound M1.
The light emitting layer 5 may contain only one type of the second compound M2, or may contain two or more types. The light emitting layer 5 may contain only one type of the first compound M1 or may contain two or more types.

・ TADF mechanism (mechanism)
FIG. 4 is a diagram showing an example of the relationship between the energy levels of the second compound M2 and the first compound M1 in the light emitting layer. In FIG. 4, S0 represents the ground state. S1 (Mat1) represents the lowest excited singlet state of the first compound M1. T1 (Mat1) represents the lowest excited triplet state of the first compound M1. S1 (Mat2) represents the lowest excited singlet state of the second compound M2. T1 (Mat2) represents the lowest excited triplet state of the second compound M2.
The dashed arrow from S1 (Mat1) to S1 (Mat2) in FIG. 4 represents the Felster-type energy transfer from the lowest excited singlet state of the second compound M2 to the first compound M1.
As shown in FIG. 4, when a compound having a small ΔST (Mat2) is used as the second compound M2, the lowest excited triplet state T1 (Mat2) is reversed to the lowest excited singlet state S1 (Mat2) by thermal energy. Intersystem crossing is possible. Then, Felster-type energy transfer from the lowest excited singlet state S1 (Mat2) of the second compound M2 to the first compound M1 occurs, and the lowest excited singlet state S1 (Mat1) is generated. As a result, fluorescence emission from the lowest excited singlet state S1 (Mat1) of the first compound M1 can be observed. It is believed that the internal efficiency can theoretically be increased to 100% by utilizing the delayed fluorescence by this TADF mechanism.

The organic EL device 1 according to the first embodiment includes a second compound M2 and a first compound M1 having a singlet energy smaller than that of the second compound M2 in the light emitting layer 5.
The organic EL element 1 according to the first embodiment can be used for electronic devices such as a display device and a light emitting device.

The configuration of the organic EL element 1 will be further described. Hereinafter, the description of the reference numeral may be omitted.

(substrate)
The substrate is used as a support for an organic EL element. As the substrate, for example, glass, quartz, plastic, or the like can be used. Moreover, you may use a flexible substrate. The flexible substrate is a foldable (flexible) substrate, and examples thereof include a plastic substrate. Examples of the material for forming the plastic substrate include polycarbonate, polyarylate, polyether sulfone, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyimide, polyethylene naphthalate and the like. Inorganic vapor deposition film can also be used.

(anode)
For the anode formed on the substrate, it is preferable to use a metal having a large work function (specifically, 4.0 eV or more), an alloy, an electrically conductive compound, a mixture thereof, or the like. Specifically, for example, indium tin oxide (ITO: Indium Tin Oxide), indium tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, tungsten oxide, and indium oxide containing zinc oxide. , Graphene and the like. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( Examples thereof include Pd), titanium (Ti), and nitrides of metallic materials (for example, titanium nitride).

These materials are usually formed by a sputtering method. For example, indium oxide-zinc oxide can be formed by a sputtering method by using a target in which 1% by mass or more and 10% by mass or less of zinc oxide is added to indium oxide. Further, for example, indium oxide containing tungsten oxide and zinc oxide contained 0.5% by mass or more and 5% by mass or less of tungsten oxide and 0.1% by mass or more and 1% by mass or less of zinc oxide with respect to indium oxide. By using a target, it can be formed by a sputtering method. In addition, it may be produced by a vacuum vapor deposition method, a coating method, an inkjet method, a spin coating method or the like.

Of the EL layers formed on the anode, the hole injection layer formed in contact with the anode is formed by using a composite material that facilitates hole injection regardless of the work function of the electrode. , Materials that can be used as electrode materials (for example, metals, alloys, electrically conductive compounds, and mixtures thereof, and other elements belonging to Group 1 or Group 2 of the Periodic Table of Elements) can be used.

Elements belonging to Group 1 or Group 2 of the Periodic Table of the Elements, which are materials with a small work function, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg), calcium (Ca), and strontium. Alkaline earth metals such as (Sr), rare earth metals such as alloys containing them (for example, MgAg, AlLi), europium (Eu), ytterbium (Yb), and alloys containing these can also be used. When forming an anode using an alkali metal, an alkaline earth metal, or an alloy containing these, a vacuum vapor deposition method or a sputtering method can be used. Further, when a silver paste or the like is used, a coating method, an inkjet method, or the like can be used.

(cathode)
As the cathode, it is preferable to use a metal having a small work function (specifically, 3.8 eV or less), an alloy, an electrically conductive compound, a mixture thereof, or the like. Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the Periodic Table of the Elements, that is, alkali metals such as lithium (Li) and cesium (Cs), magnesium (Mg), and calcium (Ca). ), Alkaline earth metals such as strontium (Sr), and rare earth metals such as alloys containing them (for example, MgAg, AlLi), europium (Eu), ytterbium (Yb), and alloys containing them.

When forming a cathode using an alkali metal, an alkaline earth metal, or an alloy containing these, a vacuum vapor deposition method or a sputtering method can be used. When a silver paste or the like is used, a coating method, an inkjet method, or the like can be used.

By providing the electron injection layer, a cathode is formed by using various conductive materials such as indium tin oxide containing Al, Ag, ITO, graphene, silicon or silicon oxide, regardless of the size of the work function. can do. These conductive materials can be formed into a film by using a sputtering method, an inkjet method, a spin coating method, or the like.

(Hole injection layer)
The hole injection layer is a layer containing a substance having a high hole injection property. Substances with high hole injection properties include molybdenum oxide, titanium oxide, vanadium oxide, renium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, etc. Tungsten oxide, manganese oxide and the like can be used.

In addition, as a substance having high hole injection property, a low molecular weight organic compound 4,4', 4''-tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4' , 4''-Tris [N- (3-Methylphenyl) -N-Phenylamino] Triphenylamine (abbreviation: MTDATA), 4,4'-Bis [N- (4-diphenylaminophenyl) -N-Phenyl Amino] Biphenyl (abbreviation: DPAB), 4,4'-bis (N- {4- [N'-(3-methylphenyl) -N'-phenylamino] phenyl} -N-phenylamino) Biphenyl (abbreviation:: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation: DPA3B), 3- [N- (9-phenylcarbazole-3-yl) -N -Phenylamino] -9-Phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazole-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), Aromatic amine compounds such as 3- [N- (1-naphthyl) -N- (9-phenylcarbazole-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) and dipyrazino [2,3-f : 20,30-h] Kinoxalin-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) can also be mentioned.

Further, as a substance having high hole injection property, a polymer compound (oligomer, dendrimer, polymer, etc.) can also be used. For example, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N'-[4- (4-diphenylamino)). Phenyl] phenyl-N'-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) benzidine] (abbreviation: Polymer compounds such as Poly-TPD) can be mentioned. Further, a polymer compound to which an acid such as poly (3,4-ethylenedioxythiophene) / poly (styrene sulfonic acid) (PEDOT / PSS) or polyaniline / poly (styrene sulfonic acid) (Pani / PSS) is added is used. You can also do it.

(Hole transport layer)
The hole transport layer is a layer containing a substance having a high hole transport property. An aromatic amine compound, a carbazole derivative, an anthracene derivative, or the like can be used for the hole transport layer. Specifically, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB) and N, N'-bis (3-methylphenyl) -N, N'- Diphenyl- [1,1'-biphenyl] -4,4'-diamine (abbreviation: TPD), 4-phenyl-4'-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BAFLP), 4 , 4'-bis [N- (9,9-dimethylfluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: DFLDPBi), 4,4', 4''-tris (N, N-diphenylamino) ) Triphenylamine (abbreviation: TDATA), 4,4', 4''-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4'-bis [N- (Spiro-9,9'-bifluoren-2-yl) -N-phenylamino] Aromatic amine compounds such as biphenyl (abbreviation: BSBP) can be used. The substances described here are mainly substances having a hole mobility of ^10-6 cm ² / (V · s) or more.

The hole transport layer includes CBP, 9- [4- (N-carbazolyl)] phenyl-10-phenylanthracene (CzPA), 9-phenyl-3- [4- (10-phenyl-9-anthril) phenyl]. Carbazole derivatives such as -9H-carbazole (PCzPA) and anthracene derivatives such as t-BuDNA, DNA and DPAnth may be used. Polymer compounds such as poly (N-vinylcarbazole) (abbreviation: PVK) and poly (4-vinyltriphenylamine) (abbreviation: PVTPA) can also be used.

However, any substance other than these may be used as long as it is a substance having a higher hole transport property than electrons. The layer containing the substance having a high hole transport property is not limited to a single layer, but may be a layer in which two or more layers made of the above substances are laminated.

When two or more hole transport layers are arranged, it is preferable to arrange a material having a larger energy gap closer to the light emitting layer. Examples of such a material include HT-2 used in the examples described later.

(Electronic transport layer)
The electron transport layer is a layer containing a substance having a high electron transport property. The electron transport layer includes 1) metal complexes such as aluminum complexes, beryllium complexes and zinc complexes, 2) complex aromatic compounds such as imidazole derivatives, benzimidazole derivatives, azine derivatives, carbazole derivatives and phenanthroline derivatives, and 3) polymer compounds. Can be used. Specifically, as low-molecular-weight organic compounds, Alq, tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] quinolinato) berylium (abbreviation: BeBq ₂ ), Metal complexes such as BAlq, Znq, ZnPBO, and ZnBTZ can be used. In addition to the metal complex, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (Phenyl-butylphenyl) -1,3,4-oxadiazole-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-) Biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4- Complexes such as triazole (abbreviation: p-EtTAZ), vasofenantroline (abbreviation: BPhen), vasocuproin (abbreviation: BCP), 4,4'-bis (5-methylbenzoxadiazole-2-yl) stilben (abbreviation: BzOs) Aromatic compounds can also be used. In this embodiment, a benzimidazole compound can be preferably used. The substances described here are mainly substances having electron mobility of ^10-6 cm ² / (V · s) or more. A substance other than the above may be used as the electron transport layer as long as it is a substance having higher electron transport property than hole transport property. Further, the electron transport layer may be composed of a single layer, or may be composed of two or more layers made of the above substances.

Further, a polymer compound can also be used for the electron transport layer. For example, poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2) , 7-diyl) -co- (2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) and the like can be used.

(Electron injection layer)
The electron injection layer is a layer containing a substance having a high electron injection property. The electron injection layer includes lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), lithium oxide (LiOx), etc. Alkaline metals such as, alkaline earth metals, or compounds thereof can be used. In addition, a substance having an electron transporting property containing an alkali metal, an alkaline earth metal, or a compound thereof, specifically, a substance containing magnesium (Mg) in Alq or the like may be used. In this case, electron injection from the cathode can be performed more efficiently.

Alternatively, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer. Such a composite material is excellent in electron injection property and electron transport property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting generated electrons, and specifically, for example, a substance (metal complex, complex aromatic compound, etc.) constituting the above-mentioned electron transport layer is used. be able to. The electron donor may be any substance that exhibits electron donating property to the organic compound. Specifically, alkali metals, alkaline earth metals and rare earth metals are preferable, and lithium, cesium, magnesium, calcium, erbium, ytterbium and the like can be mentioned. Further, alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxides, calcium oxides, barium oxides and the like can be mentioned. A Lewis base such as magnesium oxide can also be used. Further, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

(Layer formation method)
The method for forming each layer of the organic EL element of the present embodiment is not limited except as specifically mentioned above, but is limited to dry film deposition methods such as vacuum deposition method, sputtering method, plasma method, ion plating method, and spin coating. Known methods such as a coating method, a dipping method, a flow coating method, and a wet film forming method such as an inkjet method can be adopted.

(Film thickness)
The film thickness of each organic layer of the organic EL element of the present embodiment is not limited except as specifically mentioned above, but in general, if the film thickness is too thin, defects such as pinholes are likely to occur, and conversely, if it is too thick, it is high. Since an applied voltage is required and efficiency is deteriorated, a range of several nm to 1 μm is usually preferable.

The organic EL element according to the first embodiment can be used for electronic devices such as display devices and light emitting devices.

According to the organic electroluminescence device according to the present embodiment, high performance, particularly long life is emitted.

[Second Embodiment]
The configuration of the organic EL element according to the second embodiment will be described. In the description of the second embodiment, the same components as those of the first embodiment are given the same reference numerals and names, and the description is omitted or simplified. Further, in the second embodiment, the same materials and compounds as those described in the first embodiment can be used for the materials and compounds not particularly mentioned.

The organic EL device according to the second embodiment is different from the organic EL device according to the first embodiment in that the light emitting layer further contains the third compound M3. Other points are the same as those in the first embodiment.
That is, in the second embodiment, the light emitting layer as the first organic layer contains the second compound M2, the first compound M1, and the third compound M3.
In this embodiment, the second compound M2 is preferably a host material, the first compound M1 is preferably a dopant material, and the third compound M3 emits a dopant material as a dispersant. It is preferably a material that is dispersed in the layer.

<Third compound>
The third compound M3 may be a delayed fluorescence compound or a compound that does not exhibit delayed fluorescence.

The third compound M3 is not particularly limited, but is preferably a compound other than the amine compound. Further, for example, as the third compound M3, a carbazole derivative, a dibenzofuran derivative, and a dibenzothiophene derivative can be used, but the derivative is not limited thereto.

The third compound M3 has a partial structure represented by the following general formula (31), a partial structure represented by the following general formula (32), and a partial structure represented by the following general formula (33A) in one molecule. , And a compound containing at least one of the partial structures represented by the following general formula (34B) is also preferable.

In the general formula (31),
Y _{31 to} Y ₃₆ are independent carbon atoms that bond with nitrogen atoms or other atoms in the molecule of the third compound M3.
However, at least one of Y _{31 to} Y ₃₆ is a carbon atom that binds to another atom in the molecule of the third compound M3.
In the general formula (32),
Y _{41 to} Y ₄₈ are independent carbon atoms that bond with nitrogen atoms or other atoms in the molecule of the third compound M3.
However, at least one of Y _{41 to} Y ₄₈ is a carbon atom that binds to another atom in the molecule of the third compound M3.
X ₃₀ is a nitrogen atom, an oxygen atom, or a sulfur atom that binds to another atom in the molecule of the third compound M3.
In the general formulas (33A) and (34A), * independently represents a bonding site with another atom or other structure in the molecule of the third compound M3.

In the general formula (32), at least two of Y _{41 to} Y ₄₈ are carbon atoms bonded to other atoms in the molecule of the third compound M3, and a ring structure containing the carbon atoms is constructed. It is also preferable.
For example, the partial structures represented by the general formula (32) are the following general formula (321), general formula (322), general formula (323), general formula (324), general formula (325), and general formula. It is preferable that it is any partial structure selected from the group consisting of the partial structures represented by (326).

In the general formulas (321) to (326),
X ₃₀ is a nitrogen atom, an oxygen atom, or a sulfur atom that independently binds to another atom in the molecule of the third compound M3.
Y _{41 to} Y ₄₈ are independent carbon atoms that bond with nitrogen atoms or other atoms in the molecule of the third compound M3.
Each of X ₃₁ is a nitrogen atom, an oxygen atom, a sulfur atom, or a carbon atom that is bonded to another atom in the molecule of the third compound M3, or a carbon atom that is bonded to another atom in the molecule of the third compound M3. And
Y _{61 to} Y ₆₄ are each independently a nitrogen atom or a carbon atom that binds to another atom in the molecule of the third compound M3.
In the present embodiment, the third compound M3 preferably has a partial structure represented by the general formula (323) among the general formulas (321) to (326).

The partial structure represented by the general formula (31) is at least one group selected from the group consisting of the group represented by the following general formula (33) and the group represented by the following general formula (34). Is preferably contained in the third compound M3.
The third compound M3 preferably has at least one of the partial structures represented by the following general formula (33) and the following general formula (34). Since the bonding sites are located at the meta positions of each other as in the partial structures represented by the following general formula (33) and the following general formula (34), the energy gap T _77K in 77 [K] of the third compound M3 ( Mat3) can be kept high.

In the general formula (33), Y ₃₁ , Y ₃₂ , Y ₃₄ , and Y ₃₆ are independently nitrogen atoms or CR ₃₁ .
In the general formula (34), Y ₃₂ , Y ₃₄ , and Y ₃₆ are independently nitrogen atoms or CR ₃₁ .
In the general formulas (33) and (34),
R ₃₁ is a hydrogen atom or a substituent independently of each other.
R ₃₁ as a substituent is independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituted or unsubstituted fluoroalkyl groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl groups having 3 to 30 carbon atoms,
Substituent or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
Substituted or unsubstituted silyl group,
Substitute germanium group,
Substituted phosphine oxide group,
Halogen atom,
Cyano group,
It is selected from the group consisting of nitro groups and substituted or unsubstituted carboxy groups.
However, the substituted or unsubstituted aryl group having 6 to 30 carbon atoms in R ₃₁ is preferably a non-condensed ring.
In the general formula (33) and the general formula (34), * independently represents a bonding site with another atom or other structure in the molecule of the third compound M3.

In the general formula (33), Y ₃₁ , Y ₃₂ , Y ₃₄ , and Y ₃₆ are preferably CR ₃₁ independently, and a plurality of R ₃₁ are the same as or different from each other.
Further, in the general formula (34), it is preferable that Y ₃₂ , Y ₃₄ , and Y ₃₆ are independently CR ₃₁ , and a plurality of R _31s are the same as or different from each other.

The substituted germanium group is preferably represented by −Ge (R ₃₀₁ ) ₃ . R ₃₀₁ is a substituent independently of each other. The substituent R ₃₀₁ is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. A plurality of R _301s are the same as or different from each other.

The partial structure represented by the general formula (32) is as at least one group selected from the group consisting of the groups represented by the following general formulas (35) to (39) and the following general formula (30a). It is preferably contained in the third compound M3.

In the general formula (35), Y _{41 to} Y ₄₈ are independently nitrogen atoms or CR ₃₂ , respectively.
In the general formulas (36) and (37), Y _{41 to} Y ₄₅ , Y ₄₇ , and Y ₄₈ are independently nitrogen atoms or CR ₃₂ , respectively.
In the general formula (38), Y ₄₁ , Y ₄₂ , Y ₄₄ , Y ₄₅ , Y ₄₇ , and Y ₄₈ are independently nitrogen atoms or CR ₃₂ , respectively.
In the general formula (39), Y _{42 to} Y ₄₈ are independently nitrogen atoms or CR ₃₂ , respectively.
In the general formula (30a), Y _{42 to} Y ₄₇ are independently nitrogen atoms or CR ₃₂ , respectively.
In the general formulas (35) to (39) and (30a),
R ₃₂ is a hydrogen atom or a substituent independently of each other.
R ₃₂ as a substituent is
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituted or unsubstituted fluoroalkyl groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl groups having 3 to 30 carbon atoms,
Substituent or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
Substituted or unsubstituted silyl group,
Substitute germanium group,
Substituted phosphine oxide group,
Halogen atom,
Cyano group,
Selected from the group consisting of nitro groups and substituted or unsubstituted carboxy groups,
A plurality of R _32s are the same as or different from each other.
In the general formulas (37) to (39) and (30a),
X ₃₀ is NR ₃₃ , an oxygen atom, or a sulfur atom.
R ₃₃ is
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituted or unsubstituted fluoroalkyl groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl groups having 3 to 30 carbon atoms,
Substituent or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
Substituted or unsubstituted silyl group,
Substitute germanium group,
Substituted phosphine oxide group,
Fluorine atom,
Cyano group,
Selected from the group consisting of nitro groups and substituted or unsubstituted carboxy groups,
The plurality of R _33s are the same as or different from each other.
However, the substituted or unsubstituted aryl group having 6 to 30 carbon atoms in R ₃₃ is preferably a non-condensed ring.
In the general formulas (35) to (39) and (30a), * independently represents a bond with another atom or other structure in the molecule of the third compound M3.

In the general formula (35), Y _{41 to} Y ₄₈ are preferably CR ₃₂ independently of each other, and in the general formula (36) and the general formula (37), Y _{41 to} Y ₄₅ , Y. It is preferable that ₄₇ and Y ₄₈ are independently CR ₃₂ , and in the general formula (38), Y ₄₁ , Y ₄₂ , Y ₄₄ , Y ₄₅ , Y ₄₇ , and Y ₄₈ are independent of each other. , CR ₃₂ , and in the general formula (39), Y _{42 to} Y ₄₈ are each independently, preferably CR ₃₂ , and in the general formula (30a), Y _{42 to} Y ₄₇ are , Each independently, preferably CR ₃₂ , and the plurality of R _32s are the same as or different from each other.

In the third compound M3, X ₃₀ is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.

In the third compound M3, R ₃₁ and R ₃₂ are independently hydrogen atoms or substituents, and R ₃₁ as a substituent and R ₃₂ as a substituent are independently fluorine atoms. , Cyano groups, substituted or unsubstituted alkyl groups with 1 to 30 carbon atoms, substituted or unsubstituted ring-forming aryl groups with 6 to 30 carbon atoms, and substituted or unsubstituted ring-forming atomic groups with 5 to 30 heteroaryl groups. It is preferably any group selected from the group consisting of groups. R ₃₁ and R ₃₂ are hydrogen atoms, cyano groups, aryl groups having 6 to 30 substituted or unsubstituted ring-forming atoms, or heteroaryl groups having 5 to 30 substituted or unsubstituted ring-forming atoms. Is more preferable. However, when R ₃₁ as a substituent and R ₃₂ as a substituent are substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, the aryl group is preferably a non-condensed ring.

The third compound M3 is also preferably an aromatic hydrocarbon compound or an aromatic heterocyclic compound.

-Method for producing the third compound The third compound M3 can be produced, for example, by the methods described in International Publication No. 2012/153780, International Publication No. 2013/038650, and the like. Further, for example, the third compound can be produced as M3 by using a known alternative reaction according to the target substance and a raw material.

Examples of substituents in the third compound M3 are, for example, as follows, but the present invention is not limited to these examples.

Specific examples of the allyl group (sometimes referred to as an aromatic hydrocarbon group) include a phenyl group, a tolyl group, a xsilyl group, a naphthyl group, a phenanthryl group, a pyrenyl group, a chrysenyl group, and a benzo [c] phenanthryl group. , Benzo [g] chrysenyl group, benzoantryl group, triphenylenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, benzofluorenyl group, dibenzofluorenyl group, biphenyl group, terphenyl group, quarterphenyl Examples thereof include a group, a fluoranthenyl group, and preferably a phenyl group, a biphenyl group, a terphenyl group, a quarterphenyl group, a naphthyl group, a triphenylenyl group, a fluorenyl group and the like.
Examples of the allyl group having a substituent include a tolyl group, a xsilyl group, a 9,9-dimethylfluorenyl group and the like.
As specific examples show, aryl groups include both condensed aryl groups and non-condensed aryl groups.
As the allyl group, a phenyl group, a biphenyl group, a terphenyl group, a quarterphenyl group, a naphthyl group, a triphenylenyl group, or a fluorenyl group is preferable.

Specific examples of the heteroaryl group (sometimes referred to as a heterocyclic group, a heteroaromatic ring group, or an aromatic heterocyclic group) include a pyrrolyl group, a pyrazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridadinyl group, and a pyridyl group. , Triazinyl group, indolyl group, isoindrill group, imidazolyl group, benzimidazolyl group, indazolyl group, imidazole [1,2-a] pyridinyl group, furyl group, benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group, azadibenzo Furanyl group, thiophenyl group, benzothienyl group, dibenzothienyl group, azadibenzothienyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, naphthyldinyl group, carbazolyl group, azacarbazolyl group, phenanthridinyl group, acridinyl group, Phenanthrolinyl group, phenazinyl group, phenothiazinyl group, phenoxadinyl group, oxazolyl group, oxadiazolyl group, frazayl group, benzoxazolyl group, thienyl group, thiazolyl group, thiadiazolyl group, benzthiazolyl group, triazolyl group, tetrazolyl group, etc. Preferred examples thereof include a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, an azadibenzofuranyl group, and an azadibenzothienyl group.
As the heteroaryl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, an azadibenzofuranyl group, or an azadibenzothienyl group is preferable, and a dibenzofuranyl group, a dibenzothienyl group, Azadibenzofuranyl groups or azadibenzothienyl groups are more preferred.

In the third compound M3, the substituted silyl group is selected from the group consisting of a substituted or unsubstituted trialkylsilyl group, a substituted or unsubstituted arylalkylsilyl group, and a substituted or unsubstituted triarylsilyl group. Is also preferable.
Specific examples of the substituted or unsubstituted trialkylsilyl group include a trimethylsilyl group and a triethylsilyl group.
Specific examples of the substituted or unsubstituted arylalkylsilyl group include a diphenylmethylsilyl group, a ditrilmethylsilyl group, a phenyldimethylsilyl group and the like.
Specific examples of the substituted or unsubstituted triarylsilyl group include a triphenylsilyl group and a tritrylsilyl group.

In the third compound M3, the substituted phosphine oxide group is also preferably a substituted or unsubstituted diarylphosphine oxide group.
Specific examples of the substituted or unsubstituted diarylphosphine oxide group include a diphenylphosphine oxide group and a ditrilphosphine oxide group.

In the third compound M3, examples of the substituted carboxy group include a benzoyloxy group and the like.

Specific examples of the third compound M3 according to the present embodiment are shown below. The third compound M3 in the present invention is not limited to these specific examples.

<Relationship between the first compound, the second compound, and the third compound in the light emitting layer>
In the organic EL device of the present embodiment, the singlet energy _S 1 (Mat1) of the second compound M2, a singlet energy _S 1 of the third compound M3 (MAT3), relationship of the following equation (Equation 2) It is preferable to satisfy.
_{S 1 (Mat3)> S 1} (Mat2) ... ( number 2)

The energy gap T _77K (Mat3) in 77 [K] of the third compound M3 is preferably larger than the energy gap T _77K (Mat2) in 77 [K] of the second compound M2, and the following formula (Equation 3A) ) Satisfy the relationship.
T _77K (Mat3)> T _77K (Mat2) ... (Equation 3A)

The energy gap T _77K (Mat3) in 77 [K] of the third compound M3 is preferably larger than the energy gap T _77K (Mat1) in 77 [K] of the first compound M1 and is preferably larger than the following formula (Equation 3B). ) Satisfy the relationship.
T _77K (Mat3)> T _77K (Mat1) ... (Number 3B)

The singlet energy _S 1 of the second compound M2 (Mat2), a singlet energy _S 1 (Mat1) of the first compound M1, and the singlet energy _S 1 of the third compound M3 (Mat3), following It is preferable to satisfy the relationship of the mathematical formula (Equation 2A).
S ₁ (Mat 3)> S ₁ (Mat 2)> S ₁ (Mat ₁ ) ... (Equation 2A)

An energy gap _T 77K (Mat1) in 77 [K] of the first compound M1, the energy gap _T 77K at 77 [K] of the second compound M2 (Mat2), 77 of the third compound M3 [K] It is preferable that the energy gap T _77K (Mat3) in the above satisfies the relationship of the following mathematical formula (Equation 3C).
T _77K (Mat3)> T _77K (Mat2)> T _77K (Mat1) ... (Number 3C)

When the organic EL element of the present embodiment is made to emit light, it is preferable that a fluorescent compound mainly emits light in the light emitting layer.
The organic EL element of the present embodiment preferably emits red light or green light, like the organic EL element of the first embodiment.
The main peak wavelength of the light emitted from the organic EL element can be measured by the same method as that of the organic EL element of the first embodiment.

-Compound content in the light emitting layer The content of the second compound M2, the first compound M1 and the third compound contained in the light emitting layer is preferably in the following range, for example.
The content of the second compound M2 is preferably 10% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and 20% by mass or more and 60% by mass or less. Is even more preferable.
The content of the first compound M1 is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less, and 0.01% by mass or more and 1 It is more preferably mass% or less.
The content of the third compound is preferably 10% by mass or more and 80% by mass or less.
The upper limit of the total content of the second compound M2, the first compound M1, and the third compound M3 in the light emitting layer is 100% by mass. The present embodiment does not exclude that the light emitting layer contains materials other than the second compound M2, the first compound M1, and the third compound M3.
The light emitting layer may contain only one type of the second compound M2, or may contain two or more types. The light emitting layer may contain only one kind of the first compound M1 or two or more kinds. The light emitting layer may contain only one type of the third compound M3, or may contain two or more types.

FIG. 5 is a diagram showing an example of the relationship between the energy levels of the second compound M2, the first compound M1, and the third compound M3 in the light emitting layer. In FIG. 5, S0 represents the ground state. S1 (Mat1) represents the lowest excited singlet state of the first compound M1, and T1 (Mat1) represents the lowest excited triplet state of the first compound M1. S1 (Mat2) represents the lowest excited singlet state of the second compound M2, and T1 (Mat2) represents the lowest excited triplet state of the second compound M2. S1 (Mat3) represents the lowest excited singlet state of the third compound M3, and T1 (Mat3) represents the lowest excited triplet state of the third compound M3.
The dashed arrow from S1 (Mat2) to S1 (Mat1) in FIG. 5 indicates the Felster-type energy transfer from the lowest excited singlet state of the second compound M2 to the lowest excited singlet state of the first compound M1. Represents.
As shown in FIG. 5, when a compound having a small ΔST (Mat2) is used as the second compound M2, the lowest excited triplet state T1 (Mat2) is reversed to the lowest excited singlet state S1 (Mat2) by thermal energy. Intersystem crossing is possible. Then, Felster-type energy transfer from the lowest excited singlet state S1 (Mat2) of the second compound M2 to the first compound M1 occurs, and the lowest excited singlet state S1 (Mat1) is generated. As a result, fluorescence emission from the lowest excited singlet state S1 (Mat1) of the first compound M1 can be observed. It is believed that the internal quantum efficiency can theoretically be increased to 100% by utilizing the delayed fluorescence by this TADF mechanism.

The organic EL element according to the second embodiment has a second compound M2, a first compound M1 having a singlet energy smaller than that of the second compound M2, and a larger one than the second compound M2 in the light emitting layer. It contains a third compound, M3, which has singlet energy.

The organic EL element according to the second embodiment can be used for electronic devices such as display devices and light emitting devices.

According to the organic electroluminescence device according to the present embodiment, high performance, particularly long life is emitted.

[Third Embodiment]
[Electronics]
The electronic device according to this embodiment is equipped with an organic EL element according to any one of the above-described embodiments. Examples of the electronic device include a display device and a light emitting device. Examples of the display device include display components (for example, organic EL panel modules, etc.), televisions, mobile phones, tablets, personal computers, and the like. Examples of the light emitting device include lighting and vehicle lighting equipment.

[Other explanations]
In the present specification, when Rx and Ry are bonded to each other to form a ring, for example, Rx and Ry include a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom, and an atom contained in Rx (carbon atom). , Nitrogen atom, oxygen atom, sulfur atom or silicon atom) and the atom contained in Ry (carbon atom, nitrogen atom, oxygen atom, sulfur atom or silicon atom) are single-bonded, double-bonded, triple-bonded, or It means that they are bonded via a divalent linking group to form a ring having 5 or more ring-forming atoms (specifically, a heterocycle or an aromatic hydrocarbon ring). x is a number, a letter, or a combination of a number and a letter. y is a number, a letter, or a combination of a number and a letter.
There is no particular restriction on the divalent linking group, _{e.g., -O -, - CO -,} - CO 2 -, - S -, - SO -, - SO 2 -, - NH -, - NRa-, and their Examples thereof include a group in which two or more linking groups of the above are combined.
Specific examples of the heterocycle include a ring structure (heterocycle) obtained by removing the bond from the "heteroaryl group Sub ₂ " exemplified in "Explanation of each substituent in the general formula" described later. These heterocycles may have substituents.
As a specific example of the aromatic hydrocarbon ring, a ring structure (aromatic hydrocarbon ring) obtained by removing the bond from the "aryl group Sub ₁ " exemplified in "Explanation of each substituent in the general formula" described later is used. Can be mentioned. These aromatic hydrocarbon rings may have a substituent.
Examples of Ra include the substituted or unsubstituted alkyl group Sub ₃ having 1 to 30 carbon atoms exemplified in the "Explanation of each substituent in the general formula" described later, and the substituted or unsubstituted ring-forming carbon number 6 to 3. Examples thereof include an aryl group Sub _{1 of} 30 and a heteroaryl group Sub ₂ having 5 to 30 substituted or unsubstituted ring-forming atoms.
For example, when Rx and Ry are bonded to each other to form a ring, in the molecular structure represented by the following general formula (E1), the atom contained in Rx ₁ and the atom contained in Ry ₁ are represented by the general formula (E1). Forming the ring (ring structure) E represented by E2); In the molecular structure represented by the general formula (F1), the atom contained in Rx ₁ and the atom contained in Ry ₁ are represented by the general formula (F1). Forming the ring F represented by F2); In the molecular structure represented by the general formula (G1), the atom contained in Rx ₁ and the atom contained in Ry ₁ are represented by the general formula (G2). In the molecular structure represented by the general formula (H1), the atom contained in Rx ₁ and the atom contained in Ry ₁ form the ring H represented by the general formula (H2). In the molecular structure represented by the general formula (I1), the atom contained in Rx ₁ and the atom contained in Ry ₁ form a ring I represented by the general formula (I2). Means;
In the general formulas (E1) to (I1), * independently represents a bond position with another atom in one molecule. The two * in the general formula (E1) correspond to the two * in the general formula (E2), respectively, and the two * in the general formula (F1) correspond to the two * in the general formula (F2), respectively. Then, the two * in the general formula (G1) correspond to the two * in the general formula (G2), respectively, and the two * in the general formula (H1) correspond to the two * in the general formula (H2). Corresponding to each, the two * in the general formula (I1) correspond to the two * in the general formula (I2), respectively.

In the molecular structures represented by the general formulas (E2) to (I2), E to I each represent a ring structure (the ring having 5 or more ring-forming atoms). In the general formulas (E2) to (I2), * independently represents a bond position with another atom in one molecule. The two * in the general formula (E2) correspond to the two * in the general formula (E1), respectively. Similarly, the two * in the general formulas (F2) to (I2) correspond to the two * in the general formulas (F1) to (I1), respectively.

For example, in the general formula (E1), when Rx ₁ and Ry ₁ are bonded to each other to form the ring E in the general formula (E2) and the ring E is an unsubstituted benzene ring, the general formula (E1) is used. The molecular structure represented is the molecular structure represented by the following general formula (E3). Here, the two * in the general formula (E3) correspond independently to the two * in the general formula (E2) and the general formula (E1), respectively.
For example, in the general formula (E1), when Rx ₁ and Ry ₁ are bonded to each other to form the ring E in the general formula (E2) and the ring E is an unsubstituted pyrrole ring, the general formula (E1) is used. The molecular structure represented is the molecular structure represented by the following general formula (E4). Here, the two * in the general formula (E4) correspond independently to the two * in the general formula (E2) and the general formula (E1), respectively. In the general formulas (E3) and (E4), * independently represents a bond position with another atom in one molecule.

In the present specification, the ring-forming carbon number constitutes the ring itself of a compound having a structure in which atoms are cyclically bonded (for example, a monocyclic compound, a fused ring compound, a crosslinked compound, a carbocyclic compound, or a heterocyclic compound). Represents the number of carbon atoms in an atom. When the ring is substituted with a substituent, the carbon contained in the substituent is not included in the ring-forming carbon number. The "ring-forming carbon number" described below shall be the same unless otherwise specified. For example, a benzene ring has a ring-forming carbon number of 6, a naphthalene ring has a ring-forming carbon number of 10, a pyridinyl group has a ring-forming carbon number of 5, and a furanyl group has a ring-forming carbon number of 4. When, for example, an alkyl group is substituted as a substituent on the benzene ring or naphthalene ring, the number of carbon atoms of the alkyl group is not included in the number of ring-forming carbon atoms. When, for example, a fluorene ring is bonded to the fluorene ring as a substituent (including a spirofluorene ring), the number of carbon atoms of the fluorene ring as a substituent is not included in the number of ring-forming carbon atoms.

In the present specification, the number of ring-forming atoms is a compound having a structure in which atoms are cyclically bonded (for example, a monocycle, a fused ring, or a ring assembly) (for example, a monocyclic compound, a fused ring compound, a crosslinked compound, a carbocyclic compound, or a complex). It represents the number of atoms constituting the ring itself of the ring compound). Atoms that do not form a ring and atoms contained in the substituent when the ring is substituted by a substituent are not included in the number of ring-forming atoms. The "number of ring-forming atoms" described below shall be the same unless otherwise specified. For example, the pyridine ring has 6 ring-forming atoms, the quinazoline ring has 10 ring-forming atoms, and the furan ring has 5 ring-forming atoms. Hydrogen atoms bonded to carbon atoms of the pyridine ring and quinazoline ring and atoms constituting substituents are not included in the number of ring-forming atoms.
When, for example, a fluorene ring is bonded to the fluorene ring as a substituent (including a spirofluorene ring), the number of atoms of the fluorene ring as a substituent is not included in the number of ring-forming atoms.

-Explanation of each substituent in the general formula (Explanation of each substituent)
Next, each substituent in the general formula in the present specification will be described.

The aryl group (sometimes referred to as an aromatic hydrocarbon group) in the present specification is, for example, an aryl group Sub ₁ , and the aryl group Sub ₁ is a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, or anthryl. Group, phenanthryl group, fluorenyl group, pyrenyl group, chrysenyl group, fluoranthenyl group, benzo [a] anthryl group, benzo [c] phenanthryl group, triphenylenyl group, benzo [k] fluoranthenyl group, benzo [g] chrysenyl It is at least one group selected from the group consisting of a group, a benzo [b] triphenylenyl group, a pisenyl group, and a perylenyl group.

As the aryl group Sub ₁ in the present specification, the ring-forming carbon number is preferably 6 to 30, more preferably 6 to 20, further preferably 6 to 14, and 6 to 12. It is even more preferable to have. Among the aryl groups Sub ₁ , phenyl group, biphenyl group, naphthyl group, phenanthryl group, terphenyl group, and fluorenyl group are preferable. For the 1-fluorenyl group, 2-fluorenyl group, 3-fluorenyl group and 4-fluorenyl group, the carbon atom at the 9-position is substituted with the substituted or unsubstituted alkyl group Sub ₃ described later, or substituted or unsubstituted. It is preferable that the aryl group Sub _{1 of the above} is substituted.

The heteroaryl group (sometimes referred to as a heterocyclic group, a heteroaromatic ring group, or an aromatic heterocyclic group) in the present specification is, for example, the heterocyclic group Sub ₂ . The heterocyclic group Sub ₂ is a group containing at least one atom selected from the group consisting of nitrogen, sulfur, oxygen, silicon, selenium atom, and germanium atom as a heteroatom. The heterocyclic group Sub ₂ is preferably a group containing at least one atom selected from the group consisting of nitrogen, sulfur, and oxygen as a heteroatom.

The heterocyclic group Sub ₂ in the present specification is, for example, pyridyl group, pyrimidinyl group, pyrazinyl group, pyridadinyl group, triazinyl group, quinolyl group, isoquinolinyl group, naphthyldinyl group, phthalazinyl group, quinoxalinyl group, quinazolinyl group, phenanthridinyl. Group, acridinyl group, phenanthrolinyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, indrill group, benzimidazolyl group, indazolyl group, imidazolylinyl group, benztriazolyl group, carbazolyl group , Frill group, thienyl group, oxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, oxadiazolyl group, thiadiazolyl group, benzofuranyl group, benzothienyl group, benzoxazolyl group, benzothiazolyl group, benzoisoxazolyl group, benzoisoti A group consisting of an azolyl group, a benzoxaziazolyl group, a benzothiasiazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a piperidinyl group, a pyrrolidinyl group, a piperazinyl group, a morpholic group, a phenazinyl group, a phenothiazinyl group, and a phenoxadinyl group. At least one of the groups selected from.

As the heterocyclic group Sub ₂ in the present specification, the number of ring-forming atoms is preferably 5 to 30, more preferably 5 to 20, and even more preferably 5 to 14. Among the above heterocyclic groups Sub ₂ , 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothienyl group, 2-dibenzothienyl group, 3- Dibenzothienyl groups, 4-dibenzothienyl groups, 1-carbazolyl groups, 2-carbazolyl groups, 3-carbazolyl groups, 4-carbazolyl groups, and 9-carbazolyl groups are even more preferred. For the 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group and 4-carbazolyl group, the nitrogen atom at the 9-position may be substituted or unsubstituted aryl group Sub ₁ or a substituted or unsubstituted heterocycle in the present specification. It is preferable that the ring group Sub ₂ is substituted.

Further, in the present specification, the heterocyclic group Sub ₂ may be, for example, a group derived from a partial structure represented by the following general formulas (XY-1) to (XY-18).

In Formula (XY-1) ~ (XY -18), it is _{X A} and _{Y A,} independently, a heteroatom, an oxygen atom, a sulfur atom, a selenium atom, silicon atom, or germanium atom Is preferable. The partial structures represented by the general formulas (XY-1) to (XY-18) have a bond at an arbitrary position to form a heterocyclic group, and this heterocyclic group has a substituent. May be good.

Further, in the present specification, the heterocyclic group Sub ₂ may be, for example, a group represented by the following general formulas (XY-19) to (XY-22). In addition, the position of the joint can be changed as appropriate.

The alkyl group in the present specification may be a linear alkyl group, a branched chain alkyl group, or a cyclic alkyl group.
The alkyl group in the present specification is, for example, the alkyl group Sub ₃ .
The linear alkyl group in the present specification is, for example, the linear alkyl group Sub ₃₁ .
The alkyl group of the branched chain in the present specification is, for example, the alkyl group Sub ₃₂ of the branched chain.
The cyclic alkyl group in the present specification is, for example, the cyclic alkyl group Sub ₃₃ .
The alkyl group Sub ₃ is, for example, at least one group selected from the group consisting of a linear alkyl group Sub ₃₁ , a branched chain alkyl group Sub ₃₂ , and a cyclic alkyl group Sub ₃₃ .

The linear alkyl group Sub ₃₁ or the branched alkyl group Sub ₃₂ is, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, a t-butyl group. , N-Pentyl group, n-Hexyl group, n-Heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group , N-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, neopentyl group, amyl group, isoamyl group, 1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group, 1- At least one group selected from the group consisting of a butylpentyl group, a 1-heptyloctyl group, and a 3-methylpentyl group.

The linear alkyl group Sub ₃₁ or the branched alkyl group Sub _{32 in} the present specification preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and preferably 1 to 10 carbon atoms. More preferably, it is even more preferably 1 to 6. The linear alkyl group Sub ₃₁ or the branched alkyl group Sub ₃₂ includes methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group and n. -Pentyl groups, n-hexyl groups, amyl groups, isoamyl groups, and neopentyl groups are even more preferred.

The cyclic alkyl group Sub ₃₃ in the present specification is, for example, a cycloalkyl group Sub ₃₃₁ .

The cycloalkyl group Sub ₃₃₁ in the present specification is, for example, at least one group selected from the group consisting of a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, an adamantyl group, and a norbornyl group. Is. The ring-forming carbon number of the cycloalkyl group Sub ₃₃₁ is preferably 3 to 30, more preferably 3 to 20, further preferably 3 to 10, and even more preferably 5 to 8. preferable. Among the cycloalkyl groups Sub ₃₃₁ , cyclopentyl groups and cyclohexyl groups are even more preferable.

The alkyl halide group in the present specification is, for example, the alkyl halide group Sub ₄ , and the alkyl halide group Sub ₄ is, for example, the alkyl group Sub ₃ substituted with one or more halogen atoms, preferably a fluorine atom. It is an alkyl group.

The alkyl halide group Sub ₄ in the present specification is, for example, a group consisting of a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a trifluoromethylmethyl group, a trifluoroethyl group, and a pentafluoroethyl group. At least one of the groups selected from.

The substituted silyl group in the present specification is, for example, the substituted silyl group Sub ₅ , and the substituted silyl group Sub ₅ is at least one selected from the group consisting of, for example, the alkylsilyl group Sub ₅₁ and the arylsilyl group Sub ₅₂ . Is the basis.

The alkylsilyl group Sub ₅₁ in the present specification is, for example, the trialkylsilyl group Sub ₅₁₁ having the above-mentioned alkyl group Sub ₃ .
The trialkylsilyl group Sub ₅₁₁ is, for example, a trimethylsilyl group, a triethylsilyl group, a tri-n-butylsilyl group, a tri-n-octylsilyl group, a triisobutylsilyl group, a dimethylethylsilyl group, a dimethylisopropylsilyl group, a dimethyl-n. At least one selected from the group consisting of a -propylsilyl group, a dimethyl-n-butylsilyl group, a dimethyl-t-butylsilyl group, a diethylisopropylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, and a triisopropylsilyl group. Is the basis. The three alkyl groups Sub ₃ in the trialkylsilyl group Sub ₅₁₁ may be the same or different from each other.

The arylsilyl group Sub ₅₂ in the present specification is, for example, at least one group selected from the group consisting of the dialkylarylsilyl group Sub ₅₂₁ , the alkyldiarylsilyl group Sub ₅₂₂ , and the triarylsilyl group Sub ₅₂₃ .

The dialkylarylsilyl group Sub ₅₂₁ is, for example, a dialkylarylsilyl group having two alkyl groups Sub ₃ and one aryl group Sub ₁ . The dialkylarylsilyl group Sub ₅₂₁ preferably has 8 to 30 carbon atoms.

The alkyldiarylsilyl group Sub ₅₂₂ is, for example, an alkyldiarylsilyl group having one of the above alkyl groups Sub ₃ and two of the above aryl groups Sub ₁ . The alkyldiarylsilyl group Sub ₅₂₂ preferably has 13 to 30 carbon atoms.

The triarylsilyl group Sub ₅₂₃ is, for example, a triarylsilyl group having three of the above aryl groups Sub ₁ . The number of carbon atoms of the triarylsilyl group Sub ₅₂₃ is preferably 18 to 30.

A substituted or unsubstituted alkylsulfonyl groups herein, for example, an alkylsulfonyl group Sub _6, an alkylsulfonyl group Sub ₆ is represented by _-SO 2 _{R w. R w} in -SO ₂ R _w represents the alkyl group Sub ₃ substituted or unsubstituted.

The aralkyl group (sometimes referred to as an arylalkyl group) in the present specification is, for example, the aralkyl group Sub ₇ . The aryl group in the aralkyl group Sub ₇ includes, for example, at least one of the aryl group Sub ₁ and the heteroaryl group Sub ₂ .

The aralkyl group Sub ₇ in the present specification is preferably a group having an aryl group Sub ₁ , and is represented by −Z ₃ −Z ₄ . The Z ₃ is, for example, an alkylene group corresponding to the above alkyl group Sub ₃ . The Z ₄ is, for example, the above aryl group Sub ₁ . In this aralkyl group Sub ₇ , the aryl moiety has 6 to 30 carbon atoms (preferably 6 to 20, more preferably 6 to 12), and the alkyl moiety has 1 to 30 carbon atoms (preferably 1 to 20, more preferably 1 to 1). 10, more preferably 1 to 6). The aralkyl group Sub ₇ includes, for example, a benzyl group, a 2-phenylpropan-2-yl group, a 1-phenylethyl group, a 2-phenylethyl group, a 1-phenylisopropyl group, a 2-phenylisopropyl group, and a phenyl-t-. Butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β It is at least one group selected from the group consisting of a-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.

The alkoxy group in the present specification is, for example, the alkoxy group Sub ₈ , and the alkoxy group Sub ₈ is represented as −OZ ₁ . This Z ₁ is, for example, the above-mentioned alkyl group Sub ₃ . The alkoxy group Sub ₈ is, for example, at least one group selected from the group consisting of a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group. The alkoxy group Sub ₈ preferably has 1 to 30 carbon atoms, and more preferably 1 to 20 carbon atoms.

The halogenated alkoxy group in the present specification is, for example, a halogenated alkoxy group Sub ₉ , and in the halogenated alkoxy group Sub ₉ , for example, the above-mentioned alkoxy group Sub ₈ is replaced with one or more halogen atoms, preferably a fluorine atom. It is an alkoxy group.

Aryloxy groups (sometimes referred to as arylalkoxy groups) in the present specification are
For example, the arylalkoxy group Sub ₁₀ . The aryl group in the arylalkoxy group Sub ₁₀ includes at least one of the aryl group Sub ₁ and the heteroaryl group Sub ₂ .

The arylalkoxy group Sub ₁₀ in the present specification is represented by −OZ ₂ . The Z ₂ is, for example, an aryl group Sub ₁ or a heteroaryl group Sub ₂ . The ring-forming carbon number of the arylalkoxy group Sub ₁₀ is preferably 6 to 30, and more preferably 6 to 20. Examples of the arylalkoxy group Sub ₁₀ include a phenoxy group.

The substituted amino group in the present specification is, for example, the substituted amino group Sub ₁₁ , and the substituted amino group Sub ₁₁ is at least one selected from the group consisting of, for example, the arylamino group Sub ₁₁₁ and the alkylamino group Sub ₁₁₂ . It is a group.
The arylamino group Sub ₁₁₁ is represented as -NHR _V1 or -N (R _V1 ) ₂ . This R _V1 is, for example, the aryl group Sub ₁ . -N _{(R V1)} of the two in _{2 R V1} are the same or different.
The alkylamino group Sub ₁₁₂ is represented as -NHR _V2 or -N (R _V2 ) ₂ . This R _V2 is, for example, an alkyl group Sub ₃ . -N _{(R V2)} 2 two _{R V2} in ₂ are the same or different.

The alkenyl group in the present specification is, for example, the alkenyl group Sub ₁₂ , and the alkenyl group Sub ₁₂ is either a linear group or a branched chain, and is, for example, a vinyl group, a propenyl group, a butenyl group, an oleyl group, an eikosa. At least one selected from the group consisting of pentaenyl group, docosahexaenyl group, styryl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, and 2-phenyl-2-propenyl. It is a group.

The alkynyl group in the present specification is, for example, the alkynyl group Sub ₁₃ , and the alkynyl group Sub ₁₃ may be either a straight chain or a branched chain, for example, a group consisting of ethynyl, propynyl, and 2-phenylethynyl. At least one of the groups selected from.

The alkylthio group in the present specification is, for example, the alkylthio group Sub ₁₄ .
The alkylthio group Sub ₁₄ is represented as -SR _V3 . This R _V3 is, for example, an alkyl group Sub ₃ . The number of carbon atoms of the alkylthio group Sub ₁₄ is preferably 1 to 30, and more preferably 1 to 20.
The arylthio group in the present specification is, for example, the arylthio group Sub ₁₅ .
The arylthio group Sub ₁₅ is represented as -SR _V4 . This R _V4 is, for example, the aryl group Sub ₁ . The ring-forming carbon number of the arylthio group Sub ₁₅ is preferably 6 to 30, and more preferably 6 to 20.

Examples of the halogen atom in the present specification include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

The substituted phosphino group in the present specification is, for example, the substituted phosphino group Sub ₁₆ , and the substituted phosphino group Sub ₁₆ is, for example, a phenylphosphanyl group.

The arylcarbonyl group in the present specification is, for example, the arylcarbonyl group Sub ₁₇ , and the arylcarbonyl group Sub ₁₇ is represented as −COY'. This Y'is, for example, the aryl group Sub ₁ . The arylcarbonyl group Sub ₁₇ in the present specification is, for example, at least one group selected from the group consisting of a phenylcarbonyl group, a diphenylcarbonyl group, a naphthylcarbonyl group, and a triphenylcarbonyl group.

The acyl group in the present specification is, for example, the acyl group Sub ₁₈ , and the acyl group Sub ₁₈ is represented as −COR'. This R'is, for example, the alkyl group Sub ₃ . The acyl group Sub ₁₈ in the present specification is, for example, at least one group selected from the group consisting of an acetyl group and a propionyl group.

The substituted phosphoryl group in the present specification is, for example, the substituted phosphoryl group Sub ₁₉ , and the substituted phosphoryl group Sub ₁₉ is represented by the following general formula (P).

In the general formula (P), Ar _P1 and Ar _P2 are any of the substituents selected from the group consisting of the alkyl group Sub ₃ and the aryl group Sub ₁ .

The ester group in the present specification is, for example, the ester group Sub ₂₀ , and the ester group Sub ₂₀ is, for example, at least one group selected from the group consisting of an alkyl ester group and an aryl ester group.
Alkyl ester groups herein, for example, an alkyl ester group _{Sub 201,} an alkyl ester group _{Sub 201} is represented by -C (= O) OR ^{E. RE} is, for example, the above-mentioned alkyl group Sub ₃ (preferably having 1 to 10 carbon atoms) substituted or unsubstituted.
The aryl ester group in the present specification is, for example, the aryl ester group Sub ₂₀₂ , and the aryl ester group Sub ₂₀₂ is represented by −C (= O) OR ^Ar . R ^Ar is, for example, the above-mentioned aryl group Sub ₁ substituted or unsubstituted.

The siroxanyl group in the present specification is, for example, the siroxanyl group Sub ₂₁ and the siroxanyl group Sub ₂₁ is a silicon compound group via an ether bond. The siroxanyl group Sub ₂₁ is, for example, a trimethylsyloxanyl group.

The carbamoyl group herein is represented by -CONH ₂ .
The substituted carbamoyl group in the present specification is, for example, the carbamoyl group Sub ₂₂ , and the carbamoyl group Sub ₂₂ is represented by -CONH-Ar ^C or -CONH- ^RC . Ar ^C is selected from the group consisting of, for example, the substituted or unsubstituted aryl group Sub ₁ (preferably having 6 to 10 ring-forming carbon atoms) and the heteroaryl group Sub ₂ (preferably having 5 to 14 ring-forming atoms). Is at least one of the groups to be. Ar ^C may be a group in which an aryl group Sub ₁ and a heteroaryl group Sub ₂ are bonded.
The ^RC is, for example, the above-mentioned alkyl group Sub ₃ (preferably having 1 to 6 carbon atoms) substituted or unsubstituted.

As used herein, the term "ring-forming carbon" means a carbon atom that constitutes a saturated ring, an unsaturated ring, or an aromatic ring. "Ring-forming atom" means a carbon atom and a heteroatom constituting a heterocycle (including a saturated ring, an unsaturated ring, and an aromatic ring).

Further, in the present specification, the hydrogen atom includes isotopes having different numbers of neutrons, that is, hydrogen (Protium), deuterium (Deuterium), and tritium (Tritium).

Hereinafter, the alkyl group Sub ₃ refers to any one or more of the linear alkyl group Sub ₃₁ , the branched alkyl group Sub ₃₂ , and the cyclic alkyl group Sub ₃₃ described in "Explanation of each substituent". means.
Similarly, the substituted silyl group Sub ₅ means any one or more groups of the alkylsilyl group Sub ₅₁ and the arylsilyl group Sub ₅₂ .
Similarly, the substituted amino group Sub ₁₁ means any one or more of the arylamino group Sub ₁₁₁ and the alkylamino group Sub ₁₁₂ .

In the present specification, the substituent in the case of "substituted or unsubstituted" is, for example, the substituent R _F1 , and the substituent R _F1 is an aryl group Sub ₁ , a heteroaryl group Sub ₂ , an alkyl group Sub ₃ , and the like. Alkyl halide Sub ₄ , substituted silyl group Sub ₅ , alkylsulfonyl group Sub ₆ , aralkyl group Sub ₇ , alkoxy group Sub ₈ , halogenated alkoxy group Sub ₉ , arylalkoxy group Sub ₁₀ , substituted amino group Sub ₁₁ , alkenyl group. Sub _12, an alkynyl group _{Sub 13,} an alkylthio group _{Sub 14,} arylthio group _{Sub 15,} a substituted phosphino group _{Sub 16,} an arylcarbonyl group _{Sub 17,} acyl group _{Sub 18,} a substituted phosphoryl group _{Sub 19,} an ester group _{Sub 20,} siloxanyl group _{Sub 21} , Carbamoyl group Sub ₂₂ , an unsubstituted amino group, an unsubstituted silyl group, a halogen atom, a cyano group, a hydroxy group, a thiol group, a nitro group, and a carboxy group, at least one group selected from the group.

In the present specification, the substituent R _F1 in the case of “substituent or unsubstituted” may be a diarylboron group (Ar _B1 Ar _B2 B−). Examples of the Ar _B1 and Ar _B2 include the above-mentioned aryl group Sub ₁ . _{Ar B1} Ar _B2 B- Ar _B1 and _{Ar B2} in the same or different.

Specific examples and preferred groups of substituents _{R F1,} substituent in "Description of the substituent" (e.g., aryl group Sub _1, heteroaryl Sub _2, alkyl group Sub _3, a halogenated alkyl group _Sub 4, Substituted silyl group Sub ₅ , alkylsulfonyl group Sub ₆ , aralkyl group Sub ₇ , alkoxy group Sub ₈ , halogenated alkoxy group Sub ₉ , arylalkoxy group Sub ₁₀ , substituted amino group Sub ₁₁ , alkenyl group Sub ₁₂ , alkynyl group Sub ₁₃ , Alkylthio group Sub ₁₄ , arylthio group Sub ₁₅ , substituted phosphino group Sub ₁₆ , arylcarbonyl group Sub ₁₇ , acyl group Sub ₁₈ , substituted phosphoryl group Sub ₁₉ , ester group Sub ₂₀ , and siloxanyl group Sub ₂₁ and carbamoyl group Sub ₂₂ ). Specific examples of the above and groups similar to the preferred groups are mentioned.

Substituents R _F1 in the case of "substituted or unsubstituted" are aryl group Sub ₁ , heteroaryl group Sub ₂ , alkyl group Sub ₃ , halogenated alkyl group Sub ₄ , substituted silyl group Sub ₅ , alkylsulfonyl group Sub ₆ , Aralkyl group Sub ₇ , alkoxy group Sub ₈ , halogenated alkoxy group Sub ₉ , arylalkoxy group Sub ₁₀ , substituted amino group Sub ₁₁ , alkenyl group Sub ₁₂ , alkynyl group Sub ₁₃ , alkylthio group Sub ₁₄ , arylthio group Sub ₁₅ , Substituted phosphino group Sub ₁₆ , arylcarbonyl group Sub ₁₇ , acyl group Sub ₁₈ , substituted phosphoryl group Sub ₁₉ , ester group Sub ₂₀ , siloxanyl group Sub ₂₁ , carbamoyl group Sub ₂₂ , unsubstituted amino group, unsubstituted silyl group, halogen atom, cyano group, hydroxy group, thiol group, at least one group selected from the group consisting of nitro groups and carboxy groups, (hereinafter also referred to as substituent R _F2) may be further substituted by. Further, a plurality of these substituents _RF2 may be bonded to each other to form a ring.

Not substituted with the substituents R _F1 is a "unsubstituted" in the case of "substituted or unsubstituted" means that a hydrogen atom is bonded.

In the present specification, "carbon number XX to YY" in the expression "ZZ group having substituted or unsubstituted carbon number XX to YY" represents the number of carbon atoms when the ZZ group is unsubstituted and is substituted. and carbon number of the substituent R _F1 where are is not included.

In the present specification, the "atomic number XX to YY" in the expression "ZZ group of atomic number XX to YY substituted or unsubstituted" represents the number of atoms when the ZZ group is unsubstituted and is substituted. atoms of the substituents R _F1 in this case is not included.

The same applies to the case of "substituted or unsubstituted" in the compound described in the present specification or its partial structure.

In the present specification, when substituents are bonded to each other to construct a ring, the structure of the ring is a saturated ring, an unsaturated ring, an aromatic hydrocarbon ring, or a heterocycle.

In the present specification, examples of the aromatic hydrocarbon group in the linking group include a divalent or higher valent group obtained by removing one or more atoms from the monovalent aryl group Sub ₁ described above.
In the present specification, examples of the heterocyclic group in the linking group include a divalent or higher valent group obtained by removing one or more atoms from the monovalent heteroaryl group Sub ₂ described above.

In the present specification, the numerical range represented by using "~" means a range including a numerical value before "~" as a lower limit value and a numerical value after "~" as an upper limit value. To do.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and changes, improvements, etc. within the range in which the object of the present invention can be achieved are included in the present invention.

For example, the light emitting layer is not limited to one layer, and a plurality of light emitting layers may be laminated. When the organic EL element has a plurality of light emitting layers, it is sufficient that at least one light emitting layer satisfies the conditions described in the above embodiment. For example, the other light emitting layer may be a fluorescence light emitting layer or a phosphorescent light emitting layer utilizing light emission by electron transition from the triplet excited state to the direct ground state.
Further, when the organic EL element has a plurality of light emitting layers, these light emitting layers may be provided adjacent to each other, or a so-called tandem type organic in which a plurality of light emitting units are laminated via an intermediate layer. It may be an EL element.

Further, for example, a barrier layer may be provided adjacent to at least one of the anode side and the cathode side of the light emitting layer. The barrier layer is preferably located in contact with the light emitting layer to block at least one of holes, electrons, and excitons.
For example, when a barrier layer is arranged in contact with the cathode side of the light emitting layer, the barrier layer transports electrons and holes reach a layer on the cathode side of the barrier layer (for example, an electron transport layer). Stop doing. When the organic EL element includes an electron transport layer, it is preferable to include the barrier layer between the light emitting layer and the electron transport layer.
When the barrier layer is arranged in contact with the anode side of the light emitting layer, the barrier layer transports holes and electrons are transferred to the layer on the anode side of the barrier layer (for example, the hole transport layer). Prevent it from reaching. When the organic EL element includes a hole transport layer, it is preferable to include the barrier layer between the light emitting layer and the hole transport layer.
Further, a barrier layer may be provided adjacent to the light emitting layer so that the excitation energy does not leak from the light emitting layer to the peripheral layer thereof. It prevents excitons generated in the light emitting layer from moving to a layer on the electrode side of the barrier layer (for example, an electron transport layer and a hole transport layer).
It is preferable that the light emitting layer and the barrier layer are joined.

In addition, the specific structure, shape, and the like in carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

Hereinafter, examples according to the present invention will be described. The present invention is not limited to these examples.

<Compound>
The structure of the compound represented by the general formula (20A) or the general formula (20B) used in the production of the organic EL device according to Examples 1 and 2 is shown below.

The structure of the comparative compound used in the production of the organic EL device according to Comparative Example 1 is shown below.

The structures of other compounds used in the production of the organic EL device according to Examples 1 and 2 and Comparative Example 1 are shown below.

<Manufacturing of organic EL element>
An organic EL device was prepared and evaluated as follows.

[Example 1]
A glass substrate (manufactured by Geomatec Co., Ltd.) with an ITO transparent electrode (anode) having a thickness of 25 mm × 75 mm × 1.1 mm was ultrasonically cleaned in isopropyl alcohol for 5 minutes, and then UV ozone cleaning was performed for 1 minute. The film thickness of ITO was 130 nm.
The glass substrate with the transparent electrode line after cleaning is mounted on the substrate holder of the vacuum vapor deposition apparatus, and the compound HA is co-deposited on the surface on the side where the transparent electrode line is formed so as to cover the transparent electrode. A hole injection layer having a thickness of 5 nm was formed.
Next, the compound HT-1 was deposited on the hole injection layer to form a hole transport layer having a film thickness of 110 nm.
Next, the compound mCBP was deposited on the hole transport layer to form an electron barrier layer having a film thickness of 10 nm.
Next, the compound mCBP as the third compound M3, the compound TADF-1 as the second compound M2, and the compound GD as the first compound M1 are co-deposited on the electron barrier layer. A light emitting layer having a thickness of 25 nm was formed. The concentration of compound mCBP in the light emitting layer was 74% by mass, the concentration of compound TADF-1 was 25% by mass, and the concentration of compound GD was 1% by mass.
Next, the compound ET-1 was deposited on the light emitting layer to form a hole barrier layer having a film thickness of 5 nm.
Next, the compound ET-2 was deposited on the hole barrier layer to form an electron transport layer having a film thickness of 50 nm.
Next, lithium fluoride (LiF) was vapor-deposited on the electron transport layer to form an electron-injectable electrode (cathode) having a film thickness of 1 nm.
Then, metallic aluminum (Al) was vapor-deposited on the electron-injectable electrode to form a metallic Al cathode having a film thickness of 80 nm.
The element configuration of the organic EL element according to the first embodiment is shown as follows.
ITO (130) / HA (5) / HT-1 (110) / mCBP (10) / mCBP: TADF-1: GD (25,74%: 25%: 1%) / ET-1 (5) / ET -2 (50) / LiF (1) / Al (80)
The numbers in parentheses indicate the film thickness (unit: nm).
Also in parentheses, the percentages (74%: 25%: 1%) indicate the proportions (mass%) of compound mCBP, compound TADF-1, and compound GD in the light emitting layer. Hereinafter, the same notation will be used.

[Example 2]
The organic EL device according to Example 2 was produced in the same manner as in Example 1 except that the compound TADF-1 in the light emitting layer of the organic EL device according to Example 1 was changed to the compound shown in Table 1.

[Comparative Example 1]
The organic EL device according to Comparative Example 1 was produced in the same manner as in Example 1 except that the compound TADF-1 in the light emitting layer of the organic EL device according to Example 1 was changed to the compound shown in Table 1.

<Evaluation of organic EL elements>
The organic EL devices produced in Examples 1 and 2 and Comparative Example 1 were evaluated as follows. The evaluation results are shown in Table 1.
The compound Ref-1 used in the light emitting layer of Comparative Example 1 is described in the column of the second compound for convenience.

・ Main peak wavelength (λp)
The spectral radiance spectrum when a voltage was applied to the element so that the current density of the organic EL element was 10 mA / cm ² was measured with a spectral radiance meter CS-2000 (manufactured by Konica Minolta Co., Ltd.). From the obtained spectral radiance spectrum, the main peak wavelength λ _p (unit: nm) was determined.

・ Life (LT95)
Using a spectral radiance meter CS-200 (manufactured by Konica Minolta Co., Ltd.), a voltage is applied to the element so that the current density is 50 mA / cm ^2, and the time until the brightness becomes 95% of the initial brightness. (Unit: h) was measured.
In the present specification, the time until the brightness becomes 95% with respect to the initial brightness may be referred to as "life (LT95)".

The relative value (unit:%) of the life (LT95) of the organic EL element according to Example 1 and Example 2 when the life (LT95) of the organic EL element according to Comparative Example 1 is 100 h is calculated by the following mathematical formula (number). It was calculated using 10).

Relative value of the life of the organic EL element according to Example 1 or 2 (LT95) = {Life of the organic EL element according to Example 1 or 2 (LT95) / Life of the organic EL element according to Comparative Example 1 (LT95)} × 100 ... (several tens)

The organic EL element according to Examples 1 and 2 has a longer life than the organic EL element according to Comparative Example 1.

<Evaluation of compounds>
The physical property values of the compounds used in Examples 1 and 2 and Comparative Example 1 were measured by the following methods.

(Delayed fluorescence)
-Delayed fluorescence of compound TADF-1 The delayed fluorescence was confirmed by measuring transient PL using the apparatus shown in FIG. The compound TADF-1 was dissolved in toluene to prepare a dilute solution having an absorbance of 0.05 or less at the excitation wavelength in order to remove the contribution of self-absorption. Further, in order to prevent quenching by oxygen, the sample solution was frozen and degassed and then sealed in a cell with a lid under an argon atmosphere to obtain an oxygen-free sample solution saturated with argon.
The fluorescence spectrum of the sample solution was measured with a spectrofluorometer FP-8600 (manufactured by Nippon Kogaku Co., Ltd.), and the fluorescence spectrum of an ethanol solution of 9,10-diphenylanthracene was measured under the same conditions. Using the fluorescence area intensities of both spectra, Morris et al. J. Phys. Chem. The total fluorescence quantum yield was calculated by the equation (1) in 80 (1976) 969.
Prompt emission (immediate emission) that is immediately observed from the excited state after being excited by pulsed light (light emitted from a pulse laser) having a wavelength absorbed by the compound TADF-1 and immediately after the excitation. Is not observed, and there is a pulsed emission (delayed emission) that is observed thereafter. The delayed fluorescence emission in this example means that the amount of Delay emission (delayed emission) is 5% or more with respect to the amount of Prompt emission (immediate emission). Specifically, the amount of Prompt luminescence (immediate emission) and _{X P,} the amount of Delay emission (delayed luminescence) is taken as _{X D,} that the value of X D / _{X P} is 0.05 or more means.
The amounts of Prompt emission and Delay emission and their ratios can be determined by the same method as described in "Nature 492, 234-238, 2012" (Reference 1). The device used to calculate the amounts of Prompt emission and Delay emission is not limited to the apparatus described in Reference 1 or the apparatus shown in FIG.
Regarding the compound TADF-1, it was confirmed that the amount of Delay emission (delayed emission) was 5% or more with respect to the amount of Prompt emission (immediate emission).
Specifically, the compound _TADF-1, the value of X D / _{X P} was 0.05 or more.

-Delayed fluorescence of compound TADF-2 The delayed fluorescence of compound TADF-2 was confirmed in the same manner as above except that compound TADF-2 was used instead of compound TADF-1.
For compound _TADF-2, the value of X D / _{X P} was 0.05 or more.

-Delayed fluorescence of the comparative compound Ref-1 The delayed fluorescence of the comparative compound Ref-1 was confirmed in the same manner as above except that the comparative compound Ref-1 was used instead of the compound TADF-1.
Comparative Compound _Ref-1, the value of X D / _{X P} was 0.05 or more.

(Singlet energy S ₁ )
Compound TADF-1, TADF-2, compounds GD, compounds mCBP, and singlet energy _{S 1} of comparative compound Ref-1, was measured by the above-mentioned solution method. The measurement results are shown in Table 1.

(Energy gap at 77 [K])
The energy gap T _77K of compound TADF-1, compound TADF-2 and comparative compound Ref-1 at 77 [K] was measured by the method described above.

(ΔST)
Based on the energy gap _{T 77K} in the measured singlet energy _{S 1} and 77 [K], was calculated .DELTA.St. The ΔST of compound TADF-1, compound TADF-2, and comparative compound Ref-1 was confirmed to be less than 0.01.

1 ... Organic EL element, 2 ... Substrate, 3 ... Anode, 4 ... Cathode, 5 ... Light emitting layer, 6 ... Hole injection layer, 7 ... Hole transport layer, 8 ... Electron transport layer, 9 ... Electron injection layer.

Claims (11)

With the anode
With the cathode
It has a light emitting layer contained between the anode and the cathode, and has.
The light emitting layer contains the first compound M1 and the second compound M2.
The first compound M1 is represented by the following general formula (1).
The second compound M2 is represented by the following general formula (20A) or general formula (20B).
Wherein the second compound singlet energy _S 1 of M2 (Mat2), said first compound M1 of singlet energy _S 1 (Mat1) and but satisfies the following equation (Equation 1),
Organic electroluminescence element.
S ₁ (Mat 2)> S ₁ (Mat ₁ ) ... (Equation 1)

(In the general formula (1),
X is a nitrogen atom or a carbon atom bonded to Y,
Y is a hydrogen atom or a substituent,
R _{21 to} R ₂₆ are independently hydrogen atoms or substituents, or R ₂₁ and R ₂₂ pairs, R ₂₂ and R ₂₃ pairs, R ₂₄ and R ₂₅ pairs, and R ₂₅ and R. Any one or more of the ₂₆ pairs combine with each other to form a ring.
Y and R _{21 to} R ₂₆ as substituents are independent of each other.
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substitutable or unsubstituted ring-forming cycloalkyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkoxy group having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylthio groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituted or unsubstituted ring-forming arylthio groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkenyl groups having 2 to 30 carbon atoms,
Substituentally substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms,
A heteroaryl group having 5 to 30 substituted or unsubstituted ring-forming atoms,
Halogen atom,
Carboxylic acid group,
Substituted or unsubstituted ester groups,
Substituted or unsubstituted carbamoyl groups,
Substituted or unsubstituted amino groups,
Nitro group,
Cyano group,
Selected from the group consisting of substituted or unsubstituted silyl groups and substituted or unsubstituted siloxanyl groups.
Z ₂₁ and Z ₂₂ are independent substituents, or Z ₂₁ and Z ₂₂ are bonded to each other to form a ring.
Z ₂₁ and Z ₂₂ as substituents are independent of each other.
Halogen atom,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkyl halide groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
It is selected from the group consisting of substituted or unsubstituted alkyl halide groups having 1 to 30 carbon atoms and substituted or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms. )

(In the general formula (20A) and the general formula (20B),
One of D ₂₁ and D ₂₂ is represented by the following general formula (21), and the other of D ₂₁ and D ₂₂ is represented by the following general formula (22).

(In the general formula (21),
R _{1 to} R ₈ are independent hydrogen atoms or substituents, respectively.
R _{1 to} R ₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
It is a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). )
(In the general formula (22),
X ₁ is a sulfur atom or an oxygen atom,
R ₁₉ and R ₂₀ are independent hydrogen atoms or substituents, respectively.
R _{31 to} R ₃₈ are independent hydrogen atoms or substituents, respectively.
R ₁₉ , R ₂₀ , and R _{31 to} R ₃₈ as substituents are independent of each other.
Substituent or unsubstituted ring-forming aryl groups having 6 to 30 carbon atoms,
Substituted or unsubstituted heterocyclic groups having 5 to 30 ring-forming atoms,
Substituent or unsubstituted alkyl groups having 1 to 30 carbon atoms,
Substituent or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylsilyl group having 6 to 60 carbon atoms,
Substituent or unsubstituted alkoxy groups having 1 to 30 carbon atoms,
Substituent or unsubstituted ring-forming aryloxy groups having 6 to 30 carbon atoms,
Substituent or unsubstituted alkylamino groups having 2 to 30 carbon atoms,
Substituent or unsubstituted ring-forming arylamino group having 6 to 60 carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring-forming alkylthio group having 6 to 30 carbon atoms.
* Represents the binding site of the benzene ring with the carbon atom in the general formula (20A) or the general formula (20B). ) In the organic electroluminescence device according to claim 1,
R ₁₉ , R ₂₀ and R _{31 to} R ₃₈ are hydrogen atoms,
Organic electroluminescence element. In the organic electroluminescence device according to claim 1,
R _{1 to} R ₈ are hydrogen atoms,
Organic electroluminescence element. In the organic electroluminescence device according to claim 1,
R _{1 to} R ₈ , R ₁₉ , R ₂₀ and R _{31 to} R ₃₈ are hydrogen atoms,
Organic electroluminescence element. In the organic electroluminescence device according to any one of claims 1 to 4.
X ₁ is a sulfur atom,
Organic electroluminescence element. In the organic electroluminescence device according to any one of claims 1 to 5.
The second compound M2 is a delayed fluorescent compound.
Organic electroluminescence element. In the organic electroluminescence device according to any one of claims 1 to 6.
Z ₂₁ and Z ₂₂ are fluorine atoms,
Organic electroluminescence element. The organic electroluminescence device according to any one of claims 1 to 7.
R ₂₁ , R ₂₃ , R ₂₄ , and R ₂₆ are independently substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, or substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, respectively. ,
Organic electroluminescence element. The organic electroluminescence device according to any one of claims 1 to 8.
The light emitting layer further contains the third compound M3.
Wherein the singlet energy _S 1 (MAT3) of the third compound M3, the second compound singlet energy _S 1 of M2 (Mat2) and but satisfies the following equation (Equation 2),
Organic electroluminescence element.
_{S 1 (Mat3)> S 1} (Mat2) ... ( number 2) The organic electroluminescence device according to any one of claims 1 to 9.
The light emitting layer does not contain a metal complex.
Organic electroluminescence element. An electronic device equipped with the organic electroluminescence device according to any one of claims 1 to 10.