CN111909146B

CN111909146B - Compound and application thereof, and organic electroluminescent device comprising compound

Info

Publication number: CN111909146B
Application number: CN201910374446.3A
Authority: CN
Inventors: 李之洋; 黄鑫鑫
Original assignee: Beijing Eternal Material Technology Co Ltd
Current assignee: Beijing Eternal Material Technology Co Ltd
Priority date: 2019-05-07
Filing date: 2019-05-07
Publication date: 2024-07-19
Anticipated expiration: 2039-05-07
Also published as: CN111909146A

Abstract

The invention discloses a compound and application thereof, and an organic electroluminescent device comprising the same, wherein the compound has a structure shown in a formula (I), the compound is used as a luminescent material in the organic electroluminescent device, the organic electroluminescent device comprises a substrate, a first electrode, a second electrode and at least one organic layer interposed between the first electrode and the second electrode, and any one or at least two of the compounds are contained in the organic layer; the compound has better electron transmission capability, can realize carrier balance, is used for an organic electroluminescent device, can effectively reduce the starting voltage and improves the luminous efficiency.

Description

Compound and application thereof, and organic electroluminescent device comprising compound

Technical Field

The invention relates to the technical field of organic electroluminescence, in particular to a compound and application thereof, and an organic electroluminescent device comprising the compound.

Background

Optoelectronic devices based on organic materials have become increasingly popular in recent years. The inherent flexibility of organic materials makes them very suitable for fabrication on flexible substrates, which can be designed to produce aesthetically pleasing and cool optoelectronic products, as desired, with no comparable advantages over inorganic materials. Examples of such organic optoelectronic devices include Organic Light Emitting Diodes (OLEDs), organic field effect transistors, organic photovoltaic cells, organic sensors, and the like. Among them, OLED has been developed particularly rapidly, and has been commercially successful in the field of information display. OLED can provide three colors of red, green and blue with high saturation, and the full-color display device manufactured by the OLED does not need extra backlight source, and has the advantages of colorful, light, thin, soft and the like.

The OLED device core is a thin film structure containing a plurality of organic functional materials. Common functionalized organic materials are: a hole injecting material, a hole transporting material, a hole blocking material, an electron injecting material, an electron transporting material, an electron blocking material, a light emitting host material, a light emitting guest (dye), and the like. When energized, electrons and holes are injected, transported to the light emitting region, respectively, and recombined therein, thereby generating excitons and emitting light.

Various organic materials have been developed, and various peculiar device structures are combined, so that carrier mobility can be improved, carrier balance can be regulated, electroluminescent efficiency can be broken through, and device attenuation can be delayed. For quantum mechanical reasons, common fluorescent emitters emit light mainly by singlet excitons generated when electrons and air are combined, and are still widely applied to various OLED products. Some metal complexes, such as iridium complexes, can emit light using both triplet and singlet excitons, known as phosphorescent emitters, and can have energy conversion efficiencies up to four times greater than conventional fluorescent emitters. The thermal excitation delayed fluorescence (TADF) technique can achieve higher luminous efficiency by promoting transition of triplet excitons to singlet excitons, and still effectively utilizing triplet excitons without using a metal complex. The thermal excitation sensitized fluorescence (TASF) technology adopts a material with TADF property, and sensitizes the luminophor in an energy transfer mode, so that higher luminous efficiency can be realized.

CN107814805A discloses a pyrimidoindole derivative and an organic electroluminescent device thereof, and relates to the technical field of organic photoelectric materials. The pyrimidoindole derivative provided by the invention is characterized in that indole and pyrimidine are connected in parallel, on the basis, two benzene rings are connected in parallel with the benzene ring of the indole to form a phenanthrene structure, so that the pyrimidoindole derivative has stronger stability, and the pyrimidoindole derivative is used as a parent nucleus structure, and the physical properties of the pyrimidoindole derivative are further improved by changing the connected groups of the pyrimidoindole derivative, so that a series of pyrimidoindole derivatives are obtained. The compound is a main material with excellent performance, has a simple preparation method and easily obtained raw materials, can be applied to OLED devices, can improve the luminous efficiency of the devices, reduce the driving voltage and prolong the service life of the devices, but the driving voltage of the devices still needs to be reduced and the service life still needs to be prolonged.

KR1020140141071A discloses a phenanthroline carbazole derivative and an organic electroluminescent device thereof, and the mother nucleus structure of the invention is a phenanthroline carbazole structure, so that the hole transmission property of the mother nucleus structure is reduced, but the driving voltage of the mother nucleus structure is still to be reduced, and the service life of the mother nucleus structure is still to be prolonged.

As OLED products continue to enter the market, there is an increasing demand for the performance of such products. The currently used OLED materials and device structures cannot completely solve the problems of OLED product efficiency, lifetime, cost, etc. The researchers of the present invention have discovered a smart molecular design through careful thought and continuous experimentation and are described in detail below. Surprisingly, the disclosed compounds are well suited for application to OLEDs and to enhance the performance of the device.

Disclosure of Invention

In view of the deficiencies of the prior art, it is an object of the present invention to provide a compound having the structure of formula (I):

In formula (I), X ¹、X²、X³ and X ⁴ are each independently selected from CR ² or a nitrogen atom, and at least one of X ¹、X²、X³ and X ⁴ is a nitrogen atom;

In formula (I), X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are CR ¹;

Ar ¹ in the formula (I) is a substituted or unsubstituted C3-C30 electron-deficient heteroaryl;

In the formula (I), R ¹ and R ² are each independently selected from any one of hydrogen, C1-C12 alkyl, C3-C12 cycloalkyl, C1-C12 alkoxy, halogen, cyano, nitro, hydroxyl, silane group, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, and at least one R ¹ or R ² is a structure shown in the formula (II):

In the formula (I) or the formula (II), L ¹ and L are independently selected from any one of single bond, substituted or unsubstituted C6-C30 arylene and substituted or unsubstituted C3-C30 heteroarylene;

In the formula (II), ar ² and Ar ³ are each independently selected from any one of substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, and Ar ² and Ar ³ are not in a ring;

". Times" represents the site of attachment to the parent nucleus;

The substituent group of the substituent is selected from any one of halogen, C1-C10 alkyl or cycloalkyl, C2-C10 alkenyl, C1-C6 alkoxy or thioalkoxy, C6-C30 monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group, and C3-C30 monocyclic heteroaromatic hydrocarbon or condensed ring heteroaromatic hydrocarbon group.

The compound provided by the invention has the advantages that the mother nucleus in the compound integrates excellent chemical property and physical property of phenanthrene ring, nitrogen-containing six-membered aromatic heterocycle and pyrrole ring, and the nitrogen atom on the pyrrole ring has higher electron-rich property, so that the compound has good charge transmission property and electron donating property, and the compound has better stability, and is matched with a specific arylamine electron donating group and an electron-deficient group substituted on the pyrrole nitrogen atom for use, so that the balance of carriers is realized, excitons are formed on a luminescent layer to the greatest extent effectively, and the compound has the effects of low starting voltage, high luminous efficiency and long service life when being used in an organic electroluminescent device; the introduction of the arylamine structure leads the HOMO of the molecule to be obviously improved, thereby reducing the voltage of the device; the electron-deficient group is connected with the nitrogen atom on the pyrrole ring, so that the electron transmission of molecules is considered, and the balance of carriers is realized by the molecular structure; the selected parent nucleus structure has a higher conjugated structure, so that the rigid structure of the molecule is increased, the molecule has better electrochemical stability, and the service life of the device is prolonged.

The "substituted substituent" referred to in the present invention is explained as follows: when the "substituted or unsubstituted" group is a substituted group, the substituent on the group is a "substituted substituent", and the range of the substituent is as described in the preceding paragraph, and the same meaning applies when the same expression is referred to below. Illustratively, when the Ar ¹ group is selected from cyano-substituted C3-C30 electron-deficient heteroaryl groups, the cyano group on the C3-C30 electron-deficient heteroaryl group is the "substituted substituent".

In the present invention, R ¹ and R ² represent only a range of substituents, and it is not considered that all groups selected from CR ¹ or all groups selected from CR ² in the compound are the same, and it should be understood that X¹、X²、X³、X⁴、X⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² may be the same or different, and the same meaning will be given below when similar descriptions are referred to.

Preferably, in formula (I), only one of X ¹、X²、X³ and X ⁴ is a nitrogen atom, because the introduction of the excessive nitrogen atom may deteriorate hole transport property of the molecule, and may easily cause unbalanced transport of carriers, resulting in degradation of device performance.

Preferably, in formula (I), at least 10 of said X¹、X²、X³、X⁴、X⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are CH.

In the invention, at least 7 of R ¹ in X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are hydrogen, 7 of R ¹ in X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are hydrogen, one of R ¹ is a structure of formula (II) and 8 of R ¹ are hydrogen, and the aim of the arrangement is that unstable factors in a molecular electrochemical environment are increased due to the introduction of excessive functional group substitution, the service life of a device is influenced, and a compound with larger molecular weight is not easy to evaporate, so that the compound with simple structure is designed as far as possible on the premise of not influencing the carrier balance and luminous efficiency of the compound.

Preferably, in formula (I), R ² of at least one of X ¹、X²、X³ and X ⁴ is a structure represented by formula (II);

Preferably, R ² of only one of X ¹、X²、X³ and X ⁴ is a structure represented by formula (II).

In the present invention, when R ² is defined as a structure represented by formula (II), that is, R ¹ is not limited, that is, R ¹ is exemplified by any one selected from hydrogen, C1-C12 alkyl, C3-C12 cycloalkyl, C1-C12 alkoxy, halogen, cyano, nitro, hydroxy, silyl, amino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, preferably hydrogen.

Preferably, R ¹ of at least one of X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² is a structure represented by formula (II);

preferably, R ¹ of only one of X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² is a structure represented by formula (II).

In the present invention, when R ¹ is defined as a structure represented by formula (II), that is, R ² is not limited, that is, R ² is exemplified by any one selected from hydrogen, C1-C12 alkyl, C3-C12 cycloalkyl, C1-C12 alkoxy, halogen, cyano, nitro, hydroxy, silyl, amino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, preferably hydrogen.

Preferably, the compounds have the following 3-1 to 3-12 structures:

Wherein L ¹、L、Ar¹、Ar² and Ar ³ each independently have the same defined ranges as described above.

Preferably, each of L ¹ and L is independently selected from any one of a single bond, a substituted or unsubstituted C6 to C30 arylene group;

preferably, the substituted or unsubstituted C6-C30 arylene group is any one selected from the following structures:

"represents the bonding position to a nitrogen atom or Ar ¹ group, and the expression of the" - "drawn ring structure indicates that the attachment site is located at any position on the ring structure capable of bonding;

Preferably, the L ¹ is a single bond.

Preferably, L is a single bond.

Preferably, ar ¹ is a substituted or unsubstituted C3-C13 electron-deficient heteroaryl group;

Preferably, ar ¹ is selected from any one of the following structures (2-1) - (2-4):

In the formula (2-1), Z ¹、Z²、Z³、Z⁴ and Z ⁵ are each independently selected from CR ³ or an N atom, and at least one of Z ¹、Z²、Z³、Z⁴ and Z ⁵ is an N atom,

In the formula (2-2), Z ⁶、Z⁷、Z⁸、Z⁹、Z¹⁰、Z¹¹、Z¹² and Z ¹³ are each independently selected from CR ³ or an N atom, and at least one of Z ⁶、Z⁷、Z⁸、Z⁹、Z¹⁰、Z¹¹、Z¹² and Z ¹³ is an N atom,

In the formula (2-3), Z ¹⁴、Z¹⁵、Z¹⁶、Z¹⁷、Z¹⁸、Z¹⁹、Z²⁰、Z²¹、Z²² and Z ²³ are each independently selected from CR ³ or an N atom, and at least one of Z ¹⁴、Z¹⁵、Z¹⁶、Z¹⁷、Z¹⁸、Z¹⁹、Z²⁰、Z²¹、Z²² and Z ²³ is an N atom,

In the formula (2-4), Z ²⁴、Z²⁵、Z²⁶、Z²⁷、Z²⁸、Z²⁹、Z³⁰、Z³¹、Z³² and Z ³³ are each independently selected from CR ³ or an N atom, and at least one of Z ²⁴、Z²⁵、Z²⁶、Z²⁷、Z²⁸、Z²⁹、Z³⁰、Z³¹、Z³² and Z ³³ is an N atom,

Wherein R ³ is any one of hydrogen, C1-C12 alkyl, C1-C12 alkoxy, halogen, cyano, nitro, hydroxy, silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

In the present invention, as is well known in the art, one Z in each of the structures of formulas (2-1), (2-2), (2-3) and (2-4) is an unsubstituted carbon atom for attachment to a linking site.

Preferably, ar ¹ is a (2-1) or (2-2) structure;

Preferably, in formula (2-1), at least two of Z ¹、Z²、Z³、Z⁴ and Z ⁵ are N atoms;

Preferably, in formula (2-2), at least two of Z ⁶、Z⁷、Z⁸、Z⁹、Z¹⁰、Z¹¹、Z¹² and Z ¹³ are N atoms;

Preferably, ar ¹ is any one of quinazolinyl and derivative groups thereof, triazinyl and derivative groups thereof, pyrimidinyl and derivative groups thereof, quinoxalinyl and derivative groups thereof, or pyridinyl and derivative groups thereof;

preferably, ar ¹ is a substituted or unsubstituted quinazoline or triazine;

Preferably, each of Ar ² and Ar ³ is independently selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, terphenyl, phenanthrene, dibenzofuran, dibenzothiophene, or carbazole.

Preferably, ar ¹ is selected from any one of the following structures A1-A11:

The substituent groups are selected from any one of halogen, C1-C10 alkyl or cycloalkyl, C2-C10 alkenyl, C1-C6 alkoxy or thioalkoxy, C6-C30 monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group, and C3-C30 monocyclic heteroarene or condensed ring heteroarene group;

preferably, ar ¹ is selected from any one of the following structures B1-B15:

Preferably, the compounds have the following P1-P74 structure:

It is a second object of the present invention to provide the use of a compound according to one of the objects as a material for a light-emitting layer in an organic electroluminescent device.

It is a further object of the present invention to provide an organic electroluminescent device comprising a first electrode, a second electrode and an organic layer between the first electrode and the second electrode, the organic layer comprising any one or a combination of at least two of the compounds according to one of the objects.

The organic electroluminescent device provided by the invention comprises a first electrode, a second electrode and an organic material layer positioned between the electrodes. The organic material may in turn be divided into a plurality of regions. For example, the organic material layer may include a hole transport region, a light emitting layer, and an electron transport region.

In particular embodiments, a substrate may be used below the first electrode or above the second electrode. The substrates are all glass or polymer materials with excellent mechanical strength, thermal stability, water resistance and transparency. A Thin Film Transistor (TFT) may be provided on a substrate for a display.

The first electrode may be formed by sputtering or depositing a material serving as the first electrode on the substrate. When the first electrode is used as the anode, an oxide transparent conductive material such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), tin dioxide (SnO 2), zinc oxide (ZnO), or the like, and any combination thereof may be used. When the first electrode is used as the cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag) and any combination thereof can be used.

The organic material layer may be formed on the electrode by vacuum thermal evaporation, spin coating, printing, or the like. The compounds used as the organic material layer may be small organic molecules, large organic molecules and polymers, and combinations thereof.

The hole transport region is located between the anode and the light emitting layer. The hole transport region may be a Hole Transport Layer (HTL) of a single layer structure including a single layer hole transport layer containing only one compound and a single layer hole transport layer containing a plurality of compounds. The hole transport region may have a multilayer structure including at least one of a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), and an Electron Blocking Layer (EBL).

The material of the hole transport region may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or conductive dopant containing polymers such as polystyrene, polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphorsulfonic acid (Pani/CSA), polyaniline/poly (4-styrenesulfonate) (Pani/PSS), aromatic amine derivatives such as the compounds shown below HT-1 to HT-34, or any combination thereof.

The hole injection layer is located between the anode and the hole transport layer. The hole injection layer may be a single compound material or a combination of a plurality of compounds. For example, the hole injection layer may employ one or more of the compounds HT-1 through HT-34 described above, or one or more of the compounds HI1 through HI3 described below; one or more of the compounds HT-1 to HT-34 may also be used to dope one or more of the compounds HI1 to HI3 described below.

The luminescent layer comprises luminescent dyes (i.e. dopants) that can emit different wavelength spectra, and may also comprise Host materials (Host). The light emitting layer may be a single color light emitting layer emitting a single color of red, green, blue, or the like. The plurality of monochromatic light emitting layers with different colors can be arranged in a plane according to the pixel pattern, or can be stacked together to form a color light emitting layer. When the light emitting layers of different colors are stacked together, they may be spaced apart from each other or may be connected to each other. The light emitting layer may be a single color light emitting layer capable of simultaneously emitting different colors such as red, green, and blue.

According to different technologies, the luminescent layer material can be made of different materials such as fluorescent electroluminescent material, phosphorescent electroluminescent material, thermal activation delayed fluorescence luminescent material and the like. In an OLED device, a single light emitting technology may be used, or a combination of different light emitting technologies may be used. The different luminescent materials classified by the technology can emit light of the same color, and can also emit light of different colors.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescence technology. The luminescent layer host material is selected from, but not limited to, one or more of GPH-1 to GPH-80.

In one aspect of the invention, the light-emitting layer employs phosphorescent electroluminescence technology. The luminescent layer phosphorescent dopant thereof may be selected from, but is not limited to, one or more combinations of the RPD-1 through RPD-28 listed below.

May be selected from, but not limited to, one or more of the combinations of GPD-1 to GPD-47 listed below.

The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be an Electron Transport Layer (ETL) of a single layer structure including a single layer electron transport layer containing only one compound and a single layer electron transport layer containing a plurality of compounds. The electron transport region may also be a multilayer structure including at least one of an Electron Injection Layer (EIL), an Electron Transport Layer (ETL), and a Hole Blocking Layer (HBL).

In one aspect of the invention, the electron transport layer material may be selected from, but is not limited to, combinations of one or more of ET-1 through ET-57 listed below.

An electron injection layer may also be included in the device between the electron transport layer and the cathode, the electron injection layer material including, but not limited to, a combination of one or more of the following compounds:

LiQ、LiF、NaCl、CsF、Li2O、Cs2CO3、BaO、Na、Li、Ca。

Compared with the prior art, the invention has the following beneficial effects:

The compound provided by the invention is used in an organic electroluminescent device, so that the organic electroluminescent device has the effects of low starting voltage, high luminous efficiency and long service life, the starting voltage is less than or equal to 4.7V, the current efficiency is more than or equal to 15cd/A, and the LT95 service life is more than or equal to 68h.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

The synthetic route of the compounds of formula (I) according to the invention:

Wherein, X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are CR ¹;

Each of X ¹、X²、X³ and X ⁴ is independently selected from CR ² or a nitrogen atom, and at least one of X ¹、X²、X³ and X ⁴ is a nitrogen atom;

HA2 is any one of Cl-L ¹-Ar¹、Br-L¹-Ar¹ or I-L ¹-Ar¹,

L ¹ and L are each independently selected from any one of a single bond, a substituted or unsubstituted C6-C30 arylene group, a substituted or unsubstituted C3-C30 heteroarylene group,

Ar ¹ is a substituted or unsubstituted C3-C30 electron-deficient heteroaryl;

Ar ² and Ar ³ are each independently selected from any one of substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, and Ar ² and Ar ³ are not cyclic with each other;

the synthesis method of the compound provided by the present invention belongs to a conventional method, and a person skilled in the art can synthesize the compound by the prior art, and by way of example, several typical synthesis methods of the compound in the following preparation examples are provided.

All compounds of the synthesis process not mentioned in the present invention are commercially available starting products. The solvents and reagents used in the present invention, such as methylene chloride, petroleum ether, ethanol, tetrahydrofuran, N-dimethylacetamide, anhydrous magnesium sulfate, pyridine boric acid, 9-phenanthreneboric acid, and other chemical reagents, can be purchased from domestic chemical product markets, such as from national pharmaceutical group reagent company, TCI company, shanghai Bi De medical company, carboline reagent company, and the like. In addition, the person skilled in the art can synthesize the compounds by known methods.

Preparation example 1

(1) Preparation of Compound P2-A:

9-phenanthreneboronic acid (100 mmol), 2-bromo-4-chloronitropyridine (100 mmol), potassium carbonate (150 mmol), dioxane (300 ml) and water (50 ml) are added into a reaction bottle, the mixture is heated to reflux for 5h, the reaction of the raw materials is detected by Thin Layer Chromatography (TLC), after water quenching, dichloromethane is added for extraction, and an organic phase is concentrated and then purified by column chromatography to obtain a product of the target compound P2-A.

(2) Preparation of Compound P2-B

The compound P2-A (80 mmol), triphenylphosphine (400 mmol) and o-dichlorobenzene (400 ml) are added into a reaction bottle, reflux reaction is carried out for 15h, the reaction is monitored by Thin Layer Chromatography (TLC), after the temperature is reduced, the reaction solution is dried by spin drying after passing through silica gel, and the P2-B is obtained by column chromatography analysis.

(3) Preparation of Compounds P2-C

The compound P2-B (50 mmol), 2-chloro-4- (2-naphthyl) quinazoline (55 mmol), cesium carbonate (100 mmol) and DMF (500 ml) are reacted under reflux for 6h, after the reaction is monitored by Thin Layer Chromatography (TLC), the reaction is poured into water, and the filter cake after filtration is washed with ethanol to obtain P2-C.

(4) Preparation of Compound P2

Compound P2-C (30 mmol), diphenylamine (50 mmol), sodium t-butoxide (80 mmol), tris (dibenzylideneacetone) dipalladium (0.5 g), 2-dicyclohexylphosphine-2 ',6' -dimethoxy-biphenyl (0.5 g) were added to a reaction flask containing 300ml of toluene, heated to reflux for 5h, monitored by Thin Layer Chromatography (TLC) to complete the reaction, cooled, and the reaction mixture was concentrated over silica gel to give a brown oil. Purifying by column chromatography to obtain pale yellow solid P2.

Characterization of the structure of P2 obtained in step (2) with nuclear magnetism, the results are as follows:

nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.08(dd,J＝14.6,3.4Hz,1H),8.98(dd,J＝14.3,3.6Hz,1H),8.46(t,J＝2.9Hz,1H),8.23-7.9(m,9H),7.86-7.41(m,8H),7.31–7.17(m,4H),7.14–6.93(m,6H),6.48(dd,J＝15.0,3.1Hz,1H).

Preparation example 2

(1) Preparation of Compound P8-A:

P2-B (50 mmol), 2- (3-fluorophenyl) -4- (2-naphthyl) quinazoline (55 mmol), cesium carbonate (100 mmol) and DMF (500 ml) prepared in preparation example 1 are added into a reaction bottle to carry out reflux reaction for 6h, after the reaction is monitored by Thin Layer Chromatography (TLC), the reaction solution is poured into water, and a filter cake after filtration is washed with ethanol to obtain P8-A.

(2) Preparation of Compound P8

Compound P8-a (30 mmol), diphenylamine (50 mmol), sodium t-butoxide (80 mmol), tris (dibenzylideneacetone) dipalladium (0.5 g), 2-dicyclohexylphosphine-2 ',6' -dimethoxy-biphenyl (0.5 g) were added to a reaction flask of 300ml toluene, heated to reflux for 5h, monitored by Thin Layer Chromatography (TLC) to complete the reaction, cooled, passed through silica gel and concentrated to give a brown oil. Purifying by column chromatography to obtain pale yellow solid P8.

Characterization of the structure of P8 obtained in step (2) with nuclear magnetism gave the following results:

nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.08(dd,J＝7.4,1.5Hz,1H),8.98(dd,J＝7.4,1.5Hz,1H),8.46(t,J＝1.4Hz,1H),8.28-7.93(m,10H),7.79(td,J＝7.5,1.4Hz,1H),7.74–7.51(m,9H),7.48(d,J＝7.5Hz,1H),7.24(t,J＝7.5,4H),7.08(dd,J＝7.5,1.4Hz,4H),7.04-6.93(m,2H),6.48(dd,J＝7.4,1.5Hz,1H).

Preparation example 3

The difference from synthesis example 1 is only that the diphenylamine is replaced by an equivalent amount of N-phenyl-4-benzidine, giving the product P11.

Characterization of the structure of P11 obtained in step (2) with nuclear magnetism gave the following results:

Nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.08(dd,J＝14.6,3.4Hz,1H),8.98(dd,J＝14.2,3.7Hz,1H),8.46(t,J＝2.9Hz,1H),8.22-7.91(m,9H),7.86-7.32(m,17H),7.31–7.17(m,2H),7.13-6.90(m,3H),6.48(dd,J＝15.0,3.1Hz,1H).

Preparation example 4

The difference from synthesis example 1 is only that 2-chloro-4- (2-naphthyl) quinazoline is replaced by an equivalent amount of 2-chloro-3- (3-biphenyl) quinoxaline, giving product P17.

Characterization of the structure of P17 obtained in step (2) with nuclear magnetism gave the following results:

Nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.07(dd,J＝14.6,3.4Hz,1H),8.97(dd,J＝14.3,3.6Hz,1H),8.60-8.43(m,2H),8.13(ddd,J＝29.9,14.4,3,6Hz,2H),8.00(d,J＝3.1Hz,1H),7.87-7.54(m,11H)),7.54-7.32(m,4H),7.32-7.17(m,4H),7.15-6.95(m,6H),6.47(dd,J＝14.9,3.0Hz,1H).

Preparation example 5

(1) Preparation of Compound P19-A:

P2-B (50 mmol), 2-chloro-3-phenylquinoxaline (55 mmol), cesium carbonate (100 mmol) and DMF (500 ml) prepared in preparation example 1 were added into a reaction flask and reacted for 6h under reflux, after the reaction was monitored by Thin Layer Chromatography (TLC), the reaction solution was poured into water, and the filter cake after filtration was washed with ethanol to obtain P19-A.

(2) Preparation of Compound P19

Compound P19-a (30 mmol), triphenylamine 3-borate (50 mmol), potassium carbonate (100 mmol), dioxane (300 ml), water (50 ml), tris (dibenzylideneacetone) dipalladium (0.5 g), 2-dicyclohexylphosphine-2 ',6' -dimethoxy-biphenyl (0.5 g) were added to a reaction flask containing 300ml toluene, heated to reflux for 5h, monitored by Thin Layer Chromatography (TLC) for completion of the reaction, and the reaction mixture was concentrated after passing through silica gel to give a brown oil. Purifying by column chromatography to obtain pale yellow solid P19.

Characterization of the structure of P19 obtained in step (2) with nuclear magnetism gave the following results:

Nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.05(dd,J＝14.6,3.4Hz,1H),8.95(dd,J＝14.2,3.7Hz,1H),8.54(d,J＝3.1Hz,1H),8.44-8.29(m,2H),8.12(ddd,J＝29.9,14.4,3.5Hz,2H),7.89-7.72(m,3H),7.72-7.46(m,10H),7.28-7.10(m,7H),7.10-6.90(m,6H).

Preparation example 6

Synthesis example 5 differs from synthesis example 5 only in that 2-chloro-3-phenylquinoxaline is replaced by an equivalent amount of 2-chloro-4, 6-diphenyl (1, 3, 5) triazine, giving product P28.

Characterization of the structure of P28 obtained in step (2) with nuclear magnetism gave the following results:

nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.08(dd,J＝14.6,3.4Hz,1H),8.98(dd,J＝14.2,3.7Hz,1H),8.60(d,J＝2.9Hz,1H),8.45-8.29(m,4H),8.14(ddd,J＝30.0,14.4,3.6Hz,2H),7.87(dd,J＝15.0,3.1Hz,1H),7.77-7.42(m,11H),7.33-7.13(m,7H),7.13-6.93(m,6H).

Preparation example 7

The difference from synthesis example 1 is only that 2-chloro-3-phenylquinoxaline is replaced by an equivalent amount of 3-phenyl-5- (pyridin-3-yl) bromobenzene, giving product P42.

Characterization of the structure of P42 obtained in step (2) with nuclear magnetism gave the following results:

Nuclear magnetism ¹H NMR(500MHz,Chloroform)δ:9.27-9.20(m,1H),9.08(dd,J＝14.6,3.4Hz,1H),8.98(dd,J＝14.2,3.7Hz,1H),8.76-8.63(m,1H),8.49(d,J＝3.0Hz,1H),8.39-8.26(m,3H)),8.23-8.05(m,3H),7.87(dd,J＝15.0,3.1Hz,1H),7.80-7.31(m,11H),7.30-7.13(m,7H),7.13-6.91(m,6H).

Example 1

The embodiment provides an organic electroluminescent device, which is prepared by the following steps:

the glass plate coated with the ITO transparent conductive layer was sonicated in commercial cleaners, rinsed in deionized water, and rinsed in acetone: ultrasonic degreasing in ethanol mixed solvent, baking in clean environment to completely remove water, cleaning with ultraviolet light and ozone, and bombarding surface with low-energy cation beam;

Placing the glass substrate with the anode in a vacuum cavity, vacuumizing to < 1X 10 ^-5 Pa, and sequentially vacuum thermally evaporating 10nm of HT-4:HIL-3 (97/3,w/w) mixture serving as a hole injection layer, 60nm of compound HT-4 serving as a hole transport layer and 40nm of compound P2:RPD-8 (100:3, w/w) binary mixture serving as a light-emitting layer on the anode layer film; 25nm compound ET-46:ET-57 (50/50, w/w) mixture as electron transport layer, 1nm LiF as electron injection layer, 150nm metallic aluminum as cathode. The total evaporation rate of all organic layers and LiF was controlled at 0.1 nm/sec, and the evaporation rate of the metal electrode was controlled at 1 nm/sec.

The device embodiments IVD-2 to IVD-11 were fabricated by the same method as IVD-1 except that P2 in the light emitting layer was replaced with P8, P11, P17, P19, P28, P42, P25, P47, P74, P49, respectively;

the device comparative examples CCD-1 to CCD-2 were fabricated in the same manner as in device example IVD-1, except that P2 in the light-emitting layer was replaced with C1 and C2, respectively.

Performance testing

The driving voltage and current efficiency and the lifetime of the organic electroluminescent devices prepared in examples and comparative examples were measured using a digital source meter and a luminance meter at the same luminance. Specifically, the voltage was raised at a rate of 0.1V per second, and the driving voltage, which is the voltage when the luminance of the organic electroluminescent device reached 10000cd/m ², was measured, while the current density at that time was measured; the ratio of brightness to current density is the current efficiency; the lifetime test of LT95 is as follows: the time for the luminance of the organic electroluminescent device to drop to 9500cd/m ² was measured in hours using a luminance meter maintaining a constant current at 10000cd/m ² luminance.

The results of the performance test are shown in Table 1:

TABLE 1

Device numbering	Main body material	The brightness/cd/m is required ²	Voltage/V	Current efficiency/cd/a	Lifetime (LT 95)
						Comparative example 1	C1	10000.00	5.2	16	45
Comparative example 2	C2	10000.00	5.0	14	38
						Example 1	P2	10000.00	4.4	20	75
Example 2	P51	10000.00	4.7	18	67
						Example 3	P11	10000.00	4.6	18	74
Example 4	P17	10000.00	4.5	18	72
						Example 5	P19	10000.00	4.5	17	76
Example 6	P28	10000.00	4.4	17	79
						Example 7	P42	10000.00	4.6	16	72
Example 8	P25	10000.00	4.5	16	70
						Example 9	P47	10000.00	4.7	15	68
Example 10	P74	10000.00	4.4	16	60
						Example 11	P49	10000.00	4.5	15	45

As can be seen from Table 1, the OLED devices in the examples have a starting voltage of 4.7V or less, a current efficiency of 15cd/A or more, and a LT95 lifetime of 65h or more, and the devices have higher luminous efficiency, lower starting voltage and longer lifetime;

The luminescent material of the device of comparative example 1 is replaced by C1, i.e., the mother nucleus is replaced by phenanthroline benzopyrrole, the turn-on voltage and the maximum external quantum efficiency are obviously deteriorated, because the hole transport property of the mother nucleus is deteriorated due to the electric absorption property of the phenanthroline, and the balance transport of carriers is caused, resulting in the deterioration of the device performance;

The light emitting material of the device of comparative example 2 was changed to C2, and the turn-on voltage and maximum external quantum efficiency were remarkably deteriorated because the electron transport property was enhanced, the hole type was weakened, and the electrons were excessive, and effective excitons could not be formed to transfer to the hole transport layer, resulting in deterioration of the device performance, due to the introduction of excessive nitrogen atoms in the parent nucleus structure.

The results prove that when the compound provided by the invention is used as a luminescent layer material of an OLED device, the luminescent efficiency of the device can be improved, and the starting voltage is reduced, because the compound provided by the invention uses phenanthro six-membered nitrogen-containing aromatic ring and pyrrole as a parent nucleus and is matched with specific arylamine electron donating groups and C3-C30 electron-deficient heteroaryl groups, the compound has good charge transmission performance and electron donating performance, and has better stability, and the compound is matched with the electron donating groups and electron deficient groups of the arylamine structure to be used together, so that the compound has the effects of low starting voltage, high luminescent efficiency and long service life when being used in the organic electroluminescent device.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A compound, characterized in that the compound has the structure of formula (I):

In formula (I), X ¹、X²、X³ and X ⁴ are each independently selected from CR ² or a nitrogen atom, and one of X ¹、X²、X³ and X ⁴ is a nitrogen atom;

In the formula (I), X ⁵、X⁶、X⁷、X⁸、X⁹、X¹⁰、X¹¹ and X ¹² are any one of CR ¹;L¹ which is a single bond or arylene of C6-C30;

In formula (I), ar ¹ is a substituted or unsubstituted quinazoline, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted pyridine or a substituted or unsubstituted triazine,

In formula (I), R ¹ or R ² are each independently selected from hydrogen or a structure of formula (II), and only one of each R ¹ or R ² is a structure of formula (II):

In the formula (II), ar ² and Ar ³ are each independently selected from any one of substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, and Ar ² and Ar ³ are not in a ring; l is selected from any one of single bond and arylene of C6-C30;

". Times" represents the site of attachment to the parent nucleus;

The substituent group of the substituent is selected from any one of halogen, C1-C10 alkyl or cycloalkyl, C6-C30 monocyclic aromatic hydrocarbon or condensed ring aromatic hydrocarbon group, and C3-C30 monocyclic heteroaromatic hydrocarbon or condensed ring heteroaromatic hydrocarbon group.

2. The compound of claim 1, wherein the compound has the following 3-1 to 3-12 structure:

wherein L ¹、L、Ar¹、Ar² and Ar ³ each independently have the same defined range as claim 1.

3. The compound of claim 1, wherein the C6-C30 arylene is any one selected from the group consisting of the following structures:

4. the compound of claim 1, wherein Ar ¹ is selected from any one of the following A1-a11 structures:

5. The compound of claim 1, wherein Ar ¹ is selected from any one of the following B1-B15 structures:

6. The compound of claim 1, wherein each of Ar ² and Ar ³ is independently selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, terphenyl, phenanthrene, dibenzofuran, dibenzothiophene, or carbazole.

7. A compound having the structure, characterized in that,

8. Use of a compound according to any one of claims 1-7, characterized in that the use is as a material for a light-emitting layer in an organic electroluminescent device.

9. An organic electroluminescent device, characterized in that the organic electroluminescent device comprises a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode;

the organic layer comprises any one or a combination of at least two of the compounds of any one of claims 1-7.