JP2003257674A - Organic electroluminescence element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence element of simple structure equipped with an electron blocking effect while the hole injection is maintained certainly. <P>SOLUTION: The organic electroluminescence element is composed of an anode layer 10, a cathode layer 70, and a light emitting layer 40 and hole transport layer 20 which are formed between the two electrode layers 10 and 70, wherein a hole transport material to constitute the hole transport layer 20 is formed from a conducive highpolymer and an electron receiving compound added in an amount of 0.1-5 mol% with respect to the conductive highpolymer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence device capable of emitting light with high brightness.

[0002]

2. Description of the Related Art It is known that a hole injection layer is provided between an anode layer and a hole transport layer or a light emitting layer in order to secure stability during driving of an organic electroluminescence device and improve driving life. ing. The material of the hole injection layer is required to have a function of improving the electrical connection between the anode layer and the light emitting layer and reducing the driving voltage of the organic electroluminescence element.

Conventionally, as such a material,

[0004]

[Chemical 11]

A hole-injecting low molecule such as copper phthalocyanine (hereinafter also referred to as CuPc) shown in [Chemical formula 11],

[0006]

[Chemical 12]

A hole injecting polymer such as poly (3,4) ethylenedioxythiophene (hereinafter also referred to as PEDT) shown in [Chemical Formula 12] is used. In addition, JP-A-200
0-36390 and JP-A-2000-150169
It is known from the publication that an aromatic amine-containing polymer to which an electron-accepting compound is added is used as a material for a hole injection layer. In this case, charge transfer occurs between the hole-transporting polymer and the electron-accepting compound to generate holes, and a hole-injecting substance composed of the hole-transporting polymer and the electron-accepting compound is formed. The electrical conductivity is increased, which improves the electrical connection between the anode layer and the light emitting layer.

[0008]

However, in the case of increasing the electrical junction as described above, depending on the electron transfer reaction between the hole transporting polymer and the electron accepting compound,
Since the electric conductivity of the hole injection layer is improved, the mobility of electrons is increased and the electron blocking effect is reduced.
Therefore, the opportunity of recombination of holes and electrons in the light emitting layer is suppressed, and the emission brightness of the organic electroluminescent element thus formed may be reduced.
Therefore, the light emission efficiency defined by the light emission luminance with respect to the drive voltage may decrease.

Therefore, it is conceivable to stack an electron block layer on the anode layer side of the light emitting layer to form an organic electroluminescence device, but such a structure causes a problem that the number of steps for manufacturing the device increases.

In view of the above problems, it is an object of the present invention to provide an organic electroluminescence device having a simple structure having an electron blocking effect while maintaining reliable hole injection.

[0011]

In order to solve the above problems, the present invention provides an organic electroluminescent device having both electrode layers of an anode layer and a cathode layer, a light emitting layer formed between the both electrode layers, and a hole transport layer. As the hole-transporting substance forming the hole-transporting layer of the luminescence device, a conductive polymer to which an electron-accepting compound is added in an amount of 0.1 to 5 mol% based on the conductive polymer is used. .

In this structure, the electric charge transfer between the conductive polymer and the electron-accepting compound improves the electrical conductivity of the hole-transporting substance composed of the conductive polymer and the electron-accepting compound. The hole transport layer can have an electron blocking effect. Therefore, holes are surely injected from the anode layer, and electrons injected from the cathode layer are suppressed from passing through the light emitting layer as they are, so that holes and electrons are recombined in the light emitting layer. Opportunities to do so increase. Therefore, the emission brightness can be improved without increasing the number of thin film layers forming the organic electroluminescence element.

By the way, as the conductive polymer,
Suitable examples include a polyfluorene compound having a repeating unit represented by [Chemical Formula 1].

As the electron-accepting compound, simple halogens such as bromine, chlorine and iodine, Lewis acids such as boron trifluoride, phosphorus pentafluoride, antimony pentafluoride and arsenic pentafluoride, and nitric acid. Protonic acid such as sulfuric acid, perchloric acid, hydrochloric acid, hydrofluoric acid, fluorosulfuric acid, trifluoromethanesulfonic acid, or iron trichloride, molybdenum pentachloride, tungsten pentachloride, tin tetrachloride, molybdenum pentafluoride, penta It is possible to use transition metal halides such as ruthenium fluoride, tantalum pentabromide and tin tetraiodide. Since these compounds have strong oxidizing power, they have an excellent electron accepting property.

As the above-mentioned electron-accepting compound,
Tetracyanoethylene represented by [Chemical Formula 2] (hereinafter TCN
Also called E. ), [Chemical Formula 3] 7,7,8,8-
Tetracyanoquinodimethane (hereinafter also referred to as TCNQ), tetracyanonaphthoquinodimethane (hereinafter also referred to as TNAP) represented by [Chemical formula 4], and hexacyanobutadiene (hereinafter also referred to as HCBD) represented by [Chemical formula 5]. , Hexacyanotrimethylcyclopropane (hereinafter also referred to as TCTMCP) represented by [Chemical Formula 6], TCQQ represented by [Chemical Formula 7], 2,3-
Dichloro-5,6-dicyano-1,4-benzoquinone (hereinafter also referred to as DDQ), [FeC
It is also possible to use a conductive organic compound such as p ₂ ] PF ₆ .

Furthermore, as the electron-accepting compound, a compound having a molecular structure represented by the general formula [Chemical Formula 10] can be used.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a basic structure of an organic electroluminescence device having a device structure laminated in multiple layers for the purpose of improving luminous efficiency. The element structure of the organic electroluminescence element is such that each of the hole transport layer 20, the electron block layer 30, the light emitting layer 40, the hole block layer 50, and the electron transport layer 60 is formed on the anode layer 10 formed on a substrate (not shown). The thin film layer has a multi-layered structure in which the anode layer 10 and the cathode layer 70 are sequentially laminated between both electrode layers, and the light emitting layer 40 includes a light emitting layer doping agent 41 and a light emitting layer host agent 42. Has been done.

In the element structure shown in FIG. 1, for the anode layer 10, a transparent conductive material formed on a transparent insulating support such as a glass substrate is used, and the material thereof is tin oxide or oxide. Indium, indium tin oxide (I
Conductive oxides such as TO) or metals such as gold, silver and chromium, inorganic conductive substances such as copper iodide and copper sulfide,
Conductive polymers such as polythiophene, polypyrrole, and polyaniline can be used.

When the cathode layer 70 is made of a transparent material, the anode layer 10 may be made of an opaque material.

In addition, in the device structure shown in FIG.
The cathode layer 70 includes niobium, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, boron, aluminum,
A simple substance such as copper, silver or gold or an alloy can be used. Further, these may be laminated and used. It can also be formed by a wet process using tetrahydroaluminate. In this case, examples of the tetrahydroaluminate used for the cathode layer 70 include lithium aluminum hydride, potassium aluminum hydride, magnesium aluminum hydride, and aluminum calcium hydride. Among these, lithium aluminum hydride is particularly excellent in the electron injection property into the electron transport layer.

The hole transport layer 20 is a layer for transporting holes injected from the anode layer 10 and is an organic layer containing a hole transporting organic substance. As an example of the hole transport layer organic material, a polyfluorene compound having a repeating unit represented by [Chemical Formula 1], for example,

[0022]

[Chemical 13]

Dinormal octyl polyfluorene represented by the formula

[0024]

[Chemical 14]

Poly (N-vinylcarbazole) represented by [Chemical Formula 14] (hereinafter also referred to as PVK),

[0026]

[Chemical 15]

It is preferably composed of a polymer such as poly (para-phenylene vinylene) shown in [Chemical Formula 15].

Alternatively, CuPc shown in [Chemical Formula 11],

[0029]

[Chemical 16]

Carbazole biphenyl (hereinafter also referred to as CBP) shown in [Chemical Formula 16],

[0031]

[Chemical 17]

N, N'-diphenyl-shown in [Chemical Formula 17]
N, N′-bis (1-naphthyl) -1,1′-biphenyl-4,4′-diamine (hereinafter also referred to as NPD),

[0033]

[Chemical 18]

N, N'-diphenyl-shown in [Chemical Formula 18]
N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (hereinafter also referred to as TPD),

[0035]

[Chemical 19]

4,4'-bis (10-
Smaller molecules such as phenothiazinyl) biphenyl can also be used.

By the way, when the hole transport layer is formed by using a conductive polymer doped with an electron-accepting compound as the hole-transporting substance, an electron between the conductive polymer and the electron-accepting compound is formed. Due to the transfer reaction, charge transfer occurs and holes are generated, and the electric conductivity of the hole transport layer is improved. This can further improve the electrical connection between the anode layer and the light emitting layer.

At this time, when the amount of the electron-accepting compound added to the conductive polymer is set to 0.1 to 5 mol%, the hole-transporting layer composed of these has an electron blocking effect. be able to. Therefore, the chances of recombination of holes and electrons in the light emitting layer increases, and the emission brightness of the organic electroluminescence element can be improved.

As the conductive polymer used for the hole transport layer, for example, dinormal octyl polyfluorene represented by the chemical formula 13

[0040]

[Chemical 20]

Poly (2-methoxy-5-) shown in [Chemical Formula 20]
Examples thereof include conductive polymers such as (2-ethylhexoxy) -1,4-phenylene vinylene (hereinafter also referred to as MEH-PPV).

As the electron-accepting compound used for the hole transport layer, TCNE shown in [Chemical Formula 2], TCNQ shown in [Chemical Formula 3], TNAP shown in [Chemical Formula 4], and [Chemical Formula 5] are shown. HCBD, TCTMCP shown in [Chemical 6],
TCQQ shown in [Chemical Formula 7], DDQ shown in [Chemical Formula 8], [FeCp ₂ ] PF ₆ shown in [Chemical Formula 9],

[0043]

[Chemical 21]

The tris (4-bromophenyl) aminium hexachloroantimonate shown in [Chemical Formula 21] (hereinafter referred to as TB
Also called PAH. ), Halogen simple substance such as bromine, chlorine, iodine, Lewis acid such as boron trifluoride, phosphorus pentafluoride, antimony pentafluoride, arsenic pentafluoride, nitric acid, sulfuric acid, perchloric acid, hydrochloric acid, hydrofluoric acid, fluoro Sulfuric acid, protonic acid such as trifluoromethanesulfonic acid, or iron trichloride, molybdenum pentachloride, tungsten pentachloride, tin tetrachloride, molybdenum pentafluoride, ruthenium pentafluoride, tantalum pentabromide,
Mention may be made of transition metal halides such as tin tetraiodide.

The electron block layer 30 is the cathode layer 70.
Electrons injected into the light emitting layer 40 from the anode layer 10 as they are.
It is a layer for blocking electrons in order to prevent it from passing through, and is composed of an electron blocking substance. Examples of the electron blocking substance include P shown in [Chemical Formula 14].
VK, poly (para-phenylene vinylene) shown in [Chemical Formula 15], CBP shown in [Chemical Formula 16], NP shown in [Chemical Formula 17]
D, TPD shown in [Chemical formula 18], 4, shown in [Chemical formula 19]
4'-bis (10-phenothiazinyl) biphenyl,

[0046]

[Chemical formula 22]

2,4,6-triphenyl-1,3,5-triazole represented by the formula:

[0048]

[Chemical formula 23]

Examples include fluorene shown in [Chemical Formula 23].

Further, the light emitting layer 40 has a doping agent 41 and a host agent 42, and in order to uniformly disperse the doping agent 41 and the host agent 42, it is possible to add a binder polymer. In the host agent 42, holes and electrons injected from the anode layer 10 and the cathode layer 70, respectively, are emitted from the light emitting layer 4.
A polyfluorene compound having a repeating unit represented by [Chemical Formula 1] (for example, dinormaloctylpolyfluorene represented by [Chemical Formula 13]), which is a substance that is activated and acts as an exciton when recombined at 0. PVK shown in Chemical formula 14], CBP shown in Chemical formula 16

[0051]

[Chemical formula 24]

Poly (3-hexylthiophene) shown in [Chemical Formula 24],

[0053]

[Chemical 25]

1,3,5-tri (5-
(4-tert-butylphenyl) -1,3,4-oxadiazole) phenyl (hereinafter also referred to as OXD-1),

[0055]

[Chemical formula 26]

1,3-di (5-
(4-tert-butylphenyl) -1,3,4-oxadiazole) phenyl (hereinafter also referred to as OXD-7),

[0057]

[Chemical 27]

2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1, shown in [Chemical Formula 27],
3,4-oxadiazole, (hereinafter also referred to as PBD),

[0059]

[Chemical 28]

N-phenylpolycarbazole represented by [Chemical Formula 28],

[0061]

[Chemical 29]

Bathocuproine (hereinafter referred to as B)
Also called CP. ),

[0063]

[Chemical 30]

Examples include tris (8-hydroxyquinolinato) aluminum (hereinafter also referred to as Alq3) shown in [Chemical Formula 30] and the like.

On the other hand, the dopant 41 of the light emitting layer 40 is a substance which emits phosphorescence by the excitation energy of the host agent 42 which is an exciton,

[0066]

[Chemical 31]

A tri (2phenylpyridine) iridium complex represented by [Chemical Formula 31] (hereinafter also referred to as Ir (ppy) ₃ ),

[0068]

[Chemical 32]

[0069]

[Chemical 33]

[0070]

[Chemical 34]

[0071]

[Chemical 35]

[0072]

[Chemical 36]

[0073]

[Chemical 37]

(In the chemical formula [Chemical Formula 37], acac is

[0075]

[Chemical 38]

The functional group represented by [Chemical Formula 38] is shown below. following
The same applies to the chemical formulas shown in [Chemical Formula 39] to [Chemical Formula 43]. )

[0077]

[Chemical Formula 39]

[0078]

[Chemical 40]

[0079]

[Chemical 41]

[0080]

[Chemical 42]

[0081]

[Chemical 43]

Iridium complex compounds represented by [Chemical Formula 32] to [Chemical Formula 37] and [Chemical Formula 39] to [Chemical Formula 43],

[0083]

[Chemical 44]

2, 3, 7, 8, 12, shown in [Chemical 44]
13,17,18-octaethyl-21H, 23H-platinum (II) porphine (hereinafter also referred to as PtOEP),

[0085]

[Chemical formula 45]

3- (2'-benzothiazolyl) -7-diethylaminocoumarin (hereinafter referred to as coumarin 6) shown in [Chemical Formula 45]
Also say. )

[0087]

[Chemical formula 46]

(2-Methyl-6- (2-
(2,3,6,7-Tetrahydro-1H, 5H-benzo (ij) quinolidin-9-yl) ethenyl) -4H-pyran-4-ylidene) propane-dinitrile (hereinafter DCM2
Also say. ) And the like.

Examples of the binder polymer that can be added to the light emitting layer 40 include polystyrene, polyvinyl biphenyl, polyvinyl phenanthrene, polyvinyl anthracene, polyvinyl perylene, poly (ethylene-co-vinyl acetate), and polybutadiene cis and tran.
s, poly (2-vinylnaphthalene), polyvinylpyrrolidone, polystyrene, poly (methylmethacrylate),
Poly (vinyl acetate), poly (2-vinyl pyridine-co-styrene), polyacenaphthylene, poly (acrylonitrile-co-butadiene), poly (benzyl methacrylate), poly (vinyltoluene), poly (styrene-co-) Acrylonitrile), poly (4-vinylbiphenyl), polyethylene glycol and the like.

Further, the hole blocking layer 50 is the anode layer 10
The holes injected into the light emitting layer 40 from the cathode layer 70 as they are.
It is a layer for blocking holes in order to prevent the holes from passing through and is composed of a hole blocking substance. Examples of the hole blocking substance include OX shown in [Chemical Formula 25].
D-1, PBD shown in [Chemical 27], BC shown in [Chemical 29]
P, Alq3 shown in [Chemical Formula 30],

[Chemical 47]

3- (4-biphenylyl) -5- (4-tert-butylphenyl) -4-phenyl-1,2,4-triazole (hereinafter also referred to as TAZ) shown in [Chemical Formula 47],

[0092]

[Chemical 48]

4,4'-bis (1,1 shown in [Chemical Formula 48]
-Diphenylethenyl) biphenyl (hereinafter DPVBi
Also called. ),

[0094]

[Chemical 49]

2,5-bis (1-naphthyl) -1.3.4-oxadiazole (hereinafter referred to as BND
Also called. )

[0096]

[Chemical 50]

4,4'-bis (1,1-bis (4-methylphenyl) ethenyl) biphenyl (hereinafter also referred to as DTVBi) represented by [Chemical Formula 50],

[0098]

[Chemical 51]

2,5-bis (4-
Biphenylyl) -1,3,4-oxadiazole (hereinafter also referred to as BBD),

[0100]

[Chemical 52]

Examples thereof include polyvinyl oxadiazole type polymer compounds (hereinafter also referred to as PV-OXD) as shown in [Chemical Formula 52].

The electron transport layer 60 is a layer for transporting electrons injected from the cathode layer 70 and contains an electron transport agent. The electron transport agent is composed of an electron transporting polymer,
Further, a structure containing a low molecule having an electron transport property is possible.

Here, as an example of the electron transporting low molecule,
OXD-7 shown in [Chemical 26], P shown in [Chemical 27]
BD, BCP shown in [Chemical formula 29], Alq shown in [Chemical formula 30]
3, TAZ shown in [Chemical 47], DPV shown in [Chemical 48]
Bi, BND shown in [Chemical 49], DT shown in [Chemical 50]
VBi, the BBD shown in [Chemical 51],

[0104]

[Chemical 53]

2,5-diphenyl-represented by [Chemical Formula 53]
1,3,4-oxadiazole (hereinafter also referred to as PPD) and the like.

As an example of the electron-transporting polymer, PV-OXD shown in [Chemical Formula 52] may be mentioned.

The element structures shown in FIGS. 2 to 5 are possible by modifying the basic structure of the organic electroluminescence element shown in FIG. 1 in order to further improve the luminous efficiency and simplify the structure.

The element structure of the organic electroluminescent element shown in FIG. 2 shows the first embodiment of the organic electroluminescent element according to the present invention. In the device structure shown in FIG. 1, the electron blocking layer 30 is omitted and the hole injection layer 21 is formed between the anode layer 10 and the hole transport layer 20.

The hole injection layer 21 is a layer for improving the electrical connection between the anode layer and the light emitting layer.
Examples of the hole-injecting substance that constitutes
A metal phthalocyanine such as CuPc shown in [Chemical Formula 12]
PEDT shown in, poly (3-hexylthiophene) shown in [Chemical Formula 24],

[0110]

[Chemical 54]

Examples include poly (3,4) ethylenedioxythiophene / polystyrene sulfonate (hereinafter also referred to as PEDT / PSS) represented by [Chemical Formula 54].

The device structure of the organic electroluminescent device shown in FIG. 3 is obtained by omitting the electron block layer 30 of FIG.

The element structure of the organic electroluminescence element shown in FIG. 4 is the same as the element structure shown in FIG.
The electron block layer 30 and the electron transport layer 60 are omitted, and the hole injection layer 21 is formed between the anode layer 10 and the hole transport layer 20.

The element structure of the organic electroluminescence element shown in FIG. 5 is the same as the element structure shown in FIG.
The electron block layer 30 and the hole block layer 50 are omitted,
A hole injection layer 21 is formed between the anode layer 10 and the hole transport layer 20.

Next, a method of manufacturing an organic electroluminescence device will be described using the device structure shown in FIG. 3 which is the second embodiment of the present invention.

First, the anode layer 10 is formed on a transparent insulating support, which is a substrate (not shown), such as a glass substrate, by vapor deposition or sputtering.

Next, a first solution is prepared by dissolving or dispersing a conductive polymer doped with an electron accepting compound in a solvent. Here, it is also possible to further dissolve or disperse the binder polymer in the first solution. And
By a wet method using the first solution, on the anode layer 10,
The hole transport layer 20 is formed.

Then, the hole transporting material on the anode layer 10 is subjected to an insolubilization treatment such as heating at 100 ° C. for about 20 hours. The electron transfer reaction with the molecule or the binder polymer is promoted.

Further, a second solution is prepared by dissolving or dispersing the doping agent 41 and the host agent 42 of the light emitting layer 40 in a solvent. Here, it is also possible to further dissolve or disperse the binder polymer in the second solution. Then, the hole transport layer 2 is formed by the wet method using the second solution.
The light emitting layer 40 is formed on the transparent layer 0.

Further, a third solution is prepared by dissolving or dispersing the hole blocking substance in a solvent. Here, the binder polymer can be further dissolved or dispersed in the third solution. The hole blocking layer 50 is formed on the light emitting layer 40 by a wet method using the third solution.

Then, a fourth solution is prepared by dissolving or dispersing the electron transporting polymer or the electron transporting low molecule in the solvent. Here, the binder polymer can be further dissolved or dispersed in the fourth solution. The electron transport layer 60 is formed on the hole blocking layer 50 by a wet method using the fourth solution.

At this time, the solubility parameter of the solvent used in the second solution depends on the substances contained in the hole transport layer 20 (conductive polymer, electron accepting compound, etc.) at the film formation temperature of the light emitting layer 40. On the other hand, in combination with having a value outside the soluble range and insolubilizing the hole transporting substance, the light emitting layer 40 by a wet method using such a solvent is used. In the formation of, the organic substance contained in the lower hole transport layer 20 is not dissolved.

Similarly, the solubility parameter of the solvent used in the third solution is determined by the substances contained in the light emitting layer 40 (the doping agent 41, the host agent 42, the high conductivity) at the film formation temperature of the hole blocking layer 50. The solubility parameter of the solvent used for the fourth solution has a value that is out of the soluble range for the molecule and the binder polymer). Since it has a value out of the soluble range with respect to contained substances (hole blocking substance and binder polymer, etc.), the hole blocking layer 50 by the wet method is used.
In forming the electron transport layer 60 and the electron transport layer 60, the organic substances contained in the light emitting layer 40 and the hole blocking layer 50, which are the lower layers, are not dissolved.

At this time, the solvent used for the above-mentioned first to fourth solutions is evaporated by natural drying to form the hole transport layer 20, the light emitting layer 40, the hole blocking layer 50, and the electron transport layer 60. It In this case, there is no need to perform treatments such as heating, polymerization by irradiation of ultraviolet rays, and curing, and therefore the manufacturing process is simple and the production efficiency can be improved.

The wet method used in the present invention includes ordinary coating methods such as casting method, blade coating method, dip coating method, spin coating method, spray coating method, roll coating method and ink jet coating method. .

Finally, the cathode layer 70 is formed on the electron transport layer 60 by using the vapor deposition method or the like to obtain the organic electroluminescence device according to the present invention.

The solubility parameter SP is defined by SP = {(ΔH-RT) / V} ^1/2 at the absolute temperature T of the liquid having a molar evaporation heat ΔH and a molar volume V. However, in the above formula, SP is a solubility parameter (unit: (cal / cm ³ ) ^1/2 ), ΔH is a heat of molar evaporation (unit: cal / mol), and R is a gas constant (unit: cal / mol). (Mol · K)), T is the absolute temperature (unit: K), and V is the molar volume (unit: cm ^3).
/ Mol).

FIG. 2 shows a first embodiment of the organic electroluminescent device according to the present invention. During the manufacturing process of the device structure shown in FIG. 3, before forming the hole transport layer 20, the anode is formed. The hole injection layer 21 is formed on the layer 10, and then the hole transport layer 20, the light emitting layer 40, the hole blocking layer 50, and the electron transport layer are formed on the hole injection layer 21 in the same manner as the device of FIG. It is obtained through a manufacturing process in which 60 and the cathode layer 70 are sequentially formed.

FIG. 4 shows a third embodiment of the organic electroluminescent device according to the present invention. In the device manufacturing process of the device structure shown in FIG. It is obtained through the manufacturing process of forming the cathode layer 70 on the hole blocking layer 50.

Further, FIG. 5 shows a fourth embodiment of the organic electroluminescent device according to the present invention, which is performed after the light emitting layer 40 is formed during the manufacturing process of the device structure shown in FIG. It is obtained through a manufacturing process in which the electron transport layer 60 and the cathode layer 70 are sequentially formed thereon.

[0131]

EXAMPLES Example 1 An ITO glass substrate (commercial ITO, Asahi Glass) that has been subjected to O ₂ plasma treatment under the conditions of 1.25 kW, oxygen flow rate 150 cc / min, and treatment time 1 minute in a down-flow type plasma device. (Manufactured by the company: 20 Ω / □), pressure condition 10 ⁻³ Pa, vapor deposition rate 0.1 nm / sec
Then, CuPc shown in [Chemical Formula 11] was vapor-deposited to form a hole injection layer having a thickness of 40 nm.

Furthermore, 5 mg of dinormal octyl polyfluorene shown in [Chemical formula 13] of 60,000 as a polystyrene-converted weight average amount (hereinafter referred to as molecular weight) measured by gel permeation chromatography and [Chemical formula 21] 0.28 mg (2.6 mol% with respect to di-normal octyl polyfluorene) as TBPAH shown is dissolved in 1 ml of tetrahydrofuran to prepare a solution 1 and spin-coated on the hole injection layer at 1000 rpm for 1 second. Then, a hole transport layer having a thickness of 55 nm was formed.

Further, under the pressure condition of 10 ⁻³ Pa, the CB shown in [Chemical Formula 16] at the vapor deposition rate of 0.092 nm / sec.
P and Ir (ppy) ₃ shown in [Chemical Formula 31] were co-evaporated at a vapor deposition rate of 0.008 nm / sec to give 1 on the hole transport layer.
A light emitting layer having a film thickness of 8 nm was formed.

Then, BCP shown in [Chemical Formula 29] was vapor-deposited under a pressure condition of 10 ⁻³ Pa and a vapor deposition rate of 0.1 nm / sec to form a hole blocking layer having a thickness of 20 nm on the light emitting layer.

Further, Alq3 shown in [Chemical Formula 30] was vapor-deposited under a pressure condition of 10 ⁻³ Pa and a vapor deposition rate of 0.1 nm / sec to form an electron-transporting layer having a thickness of 6 nm on the hole blocking layer.

Further, lithium fluoride was deposited in a film thickness of 0.5 nm at a deposition rate of 0.01 nm / sec, and a deposition rate of 1 nm.
2 was produced by forming aluminum by vapor-depositing aluminum to a film thickness of 50 nm at a current density of 1 mA / cm ² , a driving voltage of 3.9 V, and a luminance of 380 c.
Light emission of d / m ² was obtained.

[Comparative Example 1] TBPAH shown in [Chemical Formula 21]
Except that the hole-transporting layer was formed only with the dinormal octyl polyfluorene shown in [Chemical Formula 13] without doping
When the device shown in FIG. 2 was produced in the same manner as in [Example 1], the current density was 1 mA / cm ² , and the driving voltage was 4.3 V.
Thus, light emission with a luminance of 350 cd / m ² was obtained.

Comparative Example 2 The dinormal shown in [Chemical Formula 13]
Octyl polyfluorene and TBPAH shown in [Chemical Formula 21]
Instead of using, NPD shown in [Chem.
10 ^-3Vapor deposition at a deposition rate of 0.1 nm / sec.
Example except that a hole transport layer having a thickness of 40 nm was formed.
2] was manufactured in the same manner as in [1].
Flow density 1 mA / cm², Drive voltage 4.4V, brightness 35
0 cd / m²Luminescence was obtained.

It can be seen from [Example 1] and [Comparative Example 1] that the driving voltage required for light emission decreases when the electron-accepting compound is doped. Further, it can be seen from [Example 1] and [Comparative Example 2] that the device of the present invention can emit light at a driving voltage lower than that of the conventional phosphorescent device.

[Examples 2 to 5] [Comparative examples 3 and 4]: [Example 1] except that the doping concentration (mol%) of TBPAH shown in [Chemical formula 21] was changed as shown in [Table 1] below. 2 was manufactured in the same manner as in [1], [Table 1]
Light emission with the luminous efficiency shown in was obtained.

[0141]

[Table 1]

[Table 1] shows that the concentration of the dopant is 0.1 mol.
If it is less than%, the driving voltage required for light emission increases and the
It can be seen that when it is larger than 1%, the emission brightness decreases.

[Examples 6 to 30] TB shown in [Chemical formula 21]
A device shown in FIG. 2 was produced in the same manner as in [Example 1] except that the hole transport layer was formed by using the doping agent shown in [Table 2] below instead of PAH. ] The light emission of the luminous efficiency shown in was obtained. The amount of the doping agent added was 2.6 mol% with respect to the dinormal octyl polyfluorene shown in [Chemical Formula 13].

[0144]

[Table 2]

[Embodiment 31] A down flow type plasma apparatus was used, and the oxygen flow rate was 150 cc / mi and 1.25 kW.
n, O ₂ plasma treatment was performed under the condition of treatment time of 1 minute I
TO glass substrate (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω /
□), 10 mg of dinormal octyl polyfluorene shown in [Chemical formula 13] having a molecular weight of 10,000 and [Chemical formula 21]
0.56 mg (2.6 mol% with respect to dinormal octyl polyfluorene) as TBPAH shown in 1 was dissolved in 1 ml of tetrahydrofuran to prepare a solution 1 and spin coating was performed on the anode layer at 1000 rpm for 1 second. As a result, a hole transport layer having a thickness of 55 nm was formed.

Further, under a pressure condition of 10 ⁻³ Pa, the CB shown in [Chemical Formula 16] at a vapor deposition rate of 0.092 nm / sec.
P and Ir (ppy) ₃ shown in [Chemical Formula 31] were co-evaporated at a vapor deposition rate of 0.008 nm / sec to give 1 on the hole transport layer.
A light emitting layer having a film thickness of 8 nm was formed.

Then, BCP shown in [Chemical Formula 29] was vapor-deposited under a pressure condition of 10 ⁻³ Pa and a vapor deposition rate of 0.1 nm / sec to form a hole blocking layer having a thickness of 20 nm on the light emitting layer.

Further, Alq3 shown in [Chemical Formula 30] was vapor-deposited under a pressure condition of 10 ⁻³ Pa and a vapor deposition rate of 0.1 nm / sec to form an electron-transporting layer having a thickness of 6 nm on the hole blocking layer.

Further, lithium fluoride was deposited with a film thickness of 0.5 nm at a deposition rate of 0.01 nm / sec and a deposition rate of 1 nm.
Aluminum was vapor-deposited at a film thickness of 50 nm / sec to form a cathode, and the device shown in FIG. 3 was produced. The current density was 1 mA / cm ² , the driving voltage was 3.9 V, and the luminance was 380 c.
Light emission of d / m ² was obtained.

[Embodiment 32] A down-flow type plasma apparatus was used, and the flow rate was 1.25 kW and the oxygen flow rate was 150 cc / mi.
n, O ₂ plasma treatment was performed under the condition of treatment time of 1 minute I
TO glass substrate (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω /
□), an aqueous dispersion of PEDT / PSS (manufactured by Bayer Co.) represented by [Chemical formula 54] is used as solution 1 and slope 100 is obtained.
After spin coating at 0 rpm / s at a rotation speed of 1500 rpm for 60 seconds, heating at 200 ° C. for 5 minutes,
A hole injection layer having a film thickness of 60 nm was formed.

Furthermore, a compound having a molecular weight of 60,000
5 mg of di-normal octyl polyfluorene shown in
0.28 mg as TBPAH shown in [Chemical Formula 21] (2.6 mol based on dinormal octyl polyfluorene)
%) And a solution 2 prepared by dissolving 1% in tetrahydrofuran, spin coating is performed on the hole injecting layer at 1000 rpm for 1 second, and then heated at 100 ° C. for 20 hours to be insoluble in the upper layer laminating solvent, A hole transport layer having a film thickness of 55 nm was formed.

Further, the CBP shown in [Chemical 16] is 3
mg and Ir (ppy) shown in [Chemical Formula 31] as a doping agent
Solution 3 prepared by dissolving 0.24 mg as _{3 in} 1 ml of dichloroethane was used to form 10 on the hole transport layer.
Spin coating was performed at 00 rpm for 1 second to form a light emitting layer having a film thickness of 20 nm.

Further, the solution 4 prepared by dissolving 5 mg of PV-OXD shown in [Chemical Formula 52] in 1 ml of cyclohexane was spin-coated on the light-emitting layer at 1000 rpm for 1 second to give a film thickness of 27 nm. A hole blocking layer was prepared.

Further, lithium fluoride was deposited at a deposition rate of 0.01 nm / sec to a film thickness of 0.5 nm, and a deposition rate of 1 nm.
Aluminum was vapor-deposited at a film thickness of 50 nm at 1 / sec to form a cathode, and the device shown in FIG. 4 was produced. The current density was 1 mA / cm ² , the driving voltage was 3.6 V, and the luminance was 370 c.
Light emission of d / m ² was obtained.

[Comparative Example 5] TBPAH shown in [Chemical Formula 21]
Except that the hole-transporting layer was formed only with the dinormal octyl polyfluorene shown in [Chemical Formula 13] without doping
When the device shown in FIG. 4 was produced in the same manner as in [Example 32], the device could not be produced because the hole transport layer was dissolved during the formation of the light emitting layer. On the other hand, since the element of [Example 32] was insolubilized by heating, the element could be manufactured.

[Examples 33 to 36] [Comparative Examples 6 and 7]:
TBPAH doping concentration (mol%) shown in [Chemical Formula 21]
Except that the values are changed as shown in [Table 3] below.
2] was manufactured in the same manner as in [2],
Luminescence having the luminous efficiency shown in [Table 3] was obtained.

[0157]

[Table 3]

[Table 3] shows that the concentration of the dopant is 0.1 m.
It can be seen that when it is less than ol%, the driving voltage is high, and when it is more than 5 mol%, the emission luminance is lowered.

[Examples 37 to 61] T shown in [Chemical Formula 21]
A device shown in FIG. 4 was produced in the same manner as in [Example 32] except that the hole transport layer was formed by using the doping agent shown in [Table 4] below instead of BPAH. ] The light emission of the luminous efficiency shown in was obtained. The amount of the doping agent added was 2.6 mol% with respect to the dinormal octyl polyfluorene shown in [Chemical Formula 13].

[0160]

[Table 4]

[Embodiment 62] A down flow type plasma apparatus was used, and the flow rate was 1.25 KW and the oxygen flow rate was 150 cc / mi.
n, O ₂ plasma treatment was performed under the condition of treatment time of 1 minute I
TO glass substrate (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω /
□), pressure conditions of 10 ⁻³ Pa, vapor deposition rate of 0.1 nm /
CuPc shown in [Chemical formula 11] is vapor-deposited in sec and 40 nm
A hole injection layer having a film thickness of Furthermore, the molecular weight 60,
5 mg as MEH-PPV shown in [Chemical Formula 20] and 0.3 mg (MEH-PPV shown in [Chemical Formula 21] as TBPAH.
-1.7 mol% with respect to PPV) and 1 ml of xylene
The solution 1 prepared by dissolving in 1 is spin-coated on the hole injection layer at 1000 rpm for 1 second,
A hole transport layer having a film thickness of 5 nm was formed.

Further, under a pressure condition of 10 ⁻³ Pa, Al shown in [Chemical Formula 30] was formed at a vapor deposition rate of 0.098 nm / sec.
q3 at a deposition rate of 0.002 nm / sec
Co-deposited coumarin 6 shown in Fig. 2 and depositing 20n on the hole transport layer.
A light emitting layer having a thickness of m was formed.

Further, Alq3 shown in [Chemical Formula 30] was vapor-deposited under a pressure condition of 10 ⁻³ Pa and a vapor deposition rate of 0.1 nm / sec to form an electron transport layer having a thickness of 30 nm on the light emitting layer.

Further, lithium fluoride was deposited at a deposition rate of 0.01 nm / sec to a film thickness of 0.5 nm and a deposition rate of 1 nm.
Aluminum was vapor-deposited at a film thickness of 50 nm / sec to form a cathode, and the device shown in FIG. 5 was produced. The current density was ² mA / cm ² , the driving voltage was 5.2 V, and the luminance was 390 c.
Light emission of d / m ² was obtained.

[Comparative Example 8] NPD shown in [Chemical Formula 17] under a pressure condition of 10 ^-3 Pa and a vapor deposition rate of 0.098 nm / sec.
5 was manufactured in the same manner as in [Example 62] except that the hole transport layer having a film thickness of 55 nm was formed by vapor deposition of the above. The current density was ² mA / cm ² , the driving voltage was 5.5 V.
Thus, light emission with a luminance of 400 cd / m ² was obtained.

By [Example 62] and [Comparative Example 8],
Even in a device that only emits fluorescence instead of phosphorescence, it can be seen that the driving voltage required for light emission is reduced when the hole transport layer in which the electron-accepting compound is doped in the conductive polymer is used.

[0167]

As is apparent from the above description, in the organic electroluminescent device according to the present invention, the hole transport layer constituting the organic electroluminescent device is formed by adding the electron accepting compound to the conductive polymer. With electrical conductivity,
An electron blocking effect can also be provided by controlling the addition amount of the electron accepting compound. Therefore, holes can be surely injected from the anode layer to the light emitting layer to improve the electrical connection, and the chance of recombination of holes and electrons in the light emitting layer is increased to improve the emission brightness. it can. Such an organic electroelectroluminescent device,
It is possible to provide good light emission efficiency with a simple structure without newly forming an electron block layer.

[Brief description of drawings]

FIG. 1 is a device structure of an organic electroluminescence device.

FIG. 2 is a first embodiment of the device structure of the present invention.

FIG. 3 is a second embodiment of the device structure of the present invention.

FIG. 4 is a third embodiment of the device structure of the present invention.

FIG. 5 is a fourth embodiment of the device structure of the present invention.

[Explanation of symbols]

10 Anode layer 20 Hole transport layer 40 light emitting layer 70 cathode layer

Claims (5)

[Claims] 1. An organic electroluminescent device comprising both electrode layers of an anode layer and a cathode layer, a light emitting layer formed between the electrode layers, and a hole transport layer, wherein the hole transport layer constitutes the hole transport layer. The organic electroluminescent element is characterized in that the conductive substance is formed by adding 0.1 to 5 mol% of the electron-accepting compound of the conductive polymer to the conductive polymer. 2. The conductive polymer is represented by: (In the general formula [Chemical formula 1], R represents any one of hydrogen, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an ether group and a heterocyclic group.) Repeating unit represented by the general formula [Chemical formula 1] The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device is composed of a polyfluorene compound having: 3. The electron-accepting compound is a halogen simple substance,
The organic electroluminescence device according to claim 1 or 2, wherein the organic electroluminescence device comprises one of a Lewis acid, a protonic acid and a transition metal halide. 4. The electron-accepting compound is represented by: [Chemical 3] [Chemical 4] [Chemical 5] [Chemical 6] [Chemical 7] [Chemical 8] [Chemical 9] 3. The organic electroluminescence device according to claim 1, comprising a conductive organic compound represented by any one of structural formulas [Chemical formula 2] to [Chemical formula 9]. 5. The electron-accepting compound is represented by: (In the general formula [Chemical Formula 10], X represents a halogen atom, and ring A, ring B and ring C each independently represent an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an ether group or a heterocyclic group. Represents a benzene ring which may have a substituent.) The organic electroluminescence device according to claim 1 or 2, which has a molecular structure represented by the general formula [Chemical formula 10].