JP2003217863A - Method of fabricating organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply fabricate an organic electroluminescent element having an electron hole injection layer, using a wet method. <P>SOLUTION: In the fabrication method for the organic electroluminescent element having both electrode layers of a positive electrode layer 10 and a negative electrode layer 70, and a luminous layer 40 and a positive hole injection layer 21 formed between the electrode layers, a mixture solution of a positive hole transporting polymer and 0.1-70 wt.% of electron acceptable compound with respect to the positive hole transporting polymer is used as a positive hole injecting material for constituting the positive hole injection layer 21, the mixture solution is made to react under the solid condition where the positive electrode 10 is coated with the mixture solution, so as to generate an insoluble reaction product, and the positive hole injection layer 21 is formed by the insoluble reaction product. <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 a method for producing 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 for the hole injecting layer is required to have a function of improving the electrical connection between the anode layer and the light emitting layer to reduce the driving voltage of the organic electroluminescence element. As such a material, conventionally,

[0003]

[Chemical 5]

A hole-injecting low molecule such as copper phthalocyanine shown in [Chemical formula 5]

[0005]

[Chemical 6]

A hole injecting polymer such as poly (3,4) ethylenedioxythiophene (hereinafter also referred to as PEDT) shown in [Chemical Formula 6] is used. In addition, in order to further improve the above electrical connection, Japanese Patent Laid-Open No. 2000-3639
It is known from JP-A No. 0 and JP-A No. 2000-150169 that an aromatic amine-containing polymer doped with an electron-accepting compound is used as a material for a hole injection layer. The hole injection layer formed by using this aromatic amine-containing polymer as a base material has a low ionization potential of the aromatic amine-containing polymer, so that it is easy to inject holes from the anode layer and has a high hole mobility. Can be provided. Further, since the hole injection layer is formed by using the heat-resistant aromatic amine-containing polymer, the organic electroluminescence element formed by stacking the layers is stable against heat.

[0007]

By the way, in the above-mentioned conventional example, since the so-called dry process such as the vapor deposition process is adopted in forming the hole injection layer, the manufacturing process becomes complicated and the production efficiency is poor.

Therefore, as a simple method for forming the hole injecting layer, a wet method using a hole injecting substance in a solution state can be considered. The copper phthalocyanine shown in [5] can be formed into a film only by a vapor deposition process, and the PED shown in [Chemical formula 6] is used.
When T is brought into a solution state, T has a difficulty of forming a dispersion liquid of submicron particles. Further, the above aromatic amine-containing polymer doped with an electron-accepting compound is soluble in a solution used for forming a hole-transporting layer or a light-emitting layer formed by stacking on the hole-injecting layer. Therefore, there is a problem that the hole injecting layer is dissolved during the film formation of these and the multilayer laminated structure cannot be formed.

In view of the above problems, it is an object of the present invention to provide a method for easily producing an organic electroluminescence device having a hole injection layer by using a wet method.

[0010]

In order to solve the above-mentioned problems, the present invention provides an organic compound having both electrode layers of an anode layer and a cathode layer, a light emitting layer formed between these electrode layers, and a hole injection layer. In the method for producing an electroluminescence element, a hole-transporting polymer as a hole-injecting substance constituting a hole-injecting layer and a hole-transporting polymer having a hole-transporting polymer content of 0.
Using a mixed solution of 1 to 70% by weight of an electron-accepting compound, the mixed solution is reacted in the solid state coated on the anode layer to form an insoluble reaction product, and the insoluble reaction product is used to inject holes. It was intended to form a layer.

In this, by reacting a mixed solution of a hole transporting polymer and an electron accepting compound,
Charge transfer occurs, holes are generated, and the electrical conductivity of the hole injecting substance generated as a reaction product is improved. And
As a reaction method at this time, when an insolubilizing treatment such as heating the mixed solution on the anode layer in a solid state at a high temperature for a long time is performed, a positive hole is formed on the hole injection layer thus formed. When the hole transport layer and the light emitting layer are formed, the film structure of the hole injection layer can be maintained during the film formation of these adjacent layers, and the multi-layer structure of the organic electroluminescence device can be easily formed by the wet method.

That is, when the reaction between the hole-transporting polymer and the electron-accepting compound is promoted by heat treatment, the electron transfer reaction is increased and the charge transfer is efficiently performed.

By the way, 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, nitric acid, sulfuric acid, peroxides, etc. Protic acids such as chloric acid, hydrochloric acid, hydrofluoric acid, fluorosulfuric acid, and trifluoromethanesulfonic acid, or iron trichloride, molybdenum pentachloride, tungsten pentachloride, tin tetrachloride, molybdenum pentafluoride, ruthenium pentafluoride, penta It is possible to use transition metal halides such as tantalum bromide and tin tetraiodide. Since these compounds have strong oxidizing power, they have an excellent electron accepting property.

A compound having a molecular structure represented by the general formula [Chemical Formula 1] can be used as the electron-accepting compound.

Further, it is desirable to use a conductive polymer as the hole transporting polymer. This is because the conductive polymer has high electric conductivity.

In this case, as the conductive polymer,
For example, preferable examples include a polycarbazole compound having a repeating unit represented by [Chemical Formula 2] and a polyfluorene compound having a repeating unit of [Chemical Formula 3].

On the other hand, a compound having a carbazolyl group or a fluorenyl group can be used as the hole-transporting polymer, and the hole-transporting polymer having a carbazolyl group is represented by [Chemical Formula 4]. A polymer such as poly (N-vinylcarbazole) (hereinafter also referred to as PVK) can be a preferable example.

[0018]

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 substance formed on a transparent insulating support such as a glass substrate is used, and its material 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, PVK shown in [Chemical formula 4], a polyfluorene compound having a repeating unit shown in [Chemical formula 4], for example,

[0023]

[Chemical 7]

Dinormal octyl polyfluorene represented by [Chemical formula 7],

[0025]

[Chemical 8]

It is preferably composed of a polymer such as poly (para-phenylene vinylene) shown in [Chemical formula 8].

Alternatively, copper phthalocyanine represented by [Chemical formula 5],

[0028]

[Chemical 9]

N, N'-diphenyl-shown in [Chemical Formula 9]
N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (hereinafter also referred to as TPD),

[0030]

[Chemical 10]

N, N'-diphenyl-shown in [Chemical Formula 10]
N, N′-bis (1-naphthyl) -1,1′-biphenyl-4,4′-diamine (hereinafter also referred to as NPD),

[0032]

[Chemical 11]

Carbazole biphenyl (hereinafter also referred to as CBP) shown in [Chemical Formula 11],

[0034]

[Chemical 12]

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

Further, 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 PV shown in [Chemical Formula 4].
K, poly (para-phenylene vinylene) shown in [Chemical formula 8], TPD shown in [Chemical formula 9], NPD shown in [Chemical formula 10],
CBP shown in [Chemical Formula 11] and 4,4′-shown in [Chemical Formula 12]
Bis (10-phenothiazinyl) biphenyl,

[0037]

[Chemical 13]

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

[0039]

[Chemical 14]

Examples include fluorene shown in [Chemical Formula 14] and the like.

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 polymer as a binder. The host agent 42 is a substance that is activated and acts as an exciton when holes and electrons injected from the anode layer 10 and the cathode layer 70 are recombined in the light emitting layer 40, and is shown in [Chemical Formula 4]. PVK, a polyfluorene compound having a repeating unit represented by [Chemical Formula 4], for example, dinormal octyl polyfluorene represented by [Chemical Formula 7], CBP represented by [Chemical Formula 11],

[0042]

[Chemical 15]

Poly (2-methoxy-5-) shown in [Chemical Formula 15]
(2-Ethylhexoxy) -1,4-phenylene vinylene) (hereinafter also referred to as MEH-PPV)

[0044]

[Chemical 16]

Poly (3-hexylthiophene) shown in [Chemical Formula 16],

[0046]

[Chemical 17]

Tetracyanoethylene shown in [Chemical Formula 17] (hereinafter also referred to as TCNE)

[0048]

[Chemical 18]

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

[0050]

[Chemical 19]

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

[0052]

[Chemical 20]

2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1, shown in [Chemical Formula 20],
3,4-oxadiazole, (hereinafter also referred to as PBD),

[0054]

[Chemical 21]

N-phenyl polycarbazole represented by [Chemical Formula 21],

[0056]

[Chemical formula 22]

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

[0058]

[Chemical formula 23]

Examples include tris (8-hydroxyquinolinato) aluminum (hereinafter also referred to as Alq3) shown in [Chemical Formula 23].

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

[0061]

[Chemical formula 24]

A tri (2phenylpyridine) iridium complex represented by [Chemical Formula 24] (hereinafter also referred to as Ir (ppy) ₃ ),

[0063]

[Chemical 25]

[0064]

[Chemical formula 26]

[0065]

[Chemical 27]

[0066]

[Chemical 28]

[0067]

[Chemical 29]

[0068]

[Chemical 30]

(In the chemical formula [Chemical Formula 30], acac is

[0070]

[Chemical 31]

A functional group represented by [Chemical Formula 31] is shown. following
The same applies to the chemical formulas shown in [Chemical Formula 32] to [Chemical Formula 36]. )

[0072]

[Chemical 32]

[0073]

[Chemical 33]

[0074]

[Chemical 34]

[0075]

[Chemical 35]

[0076]

[Chemical 36]

Iridium complex compounds represented by [Chemical Formula 25] to [Chemical Formula 30] and [Chemical Formula 32] to [Chemical Formula 36],

[0078]

[Chemical 37]

2, 3, 7, 8, 12, shown in [Chemical Formula 37]
13,17,18-octaethyl-21H, 23H-platinum (II) porphine (hereinafter also referred to as PtOEP),

[0080]

[Chemical 38]

3- (2'-benzothiazolyl) -7-diethylaminocoumarin (hereinafter referred to as coumarin 6) shown in [Chemical Formula 38]
Also say. )

[0082]

[Chemical Formula 39]

[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 binder polymers 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 18].
D-1, PBD shown in [Chemical Formula 20], BC shown in [Chemical Formula 22]
P, Alq3 shown in [Chemical Formula 23],

[Chemical 40]

3- (4-biphenylyl) -5- (4-tert-butylphenyl) -4-phenyl-1,2,4-triazole (hereinafter also referred to as TAZ) shown in [Chemical Formula 40],

[0087]

[Chemical 41]

4,4'-bis (1,1 shown in [Chemical Formula 41]
-Diphenylethenyl) biphenyl (hereinafter DPVBi
Also called. ),

[0089]

[Chemical 42]

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

[0091]

[Chemical 43]

4,4'-bis (1,1-bis (4-methylphenyl) ethenyl) biphenyl (hereinafter also referred to as DTVBi) represented by [Chemical Formula 43],

[0093]

[Chemical 44]

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

[0095]

[Chemical formula 45]

Examples thereof include polyvinyl oxadiazole-based polymer compounds (hereinafter also referred to as PV-OXD) as shown in [Chemical Formula 45].

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 Formula 19] and P shown in [Chemical Formula 20]
BD, BCP shown in [Chemical Formula 22], Alq shown in [Chemical Formula 23]
3, TAZ shown in [Chemical 40], DPV shown in [Chemical 41]
Bi, BND shown in [Chemical formula 42], DT shown in [Chemical formula 43]
VBi, the BBD shown in [Chemical 44],

[0099]

[Chemical formula 46]

2,5-diphenyl-represented by [Chemical Formula 46]
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 45] and the like can be mentioned.

The element structures shown in FIGS. 2 to 5 are possible by modifying the basic structure of the organic electroluminescent 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. The hole transport layer 20, the electron blocking layer 30, and the hole blocking layer 50 of FIG.
2 and the electron transport layer 60 are omitted, and in FIG.
The hole injection layer 21 is formed between 0 and the light emitting layer 40.

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 composes are: metal phthalocyanines such as copper phthalocyanine shown in [Chemical formula 5], PEDT shown in [Chemical formula 6], and poly (3
-Hexylthiophene) or

[0105]

[Chemical 47]

Examples thereof include poly (3,4) ethylenedioxythiophene / polystyrene sulfonate (hereinafter also referred to as PEDT / PSS) represented by [Chemical Formula 47].

When a hole-transporting substance doped with an electron-accepting compound is used as a material for the hole-injection layer, an electron-accepting reaction between the hole-transporting substance and the electron-accepting compound causes a charge. The migration occurs and holes are generated, and the electric conductivity of the hole injecting layer is improved. This can further improve the electrical connection between the anode layer and the light emitting layer.

Examples of the hole-transporting substance used in the hole-injection layer as described above include PVK shown in [Chemical formula 4], dinormal octyl polyfluorene shown in [Chemical formula 7], and MEH-PPV shown in [Chemical formula 15]. N-phenyl polycarbazole represented by [Chemical Formula 21],

[0109]

[Chemical 48]

Examples thereof include hole transporting polymers such as the TPD polymer compound shown in [Chemical Formula 48] (hereinafter also referred to as poly-TPD).

As an electron-accepting compound used in the hole injecting layer as described above, TCNE shown in [Chemical Formula 17],

[0112]

[Chemical 49]

Tris (4-bromophenyl) aminium hexachloroantimonate shown in [Chemical Formula 49] (hereinafter referred to as TB
Also called PAH. ),

[0114]

[Chemical 50]

7,7,8,8-tetracyanoquinodimethane (hereinafter also referred to as TCNQ) shown in [Chemical Formula 50],

[0116]

[Chemical 51]

2,3-dichloro-5,6-shown in [Chemical Formula 51]
Dicyano-1,4-benzoquinone (hereinafter also referred to as DDQ), simple halogen such as bromine, chlorine, iodine, boron trifluoride, phosphorus pentafluoride, antimony pentafluoride, Lewis acid such as arsenic pentafluoride, 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, pentafluoride. Mention may be made of transition metal halides such as ruthenium bromide, tantalum pentabromide and tin tetraiodide.

The element structure of the organic electroluminescence element shown in FIG. 3 is the same as the element structure shown in FIG.
Hole transport layer 20, electron block layer 30, and electron transport layer 60
3, and the hole injection layer 21 is formed between the anode layer 10 and the light emitting layer 40 in FIG.

The element structure of the organic electroluminescence element shown in FIG. 4 is the same as the element structure shown in FIG.
The hole transport layer 20 and the electron block layer 30 are omitted, and FIG.
In the above, the hole injection layer 21 is formed between the anode layer 10 and the light emitting layer 40.

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 is omitted, and in FIG.
The hole injection layer 21 is formed between 0 and the hole transport layer 20.

Next, with reference to FIG. 2 as a first embodiment of the present invention, a method of manufacturing an organic electroluminescence element will be described.

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 hole-transporting polymer or a hole-transporting low molecular weight compound doped with an electron-accepting compound in a solvent. Where the first
It is also possible to further dissolve or disperse the binder polymer in the solution. Then, the hole injection layer 21 is formed on the anode layer 10 by a wet method using the first solution.

Then, the hole injecting substance on the anode layer 10 is subjected to insolubilization treatment by heating at 100 ° C. for about 20 hours.

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 injection layer 2 is formed by a wet method using the second solution.
The light emitting layer 40 is formed on the first layer 1.

The solubility parameter of the solvent used in the second solution is determined by the substance contained in the hole injection layer 21 (hole transporting polymer or hole transporting low molecule at the film formation temperature of the light emitting layer 40). And an electron-accepting compound, etc.), the value is out of the soluble range, and in combination with the fact that the hole injecting substance is insolubilized, such a solvent is In addition, in the formation of the light emitting layer 40 by the wet method, the organic substance contained in the lower hole injection layer 21 is not dissolved.

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 light emitting layer 40 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. 3 shows a second embodiment of the organic electroluminescent device according to the present invention. The light emitting layer 40 is formed after the light emitting layer 40 is formed in the manufacturing process of the device structure shown in FIG. It is obtained through a manufacturing process in which the hole blocking layer 50 and the cathode layer 70 are sequentially formed thereon.

FIG. 4 shows a third embodiment of the organic electroluminescent device according to the present invention. After the light emitting layer 40 is formed during the manufacturing process of the device structure shown in FIG. 2, the light emitting layer 40 is formed. On top, the hole blocking layer 50,
It is obtained through a manufacturing process in which the electron transport layer 60 and the cathode layer 70 are sequentially formed.

Further, FIG. 5 shows a fourth embodiment of the organic electroluminescence device according to the present invention, and the hole injection layer 21 is formed during the manufacturing process of the device structure shown in FIG.
And the hole transport layer 20 is further formed, and then the light emitting layer 40 is further formed. Then, the hole blocking layer 50, the electron transport layer 60, and the cathode layer 70 are sequentially formed on the light emitting layer 40. Obtained through.

[0133]

EXAMPLES Example 1 An ITO glass substrate (commercial ITO, Asahi Glass) that had 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 / □, work function 5.9 eV), and having a polystyrene-equivalent weight average amount (hereinafter referred to as molecular weight) of 60,000 measured by gel permeation chromatography [Chemical formula 7]
5 mg of dinormal octyl polyfluorene represented by
And 1.5 mg as TBPAH represented by [Chemical 49]
(30 Wt for di-normal octyl polyfluorene
%) And solution 1 prepared by dissolving it in 1 ml of tetrahydrofuran, spin-coat at 1000 rpm for 1 second, heat at 100 ° C. for 20 hours to insolubilize it in the upper layer solvent, and inject holes with a thickness of 55 nm. Layers were formed.

A solution 2 was prepared by dissolving 9 mg of the dinormal octyl polyfluorene represented by [Chemical Formula 7] in 1 ml of xylene, and spin-coating the solution 2 on the hole injection layer at a rotation speed of 1000 rpm for 1 second. Done, 100
A light emitting layer having a thickness of nm was formed.

[0135] on the light emitting layer, 0 under a pressure of 10 ^-4 Pa.
Calcium was vapor-deposited to a film thickness of 20 nm at a vapor deposition rate of 1 nm / sec, and further 1 was deposited thereon under a pressure condition of 10 ⁻³ Pa.
Aluminum was vapor-deposited to a film thickness of 100 nm at a vapor deposition rate of nm / sec to form a cathode, to fabricate the device shown in FIG.

At this time, driving voltage 3.5V, current density 3m
Light emission with a luminance of 100 cd / m ² was obtained at A / cm ² .

[Comparative Example 1] Instead of the solution 1, [Chemical formula 47]
The PEDT / PSS (manufactured by Bayer) aqueous dispersion shown in Figure 1 is rotated at 1500 rpm with a slope of 1000 rpm / s.
2 was prepared in the same manner as in [Example 1] except that the hole injection layer having a thickness of 60 nm was formed by spin coating for 60 seconds and heating at 200 ° C. for 5 minutes. Driving voltage 4V, current density 3mA / cm ² and brightness 1
Light emission of 00 cd / m ² was obtained.

Comparing [Example 1] and [Comparative Example 1], it can be seen that the hole injection layer of [Example 1] is PE in [Comparative Example 1].
It can be seen that the hole injection layer using DT / PSS can be formed more easily and shows higher luminous efficiency.

[Examples 2 to 5] and [Comparative Examples 2 to 3] The doping amount of TBPAH represented by [Chemical formula 49] (% by weight based on the dinormal octyl polyfluorene represented by [Chemical formula 7]) is shown in the following table. 2 was produced in the same manner as in [Example 1] except that the light emission efficiency was as shown in [Table 1] below.

[0140]

[Table 1]

From Table 1, the doping concentration is 0.1 Wt%.
If it is less than 70% by weight, the driving voltage at a current density of 1 mA / cm ² is high, and if it is more than 70 Wt%, the current density is 1 mA / c.
It can be seen that the emission luminance at m ² decreases.

Example 6 Instead of the solution 1, a molecular weight of 1,
8 mg as PVK of 100,000 [Chemical 4]
And a solution prepared by dissolving 2.4 mg of TBPAH shown in [Chemical Formula 49] in 1 ml of dichloroethane. The solution was spin-coated at 1000 rpm for 1 second, and the film thickness of 550 nm was obtained without heating at 100 ° C. The device shown in FIG. 2 was prepared in the same manner as in [Example 1] except that the hole injection layer was formed.

At this time, light emission with a luminance of 90 cd / m ² was obtained at a current density of 3 mA / cm ² and a driving voltage of 3.5 V.

[Example 7] Instead of the solution 1, a molecular weight of 2 was used.
A solution prepared by dissolving 6 mg of N-phenylpolycarbazole represented by [Chemical formula 21] of 10,000 and 1.8 mg of TBPAH represented by [Chemical formula 49] in 1 ml of dichloroethane was used. A device shown in FIG. 2 was prepared in the same manner as in [Example 1] except that the hole injection layer having a thickness of 550 nm was formed by spin coating for 2 seconds.

At this time, light emission with a current density of 3 mA / cm ² and a driving voltage of 3.5 V and a brightness of 100 cd / m ² was obtained.

[Embodiment 8] With a down-flow type plasma apparatus, 1.25 kW, oxygen flow rate 150 cc / min,
ITO subjected to O ₂ plasma treatment under the treatment time of 1 minute
A glass substrate (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω / □, work function: 5.9 eV) having a molecular weight of 60,000
5 mg as MEH-PPV shown in [5],
1.5 mg (30 Wt% with respect to MEH-PPV shown in [Chemical Formula 15]) as TBPAH shown in (1) was dissolved in 1 ml of tetrahydrofuran to prepare a solution 1.
Spin coat at 1000 rpm for 1 second, 100 ℃
At 20 nm for 55 hours to insolubilize the upper layer solvent
A hole injection layer having a film thickness of

8 as MEH-PPV shown in [Chemical Formula 15]
Solution 2 was prepared by dissolving 1 mg of xylene in 1 ml, and solution 2 was spin-coated on the hole injecting layer at 1000 rpm for 1 second to form a light emitting layer having a thickness of 100 nm.

On the light emitting layer, 1 n was applied under the pressure condition of 10 ⁻⁴ Pa.
Calcium is vapor-deposited to a film thickness of 20 nm at a vapor deposition rate of m / sec, and further 1 nm is deposited thereon under a pressure condition of 10 ^-3 Pa.
Aluminum was vapor-deposited to a film thickness of 100 nm at a vapor deposition rate of / sec to form a cathode, thereby producing the device shown in FIG.

At this time, light emission having a luminance of 300 cd / m ² was obtained at a current density of 3 mA / cm ² and a driving voltage of 2.5V.

Example 9 Instead of MEH-PPV shown in [Chemical Formula 15] used for the hole injection layer and the light emitting layer, [Chemical formula 1]
6] was prepared in the same manner as in [Example 8] except that the poly (3-hexylthiophene) shown in 6] was used.

At this time, light emission with a current density of 3 mA / cm ² and a driving voltage of 3.5 V and a luminance of 100 cd / m ² was obtained.

[Examples 10 to 21] T shown in [Chemical formula 49]
2 was prepared in the same manner as in [Example 1] except that the dopant shown in [Table 2] below (30 Wt% based on MEH-PPV shown in [Chemical Formula 15] was used in place of BPAH. However, light emission having the light emission efficiency shown in [Table 2] below was obtained.

[0153]

[Table 2]

[Embodiment 35] With a down-flow type plasma processing apparatus, 1.25 kW and oxygen flow rate 150 cc / m.
in, an ITO glass substrate subjected to O ₂ plasma treatment under the treatment time of 1 minute (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω /
□, work function of 5.9 eV) and 5 mg of dinormaloctyl polyfluorene represented by [Chemical formula 7] and [Chemical formula 49]
A solution 1 prepared by dissolving 1.5 mg (30 Wt% with respect to dinormal octyl polyfluorene) as TBPAH shown in
Spin coat at 1000 rpm for 1 second, 100 ℃
At 20 nm for 55 hours to insolubilize the upper layer solvent
A hole injection layer having a film thickness of

3 mg of PVK shown in [Chemical Formula 4] and 0.24 mg of Ir (ppy) ₃ shown in [Chemical Formula 24] as a doping agent were dissolved in 1 ml of dichloroethane to prepare Solution 2. Using 10 on the hole injection layer
Spin coating was performed at 00 rpm for 1 second to form a light emitting layer having a film thickness of 20 nm.

5 m as PV-OXD shown in [Chemical Formula 45]
g was dissolved in 1 ml of cyclohexane to prepare a solution 3, and the solution 3 was spin-coated on the light emitting layer at 1000 rpm for 1 second to form a hole blocking layer having a thickness of 270 nm.

On the hole blocking layer, 0.01 nm / se
Lithium fluoride is vapor-deposited to a film thickness of 0.5 nm at a vapor deposition rate of c, and aluminum is further vapor-deposited to a film thickness of 50 nm at a vapor deposition rate of 1 nm / sec to form a cathode. The device shown was prepared.

At this time, light emission with a luminance of 370 cd / m ² was obtained at a current density of 1 mA / cm ² and a driving voltage of 3.7V.

[Comparative Example 4] Dinormal octyl polyfluorene represented by [Chemical formula 7] and TB represented by [Chemical formula 49]
Instead of PAH, copper phthalocyanine shown in [Chemical formula 5] was used, and 0.1 nm / se was obtained under a pressure condition of 10 ⁻³ Pa.
A device shown in FIG. 3 was prepared in the same manner as in [Example 35] except that the hole injection layer having a film thickness of 40 nm was deposited at the deposition rate of c.

At this time, light emission with a current density of 1 mA / cm ² and a driving voltage of 3.8 V and a luminance of 370 cd / m ² was obtained.

Comparing [Example 35] with [Comparative Example 4], it can be seen that when the hole injection layer is formed by a wet process in [Example 35],
It can be seen that in [Comparative Example 4], the values are almost the same as those when the hole injection layer is formed by vapor deposition. [Examples 36 to 38],
[Comparative Example 5] Similar to [Example 35] except that a hole injection layer was formed by using a host agent shown in [Table 3] below in place of the dinormal octyl polyfluorene represented by [Chemical formula 7]. The device shown in FIG. 3 was prepared in the following [Table 3].
Light emission with the luminous efficiency shown in was obtained. The doping amount was 30 Wt% of the host material. Further, the hole injection layers of [Comparative Example 5] and [Example 37] were not heated.

[0162]

[Table 3]

In [Example 36], the device was able to be prepared because it was insolubilized by heating, but in [Comparative Example 5], the device was prepared because the hole injection layer was dissolved during the formation of the light emitting layer. There wasn't.

[Table 3] shows that PVK shown in [Chemical formula 4] of [Example 38] is almost insoluble in xylene which is the solvent used for forming the upper layer without insolubilization treatment. It turns out that it was.

[Examples 39 to 42], [Comparative Examples 6 and 7]
[Example 35] except that the doping concentration of TBPAH represented by [Chemical Formula 49] was changed as shown in [Table 4] below.
When the device shown in FIG. 3 was produced in the same manner as above, light emission with the light emission efficiency shown in [Table 4] below was obtained. The dope concentration is shown by weight% with respect to the host agent.

[0166]

[Table 4]

From Table 4, when the doping concentration is less than 0.1%, the driving voltage is high at a current density of 1 mA / cm ^{2, and} when it is more than 70%, the current density is 1 mA / cm ^2.
It can be seen that the emission brightness at that time decreases.

[Examples 43 to 67] Similar to [Example 35] except that the TBPAH shown in [Chemical formula 49] was replaced by the dopant shown in [Table 5] below, shown in FIG. When a device was prepared, light emission with the light emission efficiency shown in [Table 5] below was obtained.

[0169]

[Table 5]

[Example 68] PV-O shown in [Chemical Formula 45]
BCP shown in [Chemical Formula 22] was used instead of XD, and 10 ⁻³
A hole blocking layer having a film thickness of 20 nm is formed at a vapor deposition rate of 0.1 nm / sec under a pressure condition of Pa, and Alq3 shown in [Chemical Formula 23] is further used to form a hole blocking layer of 0.1 nm / s.
A device shown in FIG. 4 was prepared in the same manner as in [Example 35] except that the electron transport layer having a film thickness of 6 nm was formed at a deposition rate of ec.

At this time, light emission with a luminance of 370 cd / m ² was obtained at a current density of 1 mA / cm ² and a driving voltage of 4V.

[Embodiment 69] A down-flow type plasma processing apparatus was used, and the flow rate was 1.25 KW and the oxygen flow rate was 150 cc / m.
in, an ITO glass substrate subjected to O ₂ plasma treatment under the treatment time of 1 minute (commercial ITO, manufactured by Asahi Glass Co., Ltd .: 20Ω /
□, work function of 5.9 eV) and 5 mg of dinormaloctyl polyfluorene represented by [Chemical formula 7] and [Chemical formula 49]
A solution 1 prepared by dissolving 1.5 mg (30 Wt% with respect to dinormal octyl polyfluorene) as TBPAH shown in
Spin coat at 1000 rpm for 1 second, 100 ℃
At 20 nm for 55 hours to insolubilize the upper layer solvent
A hole injection layer having a film thickness of

Further, 2 mg of dinormal octyl polyfluorene represented by [Chemical formula 7] was dissolved in 1 ml of xylene to prepare a solution 2, and the solution 2 was spin-coated on the hole injection layer at 1000 rpm for 1 second. Go, 20n
A hole transport layer having a thickness of m was formed.

Furthermore, under pressure condition 10 ⁻³ Pa,
CBP shown in [Chemical formula 11] at a vapor deposition rate of 0.092 nm / sec and [Chemical formula 2 at a vapor deposition rate of 0.008 nm / sec.
4] and Ir (ppy) ₃ were co-evaporated on the hole transport layer to form a light emitting layer having a thickness of 18 nm.

Further, BCP represented by [Chemical Formula 22] was vapor-deposited on the light emitting layer 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.

Further, at a vapor deposition rate of 0.1 nm / sec,
Alq3 represented by [Chemical Formula 23] was vapor-deposited on the hole blocking layer to form an electron transport layer having a thickness of 6 nm.

Further, lithium fluoride was vapor-deposited to a thickness of 0.5 nm at a vapor deposition rate of 0.01 nm / sec, and aluminum was further vapor-deposited to a thickness of 50 nm at a vapor deposition rate of 1 nm / sec. A cathode was formed to produce the device shown in FIG.

At this time, light emission with a current density of 1 mA / cm ² and a driving voltage of 4.0 V and a luminance of 380 cd / m ² was obtained.

[0179]

As is apparent from the above description, in the organic electroluminescent device according to the present invention, the hole injection layer constituting the organic electroluminescent device is formed by doping the hole transporting polymer with the electron accepting compound. Therefore, it has high electric conductivity. Therefore, the electrical connection between the anode layer and the light emitting layer is improved, and an organic electroluminescence device having good light emitting efficiency can be produced.

Further, since the material constituting the hole injecting layer is subjected to insolubilization treatment, it can be formed in a solution state, that is, by a wet method into a multi-layer laminated structure, so that the element structure of the organic electroluminescence element can be easily prepared. .

[Brief description of drawings]

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

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

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

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

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

[Explanation of symbols]

10 Anode layer 21 hole injection layer 40 light emitting layer 70 cathode layer

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/10 H05B 33/10 33/14 33/14 A (72) Inventor Satoshi Ishii 1-chome Shin-Sayama, Sayama City, Saitama Prefecture 10th address 1 F term in Honda Engineering Co., Ltd. (reference) 3K007 AB03 AB15 AB18 DB03 FA01 FA03 4J032 CA03 CA12 CB01 CG01 4J043 PA02 RA33 ZA44 ZB21 4J100 AQ26P BC65P JA45

Claims (10)

[Claims] 1. A method for producing an organic electroluminescence 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 injection layer, wherein the hole injection layer is constituted. As the hole injecting substance, the hole transporting polymer and the hole transporting polymer are 0.1 to 70 relative to the hole transporting polymer.
A mixed solution with a weight% of an electron-accepting compound is used, and the mixed solution is reacted in a solid state coated on the anode layer to form an insoluble reaction product, and the insoluble reaction product is used to form the hole injection layer. A method for producing an organic electroluminescence device, which comprises forming a film. 2. The method for producing an organic electroluminescence device according to claim 1, wherein the reaction between the hole-transporting polymer and the electron-accepting compound on the anode layer is promoted by heat treatment. . 3. The method for producing an organic electroluminescence device according to claim 1, wherein any one of halogen simple substance, Lewis acid, protonic acid and transition metal halide is used as the electron accepting compound. 4. The electron-accepting compound includes: (In the general formula [Chemical Formula 1], X represents a halogen atom, and
And ring C each independently represent a benzene ring which may have a substituent consisting of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an ether group or a heterocyclic group. The compound having the molecular structure shown in [Chemical Formula 1] is used, and the method for producing an organic electroluminescent device according to claim 1 or 2. 5. The method for producing an organic electroluminescence device according to claim 1, wherein the hole transporting polymer is a conductive polymer. 6. The conductive polymer is: (In the general formula [Chemical formula 2], R represents hydrogen, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an ether group, or a heterocyclic group.) The repeating unit represented by the [Chemical formula 2] It consists of a polymer, The manufacturing method of the organic electroluminescent element of Claim 5 characterized by the above-mentioned. 7. The conductive polymer is represented by: (In the general formula [Chemical Formula 3], R represents hydrogen, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an ether group or a heterocyclic group.) From a polymer having [Chemical Formula 3] as a repeating unit The method for producing an organic electroluminescence device according to claim 5, wherein 8. The method for producing an organic electroluminescent device according to claim 1, wherein the hole transporting polymer has a carbazolyl group. 9. The hole-transporting polymer having a carbazolyl group is represented by: 9. The method for producing an organic electroluminescence device according to claim 8, which is composed of a polymer represented by [Chemical Formula 4]. 10. The hole transporting polymer has a fluorenyl group, according to any one of claims 1 to 4.
A method for producing an organic electroluminescence device according to the item 1.