JP2021068679A - Electronic device and manufacturing method thereof - Google Patents

Abstract

To provide an electronic device and a manufacturing method thereof having high luminous efficiency, low drive voltage, and long device life.SOLUTION: An electronic device having at least a light emitting layer and a pair of electrodes on a base material includes at least one electrode A directly above the light emitting layer, and the electrode A contains a metal and a nitrogen-containing aromatic heterocyclic compound, and there is also provided a manufacturing method of the electronic device.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electronic device and a method for manufacturing an electronic device, and more particularly to an electronic device having a high luminous efficiency, a low driving voltage, and a long element life, and a method for manufacturing the electronic device.

An organic electroluminescence element (hereinafter, also referred to as "organic EL element" or "organic electroluminescent element") using an organic material electroluminescence (hereinafter abbreviated as EL) is several V to several tens V. It is a thin-film type completely solid element capable of emitting light at a low voltage, and has many excellent features such as high brightness, high emission efficiency, thinness, and light weight. For this reason, it is attracting attention as a backlight for various displays, a display board for signboards and emergency lights, and a surface emitter such as an illumination light source.

Research on organic EL devices has a long history, dating back to the 1950s. Initially, a typical organic EL device had a structure in which an anode / an organic layer / a cathode, which is an organic layer, was one layer. For example, in 1982, P.M. S. Vicent et al. Have succeeded in emitting EL light with a configuration of an anode / anthracene thin film / cathode. However, in the case of the configuration in which the organic layer is one layer, there are problems that the carrier injection property and the carrier block property are low, the drive voltage is high, and the luminous efficiency is low.

On the other hand, in 1987, C.I. Tang et al. Have reported an organic EL device having a configuration in which organic layers are laminated to separate functions, and a significant improvement in device performance has been realized. Since then, the development of organic EL devices in which a plurality of organic layers are laminated has been accelerated, and it is now widely commercialized. For example, as a typical configuration, an organic EL device including an anode / hole injection layer / hole transport layer / electron block layer / light emitting layer / electron transport layer / electron injection layer / cathode can be mentioned. However, in an organic EL device having such a configuration, since a plurality of organic layers are laminated, the number of man-hours in the manufacturing process increases, and as a result, there is a problem that the robustness of the device performance is lowered.

In response to the above problem, as an attempt to reduce the number of constituent layers of the organic EL device, in an organic EL device having a plurality of organic layers including a light emitting layer between the cathode and the anode, the cathode is made of a metal and a halide of an alkali metal. The structure formed by the copolymerization of the above is disclosed (see, for example, Patent Document 1). According to Patent Document 1, it is possible to have an organic EL that can reduce the number of electron transport layers and the like, can be driven at a low voltage, has high brightness, and has a long element life.

However, it has been found that when a cathode having the configuration disclosed in Patent Document 1 is formed directly above the light emitting layer, the efficiency and life of the organic EL element are reduced. As a result of proceeding with the analysis of the cause causing this problem, the metal of the material constituting the cathode, for example, silver, is ionized and adjacent to each other due to the water content in the organic EL element and the water content that invades during long-term storage. It was found that it diffuses into the light emitting layer, and as a result, the light emitting exciter is quenched, which causes a decrease in the luminous efficiency of the device and a decrease in the life of the device.

JP-A-2010-146746

The present invention has been made in view of the above problems and situations, and a solution thereof is to provide an electronic device having a high luminous efficiency, a low driving voltage, and a long device life, and a method for manufacturing the electronic device.

In order to solve the above problems, the present inventor has high luminous efficiency by incorporating a metal and a nitrogen-containing aromatic heterocyclic compound in the electrode directly above the light emitting layer in the process of examining the cause of the above problem. We have found that it is possible to provide an electronic device having a low drive voltage and a long element life, and have arrived at the present invention.

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An electronic device having at least a light emitting layer and a pair of electrodes on a substrate.
At least one electrode A is provided directly above the light emitting layer, and the light emitting layer is directly above the light emitting layer.
The electrode A contains a metal and a nitrogen-containing aromatic heterocyclic compound.
An electronic device characterized by that.

2. The electronic device according to item 1, wherein the electrode A contains a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound, and a solvent.

3. 3. The electronic device according to item 1 or 2, wherein the metal is silver.

4. The electronic device according to item 2 or 3, wherein the solvent contains fluorinated alcohol or water.

5. The electronic device according to any one of items 1 to 4, wherein the electrode A contains a metal ion and a surfactant containing fluorine.

6. The electronic device according to any one of items 1 to 5, wherein the electronic device is an organic electroluminescence element and the electrode A is a cathode.

7. At least, it is a method for manufacturing an electronic device that forms a pair of electrodes with a light emitting layer on a base material.
A method for producing an electronic device, which comprises forming at least one electrode A directly above the light emitting layer by a dry method using a metal and a nitrogen-containing aromatic heterocyclic compound.

8. At least, it is a method for manufacturing an electronic device that forms a pair of electrodes with a light emitting layer on a base material.
An electron characterized by forming at least one electrode A directly above the light emitting layer by a wet method using an electrode-forming coating liquid containing a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound and a solvent. How to make the device.

9. The method for manufacturing an electronic device according to item 7 or 8, wherein silver is used as the metal.

10. The method for producing an electronic device according to item 8 or 9, wherein the solvent is alcohol fluoride or water.

11. The method for manufacturing an electronic device according to any one of items 7 to 10, wherein the electrode A contains a metal ion and a surfactant containing fluorine.

According to the above means of the present invention, it is possible to provide an electronic device having a high luminous efficiency, a low driving voltage, and a long device life, and a method for manufacturing the electronic device.

Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.

As described above, in conventional electronic devices, for example, organic EL devices, the mainstream configuration is composed of an anode / hole injection layer / hole transport layer / electron block layer / light emitting layer / electron transport layer / electron injection layer / cathode. However, when a plurality of organic layers are laminated as shown in FIG. 1A, the number of steps in the manufacturing process increases, and as a result, the reliability of the device performance such as robustness decreases. ..

On the other hand, as a configuration of an electrode layer (cathode) adjacent to a light emitting layer as disclosed in Patent Document 1, as shown in FIG. 1 (b-1), as a metal with silver and as a low work function material. By applying the alkali metal halide, the low work function material improves the efficiency of electron injection into the light emitting layer. The work function referred to here is the minimum energy required to extract one electron from the surface to infinity on the surface of a substance, and a material having a work function smaller than about 4 eV is called a low work function material. Examples of the low work function material include alkali metals such as K, Rb, Cs, Ca, Sr, and Ba, or alkaline earth metals.

However, the low work function material proposed in Patent Document 1 does not have a function of suppressing the interlaminar movement to the adjacent layer due to silver ionization of silver, which is a metal material applied to the cathode, and thus has luminous efficiency and an element. It caused a decrease in life.

As shown in FIG. 1 (b-2), the cathode material, for example, silver, is ionized as silver ions by the moisture in the electronic device and diffuses into the light emitting layer, resulting in the light emitting layer. It was found that the transferred silver ions cause a decrease in the luminous efficiency and device life of the electronic device by quenching the luminescent exciter in the light emitting layer.

In the present invention, as a cathode applied to an electronic device, as shown in FIGS. 1 (c-1) and 1 (C-2), at least one electrode A is provided directly above the light emitting layer, and the electrode A is provided. It has been found that the above-mentioned problem can be solved by the constitution containing a metal and a nitrogen-containing aromatic heterocyclic compound.

That is, in the electrode A, the constituent metal and the nitrogen-containing aromatic heterocyclic compound interact with each other, and electric charges are exchanged between the two. As a result, the electron injection property from the electrode A, for example, the cathode to the light emitting layer is improved, and it is possible to suppress a decrease in the initial voltage, an improvement in the luminance life, an increase in the driving voltage before and after the life evaluation, and a change in chromaticity. Further, the interaction between the nitrogen-containing aromatic heterocyclic compound and the metal ion can prevent the diffusion (migration) of the metal ion to the light emitting layer. As a result, the brightness life of the electronic device is improved, the increase in the driving voltage and the change in chromaticity before and after the life evaluation are suppressed.

Further, when the wet coating film forming method is selected as the electrode forming method, the main constituent materials of the usual electrode forming ink are metal particles (mainly Ag), a dispersant, a solvent, and during purification of the metal particles. It is a metal ion or the like which is a residue of. In addition, these electrode-forming inks contain a large amount of water, and metal ions are generated during the driving of the electronic device. Therefore, the electrode formed by the coating film forming method has a large decrease in luminous efficiency as compared with the electrode formed by the vacuum vapor deposition film forming method. On the other hand, in an electronic device, by applying an electrode A composed of a nitrogen-containing aromatic heterocyclic compound having a metal-metal interaction according to the present invention, for example, a cathode, as described above, significant performance is achieved. Improvements can be achieved. As the light emitting layer in the present invention, in addition to the layer composed of the dopant and the host material, the host layer containing no dopant is also treated as the light emitting layer in the present invention.

Schematic diagram for explaining the effect of the present invention on an electronic device Schematic cross-sectional view showing an example of the configuration of the organic EL element which is the electronic device of the present invention. Schematic cross-sectional view showing another example of the configuration of the organic EL element which is the electronic device of the present invention.

The electronic device of the present invention is an electronic device having at least a light emitting layer and a pair of electrodes on a base material, and has at least one electrode A directly above the light emitting layer, and the electrode A is a metal. It is characterized by containing a nitrogen-containing aromatic heterocyclic compound. These features are technical features that are common to or correspond to each of the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, the electrode A containing a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound and a solvent has wet coating suitability and is significantly improved. It is preferable in that a high performance improvement can be achieved.

Further, it is preferable that the metal is silver in that an electronic device having more excellent luminous efficiency, driving voltage and element life can be obtained.

Further, it is preferable to contain fluorinated alcohol or water as the solvent in that a more excellent effect can be exhibited when the solvent is formed by the wet coating method.

Further, it is preferable that the electrode A contains a metal ion and a surfactant containing fluorine in that the wettability at the time of forming the electrode can be improved.

Further, it is preferable that the electronic device is an organic electroluminescence element and the electrode A is a cathode because the effect of the present invention can be more effectively exhibited.

The method for manufacturing an electronic device of the present invention is a method for manufacturing an electronic device in which a light emitting layer and a pair of electrodes are formed on a base material. It is characterized by being formed by a dry method using a nitrogen-containing aromatic heterocyclic compound.

Further, as another method for manufacturing an electronic device of the present invention, at least, a method for manufacturing an electronic device in which a light emitting layer and a pair of electrodes are formed on a base material, and at least one electrode A is directly above the light emitting layer. Is formed by a wet method using an electrode-forming coating solution containing a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound and a solvent.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

《Electronic device》
The electronic device of the present invention has at least a light emitting layer and a pair of electrodes on a base material, and has at least one electrode A directly above the light emitting layer, and the electrode A has a metal and nitrogen-containing aromatics. It is characterized by containing a group heterocyclic compound. That is, the electronic device of the present invention is characterized in that the light emitting layer and the electrode A are in direct contact with each other without a layer in the middle.

Examples of the electronic device include various electronic devices such as a photoelectric conversion element (solar cell element), an organic electroluminescence (EL) element, a liquid crystal display element, an electronic paper, a thin film transistor, and a touch panel. In particular, it is preferable that the device is an organic EL element and the electrode A according to the present invention is a cathode.

Hereinafter, the outline of the configuration of the organic EL element, which is a typical example of the electronic device, will be described with reference to the drawings.

Typical element configurations of the organic EL according to the present invention are shown below, but the present invention is not limited to these exemplified configurations.

(I) Anode / light emitting layer / cathode (ii) anode / hole transport layer / light emitting layer / cathode (iii) anode / hole injection layer / hole transport layer / light emitting layer / cathode (iv) anode / hole injection Layer / Hole transport layer / (Electronic blocking layer /) Light emitting layer / Anode FIGS. 2 and 3 are schematic cross-sectional views showing an example of a specific configuration of the organic EL element which is the electronic device of the present invention.

In the organic EL element EL shown in FIG. 2, the anode 2, the organic functional layer group 3 and the light emitting layer 4 are sequentially laminated on the base material 1, and the cathode 5 containing a metal and a nitrogen-containing aromatic heterocyclic compound is used. It is characterized in that it is configured so as to be in direct contact with the upper part of the light emitting layer 4. With such a configuration, as described in (c-1) and (c-2) of FIG. 1, in the 5 layers of the cathode, silver ion Ag ⁺ , which is a metal, and a nitrogen-containing aromatic heterocycle are used. By causing an interaction between the ring compounds Cpd2 ^{and preventing the diffusion of silver ion Ag + into} the light emitting layer, it is possible to prevent the quenching of the luminescent exciter by the silver ion in the light emitting layer.

FIG. 3 shows the configuration of the above configuration (iii) and the specific configuration of the organic EL device produced in the examples. With respect to FIG. 2, the organic functional layer group 3 is divided into the hole injection layer 6 and the hole transport. An example of being formed by the layer 7 is shown.

<< Organic EL element >>
Hereinafter, as a typical example of the electronic device, the configuration of the organic EL device provided with the electrode A (cathode) containing the metal and the nitrogen-containing aromatic heterocyclic compound according to the present invention will be described.

[Basic configuration of organic EL element]
In the organic EL element according to the present invention, at least a light emitting layer and a pair of electrodes are provided on the base material, and at least one electrode A is provided immediately above the light emitting layer, and the electrodes A are made of metal and. It is characterized by containing a nitrogen-containing aromatic heterocyclic compound.

Hereinafter, the specific contents of the constituent materials of the organic EL element will be described. In the following description, the electrode A will be described as a cathode.

[Electrode A: Cathode]
The cathode according to the present invention contains a metal and a nitrogen-containing aromatic heterocyclic compound.

(Metal material)
As the metal forming the cathode according to the present invention, a metal having a small work function (6 eV or less) (referred to as an electron-injectable metal), an alloy or the like as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, silver, copper / magnesium mixture, silver / magnesium mixture, aluminum / magnesium mixture, indium / magnesium mixture, aluminum / aluminum oxide (Al). ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, aluminum, rare earth metals and the like. Among these, silver and aluminum are preferable, and silver is more preferable, and in particular, silver is a main component, and the content of silver in the electrode A is preferably 60% by mass or more.

As the metal component constituting the cathode, it is preferable that it is formed of silver alone or is composed of an alloy containing silver (Ag). Examples of such an alloy include silver / copper (Ag / Cu), silver / palladium (Ag / Pd), and silver / palladium / copper (Ag.) In addition to the silver / magnesium (Ag / Mg) mixture described above. Pd · Cu), silver / indium (Ag · In) and the like.

The cathode can also be used as a coatable substance such as metal nanoparticles by using these electrode materials.

(Nitrogen-containing aromatic heterocyclic compound)
The nitrogen-containing aromatic heterocyclic compound applicable to the cathode according to the present invention is not particularly limited, but is a nitrogen-containing aromatic heterocyclic compound having a nitrogen atom having an unshared electron pair that does not participate in aromaticity. Is preferable.

上記一般式（１）において、＝Ｎ−を含んで形成される環Ａ１は、芳香族複素環を表す。Ａｒは、置換基を有していてもよい芳香族炭化水素環又は芳香族複素環を表す。Ｒは、置換基を表す。ｎは、０又は１以上の整数を表す。 The nitrogen-containing aromatic heterocyclic compound in the present invention has a structure represented by the following general formula (1).

In the above general formula (1), the ring A1 formed containing = N− represents an aromatic heterocycle. Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle which may have a substituent. R represents a substituent. n represents an integer of 0 or 1 or more.

In the general formula (1), the ring A1 formed containing = N- represents an aromatic heterocycle, and the aromatic heterocycle includes an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring. , A tetrazole ring, a pyrimidine ring, a pyrazine ring, a triazole ring, a pyridine ring, or a fused ring in which a ring is further condensed with these, and among them, a pyridine ring or a fused ring in which a ring is further condensed with a pyridine ring is preferable.

R represents a substituent, and examples of the substituent include a hydrogen atom, a halogen atom, an arylalkyl group, a cycloalkyl group, an aryl group, and a cyano group.

Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle which may have a substituent, and specific examples thereof include a benzene ring and a fused ring which may have a substituent. It is preferably a benzene ring which may have a substituent.

上記一般式（１−１）において、Ａｒは、置換基を有していてもよい芳香族炭化水素環又は芳香族複素環を表す。Ｒは、置換基を表す。ｎは、０又は１以上の整数を表す。 The general formula (1) more preferably has the structure of the following general formula (1-1), and most preferably A1 is a 2-pyridine ring and Ar is replaced with the ortho position of the 2-pyridine ring. It is a compound having an orthophenylpyridine structure, which is a benzene ring having a group.

In the above general formula (1-1), Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle which may have a substituent. R represents a substituent. n represents an integer of 0 or 1 or more.

In the general formula (1-1), Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle which may have a substituent, and is specifically the same as Ar in the general formula (1). is there.

R represents a substituent, and is specifically the same as R in the general formula (1).

The nitrogen-containing aromatic heterocyclic compound having an orthophenylpyridine structure is generally known to have strong crystallinity and low solubility in a general organic solvent.

By using a fluorinated alcohol solvent such as TFPO, it is considered that the mechanism described above in the section of active hydrogen compound works and the compound is dissolved.

Specific examples of the nitrogen-containing aromatic heterocyclic compound according to the present invention are described below. 1-No. 38 is shown.

Specific examples of the nitrogen-containing aromatic heterocyclic compound other than those exemplified above include, for example, International Publication No. 2010/044342, Japanese Patent Application Laid-Open No. 2010-114180, International Publication No. 2014/0655073, International Publication No. 2014/065215. No., JP-A-2014-21964, JP-A-2015-060717, JP-A-2015-109470, JP-A-2015-122247, JP-A-2015-122253, JP-A-2015-122254, It is described in JP-A-2015-122255, JP-A-2015-125845, JP-A-2015-207773, JP-A-2016-081796, JP-A-2016-106406, JP-A-3925265 and the like. Can be mentioned as a compound.

Further, the nitrogen-containing aromatic heterocyclic compound according to the present invention can be synthesized according to a conventionally known synthetic method.

(Dispersant)
The electrode A according to the present invention preferably contains a dispersant together with a metal, a nitrogen-containing aromatic heterocyclic compound, and a solvent.

The dispersant according to the present invention can be used as a metal constituting the electrode A when it is dispersed in a coatable form such as metal nanoparticles.

As the dispersant applicable to the present invention, various conventionally known dispersants can be applied. Among them, a polymer dispersant having an adsorbent group adsorbable on the surface of metal nanoparticles and a hydrophilic structure. Is preferably applied.

Examples of the adsorbent group contained in the polymer dispersant include a hydroxy group, a carboxyl group, a thiol group and the like.

The resin constituting the polymer dispersant is preferably a homopolymer or a copolymer of a hydrophilic monomer. The copolymer of the hydrophilic monomer may be a copolymer of the hydrophilic monomer and the hydrophobic monomer.

Examples of hydrophilic monomers include monomers containing a carboxyl group or an acid anhydride group (unsaturated polycarboxylic acids such as (meth) acrylic acid and maleic acid, and maleic anhydride), and alkylene oxide modifications (meth). ) Acrylic acid ester monomers (ethylene oxide-modified (meth) acrylic acid alkyl esters, etc.) are included. In the present invention, (meth) acrylic means both acrylic and / or methacrylic.

Examples of hydrophobic monomers include (meth) acrylic acid ester-based monomers such as methyl (meth) acrylate and ethyl (meth) acrylate, styrene-based monomers such as styrene, α-methylstyrene and vinyltoluene, ethylene and propylene. , And α-olefin monomers such as 1-butene, and carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl butyrate.

When the polymer dispersant is a copolymer, it can be a random copolymer, an alternating copolymer, a block copolymer, a comb-type copolymer, or the like. Above all, from the viewpoint of further enhancing the dispersibility of the metal nanoparticles, the polymer dispersant is preferably a comb-type block copolymer.

The polymer dispersant preferably has a polyalkylene oxide structure in the molecule, and more preferably the above-mentioned comb-shaped block copolymer having a polyalkylene oxide group in the side chain. The polyalkylene oxide structure moderately reduces the cohesiveness of metal nanoparticles due to steric hindrance. As a result, it is considered that the metal ink (or the metal nanoparticles in the metal ink) can be appropriately wetted and spread on the base material to form a smoother and higher glossy image.

The polymer dispersant preferably has a weight average molecular weight of 1000 or more and 100,000 or less, and more preferably 2000 or more and 50,000 or less.

Examples of commercially available polymer dispersants include DISPERBYK-102, DISPERBYK-187, DISPERBYK-190, DISPERBYK-191, DISPERBYK-194N, DISPERBYK-199, DISPERBYK-2015, and DISPERBYK-2069 (above, Big Chemie). , "DISPERBYK" is a registered trademark of the company), EFKA 6220 (manufactured by BASF, "EFKA" is a registered trademark of the company), Solsperse 32000, Solsperse 44000, Solsperse 46000 (all manufactured by Lubrizol), Floren TG-750W (Manufactured by Kyoeisha Chemical Co., Ltd.) and the like.

The content of the polymer dispersant in the coating solution for electrode formation is not particularly limited, but is 1 to 15% by mass with respect to the total mass of the metal nanoparticles from the viewpoint of sufficiently enhancing the dispersibility of the metal nanoparticles. It is preferably in the range of 2 to 10% by mass, and more preferably in the range of 2 to 10% by mass.

(Surfactant containing fluorine)
The electrode A according to the present invention preferably contains a surfactant containing fluorine together with the metal ion.

The surfactant containing fluorine that can be applied to the present invention is not particularly limited, but is composed of a monomer, an oligomer, or a polymer containing a perfluoroalkyl group as a mother nucleus, and is composed of polyoxyethylene alkyl ether and polyoxyethylene. Examples thereof include alkylallyl ethers, polyoxyethylenes, derivatives such as polyisocyanate compounds having a urethane structure, and the like.

As the surfactant containing fluorine, a commercially available product can also be used, for example, Surflon S-381, S-382, SC-101, SC-102, SC-103, SC-104 (above, Asahi Glass Co., Ltd.), Florard FC-430, FC-431, FC-173 (above, Fluorochemical-Sumitomo 3M Ltd.), Ftop EF352, EF301, EF303 (above, manufactured by Shin-Akita Kasei Co., Ltd.) ), Schvegofluer 8035, 8036 (above, manufactured by Schvegman), BM1000, BM1100 (above, manufactured by BM Himmy), Megafuck F-171, F-470 (above, manufactured by DIC Co., Ltd.), Examples thereof include Fluorent series 251, 212MH, 250, 222F, 212D, FTX-218 (all manufactured by Neos) and the like.

(solvent)
In the method for forming the electrode A according to the present invention, it is preferable to apply fluorinated alcohol or water as the solvent. By applying fluorinated alcohol, it is preferable from the viewpoints of obtaining a device that can be driven at a low voltage and luminous efficiency.

As one of the preferable fluorinated alcohols, a compound represented by the following general formula (a) can be mentioned.

General formula (a) A-CH ₂ OH
In the general formula (a), A represents CF ₃ or CHF ₂ (CF ₂ ) _n , and n represents an integer of 1-5. It is more preferably 1 to 3, and even more preferably 1.

一般式（ｂ）及び（ｃ）において、Ａ、Ｂ及びＤは、それぞれ独立にＣＨ_３−ｘＦ_ｘ又はＣＨ_３−ｘＦ_ｘ（ＣＨ_２−ｙＦ_ｙ）_ｎを表し、ｘは１〜３、ｙは１〜２、ｎは０〜１の整数を表す。 Specific examples of the fluorinated alcohol include compounds represented by the general formula (b) or the general formula (c).

In the general formulas (b) and (c), A, B and D independently represent CH _3-x F _x or CH _3-x F _x (CH _2-y F _y ) _n , where x is 1 to 1. 3, y represents an integer of 1 to 2, n represents an integer of 0 to 1.

Specific examples of these fluorine-containing alcohols include the following compounds.

1) 2,2,3,3-tetrafluoropropanol,
2) 2,2,3,3,3-pentafluoropropanol,
3) 2-Trifolomethyl-2-propanol,
4) 2,2,3,3,4,4-hexafluorobutanol,
5) 2,2,3,3,4,5,5-octafluoropentanol,
6) 1,1,1,3,3,3-hexafluoro-2-propanol,
7) 2,2,2-trifluoro-1-ethanol,
8) 2,3-Difluorobenzyl alcohol,
9) 2,2,2-Trifluoroethanol,
10) 1,3-Difluoro-2-propanol,
11) 1,1,1-trifluoro-2-propanol,
12) 3,3,3-trifluoro-1-propanol,
13) 2,2,3,3,4,5,4-heptafluoro-1-butanol,
14) 2,2,3,3,4,5,5-octafluoro-1-pentanol,
15) 3,3,4,5,5,5-heptafluoro-2-pentanol,
16) 2,2,3,3,4,5,5,6,6,7,7,8,8,8-pentadecafluoro-1-octanol,
17) 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol,
18) 1H, 1H, 7H-dodecafluoro-1-heptanol 19) 1H, 1H, 9H-perfluoro-1-nonanol,
20) 1H, 1H, 2H, 3H, 3H-perfluorononane-1,2-diol,
21) 1H, 1H, 2H, 2H-perfluoro-1-decanol,
22) 1H, 1H, 2H, 3H, 3H-perfluoroundecane-1,2-diol Further, fluorine-containing propanol is preferable, and 2,2,3,3-tetrafluoro-2-propanol, or 1, 1,1,3,3,3-hexafluoro-2-propanol or 2,2,3,3,3-pentafluoropropanol is preferable.

(Method of forming electrode A (cathode))
One of the methods for producing an electronic device of the present invention is characterized in that at least one electrode A is formed directly above the light emitting layer by a dry method using a metal and a nitrogen-containing aromatic heterocyclic compound. Examples of the dry method applicable to the formation of the electrode A according to the present invention include a dry process such as a vapor deposition method (resistive heating, EB method, etc.), a sputtering method, and a CVD method.

Further, in another method of the method for producing an electronic device of the present invention, at least one electrode A is applied directly above the light emitting layer for electrode formation containing a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound and a solvent. It is characterized in that it is formed by a wet method using a liquid. Examples of the wet method applicable to the formation of the electrode A according to the present invention include a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, and a dip. Examples thereof include a coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, an inkjet printing method, and the like, and conventionally known methods can be appropriately selected and applied.

[Components other than the cathode of the organic EL element]
Next, the components of the organic EL element other than the cathode described above will be described.

[Light emitting layer]
The light emitting layer according to the present invention is a layer that provides a place where electrons and holes injected from an electrode or an adjacent layer are recombined and emit light via excitons, and the light emitting portion is a layer of the light emitting layer. It may be inside or at the interface between the light emitting layer and the adjacent layer. The structure of the light emitting layer according to the present invention is not particularly limited as long as it satisfies the requirements specified in the present invention.

The total thickness of the light emitting layer is not particularly limited, but the homogeneity of the formed layer, prevention of applying an unnecessary high voltage at the time of light emission, and improvement of the stability of the light emitting color with respect to the driving current are improved. From the viewpoint, it is preferably adjusted within the range of 2 nm to 5 μm, more preferably adjusted within the range of 2 to 500 nm, and further preferably adjusted within the range of 5 to 200 nm.

The thickness of each light emitting layer is preferably adjusted within the range of 2 nm to 1 μm, more preferably adjusted within the range of 2 to 200 nm, and further preferably adjusted within the range of 3 to 150 nm. ..

The light emitting layer preferably contains a light emitting dopant (a light emitting dopant compound, a dopant compound, also simply referred to as a dopant) and a host compound (a matrix material, a light emitting host compound, also simply referred to as a host).

(Luminous dopant)
As the luminescent dopant, a fluorescent dopant (also referred to as a fluorescent dopant or a fluorescent compound) and a phosphorescent dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) are preferably used. In the present invention, it is preferable that at least one light emitting layer contains a phosphorescent dopant.

The concentration of the luminescent dopant in the light emitting layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration with respect to the film thickness direction of the light emitting layer. It may have an arbitrary concentration distribution.

Further, the light emitting dopant according to the present invention may be used in combination of a plurality of types, may be used in combination of dopants having different structures, or may be used in combination of a fluorescent light emitting dopant and a phosphorescent light emitting dopant. Thereby, an arbitrary emission color can be obtained.

The color emitted by the organic EL element according to the present invention is shown in FIG. 4.16 on page 108 of the "New Color Science Handbook" (edited by the Japan Color Society, edited by the University of Tokyo Press, 1985). It is determined by the color when the result measured by Konica Minolta Co., Ltd. is applied to the CIE chromaticity coordinates.

In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting dopants having different light emitting colors and exhibits white light emission.

The combination of luminescent dopants showing white color is not particularly limited, and examples thereof include a combination of blue and orange, a combination of blue and green, and red.

The white color in the organic EL element according to the present invention is not particularly limited and may be white color closer to orange or white color closer to blue, but when the 2 degree viewing angle front luminance is measured by the above method. In addition, it is preferable that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is within the region of x = 0.39 ± 0.09 and y = 0.38 ± 0.08.

<Phosphorescent light emitting dopant>
The phosphorescent dopant (hereinafter, also referred to as “phosphorescent dopant” or “phosphorescent light emitting material”) according to the present invention will be described.

The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescent light at room temperature (25 ° C.), and has a phosphorescent quantum yield of 25. It is defined as a compound of 0.01 or more at ° C, but a preferable phosphorescence quantum yield is 0.1 or more.

The phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th edition Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescence dopant according to the present invention can achieve the above phosphorescence quantum yield (0.01 or more) in any of any solvents. Just do it.

There are two types of light emission of the phosphorescent dopant in principle. One is that carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. It is an energy transfer type that obtains light emission from a phosphorescent dopant. The other is a carrier trap type in which the phosphorescent dopant serves as a carrier trap, and carriers are recombined on the phosphorescent dopant to obtain light emission from the phosphorescent dopant. In either case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

As the phosphorescent dopant that can be used in the present invention, it can be appropriately selected from known ones used for the light emitting layer of the organic EL element.

Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

Nature 395, 151 (1998), Apple. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19,739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17,1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Publication No. 2006/835469, US Patent Publication No. 2006/20202194. Description, US Patent Publication No. 2007/0087321, US Patent Publication No. 2005/0244673, Inorg. Chem. 40,1704 (2001), Chem. Mater. 16,2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. Int. Ed. 2006, 45, 7800, Apple. Phys. Lett. 86,153505 (2005), Chem. Lett. 34,592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42,1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Publication No. 2002/0034656, US Pat. No. 7,332232, US Patent Publication No. 2009/01087737, US Patent Publication No. 2009/00397776, US Patent Publication No. 6921915, US Patent No. 6687266, US Patent Publication No. 2007/0190359, USA Publication No. 2006/0008670, US Patent Publication No. 2009/015846, US Patent Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598, US Patent Publication No. 2006/0263635, US Patent Publication No. 2003/0138657, US Patent Publication No. 2003/0152802, US Patent No. 70090928, Angew. Chem. Int. Ed. 47, 1 (2008), Chem. Mater. 18,5119 (2006), Inorg. Chem. 46,4308 (2007), Organometallics 23,3745 (2004), Apple. Phys. Lett. 74,1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/090024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Publication No. 2006/0251923, US Patent Publication No. 2005/02060441, US Patent No. 73935999, US Patent No. 75334505 , US Patent Publication No. 7445855, US Patent Publication No. 2007/0190359, US Patent Publication No. 2008/0297033, US Patent No. 7338722, US Patent Publication No. 2002/0134984, US Pat. No. 7,279,704, US Patent Publication No. 2006/098120, US Patent Publication No. 2006/103874, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008 / 140115, International Publication No. 2007/05/2431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/20327 No., International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Publication No. 2012/228583, US Patent Publication No. 2012/212126, Japanese Patent Application Laid-Open No. 2012-069737, 2012-195554, 2009-114086, 2003-81988, 2002-302671 and 2002-363552.

Among them, preferred phosphorescent dopants include organometallic complexes having Ir as the central metal. More preferably, a complex containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond is preferable.

<Fluorescent light emitting dopant>
A fluorescent dopant (hereinafter, also referred to as “fluorescent dopant” or “fluorescent material”) according to the present invention will be described.

The fluorescent dopant according to the present invention is a compound capable of emitting light from the excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.

Examples of the fluorescent dopant according to the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluorantene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes and coumarin derivatives. , Pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, rare earth complex compounds and the like.

Further, in recent years, luminescent dopants using delayed fluorescence have also been developed, and these may be used.

Specific examples of the luminescent dopant using delayed fluorescence include the compounds described in International Publication No. 2011/156793, JP-A-2011-213643, JP-A-2010-93181, etc., but the present invention includes the compounds described in JP-A-2010-93181. Not limited to these.

(Host compound)
The host compound applicable to the light emitting layer according to the present invention is a compound mainly responsible for injection and transport of electric charges in the light emitting layer, and its own light emission is not substantially observed in the organic EL device.

A compound having a phosphorescent quantum yield of less than 0.1 at room temperature (25 ° C.) is preferable, and a compound having a phosphorescent quantum yield of less than 0.01 is more preferable. Further, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more.

Further, the excited state energy of the host compound is preferably higher than the excited state energy of the luminescent dopant contained in the same layer.

The host compound may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of electric charges, and it is possible to improve the efficiency of the organic EL device.

The host compound that can be used in the present invention is not particularly limited, and compounds conventionally used in organic EL devices can be used. It may be a low molecular weight compound, a high molecular weight compound having a repeating unit, or a compound having a reactive group such as a vinyl group or an epoxy group.

As a known host compound, it has a hole transporting ability or an electron transporting ability, prevents the wavelength of light emission from being lengthened, and further stabilizes the organic EL device against heat generation during high temperature driving or device driving. It is preferable to have a high glass transition temperature (Tg) from the viewpoint of operating the device. Tg is preferably 90 ° C. or higher, and more preferably 120 ° C. or higher.

Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Calorimetry).

Specific examples of known host compounds used in the organic EL device in the present invention include, but are not limited to, the compounds described in the following documents.

JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002. 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 -3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002- 302516, 2002-305083, 2002-305084, 2002-308837, US Patent Publication No. 2003/0175553, US Patent Publication No. 2006/0280965, US Patent Publication 2005/0112407, US Patent Publication No. 2009/0017330, US Patent Publication No. 2009/0030202, US Patent Publication No. 2005/02389919, International Publication No. 2001/039234. , International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/0637996, International Publication No. 2007/0637554, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/0293947, Japanese Patent Application Laid-Open No. 2008 -074939A, Japanese Patent Application Laid-Open No. 2007-254297, European Patent No. 2034538, and the like.

In the present invention, a layer composed only of a host compound containing no light emitting dopant is also included as a light emitting layer.

[Hole transport layer]
In the present invention, the hole transport layer may be made of a material having a function of transporting holes and may have a function of transmitting holes injected from the anode to the light emitting layer.

The total film thickness of the hole transport layer is not particularly limited, but is usually in the range of 5 nm to 5 μm, more preferably in the range of 2 to 500 nm, and further preferably in the range of 5 to 200 nm. is there.

The material used for the hole transport layer (hereinafter referred to as the hole transport material) may have any of hole injection property, transport property, and electron barrier property, and is among conventionally known compounds. Any one can be selected and used from.

For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stillben derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives. , Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polymer materials or oligomers in which polyvinylcarbazole and aromatic amines are introduced into the main chain or side chains, polysilane, conductivity. Sex polymers or oligomers (eg, PEDOT: PSS, aniline-based copolymers, polyaniline, polythiophene, etc.) and the like can be mentioned.

Examples of the triarylamine derivative include a benzidine type represented by α-NPD, a starburst type represented by MTDATA, and a compound having fluorene or anthracene in the triarylamine connecting core portion.

Hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.

Further, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175. Apple. Phys. , 95, 5773 (2004) and the like.

In addition, JP-A-11-251667, J. Am. Hung et. al. So-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC as described in the authored literature (Applied Physics Letters 80 (2002), p.139) can also be used. Further, an orthometalated organometallic complex having Ir or Pt in the central metal as represented by Ir (ppy) _{3 is also preferably used.}

As the hole transporting material, the above-mentioned materials can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organic metal complex, and an aromatic amine are introduced into the main chain or the side chain. High molecular weight materials or oligomers are preferably used.

Specific examples of known and preferable hole transporting materials used in the organic EL device according to the present invention include the compounds described in the following documents in addition to the above-mentioned documents, and the present invention includes these. Not limited.

For example, Apple. Phys. Lett. 69,2160 (1996), J. Mol. Lumin. 72-74,985 (1997), Apple. Phys. Lett. 78,673 (2001), Apple. Phys. Lett. 90,183503 (2007), Apple. Phys. Lett. 90,183503 (2007), Apple. Phys. Lett. 51,913 (1987), Synth. Met. 87,171 (1997), Synth. Met. 91,209 (1997), Synth. Met. 111,421 (2000), SID SymposiumDigest, 37,923 (2006), J. Mol. Mater. Chem. 3,319 (1993), Adv. Mater. 6,677 (1994), Chem. Mater. 15, 3148 (2003), US Patent Publication No. 2003/0162053, US Patent Publication No. 2002/0158242, US Patent Publication No. 2006/0240279, US Patent Publication No. 2008/0220265. , US Patent Publication No. 5061569, International Publication No. 2007/002683, International Publication No. 2009/01809, European Patent No. 650955, US Patent Publication No. 2008/01245772, US Patent Publication No. 2007 / 0278938, US Patent Publication No. 2008/0106190, US Patent Publication No. 2008/0018221, International Publication No. 2012/115342, Japanese Patent Application Laid-Open No. 2003-591432, JP-A-2006-135145. , US Patent Application No. 2013/585981, etc.

The hole transporting material may be used alone or in combination of two or more.

[Electronic blocking layer]
The electron blocking layer is a layer having a function of a hole transporting layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, and is composed of a material having a small ability to transport electrons while transporting holes. It is possible to improve the recombination probability of electrons and holes by blocking the above.

Further, the structure of the hole transport layer described above can be used as an electron blocking layer according to the present invention, if necessary.

The electron blocking layer is preferably provided adjacent to the anode side of the light emitting layer.

The film thickness of the electron blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

As the material used for the electron blocking layer, the material used for the hole transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the electron blocking layer.

[Hole injection layer]
In the organic EL device according to the present invention, the hole injection layer (also referred to as “anode buffer layer”) is a layer provided between the anode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness. It is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "Organic EL Devices and Their Industrial Frontiers (published by NTS Co., Ltd., November 30, 1998)".

In the present invention, the hole injection layer may be provided as needed and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.

The details of the hole injection layer are described in JP-A-9-45479, 9-2660062, 8-288609, etc., and examples of the material used for the hole injection layer include. Examples thereof include materials used for the hole transport layer described above.

Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon. , Polyaniline (emeraldine), polythiophene and other conductive polymers, tris (2-phenylpyridine) iridium complex and the like, orthometallated complexes, triarylamine derivatives and the like are preferable.

The material used for the hole injection layer described above may be used alone or in combination of two or more.

〔anode〕
The organic EL element (electronic device) has a configuration in which a light emitting layer and a pair of electrodes are provided on a base material, and one electrode is an electrode A containing a metal and a nitrogen-containing aromatic heterocyclic compound according to the present invention. Although it is a (cathode), the other electrode functions as an anode.

As the anode, a metal having a large work function (4 eV or more, preferably 4.5 V or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as _{CuI, indium tin oxide (ITO), SnO 2, and ZnO.} Further, a material such as IDIXO (In ₂ O _3- ZnO) which is amorphous and can produce a transparent conductive film may be used.

For the anode, a thin film may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 μm or more). The pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.

Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can also be used. When emitting light from this anode, it is desirable to increase the transmittance to more than 10%, and the sheet resistance as the anode is several hundred Ω / sq. The following is preferable.

The film thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

"Base material"
The type of base material that can be used for the organic EL element in the present invention is not particularly limited, such as glass and plastic, and may be transparent or opaque. When light is extracted from the base material side, the base material is preferably transparent. Examples of the transparent base material preferably used include glass, quartz, and a transparent resin film. A particularly preferable base material is a resin film capable of imparting flexibility to the organic EL element.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate. CAP), cellulose acetate phthalate, cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, Arton (trade name: JSR) or Appel. Examples thereof include cycloolefin resins (trade name: manufactured by Mitsui Kagaku Co., Ltd.).

A film of an inorganic substance, an organic substance, or a hybrid film of both of them may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. oxygen relative humidity (90 ± 2)% RH) is preferably a barrier film of 0.01g ^/ (m 2 · 24h) or less, still more, as measured by the method based on JIS K 7126-1987 the ^{permeability, 10 -3 mL / (m 2} · 24h · atm) or less, the water vapor permeability ^is preferably ^{10 -5 g / (m 2 ·} 24h) or less of the high barrier film.

As the material for forming the barrier film, any material that causes deterioration of the element such as moisture and oxygen but has a function of suppressing infiltration may be used, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The stacking order of the inorganic layer and the organic layer is not particularly limited, but it is preferable to stack the inorganic layer and the organic layer alternately a plurality of times.

The method for forming the barrier film is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method. , Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used, but the atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

Examples of the opaque base material include metal plates such as aluminum and stainless steel, films and opaque resin substrates, and ceramic substrates.

The quantum efficiency of light emission of the organic EL device according to the present invention at room temperature is preferably 1% or more, and more preferably 5% or more.

Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons passed through the organic EL element × 100.

[Manufacturing method of organic EL element (excluding cathode formation)]
A method for forming an organic layer (hole injection layer, hole transport layer, light emitting layer, etc.) in the present invention will be described.

The method for forming the organic layer is not particularly limited, and a conventionally known forming method such as a vacuum vapor deposition method or a wet method (also referred to as a wet process) can be used, and the mixed composition for the organic EL device of the present invention can be used. When using, the wet method is used.

Examples of the wet method include a gravure printing method, a flexographic printing method, a screen printing method, and other printing methods, as well as a spin coating method, a casting method, an inkjet printing method, a die coating method, a blade coating method, a bar coating method, and a roll coating method. , Dip coat method, spray coat method, curtain coat method, doctor coat method, LB method (Langmuir-Blogget method), etc., but the coating liquid can be applied easily and accurately, and it is highly productive. From the point of view, it is more preferable to apply by an inkjet printing method using an inkjet head.

Further, a different film forming method may be applied to each layer. When employing the vapor deposition film, the depositing conditions thereof are varied according to kinds of materials used, generally boat temperature 50 to 450 ° C., vacuum of ¹⁰ -6 ^{to 10} -2 Pa, deposition rate 0.01 It is desirable to appropriately select in the range of 50 nm / sec, substrate temperature -50 to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.

The formation of the organic layer in the present invention is preferably carried out consistently from the hole injection layer to the cathode by one vacuuming, but it may be taken out in the middle and a different film forming method may be applied. In that case, it is preferable to carry out the work in a dry inert gas atmosphere.

[Sealing]
The organic EL produced by the above method is sealed.

Examples of the sealing means used for sealing the organic EL element include a method of adhering the sealing member to the electrode or the base material with an adhesive. The sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.

Specific examples thereof include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.

In the present invention, a polymer film or a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film had an oxygen permeability of 1 × 10 ^-3 mL / m ² / 24h or less measured by a method according to JIS K 7126-1987, and was measured by a method according to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably 1 × 10 ^-3 g / (m ² / 24h) or less.

Sandblasting, chemical etching, etc. are used to process the sealing member into a concave shape.

Specific examples of the adhesive include a photocurable and thermosetting adhesive having a reactive vinyl group of an acrylic acid-based oligomer and a methacrylic acid-based oligomer, and a moisture-curable adhesive such as 2-cyanoacrylic acid ester. be able to. In addition, heat and chemical curing type (two-component mixture) such as epoxy type can be mentioned. Further, hot melt type polyamide, polyester and polyolefin can be mentioned. In addition, a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.

Since the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing may be performed as in screen printing.

Further, the electrode A and the light emitting layer are coated on the outside of the electrode A (cathode) on the side facing the base material with the light emitting layer sandwiched therein, and layers of inorganic and organic substances are formed in contact with the support substrate to form a sealing film. Can also be preferred. In this case, the material for forming the film may be any material having a function of suppressing infiltration of a material that causes deterioration of the element such as moisture and oxygen, and for example, silicon oxide, silicon dioxide, silicon nitride or the like may be used. it can.

Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The method for forming these films is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight. Legal, plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used.

In the gas phase and liquid phase, an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicone oil may be injected into the gap between the sealing member and the display region of the organic EL element. preferable. It is also possible to create a vacuum. Further, a hygroscopic compound can be enclosed inside.

Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). , Metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (eg, barium perchlorate, etc.) Magnesium perchlorate, etc.) and the like, and anhydrous salts are preferably used for sulfates, metal halides and perchlorates.

[Protective film, protective plate]
A protective film or a protective plate may be provided on the outside of the sealing film or the sealing film on the side facing the base material with the light emitting layer sandwiched in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, the mechanical strength thereof is not necessarily high, so it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, a glass plate, a polymer plate / film, a metal plate / film, etc. similar to those used for the sealing can be used, but the polymer film is lightweight and thin. Is preferably used.

Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass". Unless otherwise specified, each operation was performed at room temperature (25 ° C.).

<< Fabrication of organic EL element >>
[Manufacturing of organic EL element 1]
An anode (anode) / hole injection layer (HIL) / hole transport layer (HTL) / light emitting layer (EML) / cathode (cathode) are sequentially laminated on the substrate according to the following method, and then sealed. The bottom emission type organic EL element 1 was produced.

(Preparation of base material)
A polyethylene naphthalate film (manufactured by Teijin DuPont, hereinafter abbreviated as PEN) is used as a base material, and an atmospheric pressure plasma having the configuration described in JP-A-2004-68143 is applied to the entire surface on the side where the anode is formed. Using a discharge treatment device, _{a gas barrier layer of an inorganic oxide made of SiO x} was formed into a film so that the layer thickness was 500 nm. Accordingly, the oxygen permeability of at ^{0.001mL / (m 2 · 24h ·} atom) or less, a substrate having flexibility water vapor permeability has a 0.001g ^/ (m 2 · 24h) The following gas barrier properties Made.

(Formation of anode)
An ITO (indium tin oxide) having a thickness of 120 nm was formed on the surface of the base material having a gas barrier layer by a sputtering method, and then patterned by a photolithography method to form an anode. The anode was formed in a pattern such that the area of the light emitting region was 5 cm × 5 cm.

(Formation of hole injection layer)
The base material on which the anode was formed was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and treated with UV ozone for 5 minutes. Next, poly (3,4-ethylenedioxythiophene) / polystyrene sulfonate (abbreviation: PEDOT /) prepared in the same manner as in Example 16 of Japanese Patent No. 4509787 on the base material on which the anode was formed. The dispersion of PSS) was diluted with isopropyl alcohol, and a 2% by mass solution of PEDOT / PSS was applied by an inkjet method and dried at 80 ° C. for 5 minutes to form a hole injection layer having a layer thickness of 40 nm.

(Formation of hole transport layer)
Next, the base material on which the hole injection layer was formed was coated by an inkjet method using a coating solution for forming a hole transport layer having the following composition in an atmospheric environment, dried at 130 ° C. for 30 minutes, and layered. Formed a hole transport layer of 30 nm.

<Coating liquid for forming hole transport layer>
Hole transport material (weight average molecular weight Mw = 80000, see below) 10 parts by mass Chlorobenzene 3000 parts by mass

(Formation of light emitting layer)
Next, the base material on which the hole transport layer was formed was applied by an inkjet method using a coating liquid for forming a light emitting layer having the following composition, and dried at 120 ° C. for 30 minutes to form a light emitting layer having a layer thickness of 50 nm.

(Coating liquid for forming a light emitting layer)
Host compound 10 parts by mass Phosphorescent light emitting material 1 part by mass Fluorescent light emitting material 0.1 parts by mass Normal butyl acetate 2200 parts by mass

(Cathode formation)
Next, the base material formed up to the light emitting layer was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. On the other hand, aluminum as a metal material and nitrogen-containing aromatic heterocyclic compound A as a nitrogen-containing aromatic heterocyclic compound were loaded into two tungsten resistance heating boats and attached to a vacuum vapor deposition apparatus. Next, after reducing the degree of vacuum to 1 × 10 ^-4 Pa, a boat containing aluminum and a boat containing a nitrogen-containing aromatic heterocyclic compound A were simultaneously energized, and the film formation rate was 1.0 Å / s, respectively. A cathode was formed by vapor deposition so that the total layer thickness was 200 nm while adjusting the concentration to 0.250 Å / s.

(Sealing process)
A sealing base material was adhered to the laminate formed up to the cathode by the above steps using a commercially available roll laminating apparatus to perform a sealing treatment.

The sealing base material is a flexible aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) with a thickness of 1.5 μm using a two-component reaction type urethane adhesive for dry lamination. A layer was provided, and a polyethylene terephthalate (PET) film having a thickness of 12 μm was laminated.

As the sealing adhesive, a thermosetting adhesive was uniformly applied to a thickness of 20 μm along the adhesive surface (glossy surface) of the aluminum foil of the sealing base material using a dispenser. This was dried under a vacuum of 100 Pa or less for 12 hours. Further, the sealing base material is moved to a nitrogen atmosphere having a dew point temperature of -80 ° C or less and an oxygen concentration of 0.8 ppm and dried for 12 hours or more so that the water content of the sealing adhesive becomes 100 ppm or less. It was adjusted.

As the thermosetting adhesive, an epoxy-based adhesive in which the following (A) to (C) were mixed was used.

(A) Bisphenol A Diglycidyl Ether (DGEBA)
(B) Dicyanodiamide (DICY)
(C) Epoxy Adduct Curing Accelerator The sealing base material is adhered to and arranged on the laminate, and a crimping roll is used to obtain a crimping roll temperature of 100 ° C., a pressure of 0.5 MPa, and an apparatus speed of 0.3 m. The organic EL element 1 was manufactured by tightly sealing under a crimping condition of / min.

[Manufacturing of Organic EL Element 2 and Organic EL Element 3]
In the production of the organic EL element 1, the same applies except that the nitrogen-containing aromatic heterocyclic compound A used for forming the cathode is changed to the nitrogen-containing aromatic heterocyclic compound B and the nitrogen-containing aromatic heterocyclic compound C, respectively. The organic EL element 2 and the organic EL 3 were produced.

[Manufacturing of organic EL element 4]
In the production of the organic EL element 1, the organic EL element 4 is formed in the same manner except that the cathode is formed of aluminum alone except for the nitrogen-containing aromatic heterocyclic compound A which is a nitrogen-containing aromatic heterocyclic compound. Made.

[Manufacturing of organic EL element 5]
In the production of the organic EL element 1, the organic EL element 5 was produced in the same manner except that potassium fluoride was used instead of the nitrogen-containing aromatic heterocyclic compound A used for forming the cathode.

[Manufacturing of organic EL elements 6 to 10]
In the production of the organic EL elements 1 to 5, the organic EL elements 6 to 10 were produced in the same manner except that silver was used instead of aluminum as the metal material.

[Manufacturing of organic EL element 11]
In the production of the organic EL element 6, the organic EL element 11 is formed in the same manner except that the cathode is formed by the wet coating method using the cathode forming coating liquid 1 described below instead of the vapor deposition method. Was produced.

(Preparation of metal fine particle dispersion liquid 1)
100 mL of a 1000 mM silver nitrate aqueous solution was placed in a beaker. In another beaker, 3 g of a non-volatile polymer dispersant (Disperbic 190 (trade name), manufactured by Big Chemie Japan, 40% aqueous solution) was taken as an aqueous wet dispersant, and 100 g of pure water was added thereto.

To a beaker containing an aqueous silver nitrate solution, 27 g of a Disperbic 190 aqueous solution prepared in another beaker was added. After sufficiently stirring, 15 g of triethanolamine was added, and the mixture was stirred at 60 ° C. for 6 hours. Then, centrifugation and purification were performed three times. Pure water was added to the obtained silver particles to make a total of 50 g, and a metal fine particle dispersion liquid 1 in which silver particles were dispersed was prepared.

(Cathode formation)
A cathode-forming coating liquid 1 having the following composition was applied to a substrate having a film formed up to the electron transport layer using a dispenser to form a cathode. The amount of liquid and the coating rate were adjusted in advance so that the film thickness after drying would be 200 nm. After application, it was dried in a constant temperature bath at 120 ° C. for 30 minutes.

<Cathode forming coating liquid 1>
Metal fine particle dispersion liquid 1 25 parts by mass Nitrogen-containing aromatic heterocyclic compound A 6.25 parts by mass Water 210 parts by mass

[Manufacturing of organic EL element 12]
In the production of the organic EL element 6, the organic EL element 12 is formed in the same manner except that the cathode is formed by the wet coating method using the cathode forming coating liquid 2 described below instead of the vapor deposition method. Was produced.

(Preparation of metal fine particle dispersion liquid 2)
100 mL of a 1000 mM silver nitrate aqueous solution was placed in a beaker. In another beaker, take 3 g of a non-volatile polymer dispersant (Dispervic 190 (trade name), manufactured by Big Chemie Japan, 40% aqueous solution) as an aqueous wet dispersant, and add 2,2,2 as fluorinated alcohol to it. 100 g of 3,3-tetrafluoropropanol was added.

To a beaker containing an aqueous silver nitrate solution, 27 g of a Disperbic 190 aqueous solution prepared in another beaker was added. After sufficiently stirring, 15 g of triethanolamine was added, and the mixture was stirred at 60 ° C. for 6 hours. Then, centrifugation and purification were performed three times. 2,2,3,3-tetrafluoropropanol was added to the obtained silver particles to make a total of 50 g, and a metal fine particle dispersion 2 in which the silver particles were dispersed was prepared.

(Cathode formation)
A cathode forming coating liquid 2 having the following composition was applied to a substrate having a film formed up to the electron transport layer using a dispenser to form a cathode. The amount of liquid and the coating rate were adjusted in advance so that the film thickness after drying would be 200 nm. After application, it was dried in a constant temperature bath at 120 ° C. for 30 minutes.

<Cathode forming coating liquid 2>
Metal Fine Particle Dispersion Liquid 125 parts by mass Nitrogen-containing aromatic heterocyclic compound A 6.25 parts by mass 2,2,3,3-tetrafluoropropanol 210 parts by mass

[Manufacturing of organic EL elements 13 to 14]
In the production of the organic EL element 11, the same applies except that the nitrogen-containing aromatic heterocyclic compound A used for forming the cathode is changed to the nitrogen-containing aromatic heterocyclic compound B and the nitrogen-containing aromatic heterocyclic compound C, respectively. The organic EL element 13 and the organic EL element 14 were produced.

[Manufacturing of organic EL element 15]
In the production of the organic EL element 11, the cathode is formed in the same manner except for the cathode forming coating liquid 1 and using the same volume of water as the metal fine particle dispersion liquid 1 and the cathode forming coating liquid 1. The EL element 15 was manufactured.

[Manufacturing of organic EL element 16]
In the production of the organic EL element 11, the organic EL element 16 was produced in the same manner except that potassium fluoride was used instead of the nitrogen-containing aromatic heterocyclic compound A used for forming the cathode.

<< Evaluation of organic EL elements >>
The organic EL devices 1 to 16 produced above were comprehensively evaluated based on the initial brightness, the drive voltage, the device life (LT50, drive voltage) under a high temperature environment, and the results thereof according to the following methods.

(Evaluation of initial brightness and drive voltage)
^{The front luminance when a constant current of 2.5} mA / cm 2 was applied to each organic EL element in an atmosphere of dry nitrogen at 23 ° C. was measured and used as the initial luminance. A spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.) was used for the measurement. The initial brightness was represented by a relative value with the measured value of the organic EL element 1 as 100.

The drive voltage was expressed as a relative value with the measured value of the organic EL element 1 as 100 by measuring the voltage value when the front luminance became 1000 cd / m ^2.

(Evaluation of device life in high temperature environment)
^{Each organic EL element was continuously driven with a constant current giving 1000 cd / m 2} as the initial brightness under an atmosphere of dry nitrogen at 40 ° C., and the time required for the brightness to be halved (500 cd / m ^{2) was measured.} This was used as an index of device life as a half life time (LT50). The half-life time (LT50) was expressed as a relative value with the measured value of the organic EL element 1 as 100.

In addition, the drive voltage during the half-life time (LT50) was also measured and expressed as a relative value with the measured value of the organic EL element 1 as 100.

(Comprehensive evaluation)
For each of the above evaluation results, when the characteristic of the organic EL element 1 was set to "◯", a comprehensive evaluation was performed according to the following criteria.

表Ｉに記載の結果より明らかなように、陰極に金属と含窒素芳香族複素環化合物を含有する構成とすることにより、初期輝度（正面輝度）が高く、低電圧で駆動でき、かつＹ高温環境下での素子寿命特性が優れていることが分かる。更に、有機ＥＬ素子１４、１５の塗布成膜の場合は、有機ＥＬ素子９、１０の真空蒸着成膜よりも効率が悪いことがわかる。一方、本発明である金属と含窒素芳香族複素環化合物を含有する陰極を湿式塗布法で形成した有機ＥＬ素子１１〜１４の場合、大幅な性能向上を達成していることが分かる。 〇: When the characteristic value of the organic EL element 1 is 100 in all the evaluation items, the relative value of each item is in the range of 70 to 130%. ×: When the characteristic value of the organic EL element 1 is 100. , At least three relative values of each item are in the range of 45 to 60, or 200 or more. XX: When the characteristic value of the organic EL element 1 is 100, some characteristics are 20 or less or 300 or more. The results obtained as described above are shown in Table I.

As is clear from the results shown in Table I, the cathode contains a metal and a nitrogen-containing aromatic heterocyclic compound, so that the initial brightness (front brightness) is high, the drive can be performed at a low voltage, and the Y high temperature is obtained. It can be seen that the element life characteristics in the environment are excellent. Further, it can be seen that the efficiency of the coating film formation of the organic EL elements 14 and 15 is lower than that of the vacuum vapor deposition film formation of the organic EL elements 9 and 10. On the other hand, in the case of the organic EL devices 11 to 14 in which the cathode containing the metal and the nitrogen-containing aromatic heterocyclic compound of the present invention is formed by a wet coating method, it can be seen that significant performance improvement is achieved.

1 Base material 2 Anode 3 Organic functional layer group 4 Light emitting layer 5 Cathode (electrode A)
6 Hole injection layer 7 Hole transport layer EL Organic EL element

Claims (11)

An electronic device having at least a light emitting layer and a pair of electrodes on a substrate.
At least one electrode A is provided directly above the light emitting layer, and the light emitting layer is directly above the light emitting layer.
The electrode A contains a metal and a nitrogen-containing aromatic heterocyclic compound.
An electronic device characterized by that. The electronic device according to claim 1, wherein the electrode A contains a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound, and a solvent. The electronic device according to claim 1 or 2, wherein the metal is silver. The electronic device according to claim 2 or 3, wherein the solvent contains fluorinated alcohol or water. The electronic device according to any one of claims 1 to 4, wherein the electrode A contains a metal ion and a surfactant containing fluorine. The electronic device according to any one of claims 1 to 5, wherein the electronic device is an organic electroluminescence element and the electrode A is a cathode. At least, it is a method for manufacturing an electronic device that forms a pair of electrodes with a light emitting layer on a base material.
A method for producing an electronic device, which comprises forming at least one electrode A directly above the light emitting layer by a dry method using a metal and a nitrogen-containing aromatic heterocyclic compound. At least, it is a method for manufacturing an electronic device that forms a pair of electrodes with a light emitting layer on a base material.
It is characterized in that at least one electrode A is formed directly above the light emitting layer by a wet method using an electrode forming coating liquid containing a metal, a dispersant, a nitrogen-containing aromatic heterocyclic compound and a solvent. How to manufacture electronic devices. The method for manufacturing an electronic device according to claim 7 or 8, wherein silver is used as the metal. The method for manufacturing an electronic device according to claim 8 or 9, wherein the solvent is alcohol fluoride or water. The method for manufacturing an electronic device according to any one of claims 7 to 10, wherein the electrode A contains a metal ion and a surfactant containing fluorine.

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