JP2008305996A - Organic electric field light emitting element and display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electric field light emitting element which has high brightness, is excellent in stability and durability, capable of enlarging an area and easy to manufacture, and to provide a display unit. <P>SOLUTION: The organic electric field light emitting element is characterized in that an organic compound layer consists of one or more layers including a light-emitting layer, at least one layer of the organic compound layer contains one kind of charge transport polyurethane, and a buffer layer is provided in contact with at least one layer containing the charge transport polyurethane and a positive electrode, and contains at least one kind of charge injection material chosen from an inorganic oxide, inorganic nitride, and inorganic acid nitride. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent element (hereinafter referred to as “organic EL element”) and a display device.

  An electroluminescent element (hereinafter referred to as an “EL element”) is a self-luminous all-solid-state element, and is highly visible and resistant to impacts. Currently, those using inorganic phosphors are the mainstream.

  On the other hand, EL device research using organic compounds (for example, anthracene) has also been conducted, and in addition to research using single crystals, thinning by vapor deposition has been attempted (Thin Solid Films, Vol. 94, 171). (1982)).

In recent years, in a functional separation type EL device in which a thin film of a hole transporting organic low molecular weight compound and a fluorescent organic low molecular weight compound having an electron transporting ability are sequentially stacked by a vacuum deposition method, it is 1000 cd / It has been reported that high luminance of m ² or more can be obtained (Applied Physics Letter, Vol. 51, 913 (1987)), and since then, research and development of stacked EL devices have been actively conducted.
These stacked devices are injected from the electrode through a charge transport layer made of a charge transporting organic compound into a light emitting layer made of a fluorescent organic compound while maintaining the carrier balance of holes and electrons, High-luminance light emission is realized by recombination of the confined holes and electrons.

  In addition, in order to suppress the generation of Joule heat during driving, a starburst amine capable of obtaining a stable amorphous glass state can be used as a hole transporting material (Procedure of the 40th Applied Physics Related Conference Lecture 30a-SZK) -14 (1993), etc.), and an EL device using a polymer in which triphenylamine is introduced into the side chain of polyphosphazene (the 42nd Polymer Symposium Proceedings 20J21 (1993)) has been reported.

  In addition, research and development of organic EL devices with a single layer structure that can shorten the process has progressed, and devices using conductive polymers such as poly (p-phenylene vinylene) (Nature, Vol.357, 477 (1992), etc.) ) And electron transporting materials and fluorescent dyes mixed in hole transporting polyvinyl carbazole (The 38th Applied Physics Related Conference Preliminary Proceedings 31p-g-12 (1991)) has been proposed. .

Also, from the viewpoint of manufacturing methods, wet coating methods have been studied from the viewpoints of manufacturing simplification, workability, large area, cost, etc., and it has been reported that elements can also be obtained by casting methods ( Proceedings of the 50th Japan Society of Applied Physics, 29p-ZP-5 (1989), Proceedings of the 51st Japan Society of Applied Physics, 28a-PB-7 (1990)).
Thin Solid Films, Vol. 94, 171 (1982) Applied Physics Letter, Vol.51, 913 (1987) Proceedings of the 40th Joint Conference on Applied Physics 30a-SZK-14 (1993) 42nd Polymer Symposium Proceedings 20J21 (1993) Nature, Vol.357, 477 (1992) Proceedings of the 38th Joint Conference on Applied Physics 31p-g-12 (1991) Proceedings of the 50th Japan Society of Applied Physics, 29p-ZP-5 (1989) Proceedings of the 51st Japan Society of Applied Physics, 28a-PB-7 (1990)

  An object of the present invention is to provide an organic electroluminescent element and a display device that have high luminance, are excellent in stability and durability, can be increased in area, and are easily manufactured.

The above problem is solved by the following means. That is,
The invention according to claim 1
A pair of anode and cathode, at least one of which is transparent or translucent, and a buffer layer and an organic compound layer sandwiched between the anode and cathode,
The organic compound layer is composed of one or more layers including at least a light emitting layer,
The organic compound layer of at least one layer, contains at least one charge-transporting polyurethane, the charge-transporting polyurethane is represented by the following general formula (I-1) and (I-2) shown by electrostatic charge transport polyurethane with At least one,
At least one layer containing the charge transporting polyurethane is provided in contact with the buffer layer;
The buffer layer is provided in contact with the anode and contains one or more charge injection materials, and the charge injection material is at least one selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides. It is an organic electroluminescent element characterized by being an inorganic material.

  Here, in the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the following general formulas (II-1) and (II-2), and R Represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and T represents a divalent straight-chain hydrocarbon having 1 to 6 carbon atoms or 2 to 10 carbon atoms. Represents a divalent branched hydrocarbon, Y represents a divalent diisocyanate residue or a divalent amine residue, Z represents a divalent alcohol residue or a divalent bischloroformate residue, m represents 0 or 1, and p represents an integer of 5 to 5,000. The residue shown here refers to a portion excluding the reactive group of the linking compound.

  Here, in the general formulas (II-1) and (II-2), Ar represents a substituted or unsubstituted monovalent aromatic group, and X represents a substituted or unsubstituted divalent aromatic group. , K represents 0 or 1.

The invention according to claim 2
2. The organic electroluminescence device according to claim 1, wherein the buffer layer includes one or both of molybdenum oxide and vanadium oxide.

The invention according to claim 3
The Ar in the general formulas (II-1) and (II-2) is a monovalent aromatic group selected from benzene, biphenyl, naphthalene, and fluorene. It is an organic electroluminescent element.

The invention according to claim 4
The T in the general formulas (I-1) and (I-2) is — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, or — (CH ₂ ) ₄ —. The organic electroluminescent device according to claim 1.

The invention according to claim 5
2. The organic electroluminescent element according to claim 1, wherein the buffer layer has a thickness of 1 nm to 15 nm.

The invention according to claim 6
The organic compound layer is composed of at least the light emitting layer and the electron transport layer, and at least the light emitting layer contains at least one kind of charge transporting polyurethane represented by the general formulas (I-1) and (I-2). The organic electroluminescent element according to claim 1, wherein the buffer layer is provided between the anode and the light emitting layer.

The invention according to claim 7 provides:
The organic electroluminescent element according to claim 6, wherein the light emitting layer contains a charge transporting material other than the charge transporting polyurethane.

The invention according to claim 8 provides:
The organic compound layer is composed of at least a hole transport layer, the light emitting layer, and an electron transport layer, and at least the hole transport layer is represented by the general formulas (I-1) and (I-2). 2. The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device comprises at least one kind of charge transporting polyurethane, and the buffer layer is provided between the anode and the hole transport layer.

The invention according to claim 9 is:
9. The organic electroluminescent element according to claim 8, wherein the light emitting layer contains a charge transport material other than the charge transport polyurethane.

The invention according to claim 10 is:
The organic compound layer is composed of at least a hole transport layer and the light emitting layer, and at least the hole transport layer includes at least the charge transporting polyurethane represented by the general formulas (I-1) and (I-2). The organic electroluminescent element according to claim 1, wherein the organic electroluminescent element is contained in one kind, and the buffer layer is provided between the anode and the hole transport layer.

The invention according to claim 11 is:
The organic light emitting device according to claim 10, wherein the light emitting layer contains a charge transporting material other than the charge transporting polyurethane.

The invention according to claim 12
The organic compound layer is composed of only the light emitting layer, the light emitting layer is a light emitting layer having a charge transporting ability, and the light emitting layer having the charge transporting ability is represented by the general formulas (I-1) and (I- 2. The organic material according to claim 1, wherein the buffer layer is provided between the anode and the light emitting layer having the charge transporting capability. An electroluminescent element.

The invention according to claim 13 is:
The organic electroluminescence device according to claim 12, wherein the light emitting layer having the charge transporting capability contains a charge transporting material other than the charge transporting polyurethane.

The invention according to claim 14 is:
An organic electroluminescent device arranged in a matrix, and a driving means for driving the organic electroluminescent device,
The organic electroluminescent element has a pair of an anode and a cathode, at least one of which is transparent or translucent, and a buffer layer and an organic compound layer sandwiched between the anode and the cathode,
The organic compound layer is composed of one or more layers including at least a light emitting layer,
At least one of the organic compound layers contains at least one charge transporting polyurethane, and the charge transporting polyurethane is at least one of the charge transporting polyurethanes represented by the following general formulas (I-1) and (I-2). One kind,
At least one layer containing the charge transporting polyurethane is provided in contact with the buffer layer;
The buffer layer is provided in contact with the anode and contains one or more charge injection materials, and the charge injection material is at least one selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides. It is a display device characterized by being an inorganic material.

  Here, in the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the following general formulas (II-1) and (II-2), and R Represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and T represents a divalent straight-chain hydrocarbon having 1 to 6 carbon atoms or 2 to 10 carbon atoms. Represents a divalent branched hydrocarbon, Y represents a divalent diisocyanate residue or a divalent amine residue, Z represents a divalent alcohol residue or a divalent bischloroformate residue, m represents 0 or 1, and p represents an integer of 5 to 5,000. The residue shown here refers to a portion excluding the reactive group of the linking compound.

  Here, in the general formulas (II-1) and (II-2), Ar represents a substituted or unsubstituted monovalent aromatic group, and X represents a substituted or unsubstituted divalent aromatic group. , K represents 0 or 1.

  According to the present invention, at least one charge transporting polyurethane used in the present invention is not used as at least one layer of the organic compound layer of the present invention, and the buffer layer used in the present invention has an inorganic oxide, an inorganic nitride, Compared with the case where at least one inorganic material selected from inorganic oxynitrides is not used as a charge injection material, it has a high brightness, excellent stability and durability while being easy to enlarge and manufacture. There is an effect that an organic electroluminescence element can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  At least one of the organic electroluminescent elements according to this exemplary embodiment is transparent or translucent (here, transparent or translucent means that the transmittance of visible light is 50% or more. The same applies hereinafter. And a buffer layer and an organic compound layer sandwiched between the anode and the cathode.

  The organic compound layer is composed of one or more layers including at least a light emitting layer. Further, at least one of the organic compound layers contains at least one charge transporting polyurethane represented by the following general formulas (I-1) and (I-2).

  Here, in the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the following general formulas (II-1) and (II-2), and R Represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and T represents a divalent straight-chain hydrocarbon having 1 to 6 carbon atoms or 2 to 10 carbon atoms. Represents a divalent branched hydrocarbon, Y represents a divalent diisocyanate residue or a divalent amine residue, Z represents a divalent alcohol residue or a divalent bischloroformate residue, m represents 0 or 1, and p represents an integer of 5 to 5,000. The residue shown here refers to a portion excluding the reactive group of the linking compound.

  Here, in the general formulas (II-1) and (II-2), Ar represents a substituted or unsubstituted monovalent aromatic group, and X represents a substituted or unsubstituted divalent aromatic group. , K represents 0 or 1.

  At least one layer containing the charge transporting polyurethane is provided in contact with the buffer layer. The buffer layer is also provided in contact with the anode.

  The buffer layer contains one or more charge injection materials, and the charge injection material is at least one inorganic material selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides. .

By setting it as the said composition and structure, the brightness | luminance of organic electroluminescent element, stability, and durability can be improved.
Although the reason why the luminance, stability, and durability of the organic electroluminescence device are improved by the above composition and configuration is not clear, the charge injection material of the buffer layer reduces the energy barrier between the anode and the organic compound layer, thereby increasing the charge. As the injection property is improved, not only the adhesion between the anode and the buffer layer is good, but also the adhesion between the organic compound layer containing the specific charge transporting polyurethane and the buffer layer is improved, so that luminance stability and durability are improved. Presumed to improve.
In addition, since the specific charge transporting polyurethane contained in the organic compound layer is easy to synthesize and the control of the average molecular weight, molecular weight distribution, etc. is easy, for example, a carrier having a terminal group using a polyurethane having a high average molecular weight. It is presumed that the luminance, stability and durability of the organic electroluminescent element can be increased by reducing the number of traps.
In addition, by using an organic material for a main functional layer such as a light-emitting layer, an increase in area and manufacturing are facilitated.

Hereinafter, each layer will be described.

[1] Buffer layer The charge injection material contained in the buffer layer is at least one inorganic material selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides.

  Examples of inorganic oxides include, for example, transition metals containing rare earth elements, aluminum, silicon, zinc, gallium, germanium, cadmium, indium, tin, antimony, thallium, lead, bismuth, and complex oxides thereof. Although things can be mentioned, it is not restricted to this.

  Examples of inorganic nitrides include, for example, gallium, indium, aluminum, magnesium, lithium, magnesium, molybdenum, vanadium, lanthanum, chromium, silicon, boron, iron, copper, zinc, barium, titanium, yttrium, calcium, tantalum, Examples thereof include nitrides such as zirconium and tantalum, and composite nitrides thereof, but are not limited thereto.

Examples of inorganic oxynitrides include, for example, oxynitrides called sialon (SiAlON) formed by dissolving Al ₂ O ₃ (alumina), SiO ₂ (silica), etc. in Si ₃ N ₄ (silicon nitride). This includes, but is not limited to, composite sialons containing lithium, calcium, barium, lanthanum, etc., multi-element sialons in which other inorganic oxides and inorganic nitrides are dissolved, and the like. .

  Among these inorganic oxides, inorganic nitrides, and inorganic oxynitrides, molybdenum oxide and vanadium oxide are preferable.

When the buffer layer contains either or both of molybdenum oxide and vanadium oxide, the luminance of the organic electroluminescent device can be further improved.
The reason why the luminance of the organic electroluminescent device is further improved by the above configuration is not clear, but molybdenum oxide and vanadium oxide not only efficiently reduce the energy barrier between the anode and the organic compound layer, but also compared with other materials. It is presumed that this is because the light absorptivity of visible light is low and the film can be made thin, so that the light transmittance of the film is good and the light extraction efficiency of the organic electroluminescence device is improved.

  The thickness of the buffer layer is preferably from 1 nm to 200 nm, more preferably from 1 nm to 15 nm, and even more preferably from 5 nm to 15 nm.

By setting the film thickness of the buffer layer in the above range, the luminance of the organic electroluminescent element can be further improved.
Although the reason why the brightness of the organic electroluminescent device is further improved by setting the thickness of the buffer layer in the above range is not clear, it is possible to further increase the organic electroluminescence by satisfying both the charge injection property and the light transmitting property of the buffer layer. This is presumably because the luminance of the element can be improved.
The film thickness of the buffer layer is measured by a film thickness sensor.

[2] Organic Compound Layer At least one of the layers constituting the organic compound layer contains the charge transporting polyurethane. Hereinafter, the charge transporting polyurethane will be described in detail.

  The charge transporting polyurethane is represented by the above general formulas (I-1) and (I-2), and in the above general formulas (I-1) and (I-2), A represents the above general formula (II-1). And at least one selected from the structures represented by (II-2).

  Specific examples of Ar in the general formulas (II-1) and (II-2) include substituted or unsubstituted phenyl groups, substituted or unsubstituted monovalent polynuclear aromatic hydrocarbons, substituted or unsubstituted A substituted monovalent condensed ring aromatic hydrocarbon, a substituted or unsubstituted monovalent aromatic heterocyclic ring, or a substituted or unsubstituted monovalent aromatic group containing at least one aromatic heterocyclic ring .

  In the present invention, the polynuclear aromatic hydrocarbon and the condensed ring aromatic hydrocarbon specifically mean a polycyclic aromatic as defined below. That is, “polynuclear aromatic hydrocarbon” is a hydrocarbon compound in which two or more aromatic rings composed of carbon and hydrogen are present, and these aromatic rings are bonded by a carbon-carbon single bond. Represents. The “fused ring aromatic hydrocarbon” means that two or more aromatic rings composed of carbon and hydrogen are present, and these aromatic rings are bonded to each other in a pair of two or more carbon atoms. Represents a hydrocarbon compound sharing

  The number of aromatic rings constituting the polynuclear aromatic hydrocarbon and the condensed ring aromatic hydrocarbon is not particularly limited, but is preferably 2 to 10 aromatic rings, more preferably 2 to 5 aromatic rings. Further, in the condensed ring aromatic hydrocarbon, a fully condensed ring aromatic hydrocarbon is desirable. Here, the “fully condensed ring aromatic hydrocarbon” in the present invention represents a condensed ring aromatic hydrocarbon in which all the aromatic rings are adjacent to each other more continuously in the condensed ring structure.

  Specific examples of the polynuclear aromatic hydrocarbon include biphenyl and terphenyl. Specific examples of the condensed ring aromatic hydrocarbon include naphthalene, anthracene, phenanthrene, fluorene and the like.

  In the present invention, the aromatic heterocyclic ring represents an aromatic ring containing an element other than carbon and hydrogen. The number of atoms (Nr) constituting the ring skeleton is preferably Nr = 5 and / or 6. The type and number of elements (heterogeneous elements) other than C constituting the ring skeleton are not particularly limited. For example, S, N, O and the like are preferably used, and two or more types and / or 2 are included in the ring skeleton. One or more hetero atoms may be contained. In particular, as a heterocyclic ring having a 5-membered ring structure, thiophene, thiofin and furan, or a heterocyclic ring obtained by further substituting the carbons at the 3- and 4-positions with nitrogen, pyrrole, or carbons at the 3- and 4-positions thereof are further nitrogenated. The heterocyclic ring substituted with is preferably used, and pyridine is preferably used as the heterocyclic ring having a 6-membered ring structure.

  Furthermore, in the present invention, the aromatic group containing an aromatic heterocyclic ring represents a linking group containing at least one kind of the aromatic heterocyclic ring in the atomic group constituting the skeleton. These may be either all composed of conjugated systems or at least partially composed of non-conjugated systems, but all composed of conjugated systems in terms of charge transportability and luminous efficiency. Is desirable.

  As a substituent of an aromatic group containing a benzene ring, polynuclear aromatic hydrocarbon, condensed ring aromatic hydrocarbon, heterocycle, or aromatic heterocycle selected as a structure representing Ar, a hydrogen atom, alkyl group, alkoxy Group, phenoxy group, aryl group, aralkyl group, substituted amino group, halogen atom and the like. The alkyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. As the alkoxyl group, those having 1 to 10 carbon atoms are preferable, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group. The aryl group preferably has 6 to 20 carbon atoms, and examples thereof include a phenyl group and a toluyl group. The aralkyl group preferably has 7 to 20 carbon atoms, such as a benzyl group and a phenethyl group. Is mentioned. Examples of the substituent of the substituted amino group include an alkyl group, an aryl group, an aralkyl group, and the like, and specific examples are as described above.

Ar is preferably a monovalent aromatic group selected from benzene, biphenyl, naphthalene, and fluorene among the specific examples given above.
When Ar is the above substituent, the brightness, stability, and durability of the organic electroluminescent device can be further improved.
The reason why the brightness, stability, and durability of the organic electroluminescence device are improved by Ar being the above substituent is not clear, but it is presumed that the adhesion with the buffer layer is improved.

Specific examples of X in the general formulas (II-1) and (II-2) include, for example, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted divalent polynuclear having 2 to 10 aromatic rings. An aromatic hydrocarbon, a substituted or unsubstituted aromatic divalent aromatic ring having 2 to 10 aromatic rings, a substituted or unsubstituted divalent aromatic heterocyclic ring, or at least one aromatic heterocyclic A substituted or unsubstituted divalent aromatic group containing a ring is represented.
Here, “polynuclear aromatic hydrocarbon”, “fused ring aromatic hydrocarbon”, “aromatic heterocycle”, and “aromatic group containing an aromatic heterocycle” are as described above.

  In the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the general formulas (II-1) and (II-2). Two or more types of structures A may be included in the structure.

In the general formulas (I-1) and (I-2), T represents a divalent linear hydrocarbon group having 1 to 6 carbon atoms or a divalent branched hydrocarbon group having 2 to 10 carbon atoms. Preferably a divalent linear hydrocarbon group having 2 to 6 carbon atoms or a divalent branched hydrocarbon group having 3 to 7 carbon atoms.
Specific examples of T include those having the structure shown below,

T is particularly preferably — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, — (CH ₂ ) ₄ — or the like among the specific examples given above.
When T is the above substituent, the luminance, stability, and durability of the organic electroluminescent device can be further improved.
The reason why the brightness, stability, and durability of the organic electroluminescent element are improved by T being the above substituent is not clear, but it is presumed that the adhesiveness with the buffer layer is improved.

  In the general formulas (I-1) and (I-2), R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. The alkyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. As the aryl group, those having 6 to 20 carbon atoms are preferable, and examples thereof include a phenyl group and a toluyl group. As the aralkyl group, those having 7 to 20 carbon atoms are preferable, and examples thereof include a benzyl group and a phenethyl group. In addition, examples of the substituent of the substituted aryl group and the substituted aralkyl group include a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, and a halogen atom.

  In the general formula (I-1) or (I-2), Y represents a divalent diisocyanate residue or a divalent amine residue, and Z represents a divalent alcohol residue or a divalent bischloroformate. Represents a residue. Specific examples of Y and Z include groups selected from the following formulas (1) to (7).

In the above formulas (1) to (7), R ₁₁ and R ₁₂ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, substituted or unsubstituted Represents an unsubstituted aralkyl group or a halogen atom, a, b and c each represents an integer of 1 to 10; d and e each represents an integer of 0, 1 or 2; and f represents 0 or 1 and V represents a group selected from the following formulas (8) to (18).

  In the above formulas (8) to (18), g represents an integer of 1 to 10, and h represents an integer of 0 to 10, respectively.

  In the above general formula (I-1) or (I-2), p represents the degree of polymerization and is in the range of 5 to 5,000, preferably in the range of 10 to 1,000.

The weight average molecular weight _Mw of the charge transporting polyurethane used in the present embodiment is in the range of 5,000 to 1,000,000, but is preferably in the range of 10,000 to 300,000.

The weight average molecular weight _Mw of the charge transporting polyurethane can be measured by the following method.
First, a 1.0 mass% THF (tetrahydrofuran) solution of charge transporting polyurethane was prepared, and gel permeation chromatography (GPC) was performed using a differential refractive index detector (RI, manufactured by TOSOH, trade name: UV-8020). ) Using a styrene polymer as a standard sample.

  Here, specific examples of the charge transporting polyurethanes of the general formulas (I-1) and (I-2) include those disclosed in, for example, JP-A Nos. 2002-117882 and 2002-117993. .

Next, a method for synthesizing the charge transporting polyurethane will be described.
The charge transporting polyurethane used in the present embodiment is, for example, a charge transporting monomer represented by the following general formulas (III-1) to (III-4). , 1992) and the like.

  In the general formulas (III-1) to (III-4), A, T, and m are the same as A, T, and m in the general formulas (I-1) and (I-2).

  That is, the charge transporting polyurethane represented by the general formula (I-1) and the general formula (I-2) can be synthesized, for example, as follows.

  When the dihydric alcohol represented by the general formula (III-1) is used as the charge transporting monomer, 1 equivalent of the charge transporting monomer and 1 equivalent of the “diisocyanate represented by OCN—Y—NCO” are mixed. By performing the polyaddition reaction, the charge transporting polyurethane represented by the general formula (I-1) can be synthesized.

  On the other hand, when the diisocyanate represented by the general formula (III-2) is used as the charge transporting monomer, 1 equivalent of the charge transporting monomer and 1 equivalent of the “dihydric alcohol represented by HO—Z—OH” are used. By mixing and performing a polyaddition reaction, the charge transporting polyurethane represented by the above general formula (I-2) can be synthesized.

  Examples of the catalyst used in the polyaddition reaction include organometallic compounds such as dibutyltin dilaurate (II), dibutyltin diacetate (II), and lead naphthenate. These catalysts can be used.

  When an aromatic diisocyanate is used as the diisocyanate, a tertiary amine such as triethylenediamine can be used as the catalyst. The organometallic compound and the tertiary amine may be used as a mixture.

  The amount of the catalyst is desirably 1 / 10,000 parts by weight or more and 1/10 parts by weight or less, more desirably 1 / 1,000 parts by weight or more and 1/50 parts by weight or less based on 1 part by weight of the charge transporting monomer. It is used in the range.

The solvent is a raw material used for the polyaddition reaction (charge transporting monomer represented by general formula (III-1) and "diisocyanate represented by OCN-Y-NCO", or represented by general formula (III-2)). Although it is not particularly limited as long as it dissolves a charge transporting monomer and “dihydric alcohol represented by HO—Z—OH”), it causes a hydrogen bond with a less polar solvent or alcohol in terms of reactivity. It is desirable to use no solvent. Desirable solvents include, for example, toluene, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like.
The amount of the solvent to be used is desirably 1 to 100 parts by weight, more desirably 2 to 50 parts by weight, with respect to 1 part by weight of the charge transporting monomer.
The reaction temperature is not particularly limited and can be set arbitrarily.

  After completion of the reaction, the reaction solution is dropped as it is into a poor solvent in which the charge transport polyurethane is difficult to dissolve (specifically, alcohols such as methanol and ethanol, acetone, etc.), and the charge transport polyurethane is deposited. After separation, the substrate is thoroughly washed with water or an organic solvent and dried.

Furthermore, if necessary, a reprecipitation process (specifically, a process of dissolving in an organic solvent and dropping in a poor solvent to precipitate a charge transporting polyurethane) may be repeated.
The reprecipitation treatment is preferably carried out with efficient stirring with a mechanical stirrer or the like.

  The solvent for dissolving the charge transporting polyurethane in the reprecipitation treatment is preferably 1 part by weight or more and 100 parts by weight or less, more preferably 2 parts by weight or more and 50 parts by weight or less with respect to 1 part by weight of the charge transporting polyurethane. Used in a range. The poor solvent is preferably used in an amount of 1 to 1,000 parts by weight, more preferably 10 to 500 parts by weight, based on 1 part by weight of the charge transporting polyurethane.

When the bischloroformate represented by the general formula (III-3) is used as the charge transporting monomer, 1 equivalent of the charge transporting monomer and 1 equivalent of the “diamine represented by H ₂ N—Y—NH ₂ ” And a polycondensation reaction are carried out to synthesize a charge transporting polyurethane represented by the general formula (I-1).

  On the other hand, when the diamine represented by the general formula (III-4) is used as the charge transporting monomer, 1 equivalent of the charge transporting monomer and 1 equivalent of “bischloroformate represented by ClCOO—Z—OCOCl” Are mixed and a polycondensation reaction is performed to synthesize a charge transporting polyurethane represented by the above general formula (I-2).

As the solvent used for the polycondensation reaction, for example, methylene chloride, dichloroethane, trichloroethane, tetrahydrofuran (THF), toluene, chlorobenzene, 1-chloronaphthalene and the like are desirably used. The solvent is preferably used in the range of 1 to 100 parts by weight, more preferably 2 to 50 parts by weight with respect to 1 part by weight of the charge transporting monomer.
The reaction temperature is not particularly limited and can be set arbitrarily.

  After completion of the polymerization reaction, purification is performed by reprecipitation as described above.

In addition, when the bischloroformate represented by the general formula (III-3) is used as the charge transporting monomer, the compound having a high basicity as the “diamine represented by H ₂ N—Y—NH ₂ ” When is used, an interfacial polymerization method can also be used.

  Specifically, for example, the above diamines are added to water, 1 equivalent of an acid (for example, terephthalic acid chloride, etc.) is added to 1 equivalent of the diamine and dissolved, and then 1 equivalent of the diamine is stirred vigorously. Polymerization can also be carried out by adding 1 equivalent of the “charge transporting monomer represented by the general formula (III-3)”.

The amount of water used is preferably in the range of 1 to 1,000 parts by weight, more preferably 10 to 500 parts by weight with respect to 1 part by weight of the diamine.
As the solvent for dissolving the charge transporting monomer, for example, methylene chloride, dichloroethane, trichloroethane, toluene, chlorobenzene, 1-chloronaphthalene and the like are desirably used.
The reaction temperature is not particularly limited and can be set arbitrarily.

  In order to accelerate the interfacial polymerization reaction, it is desirable to use a phase transfer catalyst such as an ammonium salt or a sulfonium salt. The phase transfer catalyst is preferably used in the range of 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight with respect to 1 part by weight of the charge transporting monomer.

[3] Layer Configuration of Organic Electroluminescent Device Next, the layer configuration of the organic electroluminescent device of the present embodiment will be described in detail.

  The organic electroluminescent element of the present embodiment is composed of a buffer layer and an organic compound layer provided in contact with the anode, sandwiched between a pair of anode and cathode, at least one of which is transparent or translucent. .

  In the organic electroluminescent device of the present embodiment, when the organic compound layer is composed of one layer, the organic compound layer means “a light emitting layer having a carrier transporting ability”, and the light emitting layer is the charge transport layer. Containing a functional polyurethane. When the organic compound layer is composed of a plurality of layers (in the case of function separation type), at least one layer is a light emitting layer, and the other organic compound layer is a carrier transport layer, that is, a hole transport layer, It means an electron transport layer or a layer comprising a hole transport layer and an electron transport layer, and at least one of these contains the charge transporting polyurethane. Specifically, for example, the organic compound layer is composed of at least a light emitting layer and an electron transport layer, at least composed of a hole transport layer, a light emitting layer and an electron transport layer, or at least composed of a hole transport layer and a light emitting layer. And those in which at least one layer (a hole transport layer, a light emitting layer, and an electron transport layer) contains the charge transporting polyurethane. In the organic electroluminescent element of the present invention, the light emitting layer may contain a charge transporting material (a hole transporting material other than the charge transporting polyurethane, an electron transporting material). Details will be described later.

Hereinafter, although it demonstrates in detail, referring drawings, it is not necessarily limited to these.
1 to 4 are schematic cross-sectional views for explaining the layer structure of the organic electroluminescent element of the present embodiment. In the case of FIGS. 1, 2, and 3, there are a plurality of organic compound layers. FIG. 4 shows an example in the case of one organic compound layer. In FIG. 1 to FIG. 4, components having similar functions are described with the same reference numerals.

  The organic electroluminescent element 10 shown in FIG. 1 is formed by sequentially laminating a transparent electrode 2, a buffer layer 3, a light emitting layer 5, an electron transport layer 6 and a back electrode 8 on a transparent insulator substrate 1. At least the light emitting layer 5 contains a charge transporting polyurethane.

When the organic electroluminescent element 10 has the above-described configuration, both manufacturability and luminous efficiency can be achieved as compared with other layer configurations.
Although the reason why the above structure can achieve both the manufacturability and the light emission efficiency compared to other layer structures is not clear, this is because the number of layers is generally smaller than that of a layer structure in which all functions are separated, but generally the hole It is presumed that this is because the electron injection efficiency, which has a lower mobility than that, is compensated for and the charge balance in the light emitting layer is balanced.

  An organic electroluminescent device 10 shown in FIG. 2 is formed by sequentially laminating a transparent electrode 2, a buffer layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6 and a back electrode 8 on a transparent insulator substrate 1. Become. At least the hole transport layer 4 contains a charge transporting polyurethane.

When the organic electroluminescent element 10 has the above-described configuration, it has excellent luminous efficiency and can be driven at a low voltage as compared with elements having other layer configurations.
Although the reason why the above structure is superior in luminous efficiency and can be driven at a low voltage as compared with other layer configuration elements is not clear, this is because all the functions are separated, so that the charge is reduced compared to other layer configurations. This is presumably because the injection efficiency is the highest and charges can be recombined in the light emitting layer.

  The organic electroluminescent element 10 shown in FIG. 3 is formed by sequentially laminating a transparent electrode 2, a buffer layer 3, a hole transport layer 4, a light emitting layer 5, and a back electrode 8 on a transparent insulator substrate 1. At least the hole transport layer 4 contains a charge transporting polyurethane.

When the organic electroluminescent element 10 has the above-described configuration, both manufacturability and durability can be achieved as compared with other configurations.
Although the reason why both the ease of manufacture and durability can be achieved by the above configuration compared to other configurations is not clear, this is because the number of layers is smaller than that of the functionally separated layer configuration, while It is presumed that the hole injection efficiency is improved and excessive electron injection is suppressed in the light emitting layer.

  An organic electroluminescent element 10 shown in FIG. 4 is formed by sequentially laminating a transparent electrode 2, a buffer layer 3, a light emitting layer 7 having a carrier transport capability, and a back electrode 8 on a transparent insulator substrate 1. The light emitting layer 7 having a carrier transporting ability contains a charge transporting polyurethane.

When the organic electroluminescence device 10 has the above configuration, the device can be easily increased in area and manufactured as compared with other layer configurations.
The reason why it is easy to increase the area and manufacture of the element compared to other layer configurations is not certain due to the above configuration, but this is presumed to be because the number of layers is small and it can be produced by, for example, wet coating. The

  Here, the light emitting layer 5 and the light emitting layer 7 having a carrier transporting ability may include a charge transporting material (a hole transporting material other than the above charge transporting polyurethane, an electron transporting material).

When the organic electroluminescent element 10 has the above-described configuration, it becomes difficult for charges to be accumulated in the light emitting layer, and durability is improved.
The reason why the structure makes it difficult for charges to accumulate in the light emitting layer and improves durability is not clear, but this is presumed to be because charge transporting ability is imparted to or improved in the light emitting layer and charges are difficult to accumulate. The

Here, among the organic compound layers containing the specific charge transporting polyurethane, the thickness of the organic compound layer in contact with the buffer layer is preferably in the range of 20 nm to 100 nm.
Each will be described in detail below.

  In the case of the layer structure of the organic electroluminescent element 10 shown in FIG. 1, for example, the layer containing the charge transporting polyurethane can act as both the light emitting layer 5 and the electron transport layer 6, and FIG. In the case of the layer structure of the organic electroluminescent element 10 shown, any of the hole transport layer 4, the light emitting layer 5, and the electron transport layer 6 can act, and the layer structure of the organic electroluminescent element 10 shown in FIG. In this case, both the hole transport layer 4 and the light emitting layer 5 can act, and in the case of the layer configuration of the organic electroluminescent element 10 shown in FIG. 4, it can act as the light emitting layer 7 having a carrier transport ability. .

  In the case of the layer configuration of the organic electroluminescent element 10 shown in FIGS. 1 to 4, the transparent insulator substrate 1 is preferably transparent in order to extract emitted light. Specifically, for example, glass, plastic film or the like is used. However, it is not limited to these.

  The transparent electrode 2 is transparent in order to extract emitted light in the same manner as the transparent insulator substrate, and preferably has a high work function for injecting holes. Specifically, for example, indium tin oxide (ITO) In addition, an oxide film such as tin oxide (NESA), indium oxide, and zinc oxide, and vapor deposited or sputtered gold, platinum, palladium, and the like are used, but not limited thereto.

In the case of the layer structure of the organic electroluminescent device 10 shown in FIGS. 1 and 2, the electron transport layer 6 is formed of the charge transporting polyurethane provided with a function (electron transport ability) according to the purpose. However, in order to adjust the electron mobility for the purpose of further improving the electrical characteristics, an electron transporting material other than the charge transporting polyurethane is mixed and dispersed in the range of 1 to 50% by weight. It may be formed.
Suitable examples of such electron transporting materials include oxazole derivatives, oxadiazole derivatives, nitro-substituted fluorenone derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, fluorenylidenemethane derivatives, and the like. More preferable specific examples include, but are not limited to, the following exemplary compounds (V-1) to (V-3). When the charge transporting polyurethane is not used, the electron transport layer 6 is formed only of these electron transporting materials.

In the case of the layer configuration of the organic electroluminescent element 10 shown in FIGS. 2 and 3, the hole transport layer 4 is formed of a charge transporting polyurethane alone provided with a function (hole transport ability) according to the purpose. However, in order to adjust the hole mobility, a hole transporting material other than the charge transporting polyurethane may be mixed and dispersed in the range of 1 wt% to 50 wt%.
Specific examples of such hole transporting materials include tetraphenylenediamine derivatives, triphenylamine derivatives, carbazole derivatives, stilbene derivatives, arylhydrazone derivatives, porphyrin-based compounds, and the like. Examples thereof include the following exemplary compounds (VI-1) to (VI-7). Furthermore, a tetraphenylenediamine derivative is more desirable because of its good compatibility with the charge transporting polyurethane. Moreover, it is good also as a mixture with other general purpose resin etc. In the case where the charge transporting polyurethane is not used, the hole transporting layer 4 is formed only of these hole transporting materials.

  Here, in the general formula (VI-6), n is an integer value, preferably in the range of 10 to 100,000, and more preferably in the range of 1000 to 50000.

  In the case of the layer configuration of the organic electroluminescent element 10 shown in FIG. 1, FIG. 2, or FIG. 3, the light emitting layer 5 uses a compound that exhibits a higher fluorescence quantum yield in a solid state as a light emitting material than other types. In the case where the light emitting material is an organic low molecule, it is a condition that a good thin film can be formed by applying and drying a solution or dispersion containing a low molecular weight and a binder resin. In the case of a polymer, it is a condition that a good thin film can be formed by applying and drying a solution or dispersion containing itself. Specific examples of suitable organic low molecular weight compounds include chelate-type organometallic complexes, polynuclear or condensed aromatic ring compounds, perylene derivatives, coumarin derivatives, styrylarylene derivatives, silole derivatives, oxazole derivatives, oxathiazole derivatives, oxadiazoles In the case of a polymer, examples include polyparaphenylene derivatives, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyacetylene derivatives, polyfluorene derivatives, and the like. More preferable specific examples include, but are not limited to, the following compounds (VII-1) to (VII-17).

  Here, in the general formulas (VII-13) to (VII-17), Ar and X are monovalent having the same structure as Ar and X in the general formulas (II-1) and (II-2). A group or a divalent group, n and x are integers of 1 or more, and y is 0 or 1.

  In addition, for the purpose of improving the durability of the organic electroluminescent device 10 or improving the light emission efficiency, the light emitting material may be doped with a dye compound different from the light emitting material as a guest material. When the light emitting layer is formed by vacuum deposition, doping is performed by co-evaporation, and when the light emitting layer is formed by applying and drying a solution or dispersion, doping is performed by mixing in the solution or dispersion. The doping ratio of the dye compound in the light emitting layer is about 0.001 to 40% by weight, preferably about 0.01 to 10% by weight. As the coloring compound used for such doping, an organic compound that has good compatibility with the light emitting material and does not hinder the formation of a good thin film of the light emitting layer is used. For example, a DCM derivative, a quinacridone derivative, Examples include rubrene derivatives and porphyrin compounds. As more preferred specific examples, for example, the following compounds (VIII-1) to (VIII-4) are used, but are not limited thereto.

In the case of the layer structure of the organic electroluminescent element 10 shown in FIG. 1, the light emitting layer 5 includes the above-described charge transporting polyurethane in addition to the light emitting material. Further, in the case of the layer configuration of the organic electroluminescent element 10 shown in FIG. 2 or FIG. 3, the light emitting layer 5 may be formed of the light emitting material alone, but the electrical characteristics and the light emitting characteristics are further improved. For the purpose, the charge transporting polyurethane may be included in addition to the light emitting material. Moreover, the light emitting layer 5 may contain other charge transport materials in addition to the charge transport polyurethane.
When the charge transporting polyurethane or other charge transporting material is included in the light emitting layer 5, the charge transporting polyurethane is mixed and dispersed in the range of 1% by weight to 50% by weight, or the light emitting high A charge transporting material other than the charge transporting polyurethane may be mixed and dispersed in the molecule in the range of 1% by weight to 50% by weight. Further, when the charge transporting polymer also has a light emitting property, it may be used as a light emitting material. In this case, the charge is added to the light emitting material for the purpose of further improving the electrical property and the light emitting property. A charge transporting material other than the transporting polyurethane may be mixed and dispersed in the range of 1% by weight to 50% by weight.

  In the case of the layer configuration of the organic electroluminescent device 10 shown in FIG. 4, the light-emitting layer 7 having a carrier transporting ability has the charge transporting function provided with a function (hole transporting ability or electron transporting ability) according to the purpose. An organic compound layer in which a light emitting material (specifically, for example, the light emitting materials (VII-1) to (VII-17)) is dispersed in a polyurethane in an amount of 50% by weight or less, is injected into the organic electroluminescent element 10. In order to adjust the balance between holes and electrons, 10 wt% to 50 wt% of a charge transport material other than the charge transport polyurethane may be dispersed.

  As such a charge transporting material, when adjusting the electron mobility of the light emitting layer 7 having a carrier transporting capability, the electron transporting material is preferably an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, Examples include thiopyran dioxide oxide derivatives and fluorenylidenemethane derivatives. More preferable specific examples include the exemplary compounds (V-1) to (V-3) described above. In addition, it is desirable to use an organic compound that does not exhibit a strong electron interaction with the charge transporting polyurethane, and more desirably the following exemplified compound (19) is used, but it is not limited thereto.

  In the case of adjusting the hole mobility of the light emitting layer 7 having a carrier transport ability, the hole transport material is preferably a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an aryl hydrazone derivative, a porphyrin, for example. Specific examples of particularly suitable compounds such as the series compounds include the above-described exemplary compounds (VI-1) to (VI-7), and a tetraphenylenediamine derivative is preferable because of its good compatibility with the charge transporting polyurethane.

In the case of the layer configuration of the organic electroluminescent device 10 shown in FIGS. 1 to 4, the back electrode 8 is made of a metal that can be vacuum-deposited and has a low work function for performing electron injection. Further, magnesium, aluminum, silver, indium and alloys thereof, metal halide compounds such as lithium fluoride and lithium oxide, metal oxides, alkali metals such as lithium, calcium, barium, and cesium are also used. Further, a protective layer may be provided on the back electrode 8 in order to prevent deterioration of the element due to moisture or oxygen. Specific protective layer materials include, for example, metals such as In, Sn, Pb, Au, Cu, Ag, and Al, metal oxides such as MgO, SiO ₂ , and TiO ₂ , polyethylene resins, polyurea resins, and polyimide resins. And the like. For forming the protective layer, for example, a vacuum deposition method, a sputtering method, a plasma polymerization method, a CVD method, or a coating method can be applied.

[4] Manufacturing Method of Organic Electroluminescent Device In the organic electroluminescent device 10 shown in FIGS. 1 to 4, the buffer layer 3 is first formed on the transparent electrode 2.
The buffer layer is formed into a thin film by using the above materials by vacuum deposition, sputtering, CVD, or the like.

  Next, the hole transport layer 4, the light emitting layer 5, the electron transport layer 6, or the light emitting layer 7 having a carrier transport ability is sequentially formed according to the layer configuration of each organic electroluminescent element 10. The hole transport layer 4, the light emitting layer 5, the electron transport layer 6 or the light emitting layer 7 having carrier transporting ability is prepared by dissolving or dispersing each of the above materials in a vacuum deposition method or an organic solvent. The film is formed on the transparent electrode by using, for example, a spin coating method, a dip method or the like.

  Further, when a polymer is used as the charge transport material and the light emitting material, each layer is preferably formed by a film forming method using a coating solution, but may be formed using an ink jet method or the like, for example.

  The film thicknesses of the hole transport layer 4, the light emitting layer 5, and the electron transport layer 6 to be formed are each preferably in the range of 20 to 100 nm, particularly 30 to 80 nm, for example. Further, the film thickness of the light emitting layer 7 having a carrier transporting capability is desirably about 30 to 200 μm, for example. The dispersion state of each of the materials (the charge transporting polyurethane, the light emitting material, etc.) may be a molecular dispersion state or a particle dispersion state. In the case of a film forming method using a coating solution, it is necessary to use a common solvent for each of the above materials as a dispersion solvent in order to obtain a molecular dispersion state. It is necessary to select in consideration of solubility and solubility. In order to disperse into particles, for example, a ball mill, a sand mill, a paint shaker, an attritor, a homogenizer, an ultrasonic method, or the like can be used.

  Finally, the back electrode 8 is formed on the light-emitting layer 5, the electron transport layer 6 or the light-emitting layer 7 having carrier transport capability by, for example, vacuum deposition, thereby completing the device.

[5] Display Device The display device according to the present embodiment includes the organic electroluminescent element according to the present embodiment and driving means for driving the organic electroluminescent element.
The display device of the present embodiment has the organic electric field issuance element of the present embodiment, thereby realizing improvement in luminance, stability, and durability while preparing to increase the area and manufacturing the display device. Can do.

Specifically, for example, as shown in FIGS. 1 to 4, the display device is connected to a pair of electrodes (transparent electrode 2, back electrode 8) of the organic electroluminescent element 10, and a DC voltage is applied between the pair of electrodes. For example, a device provided with a voltage applying device 9 as a driving means may be used.
As a driving method of the organic electroluminescent element 10 using the voltage applying device 9, for example, organic electroluminescence is applied by applying a DC voltage of 4 to 20 V and a current density of 1 to 200 mA / cm ² between a pair of electrodes. The element 10 can emit light.

In addition, the organic electroluminescent element 10 of the present embodiment has been described with respect to the configuration of the minimum unit (one pixel unit). Applied. Of course, the electrode pairs may be arranged in a matrix.
As a driving method of the display device, a conventionally known technique, for example, a plurality of row electrodes and column electrodes are arranged, and the column electrodes are collectively processed according to image information corresponding to each row electrode while scanning the row electrodes. Simple matrix driving for driving, active matrix driving using pixel electrodes arranged for each pixel, or the like can be used.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention.

―Synthesis of charge transporting polyurethane―
(Synthesis Example 1)
The following compound (XV-1) 2.0 g and chlorobenzene 30 ml were placed in a 50 ml flask and dissolved under stirring in a nitrogen stream. Next, a solution prepared by dissolving 0.54 g of hexamethylene diisocyanate in 10 ml of chlorobenzene was dropped into the flask over 30 minutes, heated to 150 ° C. and stirred for 2 hours. Then, it cooled to room temperature, melt | dissolved in tetrahydrofuran (THF) 50 ml, and filtered the insoluble matter with a 0.2 micrometer polytetrafluoroethylene (PTFE) filter. The reprecipitation treatment in which the filtrate was dropped into 500 ml of methanol while stirring was performed three times to wash and precipitate the polymer.
The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 1.9 g of charge transporting polyurethane (XV-2).
When the molecular weight distribution of the charge transporting polyurethane (XV-2) was measured by gel permeation chromatography (GPC), the weight average molecular weight Mw was 9.67 × 10 ⁴ (in terms of styrene), and the number average molecular weight Mn And the weight average molecular weight Mw (Mw / Mn) = 1.44.

(Synthesis Example 2)
The following compound (XVI-1) 2.0 g and chlorobenzene 30 ml were placed in a 50 ml flask and dissolved under stirring in a nitrogen stream. Next, a solution prepared by dissolving 0.54 g of hexamethylene diisocyanate in 10 ml of chlorobenzene was dropped into the flask over 30 minutes, heated to 150 ° C. and stirred for 2 hours. Then, it cooled to room temperature, melt | dissolved in tetrahydrofuran (THF) 50 ml, and filtered the insoluble matter with a 0.2 micrometer polytetrafluoroethylene (PTFE) filter. The reprecipitation treatment in which the filtrate was dropped into 500 ml of methanol while stirring was performed three times to wash and precipitate the polymer.
The obtained polymer was filtered, washed sufficiently with methanol and then dried to obtain 1.8 g of a charge transporting polyurethane (XVI-2).
When the molecular weight distribution of the charge transporting polyurethane (XVI-2) was measured by gel permeation chromatography (GPC), the weight average molecular weight Mw = 1.23 × 10 ⁵ (in terms of styrene) and the number average molecular weight Mn And the weight average molecular weight Mw (Mw / Mn) = 2.01.

(Synthesis Example 3)
The following compound (XVII-1) 2.0 g and chlorobenzene 30 ml were placed in a 50 ml flask and dissolved under stirring in a nitrogen stream. Next, a solution prepared by dissolving 0.54 g of hexamethylene diisocyanate in 10 ml of chlorobenzene was dropped into the flask over 30 minutes, heated to 150 ° C. and stirred for 2 hours. Then, it cooled to room temperature, melt | dissolved in tetrahydrofuran (THF) 50 ml, and filtered the insoluble matter with a 0.2 micrometer polytetrafluoroethylene (PTFE) filter. The reprecipitation treatment in which the filtrate was dropped into 500 ml of methanol while stirring was performed three times to wash and precipitate the polymer.
The polymer obtained was filtered, washed thoroughly with methanol and dried to obtain 1.9 g of charge transporting polyurethane (XVII-2).
When the molecular weight distribution of the charge transporting polyurethane (XVII-2) was measured by gel permeation chromatography (GPC), the weight average molecular weight Mw = 1.17 × 10 ⁵ (in terms of styrene) and the number average molecular weight Mn And the weight average molecular weight Mw (Mw / Mn) = 1.51.

-Fabrication of organic electroluminescence device-
Next, using the charge transporting polyurethane obtained by the above method, a device was produced as follows.

Example 1
An ITO electrode is formed by etching on a 2 mm wide strip-shaped glass substrate, washed and dried, and then a buffer layer having a film thickness of 10 nm is formed by vacuum evaporation using molybdenum trioxide (MoO ₃ ) as a buffer layer material. Formed.

Next, as a charge transporting material, 0.5 parts by weight of charge transporting polyurethane [Exemplary Compound (XVI-2)] (Mw = 1.23 × 10 ⁵ (in terms of styrene)) and a light emitting polymer are exemplified below. Compound (XI, polyfluorene-based, Mw≈9.67 × 10 ⁴ ) is mixed in an amount of 0.5 parts by weight to prepare a 10% by weight chlorobenzene solution of the mixture, and a 0.1 μm polytetrafluoroethylene (PTFE) filter is used. Using this solution, a light emitting layer having a charge transport ability of 80 nm thickness was formed on the buffer layer by spin coating.

After sufficiently drying, a 5 wt% dichloroethane solution of charge transporting polyurethane [Exemplary Compound (XVI-2)] (Mw = 1.23 × 10 ⁵ ) was prepared as an electron transporting material, and 0.1 μm After filtering with a PTFE filter, it was applied onto the light emitting layer by a spin coating method to form an electron transport layer having a thickness of 30 nm.

Finally, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 150 nm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 2)
An ITO electrode is formed by etching on a 2 mm wide strip-shaped glass substrate, washed and dried, and then a buffer layer having a film thickness of 10 nm is formed by vacuum evaporation using molybdenum trioxide (MoO ₃ ) as a buffer layer material. Formed.

Next, a 5 wt% chlorobenzene solution of charge transporting polyurethane [Exemplary Compound (XV-2)] (Mw = 9.67 × 10 ⁴ ) was prepared as a hole transporting material, and 0.1 μm polytetrafluoroethylene was prepared. After filtering with a (PTFE) filter, it was applied onto the buffer layer by a spin coating method to form a 30 nm-thick hole transport layer.

After sufficiently drying, sublimated and purified Alq ₃ (exemplary number VII-1) as a light emitting material is put on a tungsten board and deposited by a vacuum vapor deposition method to form a light emitting layer having a thickness of 50 nm on the hole transport layer. did. The degree of vacuum at this time was 10 ⁻⁵ Torr, and the boat temperature was 300 ° C.

Further, as an electron transporting material, a 5 wt% dichloroethane solution of charge transporting polyurethane [Exemplary Compound (XVI-2)] (Mw = 1.23 × 10 ⁵ ) was prepared and filtered through a 0.1 μm PTFE filter. An electron transport layer having a thickness of 30 nm was formed on the light emitting layer by spin coating.

Finally, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 150 nm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 3)
An ITO electrode is formed by etching on a 2 mm wide strip-shaped glass substrate, washed and dried, and then a buffer layer having a film thickness of 10 nm is formed by vacuum evaporation using molybdenum trioxide (MoO ₃ ) as a buffer layer material. Formed.

Next, a 5 wt% chlorobenzene solution of charge transporting polyurethane [Exemplary Compound (XV-2)] (Mw = 9.67 × 10 ⁴ ) was prepared as a hole transporting material, and 0.1 μm polytetrafluoroethylene was prepared. After filtering with a (PTFE) filter, it was applied onto the buffer layer by a spin coating method to form a 30 nm-thick hole transport layer.

After sufficiently drying, sublimated and purified Alq ₃ (exemplary number VII-1) as a light emitting material is put on a tungsten board and evaporated by a vacuum evaporation method to form a light emitting layer having a thickness of 50 nm on the hole transport layer. did. The degree of vacuum at this time was 10 ⁻⁵ Torr, and the boat temperature was 300 ° C.

Finally, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 150 nm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

Example 4
An ITO electrode is formed by etching on a 2 mm wide strip-shaped glass substrate, washed and dried, and then a buffer layer having a film thickness of 10 nm is formed by vacuum evaporation using molybdenum trioxide (MoO ₃ ) as a buffer layer material. Formed.

Next, 0.5 parts by weight of charge transporting polyurethane [Exemplary Compound (XV-2)] (Mw = 9.67 × 10 ⁴ ) (styrene conversion) as a charge transporting material, Exemplified compound (XII, PPV system, Mw≈10 ⁵ ) was mixed by 0.1 part by weight to prepare a 10% by weight chlorobenzene solution of the mixture and filtered through a 0.1 μm polytetrafluoroethylene (PTFE) filter. Using this solution, a light emitting layer having a charge transporting ability of 80 nm in thickness was formed on the buffer layer by spin coating.

Finally, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 150 nm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent element was 0.04 cm ² .

(Example 5)
An element was fabricated in the same manner as in Example 1 except that vanadium trioxide (VO ₃ ) was used as the buffer layer material.

(Example 6)
A device was fabricated in the same manner as in Example 2 except that vanadium trioxide (VO ₃ ) was used as the buffer layer material.

(Example 7)
A device was fabricated in the same manner as in Example 3 except that vanadium trioxide (VO ₃ ) was used as the buffer layer material.

(Example 8)
A device was fabricated in the same manner as in Example 4 except that vanadium trioxide (VO ₃ ) was used as the buffer layer material.

Example 9
A device was fabricated in the same manner as in Example 1 except that silicon oxide (SiO ₂ ) was used as the buffer layer material.

(Example 10)
A device was fabricated in the same manner as in Example 2 except that silicon oxide (SiO ₂ ) was used as the buffer layer material.

(Example 11)
A device was fabricated in the same manner as in Example 3 except that silicon oxide (SiO ₂ ) was used as the buffer layer material.

(Example 12)
A device was fabricated in the same manner as in Example 4 except that silicon oxide (SiO ₂ ) was used as the buffer layer material.

(Example 13)
A device was fabricated in the same manner as in Example 1 except that charge transporting polyurethane [Exemplary Compound X-1] (Mw = 1.20 × 10 ⁵ ) was used as the electron transporting material.

(Example 14)
A device was fabricated in the same manner as in Example 2 except that charge transporting polyurethane [Exemplary Compound X-1] (Mw = 1.20 × 10 ⁵ ) was used as the electron transporting material.

(Example 15)
A device was fabricated in the same manner as in Example 3 except that charge transporting polyurethane [Exemplary Compound X-1] (Mw = 1.20 × 10 ⁵ ) was used as the hole transporting material.

(Example 16)
A device was fabricated in the same manner as in Example 4 except that charge transporting polyurethane [Exemplary Compound X-1] (Mw = 1.20 × 10 ⁵ ) was used as the charge transporting material.
(Example 17)
An element was fabricated in the same manner as in Example 3 except that the thickness of the buffer layer was 0.5 nm.

(Example 18)
A device was fabricated in the same manner as in Example 3 except that the thickness of the buffer layer was 5 nm.

(Example 19)
A device was fabricated in the same manner as in Example 3 except that the thickness of the buffer layer was 50 nm.

(Example 20)
A device was fabricated in the same manner as in (Example 3) except that the thickness of the buffer layer was 250 nm.

(Example 21)
A device was fabricated in the same manner as in (Example 1) except that the method for forming the light emitting layer was as follows.
That is, charge transporting polyurethane [Exemplary Compound (XVI-2)] (Mw = 1.23 × 10 ⁵ ) as a charge transporting material and 0.3 parts by weight of a luminescent polymer, the above Exemplified Compound (XI, Poly Fluorene, Mw≈9.67 × 10 ⁴ ) and 0.5 parts by weight of charge transporting material [Exemplary Compound (V-1)] are mixed by 0.2 parts by weight, and a 10% by weight chlorobenzene solution of the mixture is mixed. The resulting solution was filtered through a 0.1 μm polytetrafluoroethylene (PTFE) filter, and this solution was applied onto the buffer layer by a spin coating method to form a light-emitting layer having a charge transport ability of 80 nm in thickness. .

(Example 22)
A device was fabricated in the same manner as in (Example 2) except that the method for forming the light emitting layer was as follows.
That is, sublimated and purified Alq ₃ (exemplary number VII-1) and a charge transporting material [exemplary compound (V-1)] are placed in separate tungsten boats as a luminescent material, and co-evaporated by a vacuum evaporation method. A light emitting layer having a charge transporting ability of 50 nm in thickness was formed on the hole transporting layer. The deposition rate was adjusted so that the composition ratio of the formed film was 7: 3. At this time, the degree of vacuum was 10 ⁻⁵ Torr and the boat temperature was about 300 ° C.

(Example 23)
A device was fabricated in the same manner as in (Example 3) except that the method for forming the light emitting layer was as follows.
That is, sublimated and purified Alq ₃ (exemplary number VII-1) and a charge transporting material [exemplary compound (V-1)] are placed in separate tungsten boats as a luminescent material, and co-evaporated by a vacuum evaporation method. A light emitting layer having a charge transporting ability of 50 nm in thickness was formed on the hole transporting layer. The deposition rate was adjusted so that the composition ratio of the formed film was 7: 3. At this time, the degree of vacuum was 10 ⁻⁵ Torr and the boat temperature was about 300 ° C.

(Example 24)
A device was fabricated in the same manner as in (Example 4) except that the method for forming the light emitting layer was as follows.
That is, 0.3 parts by weight of charge transporting polyurethane [Exemplary Compound (XV-2)] (Mw = 9.67 × 10 ⁴ ) as a charge transporting material and the above Exemplified Compound (XII) as a luminescent polymer. , PPV system, Mw≈10 ⁵ ) and 0.5 parts by weight of charge transport material [Exemplary Compound (V-1)] are mixed by 0.2 parts by weight to prepare a 10% by weight chlorobenzene solution of the mixture, Filtration through a 0.1 μm polytetrafluoroethylene (PTFE) filter. Using this solution, a light emitting layer having a charge transporting ability of 80 nm in thickness was formed on the buffer layer by spin coating.

(Comparative Example 1)
A device was fabricated in the same manner as in Example 1 except that the buffer layer was not formed and the light emitting layer was directly formed on the glass substrate on which the ITO electrode was formed.

(Comparative Example 2)
A device was fabricated in the same manner as in Example 2, except that the buffer layer was not formed and the hole transport layer was directly formed on the glass substrate on which the ITO electrode was formed.

(Comparative Example 3)
A device was fabricated in the same manner as in Example 3 except that the buffer layer was not formed and the hole transport layer was directly formed on the glass substrate on which the ITO electrode was formed.

(Comparative Example 4)
A device was fabricated in the same manner as in Example 4 except that a buffer layer was not formed and a light emitting layer having a charge transport capability was directly formed on a glass substrate on which an ITO electrode was formed.

(Comparative Example 5)
Implementation was conducted except that a charge transporting polymer having a vinyl skeleton [the following compound (XIII), Mw = 5.46 × 10 ⁴ (in terms of styrene)] was used as the hole transporting material instead of the charge transporting polyurethane. A device was produced in the same manner as in Example 3.

(Comparative Example 6)
Implementation was performed except that a charge transporting polymer having a polycarbonate skeleton [the following compound (XIV), Mw = 7.83 × 10 ⁴ (in terms of styrene)] was used as the hole transporting material instead of the charge transporting polyurethane. A device was produced in the same manner as in Example 3.

(Comparative Example 7)
Implementation was carried out except that a charge transporting polymer having the vinyl skeleton [the compound (XIII), Mw = 5.46 × 10 ⁴ (in terms of styrene)] was used as the hole transporting material instead of the charge transporting polyurethane. A device was produced in the same manner as in Example 4.

(Comparative Example 8)
Implementation was carried out except that a charge transporting polymer having a polycarbonate skeleton [the compound (XIV), Mw = 7.83 × 10 ⁴ (in terms of styrene)] was used as the hole transporting material instead of the charge transporting polyurethane. A device was produced in the same manner as in Example 4.

(Comparative Example 9)
A device was fabricated in the same manner as in Example 1, except that the following compound (XX) (Mw≈2 × 10 ⁵ ) was used as the buffer layer material, and the buffer layer was formed by the following method.
That is, as a solution for forming a buffer layer, an aqueous dispersion of the following compound (XX), the concentration of which is adjusted so as to obtain a desired film thickness, is spin-coated and polytetrafluoroethylene (PTFE) having an opening of 0.5 μm. Filtered with a filter. Next, using this solution, a 20 nm thick buffer layer was formed by spin coating on the surface of the glass substrate with an ITO electrode that was washed and dried, on the side where the ITO electrode was provided.

(Comparative Example 10)
A device was fabricated in the same manner as in (Example 2) except that the compound (XX) (Mw≈2 × 10 ⁵ ) was used as the buffer layer material and the buffer layer was formed by the following method.
That is, as a buffer layer forming solution, an aqueous dispersion of the above compound (XX) whose concentration is adjusted so as to obtain a desired film thickness is spin-coated with polytetrafluoroethylene (PTFE) having an opening of 0.5 μm. Filtered with a filter. Next, using this solution, a 20 nm thick buffer layer was formed by spin coating on the surface of the glass substrate with an ITO electrode that was washed and dried, on the side where the ITO electrode was provided.

(Comparative Example 11)
A device was fabricated in the same manner as in (Example 3) except that the compound (XX) (Mw≈2 × 10 ⁵ ) was used as the buffer layer material and the buffer layer was formed by the following method.
That is, as a buffer layer forming solution, an aqueous dispersion of the above compound (XX) whose concentration is adjusted so as to obtain a desired film thickness is spin-coated with polytetrafluoroethylene (PTFE) having an opening of 0.5 μm. Filtered with a filter. Next, using this solution, a 20 nm thick buffer layer was formed by spin coating on the surface of the glass substrate with an ITO electrode that was washed and dried, on the side where the ITO electrode was provided.

(Comparative Example 12)
A device was fabricated in the same manner as in Example 4 except that the above compound (XX) (Mw≈2 × 10 ⁵ ) was used as the buffer layer material, and the buffer layer was formed by the following method.
That is, as a buffer layer forming solution, an aqueous dispersion of the above compound (XX) whose concentration is adjusted so as to obtain a desired film thickness is spin-coated with polytetrafluoroethylene (PTFE) having an opening of 0.5 μm. Filtered with a filter. Next, using this solution, a 20 nm thick buffer layer was formed by spin coating on the surface of the glass substrate with an ITO electrode that was washed and dried, on the side where the ITO electrode was provided.

-Evaluation methods-
The organic electroluminescent element produced as described above was applied with a DC voltage in vacuum (133.3 × 10 ⁻³ Pa (10 ⁻⁵ Torr)) with the ITO electrode side plus and the Mg—Ag back electrode minus. The emission was measured, and the rising voltage, maximum luminance, and driving current density at the maximum luminance were evaluated. The results are shown in Table 1. Moreover, the element lifetime of the organic electroluminescent element was measured in dry nitrogen. In the evaluation of the element lifetime, the current value was set so that the initial luminance was 50 cd / m ^2, and the time until the luminance was reduced by half from the initial value by constant current driving was defined as the element lifetime (hour). The device lifetime at this time is also shown in Table 1.

  From the above results, it can be seen that the present example has improved charge injection properties and charge balance, and exhibits stable, high luminance, high efficiency, and long life characteristics as compared with the comparative example.

It is typical sectional drawing of an example of the display apparatus in this invention. It is typical sectional drawing of an example of the display apparatus in this invention. It is typical sectional drawing of an example of the display apparatus in this invention. It is typical sectional drawing of an example of the display apparatus in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent insulator board | substrate 2 ... Transparent electrode 3 ... Buffer layer 4 ... Hole transport layer 5 ... Light emitting layer 6 ... Electron transport layer 7 ... Light emitting layer 8 with carrier transport ability ... Back electrode 9 ... Voltage application apparatus 10 ... Organic Electroluminescent device

Claims (14)

A pair of anode and cathode, at least one of which is transparent or translucent, and a buffer layer and an organic compound layer sandwiched between the anode and cathode,
The organic compound layer is composed of one or more layers including at least a light emitting layer,
At least one of the organic compound layers contains at least one charge transporting polyurethane, and the charge transporting polyurethane is at least one of the charge transporting polyurethanes represented by the following general formulas (I-1) and (I-2). One kind,
At least one layer containing the charge transporting polyurethane is provided in contact with the buffer layer;
The buffer layer is provided in contact with the anode and contains one or more charge injection materials, and the charge injection material is at least one selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides. An organic electroluminescent element characterized by being an inorganic material.

(In the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the following general formulas (II-1) and (II-2), and R represents a hydrogen atom. Represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and T represents a divalent linear hydrocarbon having 1 to 6 carbon atoms or a divalent hydrocarbon having 2 to 10 carbon atoms. Represents a branched hydrocarbon, Y represents a divalent diisocyanate residue or a divalent amine residue, Z represents a divalent alcohol residue or a divalent bischloroformate residue, and m represents 0 Or p represents an integer of 5 to 5,000, and the residue shown here refers to a portion excluding the reactive group of the linking compound.)

(In the general formulas (II-1) and (II-2), Ar represents a substituted or unsubstituted monovalent aromatic group, X represents a substituted or unsubstituted divalent aromatic group, and k represents Represents 0 or 1)   The organic electroluminescence device according to claim 1, wherein the buffer layer includes one or both of molybdenum oxide and vanadium oxide.   The Ar in the general formulas (II-1) and (II-2) is a monovalent aromatic group selected from benzene, biphenyl, naphthalene, and fluorene. Organic electroluminescent device. The T in the general formulas (I-1) and (I-2) is — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, or — (CH ₂ ) ₄ —. The organic electroluminescent element according to claim 1.   The organic electroluminescent element according to claim 1, wherein the buffer layer has a thickness of 1 nm to 15 nm.   The organic compound layer is composed of at least the light emitting layer and the electron transport layer, and at least the light emitting layer contains at least one kind of charge transporting polyurethane represented by the general formulas (I-1) and (I-2). The organic electroluminescent element according to claim 1, wherein the buffer layer is provided between the anode and the light emitting layer.   The organic light emitting device according to claim 6, wherein the light emitting layer contains a charge transporting material other than the charge transporting polyurethane.   The organic compound layer is composed of at least a hole transport layer, the light emitting layer, and an electron transport layer, and at least the hole transport layer is represented by the general formulas (I-1) and (I-2). 2. The organic electroluminescent device according to claim 1, comprising at least one kind of charge transporting polyurethane, wherein the buffer layer is provided between the anode and the hole transport layer.   The organic electroluminescent device according to claim 8, wherein the light emitting layer contains a charge transporting material other than the charge transporting polyurethane.   The organic compound layer includes at least a hole transport layer and the light emitting layer, and at least the hole transport layer includes at least the charge transporting polyurethane represented by the general formulas (I-1) and (I-2). The organic electroluminescent element according to claim 1, wherein the buffer layer is provided between the anode and the hole transport layer.   The organic light emitting device according to claim 10, wherein the light emitting layer contains a charge transporting material other than the charge transporting polyurethane.   The organic compound layer is composed of only the light emitting layer, the light emitting layer is a light emitting layer having a charge transporting ability, and the light emitting layer having the charge transporting ability is represented by the general formulas (I-1) and (I- 2. The organic material according to claim 1, wherein the buffer layer is provided between the anode and the light emitting layer having the charge transporting capability. Electroluminescent device.   The organic electroluminescent element according to claim 12, wherein the light emitting layer having the charge transporting capability contains a charge transporting material other than the charge transporting polyurethane. An organic electroluminescent device arranged in a matrix, and a driving means for driving the organic electroluminescent device,
The organic electroluminescent element has a pair of an anode and a cathode, at least one of which is transparent or translucent, and a buffer layer and an organic compound layer sandwiched between the anode and the cathode,
The organic compound layer is composed of one or more layers including at least a light emitting layer,
At least one of the organic compound layers contains at least one charge transporting polyurethane, and the charge transporting polyurethane is at least one of the charge transporting polyurethanes represented by the following general formulas (I-1) and (I-2). One kind,
At least one layer containing the charge transporting polyurethane is provided in contact with the buffer layer;
The buffer layer is provided in contact with the anode and contains one or more charge injection materials, and the charge injection material is at least one selected from inorganic oxides, inorganic nitrides, and inorganic oxynitrides. A display device characterized by being an inorganic material.

(In the general formulas (I-1) and (I-2), A represents at least one selected from the structures represented by the following general formulas (II-1) and (II-2), and R represents a hydrogen atom. Represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and T represents a divalent linear hydrocarbon having 1 to 6 carbon atoms or a divalent hydrocarbon having 2 to 10 carbon atoms. Represents a branched hydrocarbon, Y represents a divalent diisocyanate residue or a divalent amine residue, Z represents a divalent alcohol residue or a divalent bischloroformate residue, and m represents 0 Or p represents an integer of 5 to 5,000, and the residue shown here refers to a portion excluding the reactive group of the linking compound.)

(In the general formulas (II-1) and (II-2), Ar represents a substituted or unsubstituted monovalent aromatic group, X represents a substituted or unsubstituted divalent aromatic group, and k represents Represents 0 or 1)

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