JP2007201194A - Organic electroluminescence device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence device that has a sufficient luminance, has improved stability and durability, allows the area to be increased, and can be manufactured easily. <P>SOLUTION: The electroluminescence device is made of one or a plurality of organic compound layers held between a pair of electrodes, where at least one of them is transparent or translucent. At least one layer of the organic compound layers contains at least one type of charge transporting polyester made of repetitive units containing at least one type selected from a specific N phenylcarbazole derivative structure as a partial structure, and a radiating high molecule that emits light by the transition from an excited triplet state of an electron energy level to a base state or to the base state through the excited triplet state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent device (hereinafter sometimes referred to as “organic EL device”), and more particularly to an organic EL device using a specific charge transporting polymer.

  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. As the EL element, an inorganic phosphor is mainly used at present, but since an AC voltage of 200 V or more is necessary for driving, there are problems such as high manufacturing cost and insufficient luminance. is doing.

  On the other hand, research on EL devices using organic compounds first started with a single crystal such as anthracene, but in the case of a single crystal, the film thickness was as thick as about 1 mm and a driving voltage of 100 V or more was required. For this reason, attempts have been made to reduce the thickness by vapor deposition (for example, see Non-Patent Document 1). However, the thin film obtained by this method still has a high driving voltage of 30 V, a low density of electron and hole carriers in the film, and a low probability of photon generation due to carrier recombination. It was not obtained.

However, in recent years, in a function-separated EL device in which thin films of a hole-transporting organic low-molecular compound and a fluorescent organic low-molecular compound having an electron-transporting capability are sequentially stacked by a vacuum deposition method, a low driving voltage of about 10 V in 1000 cd / m ² or more high brightness have been reported those obtained (e.g., see non-Patent Document 2), since research and development of laminate type EL device has been actively conducted. In these stacked EL elements, holes and electrons are made of a fluorescent organic compound while maintaining the carrier balance between holes and electrons through a charge transport layer made of an organic compound having a charge transport property from the electrode. The holes and electrons injected into the light emitting layer and confined in the light emitting layer are recombined to realize high luminance light emission.

However, this type of EL device has the following three major problems for practical use.
(1) Since the element is driven at a high current density of several mA / cm ² , a large amount of Joule heat is generated. For this reason, hole transporting low molecular weight compounds and fluorescent organic low molecular weight compounds formed in an amorphous state by vapor deposition are gradually crystallized and finally melted, resulting in a decrease in luminance and dielectric breakdown. As a result, there is a problem that the lifetime of the device is reduced.
(2) In manufacturing the device, a thin film having a film thickness of 0.1 μm or less is formed in a plurality of vapor deposition processes with a low molecular organic compound. It is necessary to control the film thickness under controlled conditions. Therefore, there are problems that productivity is low and it is difficult to increase the area.
(3) What is used in the light emitting material is light emission from an excited singlet state, that is, fluorescence. However, the generation ratio of excitons in the excited singlet state and excited triplet state generated by recombination of holes and electrons in the light emitting layer is 1: 3 from the spin statistic rule based on quantum mechanics. The upper limit of the internal quantum efficiency of light emission in the organic EL element is theoretically 25%.

  In order to solve the problem shown in (1), a stable amorphous glass state can be obtained as a hole transport material, a polymer using starburst amine or introducing triphenylamine into the side chain of polyphosphazene is used. Used EL elements have been reported (for example, see Non-Patent Documents 3 and 4).

  However, since these alone have an energy barrier due to the ionization potential of the hole transport material, the hole injection property from the anode or the hole injection property to the light emitting layer cannot be satisfied. Further, in the case of the former starburst amine, it is difficult to purify due to low solubility, and it is difficult to increase the purity, and in the case of the latter polymer, a high current density cannot be obtained and sufficient. There is also a problem that the luminance is not obtained.

  Further, in order to solve the problem shown in (2), research and development of an EL element having a single-layer structure capable of shortening the process has been promoted, and a conductive polymer such as poly (p-phenylene vinylene) is used. A device in which an electron transporting material and a fluorescent dye are mixed in a hole transporting polyvinyl carbazole has been proposed (see, for example, Non-Patent Documents 5 and 6). It does not reach to the laminated EL element using.

  Furthermore, it has been reported that the manufacturing method is preferably a wet coating method from the viewpoint of simplification of manufacturing, workability, large area, cost, etc., and an element can also be obtained by a casting method (for example, non-processing). (See Patent Documents 7 and 8). However, since the charge transporting material has poor solubility and compatibility with solvents and resins, it is easy to crystallize, and there is a problem in manufacturing or characteristics.

  In order to solve the above problem (3), it is effective to use an excited triplet state having a high probability of exciton generation, that is, a phosphorescent material. As a phosphorescent light-emitting material, an element using a platinum complex was first proposed (for example, see Non-Patent Document 9). Further, by using an iridium complex that emits phosphorescence, an external quantum efficiency of 7.5% (external extraction efficiency) Is assumed to be 20%, the internal quantum efficiency is 37.5%), and it has been shown that it is possible to exceed the external quantum efficiency of 5%, which has been the upper limit in the past (for example, non-patent Reference 10 and Patent Document 1).

However, when using a phosphorescent light emitting material, it is necessary to use it in combination with a specific host material in order to obtain a high external quantum efficiency. In the case described above, a specific low molecular organic compound is doped as a host material. Therefore, it has the same problems as the above (1) and (2), which are the same as those of the fluorescent light emitting material.
Thin Solid Films, Vol. 94, 171 (1982) Appl. Phys. Lett. , Vol. 51,913 (1987) Proceedings of the 40th Joint Conference on Applied Physics, 30a-SZK-14 (1993) Proceedings of the 42nd Polymer Symposium, 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) Nature, Vol. 395, 151 (1998) Appl. Phys. Lett. , Vol. 75, 4 (1999) International publication 00/70655 pamphlet

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide an organic EL device that has sufficient luminance, is excellent in stability and durability, can be increased in area, and can be easily manufactured.

  As a result of intensive studies on charge transport materials and light-emitting materials to achieve the above object, the following general formulas (AI-1) and (AI-2), or the following general formulas (BI-1) and (BI-2) are shown. A charge transporting polyester containing at least one selected from the structures as a partial structure has charge injection characteristics, charge mobility, and thin film forming ability suitable for an organic electroluminescent device, and the charge transporting polyester and The durability of organic electroluminescent devices by combining with a light-emitting polymer that emits light by the transition from the excited triplet state to the ground state of the electron energy level or the transition from the excited triplet state to the ground state In addition to being excellent in luminous efficiency, it has been found that the device has high productivity, and the present invention has been completed. In addition, charge transport including as a partial structure at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2), or the following general formulas (BI-1) and (BI-2) The present inventors have found that even when the conductive polyester is used alone, it has suitable charge injection characteristics, charge mobility, and thin film forming ability as an organic electroluminescence device, and the present invention has been completed.

That is, the present invention
<1> In an organic electroluminescent device composed of one or a plurality of organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2) as a partial structure. Organic electroluminescence containing a species and a light-emitting polymer that emits light upon transition from the excited triplet state to the ground state of the electronic energy level or through the transition to the ground state via the excited triplet state It is an element.

In the general formulas (AI-1) and (AI-2), R ₁ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, and T represents 1 carbon atom. Represents a divalent linear hydrocarbon of ˜6 or a branched hydrocarbon having 2 to 10 carbon atoms, and l and m each represents 0 or 1;

<2> The organic compound layer is composed of at least a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state of an electron energy level to a ground state or by transition to a ground state via an excited triplet state <1>. The organic electroluminescent device according to 1>.

<3> The organic electroluminescent element according to <2>, wherein the light emitting layer includes a charge transporting material.

<4> The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. It is an organic electroluminescent element as described in <1>.

<5> The organic electroluminescent element according to <4>, wherein the light emitting layer includes a charge transporting material.

<6> The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, and a light emitting layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. It is an organic electroluminescent element as described in <1>.

<7> The organic electroluminescent element according to <6>, wherein the light emitting layer includes a charge transporting material.

<8> The organic compound layer is composed of a light emitting layer having at least a charge transporting capability,
The light-emitting layer has at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure, and an electron The organic electroluminescence according to <1>, comprising a light-emitting polymer that emits light by a transition from an excited triplet state of an energy level to a ground state or a transition to a ground state via an excited triplet state. It is an element.

<9> The organic electroluminescence device according to <8>, wherein the light emitting layer includes a charge transporting material.

<10> A charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure is represented by the following general formula (AII-1). ) Or the organic electroluminescence device according to <1>, which is a charge transporting polyester represented by (AII-2).

In general formulas (AII-1) and (AII-2), A represents the structure represented by general formulas (AI-1) and (AI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Or a substituted or unsubstituted aralkyl group, Y represents a divalent alcohol residue, Z represents a divalent carboxylic acid residue, and B and B ′ each independently represent a group − O— (Y—O) _n —R or a group —O— (Y—O) _n —CO—Z—CO—O—R ′ (where R, Y, Z have the same meaning as above). , R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.), N represents an integer of 1 to 5, and p represents an integer of 5 to 5000.

<11> In an organic electroluminescent element composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer composed of a repeating unit containing at least one selected from the structures represented by the following general formulas (BI-1) and (BI-2) as a partial structure. Organic electroluminescence containing a species and a light-emitting polymer that emits light upon transition from the excited triplet state to the ground state of the electronic energy level or through the transition to the ground state via the excited triplet state It is an element.

In general formulas (BI-1) and (BI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, and T represents carbon. A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.

<12> The organic compound layer is composed of at least a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state of an electron energy level to a ground state or by transition to a ground state via an excited triplet state <11>.

<13> The organic electroluminescence device according to <12>, wherein the light emitting layer includes a charge transporting material.

<14> The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state of an electron energy level to a ground state or by transition to a ground state via an excited triplet state <11>.

<15> The organic electroluminescent element according to <14>, wherein the light emitting layer includes a charge transporting material.

<16> The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, and a light emitting layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. <11> The organic electroluminescence device according to <11>.

<17> The organic electroluminescent element according to <16>, wherein the light emitting layer contains a charge transporting material.

<18> The organic compound layer includes at least a light emitting layer having charge transporting ability, and the light emitting layer is at least one selected from the structures represented by the general formulas (BI-1) and (BI-2). Containing at least one charge transporting polyester comprising a repeating unit containing a seed as a partial structure, and the light-emitting layer may exhibit an excited triplet state by a transition from an excited triplet state of an electron energy level to a ground state. <11> The organic electroluminescence device according to <11>, which contains a light-emitting polymer that emits light by transition to a ground state via the via.

<19> The organic electroluminescent element according to <18>, wherein the light emitting layer includes a charge transporting material.

<20> A charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure is represented by the following general formula (BII-1). ) Or the organic electroluminescence device according to <11>, which is a charge transporting polyester represented by (BII-2).

In general formulas (BII-1) and (BII-2), A represents the structure represented by general formulas (BI-1) and (BI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Or a substituted or unsubstituted aralkyl group, Y represents a divalent alcohol residue, Z represents a divalent carboxylic acid residue, and B and B ′ each independently represent a group —O -(Y-O) _n- R or a group -O- (Y-O) _n -CO-Z-CO-OR '(where R, Y, Z have the same meaning as above, R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.), N represents an integer of 1 to 5, and p represents an integer of 5 to 5000.

<21> In an organic electroluminescent element composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2) as a partial structure. It is an organic electroluminescent element containing at least seeds.

In general formulas (AI-1) and (AI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, and T represents carbon. A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.

<22> In an organic electroluminescent element composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer composed of a repeating unit containing at least one selected from the structures represented by the following general formulas (BI-1) and (BI-2) as a partial structure. It is an organic electroluminescent element containing at least seeds.

In general formulas (BI-1) and (BI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, and T represents carbon. A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.

  ADVANTAGE OF THE INVENTION According to this invention, it has sufficient brightness | luminance, it is excellent in stability and durability, and the organic EL element which can be enlarged and can be manufactured easily can be provided.

Hereinafter, the present invention will be described in detail.
The organic EL device of the present invention is an organic electroluminescent device comprising one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent.
At least one of the organic compound layers is at least selected from the following general formulas (AI-1) and (AI-2), or structures represented by the following general formulas (BI-1) and (BI-2) One or more charge transporting polyesters composed of repeating units containing one kind as a partial structure, and the transition from the excited triplet state to the ground state of the electronic energy level or to the ground state via the excited triplet state. It contains a light-emitting polymer that emits light by transition (hereinafter sometimes abbreviated as “light-emitting polymer”).

The organic EL device of the present invention has sufficient brightness and stability by having a layer containing a light-emitting polymer and the charge-transporting polyester that also functions as a host material for the light-emitting polymer. And excellent durability. Further, by using the charge transporting polyester, the area can be increased and the production can be easily performed.
Particularly in the present invention, since the layer containing the charge transporting polyester and the light emitting polymer can be formed by a wet coating method, the manufacturing process is greatly simplified compared to the conventional device as described above. can do.

  Further, even if the charge transporting polyester is used alone, it can have charge injection characteristics, charge mobility, and thin film forming ability suitable for an organic electroluminescence device.

In the present invention, a charge including a carbazole structure represented by the following general formula (AI-1), general formula (AI-2), general formula (BI-1), or general formula (BI-2) Although a transporting polyester is used, as the charge transporting polyether containing such a carbazole structure, a carbazole structure described in JP-A-2005-259441 (so-called 4,4′-dicarbazoly-1,1′-biphenyl) is used. And (CBP) a similar structure).
However, since the charge transporting polyester containing a carbazole structure used in the present invention is superior in solubility in a solvent as compared with a charge transporting polyether containing a CBP structure, it is easy to form a film. Uniformity is also good. In addition, there is an advantage that phase separation with the light emitting polymer to be mixed hardly occurs.

  Next, in the organic electroluminescence device of the present invention, a charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2) as a partial structure Will be described.

In the general formulas (AI-1) and (AI-2), each R ₁ independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group. Examples of the aromatic group include phenyl group derivatives such as phenyl group, tolyl group and methoxyphenyl group, condensed ring derivatives such as 1-naphthyl group, 2-naphthyl group and 9-anthranyl group, thienyl group, Heterocyclic derivatives such as methylthienyl group, furanyl group and oxadiazole group are preferably used.
T represents a divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms, and l and m represent 0 or 1. Specific examples of T include the following.

  As the charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure, the following general formula (AII-1) or ( Those represented by AII-2) are preferably used.

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

  In general formula (AII-1) or (AII-2), R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. As said alkyl group, a C1-C10 thing is preferable, For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an octyl group, 2-ethyl-hexyl group etc. are mentioned. As said aryl group, a C6-C20 thing is preferable, For example, a phenyl group, a toluyl group, etc. are mentioned. As said aralkyl group, a C7-C20 thing is preferable, For example, a benzyl group, a phenethyl group, etc. are mentioned. Examples of the substituent for 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 general formula (AII-1) or (AII-2), Y represents a divalent alcohol residue, and Z represents a divalent carboxylic acid residue. Specific examples of Y and Z include groups selected from the following formulas (1) to (7).

In formulas (1) to (7), R ₂ and R ₃ 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, and a substituted group. Or an unsubstituted aralkyl group or a halogen atom, a to c each represent an integer of 1 to 10, d and e each represent an integer of 0, 1 or 2, f represents 0 or 1, and V represents The group selected from following formula (8)-(18) is represented.

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

In general formula (AII-1) or (AII-2), n represents an integer of 1 to 5, and p representing the degree of polymerization is in the range of 5 to 5000, preferably 10 to 1000. B and B ′ are each independently —O— (Y—O) _n —R or —O— (Y—O) _n —CO—Z—CO—O—R ′ (where R, Y , Z and n are as defined above, and R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

  The weight average molecular weight Mw of the charge transporting polyester in the present invention is preferably in the range of 5,000 to 1,000,000, but more preferably in the range of 10,000 to 300,000.

The charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure in the present invention has the following structural formula (AIII-1 ) Or (AIII-2) can be synthesized by polymerizing by a known method described in, for example, the 4th edition Experimental Chemistry Course Vol. 28 (Maruzen, 1993). . Incidentally, in the structural formula (AIII-1) or _{(AIII-2), R 1} , T, l, m, n are, R ₁ in the general formula (AI-1) and (AI-2), T, l , M, and n are the same.

Specifically, the charge transporting polyester represented by the general formula (AII-1) can be synthesized, for example, as follows.
When A ′ is a hydroxyl group, divalent alcohols represented by HO— (YO) _n —H are mixed in an approximately equivalent amount and polymerized using an acid catalyst. As the acid catalyst, those used for usual esterification reaction such as sulfuric acid, toluenesulfonic acid, trifluoroacetic acid and the like can be used. The amount of the catalyst is 1 / 10,000 with respect to 1 part by mass of the hole transporting monomer. The range of ˜1 / 10 parts by mass is preferable, and the range of 1 / 1.000 to 1/50 parts by mass is more preferable.

  In order to remove water generated during the polymerization, it is preferable to use a solvent that can be azeotroped with water, and toluene, chlorobenzene, 1-chloronaphthalene and the like are effective, and with respect to 1 part by mass of the charge transporting monomer, It is used in the range of 1 to 100 parts by mass, preferably 2 to 50 parts by mass. The reaction temperature can be arbitrarily set, but it is preferable to carry out the reaction at the boiling point of the solvent in order to remove water generated during the polymerization.

  When the solvent is not used after completion of the reaction, it is dissolved in a soluble solvent. When a solvent is used, the reaction solution is dropped as it is into a poor solvent in which alcohols such as methanol and ethanol, and polymers such as acetone are difficult to dissolve, and a hole transporting polyester is precipitated, and a hole transporting property is deposited. After separating the polyester, it is thoroughly washed with water or an organic solvent and dried. Further, if necessary, the reprecipitation treatment may be repeated by dissolving in an appropriate organic solvent and dropping in a poor solvent to precipitate the hole transporting polyester. The reprecipitation treatment is preferably carried out with efficient stirring with a mechanical stirrer or the like.

  The amount of the solvent for dissolving the charge transporting polyester in the reprecipitation treatment is preferably in the range of 1 to 100 parts by weight, more preferably in the range of 2 to 50 parts by weight with respect to 1 part by weight of the charge transporting polyester. Moreover, the range of 1-1000 mass parts is preferable with respect to 1 mass part of positive hole transport polyester, and, as for the quantity of a poor solvent, the range of 10-500 mass parts is more preferable.

When A ′ is halogen, dihydric alcohols represented by HO— (Y—O) _n —H are mixed in an approximately equivalent amount and polymerized using an organic basic catalyst such as pyridine or triethylamine. The amount of the organic basic catalyst is preferably in the range of 1 to 10 equivalents and more preferably in the range of 2 to 5 equivalents with respect to 1 equivalent of the hole transporting monomer.

  As the solvent, methylene chloride, tetrahydrofuran (THF), toluene, chlorobenzene, 1-chloronaphthalene and the like are effective, and the amount of the solvent is preferably in the range of 1 to 100 parts by mass with respect to 1 part by mass of the charge transporting monomer. The range of 2-50 mass parts is more preferable. The reaction temperature can be arbitrarily set. After the polymerization, reprecipitation treatment is performed as described above, and purification is performed.

  In the case of dihydric alcohols with high acidity such as bisphenol, an interfacial polymerization method can also be used. That is, polymerization can be carried out by adding a dihydric alcohol to water, adding an equivalent base and dissolving it, and then adding a charge transporting monomer solution equivalent to the dihydric alcohol with vigorous stirring. In this case, the amount of water is preferably in the range of 1 to 1,000 parts by mass and more preferably in the range of 2 to 500 parts by mass with respect to 1 part by mass of the dihydric alcohol.

  As the solvent for dissolving the charge transporting monomer, methylene chloride, dichloroethane, trichloroethane, toluene, chlorobenzene, 1-chloronaphthalene and the like are effective. The reaction temperature can be arbitrarily set, and in order to promote the reaction, it is effective to use a phase transfer catalyst such as an ammonium salt or a sulfonium salt. The amount of the phase transfer catalyst is preferably in the range of 0.1 to 10 parts by mass and more preferably in the range of 0.2 to 5 parts by mass with respect to 1 part by mass of the charge transporting monomer.

Further, when A ′ is an alkoxyl group, the charge transporting polymer represented by the structural formulas (AIII-1) and (AIII-2) is represented by HO— (YO) _n —H. Add excessive dihydric alcohols, heat using inorganic acids such as sulfuric acid and phosphoric acid, titanium alkoxides, acetates or carbonates such as calcium and cobalt, oxides of zinc and lead as catalysts and synthesize by transesterification it can.

  The amount of the dihydric alcohol is preferably in the range of 2 to 100 equivalents and more preferably in the range of 3 to 50 equivalents with respect to 1 equivalent of the charge transporting monomer. The amount of the catalyst is preferably in the range of 1 / 10,000 to 1 part by mass, more preferably in the range of 1 / 1,000 to 1/2 part by mass with respect to 1 part by mass of the charge transporting monomer.

The reaction is carried out at a reaction temperature in the range of 200 to 300 ° C. After the transesterification from the alkoxyl group to the group —O— (Y—O) _n —H is completed, the HO— (Y—O) _n —H is removed. In order to promote polymerization due to separation, the reaction is preferably performed under reduced pressure. Also, HO- (Y-O) with _n -H and high boiling point solvent such as azeotropic 1-chloronaphthalene, the reaction while removing HO- (Y-O) _n -H at atmospheric pressure azeotropically It can also be made.

The charge transporting polyester represented by the general formula (AII-2) can be synthesized as follows.
That is, in each case in the synthesis of the charge transporting polyester represented by the general formula (AII-1), the following structural formulas (AIV-1) and (A After producing the compound represented by AIV-2), these may be used as charge transporting monomers and reacted with a divalent carboxylic acid or divalent carboxylic acid halide in the same manner as described above. A charge transporting polyester can be obtained. In the following formulae, R ₁ , T, k, l, m and n are as described above.

  Next, in the organic electroluminescent element of the present invention, a charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (BI-1) and (BI-2) as a partial structure Will be described.

In the general formulas (BI-1) and (BI-2), each R ₁ independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group. Examples of the aromatic group include phenyl group derivatives such as phenyl group, tolyl group and methoxyphenyl group, condensed ring derivatives such as 1-naphthyl group, 2-naphthyl group and 9-anthranyl group, thienyl group, Heterocyclic derivatives such as methylthienyl group, furanyl group and oxadiazole group are preferably used. The pyridinyl group represents a divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms, and l and m each represents 0 or 1.
Specific examples of T include the following.

  As a charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure, the following general formula (BII-1) or ( What is shown by BII-2) is used suitably.

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

  In general formula (BII-1) or (BII-2), R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. As said alkyl group, a C1-C10 thing is preferable, For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an octyl group, 2-ethyl-hexyl group etc. are mentioned. As said aryl group, a C6-C20 thing is preferable, For example, a phenyl group, a toluyl group, etc. are mentioned. As said aralkyl group, a C7-C20 thing is preferable, For example, a benzyl group, a phenethyl group, etc. are mentioned. Examples of the substituent for 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 general formula (BII-1) or (BII-2), Y represents a divalent alcohol residue, and Z represents a divalent carboxylic acid residue. Specific examples of Y and Z include groups selected from the following formulas (1) to (7).

In formulas (1) to (7), R ₂ and R ₃ 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, and a substituted group. Or an unsubstituted aralkyl group or a halogen atom, a to c each represent an integer of 1 to 10, d and e each represent an integer of 0, 1 or 2, f represents 0 or 1, and V represents The group selected from following formula (8)-(18) is represented.

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

In general formula (BII-1) or (BII-2), n represents an integer of 1 to 5, and p representing the degree of polymerization is in the range of 5 to 5000, preferably in the range of 10 to 1000. B and B ′ are each independently —O— (Y—O) _n —R or —O— (Y—O) _n —CO—Z—CO—O—R ′ (where R, Y , Z and n are as defined above, and R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

  The weight average molecular weight Mw of the charge transporting polyester in the present invention is preferably in the range of 5,000 to 1,000,000, but more preferably in the range of 10,000 to 300,000.

In the present invention, the charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure is represented by the following structural formula (BIII-1). ) Or (BIII-2) can be synthesized by polymerizing by a known method described in, for example, the 4th edition Experimental Chemistry Course Vol. 28 (Maruzen, 1993). . In the structural formula (BIII-1) or (BIII-2), R ₁ , T, l, m, and n are the general formulas (BI-1), (BI-2), (BII-1) and The same as R ₁ , T, 1, m, and n in (BII-2).

Specifically, the charge transporting polyester represented by the general formula (BII-1) can be synthesized, for example, as follows.
When A ′ is a hydroxyl group, divalent alcohols represented by HO— (YO) _n —H are mixed in an approximately equivalent amount and polymerized using an acid catalyst. As the acid catalyst, those used for usual esterification reaction such as sulfuric acid, toluenesulfonic acid, trifluoroacetic acid and the like can be used. The amount of the catalyst is 1 / 10,000 with respect to 1 part by mass of the hole transporting monomer. The range of ˜1 / 10 parts by mass is preferable, and the range of 1 / 1.000 to 1/50 parts by mass is more preferable.

  In order to remove water generated during the polymerization, it is preferable to use a solvent that can be azeotroped with water, and toluene, chlorobenzene, 1-chloronaphthalene and the like are effective, and with respect to 1 part by mass of the charge transporting monomer, It is used in the range of 1 to 100 parts by mass, preferably 2 to 50 parts by mass. The reaction temperature can be arbitrarily set, but it is preferable to carry out the reaction at the boiling point of the solvent in order to remove water generated during the polymerization.

  When the solvent is not used after completion of the reaction, it is dissolved in a soluble solvent. When a solvent is used, the reaction solution is dropped as it is into a poor solvent in which alcohols such as methanol and ethanol, and polymers such as acetone are difficult to dissolve, and a hole transporting polyester is precipitated, and a hole transporting property is deposited. After separating the polyester, it is thoroughly washed with water or an organic solvent and dried. Further, if necessary, the reprecipitation treatment may be repeated by dissolving in an appropriate organic solvent and dropping in a poor solvent to precipitate the hole transporting polyester. The reprecipitation treatment is preferably carried out with efficient stirring with a mechanical stirrer or the like.

  The amount of the solvent for dissolving the charge transporting polyester in the reprecipitation treatment is preferably in the range of 1 to 100 parts by weight, more preferably in the range of 2 to 50 parts by weight with respect to 1 part by weight of the charge transporting polyester. Moreover, the range of 1-1000 mass parts is preferable with respect to 1 mass part of positive hole transport polyester, and, as for the quantity of a poor solvent, the range of 10-500 mass parts is more preferable.

When A ′ is halogen, dihydric alcohols represented by HO— (Y—O) _n —H are mixed in an approximately equivalent amount and polymerized using an organic basic catalyst such as pyridine or triethylamine. The amount of the organic basic catalyst is preferably in the range of 1 to 10 equivalents and more preferably in the range of 2 to 5 equivalents with respect to 1 equivalent of the hole transporting monomer.

  As the solvent, methylene chloride, tetrahydrofuran (THF), toluene, chlorobenzene, 1-chloronaphthalene and the like are effective, and the amount of the solvent is preferably in the range of 1 to 100 parts by mass with respect to 1 part by mass of the charge transporting monomer. The range of 2-50 mass parts is more preferable. The reaction temperature can be arbitrarily set. After the polymerization, reprecipitation treatment is performed as described above, and purification is performed.

  In the case of dihydric alcohols with high acidity such as bisphenol, an interfacial polymerization method can also be used. That is, polymerization can be carried out by adding a dihydric alcohol to water, adding an equivalent base and dissolving it, and then adding a charge transporting monomer solution equivalent to the dihydric alcohol with vigorous stirring. In this case, the amount of water is preferably in the range of 1 to 1,000 parts by mass and more preferably in the range of 2 to 500 parts by mass with respect to 1 part by mass of the dihydric alcohol.

  As the solvent for dissolving the charge transporting monomer, methylene chloride, dichloroethane, trichloroethane, toluene, chlorobenzene, 1-chloronaphthalene and the like are effective. The reaction temperature can be arbitrarily set, and in order to promote the reaction, it is effective to use a phase transfer catalyst such as an ammonium salt or a sulfonium salt. The amount of the phase transfer catalyst is preferably in the range of 0.1 to 10 parts by mass and more preferably in the range of 0.2 to 5 parts by mass with respect to 1 part by mass of the charge transporting monomer.

Further, when A ′ is an alkoxyl group, the charge transporting polymer represented by the structural formulas (BIII-1) and (BIII-2) is represented by HO— (YO) _n —H. Add excessive dihydric alcohols, heat using inorganic acids such as sulfuric acid and phosphoric acid, titanium alkoxides, acetates or carbonates such as calcium and cobalt, oxides of zinc and lead as catalysts and synthesize by transesterification it can.

  The amount of the dihydric alcohol is preferably in the range of 2 to 100 equivalents and more preferably in the range of 3 to 50 equivalents with respect to 1 equivalent of the charge transporting monomer. The amount of the catalyst is preferably in the range of 1 / 10,000 to 1 part by mass, more preferably in the range of 1 / 1,000 to 1/2 part by mass with respect to 1 part by mass of the charge transporting monomer.

The reaction is carried out at a reaction temperature in the range of 200 to 300 ° C. After the transesterification from the alkoxyl group to the group —O— (Y—O) _n —H is completed, the HO— (Y—O) _n —H is removed. In order to promote polymerization due to separation, the reaction is preferably performed under reduced pressure. Also, HO- (Y-O) with _n -H and high boiling point solvent such as azeotropic 1-chloronaphthalene, the reaction while removing HO- (Y-O) _n -H at atmospheric pressure azeotropically It can also be made.

The charge transporting polyester represented by the general formula (BII-2) can be synthesized as follows.
That is, in each case in the synthesis of the charge transporting polyester represented by the above general formula (BII-1), the following structural formulas (BIV-1) and (B After producing the compound represented by BIV-2), these may be used as a charge transporting monomer and reacted with a divalent carboxylic acid or a divalent carboxylic acid halide in the same manner as described above. A charge transporting polyester can be obtained. In the following formulae, R ₁ , T, k, l, m and n are as described above.

Next, the light emitting polymer will be described.
The light-emitting polymer in the present invention includes a compound that emits light by transition from an excited triplet state to a ground state of an electronic energy level in a solid state or by transition to a ground state via an excited triplet state. Is used.

  Here, the light emission caused by the transition from the excited triplet state to the ground state of the electron energy level refers to light emitted by directly emitting phosphorescence from the excited triplet state, and the excitation of the electron energy level. The light emission by the transition to the ground state via the triplet state is, for example, light emission caused by transferring from the excited triplet state to another energy state and emitting phosphorescence and / or fluorescence at the transition to the ground state. Say.

  As a compound that emits light by transition to the ground state via the excited triplet state, for example, as disclosed in JP-A-2002-50483, it corresponds to a phosphorescent first organic compound. Energy transfer from the excited triplet state of the portion to the excited triplet state of the portion corresponding to the fluorescent organic second organic compound occurs, and the fluorescent light emission is generated from the second organic compound portion. Things.

  In the case where the light emitting polymer includes a portion that emits light through the excited triplet state, among the phosphorescent portion and the fluorescent portion included in the light emitting portion of the light emitting polymer. It is preferable that at least one of them forms part of the polymer chain or is bonded to the polymer chain. In this case, the phosphorescent portion and / or the fluorescent portion that forms a part of the polymer chain or is bonded to the polymer chain may form the main chain of the polymer, Moreover, a polymer side chain may be formed.

  In the above case, the light emitting polymer may be a mixture of a polymer containing a phosphorescent part and a polymer containing a fluorescent part, or may contain a phosphorescent part. It may be a copolymer of a monomer and a monomer containing a fluorescent portion.

  The value of the quantum yield of light emission including light emission from the excited triplet state in the light emitting polymer is preferably 0.1 or more, more preferably 0.3 or more, and further preferably 0.5 or more. It is. Examples of the compound having a high quantum yield of excited triplet emission that can be applied to these phosphorescent moieties include metal complexes, but are not limited thereto.

  Specific examples of the metal complex include (1) transition metal complexes such as iridium complexes and platinum complexes, and transition metal complexes such as derivatives thereof, and (2) rare earth metal complexes. These are preferable in that they have an excited triplet state that is relatively stable even at high temperatures. Further, as described later, it is also preferable from the viewpoint that complexation can be easily performed by coordinating a polymer having a functional group having coordination ability to a transition metal atom.

  As the transition metal used in the transition metal complex, in the periodic table, the first transition element series includes Sc from atomic number 21 to Zn of atomic number 30 and the second transition element series includes Y from atomic number 39 to atomic number. Up to Cd of 48, and from the Hf of atomic number 72 to Hg of atomic number 80 in the third transition element series. The rare earth metal used in the rare earth metal complex includes La of atomic number 57 to Lu of atomic number 71 in the periodic table.

  The luminescent moiety is preferably nonionic. This is because, when the luminescent portion is ionic, for example, when a voltage is applied to the luminescent layer containing the luminescent portion, electrochemiluminescence occurs, and the response speed of this luminescence becomes extremely slow, on the order of minutes, This is because it is not preferable for display applications.

  The above-mentioned “the luminescent part forms part of the polymer chain” means that the luminescent part structure constitutes at least one kind of repeating unit of the polymer chain. Therefore, when the light emitting polymer is a copolymer as described above, at least one of the constituent monomers has a light emitting partial structure. In addition, the light-emitting portion may form a polymer main chain or a side chain (such as a pendant group).

  In addition, the above-mentioned “the light-emitting moiety is bonded to the polymer chain” means that the light-emitting moiety may be bonded to the polymer compound regardless of its form. Specific methods for obtaining such a light-emitting polymer include a method of incorporating a light-emitting moiety as a main chain of the polymer, or a method of bonding as a side chain (including a pendant group). However, it is not limited to these. In addition, in the case of the transition metal complex and the rare earth metal complex, a method of incorporating at least one ligand among the ligands forming the complex as a main chain of the polymer, a method of bonding as a side chain, or the like can be given. However, it is not limited to these.

  Examples of the ligand coordinated to the transition metal complex and rare earth metal complex include acetylacetonate, 2,2′-bipyridine, 4,4′-dimethyl-2,2′-bipyridine, 1,10- Examples thereof include phenanthroline, 2-phenylpyridine, porphyrin, phthalocyanine, pyrimidine, quinoline and / or derivatives thereof, but are not limited thereto. One or more kinds of these ligands are coordinated with respect to one complex. Further, as such a complex compound, a binuclear complex or a polynuclear complex, or a complex of two or more kinds of complexes can be used.

  In the light-emitting portion, the metal atom serving as the central metal of the metal complex is constrained at one or more sites of the polymer chain. A method for achieving this is not particularly limited, and examples thereof include complexation by coordination bond as described above, complexation by charge transfer, ionic bond, and covalent bond. Among these, a method in which a ligand is bonded to a polymer to form a complex with a light-emitting substance is preferable because a change in the electronic state of the light-emitting substance can be reduced and immobilized on the polymer. In this case, a method in which a ligand is covalently bonded to a polymer to form a complex is particularly preferable because the material can be easily designed and synthesized.

  In addition, when the metal atom serving as the central metal is an ion, it is preferable to adopt a method in which the light-emitting portion is neutral (nonionic) for the reasons described above. Examples thereof include, but are not limited to, a method of forming an organometallic compound having a covalent bond sufficient to neutralize the valence of ions with the bond.

  The light emitting polymer for constraining metal atoms in the present invention is not particularly limited. For example, a heterocyclic compound such as a pyridine group, bipyridyl group, pyrimidine group, or quinoline group exemplified as the ligand is a polymer. Those bonded to the main chain and / or the side chain can be used. More specifically, as such a polymer, a polymer containing a ligand in the main chain such as polypyridinediyl, polybipyridinediyl, polyquinolinediyl and / or a derivative thereof, polyvinylpyridine, poly (meth) acrylic Examples thereof include a polymer having a ligand in the side chain such as pyridine and polyvinylquinoline and / or a derivative thereof, and a polymer in which the above structures are combined.

  In addition, as the light-emitting polymer used in the present invention, a copolymer of a monomer unit in which a light-emitting part is part of or bonded to a monomer unit having no light-emitting part may be used. it can. Here, examples of the monomer unit having no light-emitting moiety include alkyl (meth) acrylates such as methyl acrylate and methyl methacrylate, styrene, and derivatives thereof, but are not limited thereto. is not.

  The degree of polymerization of the luminescent polymer in the present invention is preferably an integer in the range of 5 to 10,000, and more preferably an integer in the range of 10 to 5,000. Further, the weight average molecular weight Mw of the luminescent polymer is preferably in the range of 5,000 to 1,000,000, and more preferably in the range of 10,000 to 300,000.

Next, the layer structure of the organic EL element of the present invention will be described in detail.
The organic EL device of the present invention comprises a pair of electrodes, at least one of which is transparent or translucent, and one or a plurality of organic compound layers including a light emitting layer sandwiched between the electrodes. At least one of the organic compound layers has at least one charge-transporting polyester and a ground state by transition from an excited triplet state to a ground state of an electron energy level or via an excited triplet state. And a light-emitting polymer that emits light by transition.

  In the organic electroluminescence device of the present invention, when the organic compound layer has a multi-layer structure (that is, in the case of a function separation type in which each layer has a different function), at least one of the layers consists of a light emitting layer. A light emitting layer having a transport function may be used. In this case, as a specific example of the layer structure composed of the light-emitting layer or the light-emitting layer having the charge transport function and other layers, a layer structure including a light-emitting layer, an electron transport layer and / or an electron injection layer ( 1) Layer configuration composed of a hole transport layer and / or a hole injection layer, a light emitting layer, an electron transport layer and / or an electron injection layer (2), a hole transport layer and / or a hole injection layer The layer structure (3) formed from the light emitting layer is mentioned, and the layers other than the light emitting layer and the light emitting layer having the charge transport function of these layer structures (1) to (3) are used as a charge transport layer and a charge injection layer. It has a function.

On the other hand, when the organic compound layer is a single layer, the organic compound layer means a light emitting layer having a charge transport function, and the light emitting layer having the charge transport function contains the charge transporting polyester and the light emitting polymer. .
In any one of the layer configurations (1) to (3), the light-emitting layer containing the light-emitting polymer only needs to contain the charge transporting polyester having a function as a host material. Accordingly, the charge transporting polyester may be contained in another layer. In the organic EL device of the present invention, the light emitting layer, the hole transport layer, the hole injection layer, the electron transport layer, and the electron injection layer are formed of a charge transport material (a hole transport material other than the charge transport polyester). , An electron transporting material). Details will be described later.

Hereinafter, although it demonstrates in detail, referring drawings, this invention is not necessarily limited to these.
1 to 4 are schematic cross-sectional views for explaining the layer structure of the organic EL element of the present invention, and FIGS. 1, 2, and 3 are examples of 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 EL element shown in FIG. 1 is formed by sequentially laminating a transparent electrode 2, a light emitting layer 4, an electron transport layer 5, and a back electrode 7 on a transparent insulator substrate 1. The organic EL element shown in FIG. 2 is formed by sequentially laminating a transparent electrode 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a back electrode 7 on a transparent insulator substrate 1. The organic EL element shown in FIG. 3 is formed by sequentially laminating a transparent electrode 2, a hole transport layer 3, a light emitting layer 4 and a back electrode 7 on a transparent insulator substrate 1. The organic EL element shown in FIG. 4 is formed by sequentially laminating a transparent electrode 2, a light emitting layer 6 having a carrier transporting capability, and a back electrode 7 on a transparent insulator substrate 1. In addition to these layers, a hole injection layer, an electron injection layer, and the like are provided as necessary. Each will be described in detail below.

  Depending on the structure of the organic compound layer containing the charge transporting polyester in the present invention, for example, in the case of the layer structure of the organic EL device shown in FIG. 1, the electron transport layer 5 and the light emitting layer 4 (in this case) In the case of the layer structure of the organic EL device shown in FIG. 2, the hole transport layer 3, the light emitting layer 4, the electrons Any of them can act as the transport layer 5, and in the case of the layer configuration of the organic EL element shown in FIG. 3, the hole transport layer 3 and the light emitting layer 4 (in this case, the light emitting layer has charge transporting ability). 4), and in the case of the organic EL element layer configuration shown in FIG. 4, it can act as the light emitting layer 6 having charge transporting ability.

Hereinafter, the material of the electrode and each layer and the manufacturing method will be described.
In the case of the layer structure of the organic EL element shown in FIGS. 1 to 4, the transparent insulator substrate 1 is preferably transparent in order to extract emitted light, and glass, plastic film, or the like is used. Further, the transparent electrode 2 is preferably transparent to extract emitted light in the same manner as the transparent insulator substrate, and preferably has a high work function for injecting holes. Indium tin oxide (ITO), tin oxide (NESA) ), Oxide films such as indium oxide and zinc oxide, and gold, platinum, palladium and the like deposited or sputtered are preferably used.

  In the case of the layer structure of the organic EL element shown in FIGS. 1 and 2, the electron transport layer 5 may be formed of the charge transporting polyester 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 properties, the electron transport material other than the charge transporting polyester is 1 to 1 with respect to the total mass of the material constituting the electron transport layer 5. It may be formed by mixing and dispersing in the range of 50% by mass. As such an electron transporting material, an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, a fluorenylidenemethane derivative, and the like are preferable.

  Specific examples of the electron transport material include, but are not limited to, the following exemplary compounds (V-1) to (V-4). When the charge transporting polyester is not used, the electron transport layer 5 is formed using these electron transporting materials alone. In the exemplary compound (V-4), n is an integer of 1 or more.

  For the purpose of improving the electron injection property from the cathode, the material for forming the electron injection layer between the electron transport layer 5 and the back electrode 7 has a function of injecting electrons from the cathode. Any material that is the same as the electron transport material can be used.

  In the case of the layer configuration of the organic EL device shown in FIGS. 2 and 3, the hole transport layer 3 may be formed of a charge transporting polyester alone provided with a function (hole transport ability) according to the purpose. However, in order to adjust the hole mobility, a hole transport material other than the charge transporting polyester is mixed and dispersed in the range of 1 to 50% by mass with respect to the total mass of the material constituting the hole transport layer 3. It may be formed.

  As such a hole transport material, a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an aryl hydrazone derivative, a porphyrin-based compound, or the like is preferably used. Particularly preferred specific examples include the following exemplified compounds (VI-1) to (VI-9), and among these, a tetraphenylenediamine derivative is preferred because of its good compatibility with the charge transporting polyester. . Moreover, you may use it by mixing with other general purpose resin etc. In the case where the charge transporting polyester is not used, the hole transport layer 3 is formed by using these hole transporting materials alone. In the exemplary compounds (VI-7) to (VI-9), n is an integer of 1 or more.

  For the purpose of improving the hole injection property from the anode, the material for forming the hole injection layer between the transparent electrode 2 and the hole transport layer 3 is to inject holes from the anode. The same material as the hole transport material can be used, and as a particularly preferable specific example, the following exemplified compound (VII-1) or (VII-2) can be used. ). In the exemplary compound (VII-2), n is an integer of 1 or more.

In the case of the layer structure of the organic EL element shown in FIGS. 1, 2 and 3, the light emitting layer 4 is the same as the above with respect to the whole material constituting the light emitting layer 4 containing at least the charge transporting polyester. It is formed by dispersing a light emitting polymer in the range of 0.1 to 50% by mass.
In addition to the charge transporting polyester and the light emitting polymer, the material constituting the light emitting layer 4 may include a charge transporting polymer material or an insulating polymer material other than the charge transporting polyester as necessary. Can be used together.

  In the layer structure of the organic EL element shown in FIG. 4, the light emitting layer 6 having charge transporting capability is, for example, in the charge transporting polyester provided with a function (hole transporting capability or electron transporting capability) according to the purpose. In addition, the light-emitting polymer is an organic compound layer dispersed in a range of 0.1 to 50% by mass with respect to the total mass of the material constituting the light-emitting layer 6 having the charge transport ability, In order to adjust the balance between holes and electrons injected into the EL element, a charge transporting material other than the charge transporting polyester may be dispersed in a range of 10 to 50% by mass.

As the charge transporting material, when adjusting the electron mobility, the electron transporting material is preferably an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, a fluorenylidenemethane derivative, or the like. Specific examples thereof include the exemplified compounds (V-1) to (V-3).
Moreover, it is preferable to use an organic compound that does not exhibit a strong electron interaction with the charge transporting polyester, and the following exemplified compound (VIII) is more preferably used, but the present invention is not limited thereto.

  Similarly, when adjusting the hole mobility, the hole transport material preferably includes a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an aryl hydrazone derivative, a porphyrin compound, and the like. Preferable specific examples include the exemplified compounds (VI-1) to (VI-9), and a tetraphenylenediamine derivative is preferable because of good compatibility with the charge transporting polyester.

  In the case of the layer structure of the organic EL element shown in FIGS. 1 to 4, the back electrode 7 is made of a metal that can be vacuum-deposited and has a low work function for performing electron injection. , Silver, indium and alloys thereof. Further, a protective layer may be provided on the back electrode 7 in order to prevent deterioration of the element due to moisture or oxygen.

Specific examples of the protective layer material include 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. Resin. For forming the protective layer, a vacuum deposition method, a sputtering method, a plasma polymerization method, a CVD method, or a coating method can be applied.

  Each layer formation of the organic EL element shown in FIGS. 1 to 4 is performed as follows. First, the hole transport layer 3, the light emitting layer 4, or the light emitting layer 6 having charge transporting ability is formed on the transparent electrode 2 according to the layer configuration of each organic EL element. The hole transport layer 3, the light emitting layer 4 and the light emitting layer 6 having charge transporting ability are prepared by dissolving or dispersing the above materials in a vacuum deposition method or an organic solvent, and using the obtained coating liquid, the transparent electrode 2. It is formed by forming a film using a spin coating method, a dip method or the like.

Next, according to the layer configuration of each organic EL element, the light emitting layer 4 and the electron transport layer 5 are prepared by dissolving or dispersing the above materials in a vacuum deposition method or an organic solvent, and using the obtained coating liquid. The film is formed on the surface of the hole transport layer 3 or the light emitting layer 4 using a spin coating method, a dip method or the like.
In the present invention, since a polymer is included as a charge transport material and a light emitting material, each layer is preferably formed by a film forming method using a coating solution.

  The film thicknesses of the hole transport layer 3, the light emitting layer 4, and the electron transport layer 5 to be formed are each preferably 0.1 μm or less, and particularly preferably in the range of 0.03 to 0.08 μm. Further, the thickness of the light emitting layer 6 having charge transporting ability is preferably in the range of 0.03 to 0.2 μm. In addition, it is preferable that the film thickness in the case of forming the said positive hole injection layer and an electron injection layer is a film thickness as thin as the said positive hole transport layer 3 and the electron transport layer 5, respectively.

  The dispersion state of each material (the charge transporting polyester, the light emitting material, etc.) in the layer may be a molecular dispersion state or a fine 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 material as a dispersion solvent in order to obtain a molecular dispersion state. It is necessary to select it in consideration of the dispersibility and solubility. In order to disperse into fine particles, a ball mill, a sand mill, a paint shaker, an attritor, a ball mill, a homogenizer, an ultrasonic method, or the like can be used.

Finally, the back electrode 7 is formed on the electron transport layer 5, the light emitting layer 4, or the light emitting layer 6 having charge transporting ability by a vacuum deposition method, thereby completing the device.
The organic EL device of the present invention can emit light sufficiently by applying a DC voltage between a pair of electrodes, for example, at 4 to 20 V and a current density in the range of 1 to 200 mA / cm ² .

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited to these Examples.
First, the charge transporting polyester used in the examples was obtained as follows, for example.

-Synthesis example A1-
2.0 g of the following exemplary compound (AIX-1), 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours under a nitrogen stream. After confirming that the compound (AIX-1) was consumed, the pressure was reduced to 33.3 Pa, the mixture was heated to 200 ° C. while distilling off ethylene glycol, and the reaction was continued for 6 hours. Then, it is cooled to room temperature, dissolved in 50 ml of tetrahydrofuran (THF), insoluble matter is filtered through a 0.2 μm polytetrafluoroethylene (PTFE) filter, and the filtrate is added dropwise to 500 ml of stirred methanol. To precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 1.9 g of charge transporting polyester (AIX-2) exemplified below. When the molecular weight was measured by GPC (gel permeation chromatography), Mw was 9.32 × 10 ⁴ (in terms of styrene) and Mw / Mn (Mn was the number average molecular weight) was 1.87.

-Synthesis example A2-
2.0 g of the following exemplary compound (AX-1), 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours in a nitrogen stream. After confirming that the compound (AX-1) was consumed, the pressure was reduced to 33.3 Pa, the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 1.9 g of a charge transporting polyester (AX-2) exemplified below. When the molecular weight was measured by GPC, Mw was 8.16 × 10 ⁴ (in terms of styrene), and Mw / Mn was 1.93.

-Synthesis Example A3-
2.0 g of the following exemplary compound (AXI-1), 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours under a nitrogen stream. After confirming that the compound (AXI-1) was consumed, the pressure was reduced to 33.3 Pa and the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol and then dried to obtain 1.9 g of a charge transporting polyester (AXI-2) exemplified below. When the molecular weight was measured by GPC, Mw was 1.03 × 10 ⁵ (styrene conversion), and Mw / Mn was 2.10.

Synthesis Example A4- (Copolymer with dimethyl terephthalate)
2 g of the above exemplary compound (AIX-1), 0.6 g of dimethyl terephthalate, 8.0 g of ethylene glycol and 0.1 g of tetrabutoxy titanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours in a nitrogen stream. After confirming that the compound (AIX-1) was consumed, the pressure was reduced to 33.3 Pa and the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol, and then dried to obtain 2.3 g of a charge transporting polyester (AXII) exemplified below. When the molecular weight was measured by GPC, Mw was 1.10 × 10 ⁵ (in terms of styrene), and Mw / Mn was 2.80.

-Synthesis example B1-
2.0 g of the following exemplary compound (BIX-1), 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours under a nitrogen stream. After confirming that the compound (BIX-1) was consumed, the pressure was reduced to 33.3 Pa and the mixture was heated to 200 ° C. while distilling off ethylene glycol, and the reaction was continued for 6 hours. Then, it is cooled to room temperature, dissolved in 50 ml of tetrahydrofuran (THF), insoluble matter is filtered through a 0.2 μm polytetrafluoroethylene (PTFE) filter, and the filtrate is added dropwise to 500 ml of stirred methanol. To precipitate a polymer. The obtained polymer was filtered, sufficiently washed with methanol, and dried to obtain 1.9 g of a charge transporting polyester (BIX-2) exemplified below. When the molecular weight was measured by GPC (gel permeation chromatography), the weight average molecular weight Mw was 8.78 × 10 ⁴ (in terms of styrene), and Mw / Mn (Mn was the number average molecular weight) was 1.91. It was.

-Synthesis example B2-
2.0 g of the following exemplary compound (BX-1), 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours in a nitrogen stream. After confirming that the compound (BX-1) was consumed, the pressure was reduced to 33.3 Pa, the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol and then dried to obtain 1.9 g of a charge transporting polyester (BX-2) exemplified below. When the molecular weight was measured by GPC, Mw was 9.16 × 10 ⁴ (in terms of styrene), and Mw / Mn was 1.85.

-Synthesis example B3-
The following exemplary compound (BXI-1) 2.0 g, ethylene glycol 8.0 g, and tetrabutoxy titanium 0.1 g were put into a 50 ml flask, and heated and stirred at 190 ° C. for 6 hours in a nitrogen stream. After confirming that the compound (BXI-1) was consumed, the pressure was reduced to 33.3 Pa and the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol and then dried to obtain 1.9 g of a charge transporting polyester (BXI-2) exemplified below. When the molecular weight was measured by GPC, Mw was 1.07 × 10 ⁵ (in terms of styrene) and Mw / Mn was 2.10.

Synthesis Example B4- (Copolymer with dimethyl terephthalate)
2.0 g of the above exemplary compound (BIX-1), 0.75 g of dimethyl terephthalate, 8.0 g of ethylene glycol and 0.1 g of tetrabutoxytitanium were placed in a 50 ml flask and heated and stirred at 190 ° C. for 6 hours in a nitrogen stream. . After confirming that the compound (BIX-1) was consumed, the pressure was reduced to 33.3 Pa and the mixture was heated to 210 ° C. while distilling off ethylene glycol, and the reaction was continued for 7 hours. Then, it cooled to room temperature, melt | dissolved in 50 ml of THF, the insoluble matter was filtered with a 0.2 micrometer PTFE filter, and the polymer was deposited by performing reprecipitation by dripping the filtrate in 500 ml of stirred methanol. The obtained polymer was filtered, sufficiently washed with methanol and then dried to obtain 2.2 g of a charge transporting polyester (BX-II) exemplified below. When the molecular weight was measured by GPC, Mw was 8.9 × 10 ⁴ (styrene conversion), and Mw / Mn was 2.9.

(Example A1)
1 part by mass of the charge transporting polyester (AIX-2) of Synthesis Example A1 as a charge transporting material and a phosphorescent host material and 0.1 part by mass of the following exemplified compound (XIII) as a light emitting polymer are mixed, and 10% by mass Prepared as a dichloroethane solution and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which has been washed and dried, is applied by spin coating to a light emitting layer having a thickness of 0.15 μm and a charge transporting capability. Formed.

After sufficiently drying, the charge transporting material (V-4) is prepared as a 5% by mass dichloroethane solution as an electron transporting material, filtered through a 0.1 μm PTFE filter, and this solution is spun onto the light emitting layer. Application was performed by a coating method to form an electron transport layer having a thickness of 0.1 μm. 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example A2)
A charge transporting material (VI-9) (Mw = 1.04 × 10 ⁵ (in terms of styrene), Mw / Mn = 1.87) as a hole transporting material was prepared as a 5% by mass chlorobenzene solution; Filtration through a 1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which had been washed and dried, was applied by spin coating on a glass substrate formed by etching to form a hole transport layer having a thickness of 0.1 μm.
After sufficiently drying, 1 part by mass of the charge transporting polyester (AIX-2) of Synthesis Example A1 as the charge transporting material and host material, and 0.1 parts by mass of the exemplified compound (XIII) as the light emitting polymer Are mixed as a 10% by mass dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is applied onto the hole transporting layer by a spin coating method to have a charge transporting ability of 0.15 μm. A light emitting layer was formed.
After sufficiently drying, the charge transporting polyester (AXI-2) of Synthesis Example A3 was prepared as an electron transporting material as a 5% by mass dichloroethane solution and filtered through a 0.1 μm PTFE filter. An electron transport layer having a thickness of 0.1 μm was formed on the 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example A3)
The charge transport material (VI-9) was prepared as a 5% by mass chlorobenzene solution as a hole transport material, and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which had been washed and dried, was applied by spin coating on a glass substrate formed by etching to form a hole transport layer having a thickness of 0.1 μm.
After sufficiently drying, 1 part by mass of the charge transporting polyester (AIX-2) of Synthesis Example A1 as the charge transporting material and host material, and 0.1 parts by mass of the exemplified compound (XIII) as the light emitting polymer Are mixed as a 10% by mass dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is applied onto the hole transporting layer by a spin coating method to have a charge transporting ability of 0.15 μm. A light emitting layer was formed. 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example A4)
In Example A3, before forming the hole transport layer, on the glass substrate on which the strip-shaped ITO electrode was formed, Baytron P (manufactured by Bayer Co., Ltd., polyethylene dioxide thiophene, the exemplified compound (VII-2)) ) And polystyrenesulfonic acid polymer mixed water dispersion) was applied by spin coating, and a hole injection layer having a thickness of 0.05 μm was formed between the ITO electrode and the hole transport layer. A device was fabricated in the same manner as in Example A3.

(Example A5)
0.5 parts by weight of charge transporting polyester (VI-9) as a charge transporting material, 0.5 parts by weight of charge transporting polyester (AIX-2) of Synthesis Example A1 as a charge transporting material and host material, and light emission 0.1 parts by mass of the exemplified compound (XIII) as a functional polymer was mixed to prepare a 10% by mass dichloroethane solution, and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which has been washed and dried, is applied by spin coating to a glass substrate formed by etching to form a light-emitting layer having a thickness of 0.15 μm and having a charge transporting ability. Formed. Finally, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example A6)
A device was fabricated in the same manner as in Example A1, except that the charge transporting polyester (AX-2) of Synthesis Example A2 was used as the charge transporting material and host material.

(Example A7)
A device was prepared in the same manner as in Example A2, except that the charge transporting polyester (AX-2) of Synthesis Example A2 was used as the charge transporting material and host material.

(Example A8)
A device was prepared in the same manner as in Example A3 except that the charge transporting polyester (AX-2) of Synthesis Example A2 was used as the charge transporting material and host material.

(Example A9)
A device was prepared in the same manner as in Example A4 except that the charge transporting polyester (AX-2) of Synthesis Example A2 was used as the charge transporting material and host material.

(Example A10)
A device was prepared in the same manner as in Example A5 except that the charge transporting polyester (AX-2) of Synthesis Example A2 was used as the charge transporting material and host material.

(Example A11)
A device was fabricated in the same manner as in Example A1, except that the charge transporting polyester (AXI-2) of Synthesis Example A3 was used as the charge transporting material and host material.

(Example A12)
A device was fabricated in the same manner as in Example A2, except that the charge transporting polyester (AXI-2) of Synthesis Example A3 was used as the charge transporting material and host material.

(Example A13)
A device was produced in the same manner as in Example A3 except that the charge transporting polyester (AXI-2) of Synthesis Example A3 was used as the charge transporting material and host material.

(Example A14)
A device was produced in the same manner as in Example A4, except that the charge transporting polyester (AXI-2) of Synthesis Example A3 was used as the charge transporting material and host material.

(Example A15)
A device was fabricated in the same manner as in Example A5 except that the charge transporting polyester (AXI-2) of Synthesis Example A3 was used as the charge transporting material and host material.

(Example A16)
A device was produced in the same manner as in Example A5 except that the charge transporting polyester (AXII) of Synthesis Example A4 was used as the charge transporting material and host material.

(Example B1)
1 part by mass of the charge transporting polyester (BIX-2) of Synthesis Example B1 as a charge transporting material and host material and 0.1 part by mass of the exemplified compound (XIII) as a light-emitting polymer are mixed, and 10 parts by mass. Prepared as a% dichloroethane solution and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which has been washed and dried, is applied by spin coating to a light emitting layer having a thickness of 0.15 μm and a charge transporting capability. Formed.
After sufficiently drying, the charge transporting material (V-4) is prepared as a 5% by mass dichloroethane solution as an electron transporting material, filtered through a 0.1 μm PTFE filter, and this solution is spun onto the light emitting layer. Application was performed by a coating method to form an electron transport layer having a thickness of 0.1 μm. 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example B2)
The charge transporting material (VI-9) was prepared as a 5% by mass chlorobenzene solution as a hole transporting material and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which had been washed and dried, was applied by spin coating on a glass substrate formed by etching to form a hole transport layer having a thickness of 0.1 μm.
After sufficiently drying, 1 part by mass of the charge transporting polyester (BIX-2) of Synthesis Example B1 as the charge transporting material and host material, and 0.1 part by mass of the exemplified compound (XIII) as the light emitting polymer Are mixed as a 10% by mass dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is applied onto the hole transporting layer by a spin coating method to have a charge transporting ability of 0.15 μm. A light emitting layer was formed.
After sufficiently drying, the charge transporting polyester (BXI-2) of Synthesis Example B3 was prepared as an electron transporting material as a 5% by mass dichloroethane solution and filtered through a 0.1 μm PTFE filter. An electron transport layer having a thickness of 0.1 μm was formed on the 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example B3)
The charge transporting material (VI-9) was prepared as a 5% by mass chlorobenzene solution as a hole transporting material and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which had been washed and dried, was applied by spin coating on a glass substrate formed by etching to form a hole transport layer having a thickness of 0.1 μm.
After sufficiently drying, 1 part by mass of the charge transporting polyester (BIX-2) of Synthesis Example B1 as the charge transporting material and host material, and 0.1 part by mass of the exemplified compound (XIII) as the light emitting polymer Are mixed as a 10% by mass dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is applied onto the hole transporting layer by a spin coating method to have a charge transporting ability of 0.15 μm. A light emitting layer was formed. 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 0.15 μm so as to intersect the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example B4)
In Example B3, before forming the hole transport layer, on the glass substrate on which the strip-shaped ITO electrode was formed, Baytron P (manufactured by Bayer Co., Ltd., polyethylene dioxide thiophene, the exemplified compound (VII-2)) ) And polystyrenesulfonic acid polymer mixed water dispersion) was applied by spin coating, and a hole injection layer having a thickness of 0.05 μm was formed between the ITO electrode and the hole transport layer. A device was fabricated in the same manner as in Example B3.

(Example B5)
0.5 parts by weight of charge transporting polyester (VI-9) as a charge transporting material, 0.5 parts by weight of charge transporting polyester (BIX-2) of Synthesis Example B1 as a charge transporting and host material, and light emission 0.1 parts by mass of the exemplified compound (XIII) as a functional polymer was mixed to prepare a 10% by mass dichloroethane solution, and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which has been washed and dried, is applied by spin coating to a glass substrate formed by etching to form a light-emitting layer having a thickness of 0.15 μm and having a charge transporting ability. Formed. Finally, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Example B6)
A device was fabricated in the same manner as in Example B1, except that the charge transporting polyester (BX-2) of Synthesis Example B2 was used as the charge transporting material and host material.

(Example B7)
A device was fabricated in the same manner as in Example B2, except that the charge transporting polyester (BX-2) of Synthesis Example B2 was used as the charge transporting material and host material.

(Example B8)
A device was prepared in the same manner as in Example B3 except that the charge transporting polyester (BX-2) of Synthesis Example B2 was used as the charge transporting material and host material.

(Example B9)
A device was produced in the same manner as in Example B4 except that the charge transporting polyester (BX-2) of Synthesis Example B2 was used as the charge transporting material and host material.

(Example B10)
A device was produced in the same manner as in Example B5 except that the charge transporting polyester (BX-2) of Synthesis Example B2 was used as the charge transporting material and host material.

(Example B11)
A device was fabricated in the same manner as in Example B1, except that the charge transporting polyester (BXI-2) of Synthesis Example B3 was used as the charge transporting material and host material.

(Example B12)
A device was produced in the same manner as in Example B2, except that the charge transporting polyester (BXI-2) of Synthesis Example B3 was used as the charge transporting material and host material.

(Example B13)
A device was fabricated in the same manner as in Example B3 except that the charge transporting polyester (BXI-2) of Synthesis Example B3 was used as the charge transporting material and host material.

(Example B14)
A device was prepared in the same manner as in Example B4 except that the charge transporting polyester (BXI-2) of Synthesis Example B3 was used as the charge transporting material and host material.

(Example B15)
A device was fabricated in the same manner as in Example B5 except that the charge transporting polyester (BXI-2) of Synthesis Example B3 was used as the charge transporting material and host material.

(Example B16)
A device was fabricated in the same manner as in Example B3, except that the charge transporting polyester (BXII) of Synthesis Example B4 was used as the charge transporting material and host material.

(Comparative Example 1)
The following exemplified compound (XVI) 1 part by weight as a host material and the following exemplified compound (XIII) 0.05 as a light-emitting polymer on a glass substrate formed by etching a 2 mm wide strip-shaped ITO electrode that has been dried after washing. Part by weight was mixed to prepare a 5% by weight dichloroethane solution and filtered through a 0.1 μm PTFE filter. Using this solution, a strip-like ITO electrode having a width of 2 mm, which was washed and dried, was applied onto a glass substrate formed by etching by a spin coating method to form a light emitting layer having a thickness of 0.065 μm. Next, an electron transport layer having a thickness of 0.05 μm was formed on the light emitting layer by vacuum deposition using the exemplified compound (V-1) as an electron transport material. Finally, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Comparative Example 2)
A positive electrode having a thickness of 0.05 μm is formed on a glass substrate formed by etching a 2 mm-wide strip-shaped ITO electrode, which has been washed and dried, by a vacuum deposition method using the exemplified compound (VI-2) as a hole transport material. A hole transport layer was formed. Further, on this hole transport layer, 1 part by weight of the following exemplified compound (XVI) as a host material and 0.05 part by weight of the following exemplified compound (XIII) as a light emitting polymer are mixed, and a 5 wt% dichloroethane solution. And filtered through a 0.1 μm PTFE filter. Using this solution, a strip-like ITO electrode having a width of 2 mm, which was washed and dried, was applied onto a glass substrate formed by etching by a spin coating method to form a light emitting layer having a thickness of 0.065 μm. Next, an electron transport layer having a thickness of 0.05 μm was formed on the light emitting layer by vacuum deposition using the exemplified compound (V-1) as an electron transport material. Finally, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Comparative Example 3)
A positive electrode having a thickness of 0.05 μm is formed on a glass substrate formed by etching a 2 mm-wide strip-shaped ITO electrode, which has been washed and dried, by a vacuum deposition method using the exemplified compound (VII-2) as a hole transport material. A hole transport layer was formed. Further, on this hole transport layer, 1 part by weight of the following exemplified compound (XVI) as a host material and 0.05 part by weight of the following exemplified compound (XIII) as a light emitting polymer are mixed, and a 5 wt% dichloroethane solution. And filtered through a 0.1 μm PTFE filter. Using this solution, a strip-like ITO electrode having a width of 2 mm, which was washed and dried, was applied onto a glass substrate formed by etching by a spin coating method to form a light emitting layer having a thickness of 0.065 μm. Finally, a Mg—Ag alloy was vapor-deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Comparative Example 4)
1 part by weight of the exemplified compound (VI-6) as a charge transport material, 0.5 part by weight of the exemplified compound (XVI) as a host material, and 0.05 part by weight of the exemplified compound (XIII) as a light-emitting polymer Were mixed to prepare a 5% by mass dichloroethane solution and filtered through a 0.1 μm PTFE filter. Using this solution, a 2 mm wide strip-shaped ITO electrode, which has been washed and dried, is applied by spin coating to a light emitting layer having a thickness of 0.15 μm and a charge transporting capability. Formed. Thereafter, a Mg—Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the produced organic EL element was 0.04 cm ² .

(Comparative Example 5)
Example A5 except that charge transporting polyester (XVII) (Mw = 6.13 × 10 ⁴ (styrene equivalent), Mw / Mn = 2.34) of the following exemplary compound was used as the charge transporting material and host material. And the element was produced like B5.

The organic EL device manufactured as described above was measured for light emission by applying a DC voltage of 10 V in vacuum (1.33 × 10 ⁻¹ Pa) with the ITO electrode side plus and the Mg—Ag back electrode minus. The maximum brightness and emission color at this time were evaluated. The results are shown in Tables 1 to 3. Moreover, the light emission lifetime of the organic EL element was measured in dry nitrogen. In the evaluation of the light emission 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. The driving current density at this time is shown in Tables 1 to 3 together with the element lifetime.
In addition, Table 4 shows the solubility of the host material / charge transporting polyester used in Examples and Comparative Examples in various solvents. In addition to the dichloroethane / chlorobenzene used in Examples / Comparative Examples, Table 4 also shows the results of other solvents that are practically suitable for producing organic EL devices. The solubility test was performed by dissolving 5 g of the compound in 100 ml of the solvent and visually observing the situation.

  As shown in the above examples, at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) or the general formulas (BI-1) and (BI-2) is used. Charge transporting polyester composed of repeating structural units included as a partial structure has an ionization potential and charge mobility suitable for an organic EL device, and can form a good thin film using a wet process such as a spin coating method or a dip method. It was possible. In addition, the use of a light-emitting polymer that emits light by transition from the excited triplet state to the ground state of the electron energy level or the transition from the excited triplet state to the ground state shows sufficiently high brightness. It was. Furthermore, in the present invention, since it is used for a light emitting layer as a host material of a light emitting polymer having a good film forming property, it is easy to produce the entire device, and the obtained organic EL device has a defect such as a pinhole. However, it was easy to increase the area, and had excellent durability and light emission characteristics.

  In addition, the charge transporting polyester of the present invention is superior in solubility in a solvent as compared with other polymer phosphorescent light emitting host materials, and therefore, the uniformity of the formed film is easy. Also, it has an advantage that phase separation with the light emitting polymer to be mixed hardly occurs.

It is typical sectional drawing which shows an example of the organic EL element of this invention. It is typical sectional drawing which shows another example of the organic EL element of this invention. It is typical sectional drawing which shows another example of the organic EL element of this invention. It is typical sectional drawing which shows another example of the organic EL element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent insulator board | substrate 2 Transparent electrode 3 Hole transport layer and / or hole injection layer 4 Light emitting layer 5 Electron transport layer and / or electron injection layer 6 Light emitting layer which has charge transport ability 7 Back electrode

Claims (22)

In an organic electroluminescent device composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2) as a partial structure. And a light-emitting polymer that emits light by transition from an excited triplet state to a ground state of an electron energy level or from a transition to a ground state via an excited triplet state. An organic electroluminescent element.

(In the general formulas (AI-1) and (AI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group. A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.) The organic compound layer is composed of at least a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 1.   The organic electroluminescent element according to claim 2, wherein the light emitting layer contains a charge transporting material. The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 1.   The organic light emitting device according to claim 4, wherein the light emitting layer includes a charge transporting material. The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, and a light emitting layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure. ,and,
The light-emitting layer contains one or more luminescent polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 1.   The organic electroluminescent device according to claim 6, wherein the light emitting layer contains a charge transporting material. The organic compound layer is composed of a light emitting layer having at least a charge transporting capability,
The light-emitting layer has at least one charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure, and an electron 2. A light-emitting polymer that emits light by transition from an excited triplet state of an energy level to a ground state or by transition to a ground state via an excited triplet state. The organic electroluminescent element as described.   The organic electroluminescent device according to claim 8, wherein the light emitting layer contains a charge transporting material. A charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (AI-1) and (AI-2) as a partial structure is represented by the following general formula (AII-1) or ( The organic electroluminescent element according to claim 1, which is a charge transporting polyester represented by AII-2).

(In the general formulas (AII-1) and (AII-2), A represents the structure represented by the general formulas (AI-1) and (AI-2), and R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted group. A substituted aryl group or a substituted or unsubstituted aralkyl group, Y represents a divalent alcohol residue, Z represents a divalent carboxylic acid residue, and B and B ′ each independently represent a group —O— (Y—O) _n —R or a group —O— (Y—O) _n —CO—Z—CO—O—R ′ (where R, Y and Z have the same meaning as above). R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. N represents an integer of 1 to 5, and p represents an integer of 5 to 5000. .) In an organic electroluminescent device composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer composed of a repeating unit containing at least one selected from the structures represented by the following general formulas (BI-1) and (BI-2) as a partial structure. And a light-emitting polymer that emits light by transition from an excited triplet state to a ground state of an electron energy level or from a transition to a ground state via an excited triplet state. An organic electroluminescent element.

(In the general formulas (BI-1) and (BI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.) The organic compound layer is composed of at least a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 11.   The organic electroluminescent device according to claim 12, wherein the light emitting layer contains a charge transporting material. The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, a light emitting layer, an electron transport layer and / or an electron injection layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 11.   The organic electroluminescent device according to claim 14, wherein the light emitting layer includes a charge transporting material. The organic compound layer is composed of at least a hole transport layer and / or a hole injection layer, and a light emitting layer,
At least the light emitting layer contains one or more charge transporting polyesters composed of repeating units containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure. ,and,
The light-emitting layer contains one or more light-emitting polymers that emit light upon transition from an excited triplet state to a ground state of an electron energy level or a transition to a ground state via an excited triplet state. The organic electroluminescent element according to claim 11.   The organic electroluminescent device according to claim 16, wherein the light emitting layer contains a charge transporting material.   The organic compound layer is composed of a light emitting layer having at least a charge transporting ability, and the light emitting layer partially includes at least one selected from the structures represented by the general formulas (BI-1) and (BI-2). 1 or more types of the charge transportable polyester which consists of a repeating unit included as a structure is contained, and also the said light emitting layer is by the transition from the excited triplet state of an electronic energy level to a ground state, or via an excited triplet state. The organic electroluminescent element according to claim 11, comprising a light-emitting polymer that emits light upon transition to a ground state.   The organic electroluminescent device according to claim 18, wherein the light emitting layer contains a charge transporting material. A charge transporting polyester comprising a repeating unit containing at least one selected from the structures represented by the general formulas (BI-1) and (BI-2) as a partial structure is represented by the following general formula (BII-1) or ( The organic electroluminescent device according to claim 11, which is a charge transporting polyester represented by BII-2).

(In the general formulas (BII-1) and (BII-2), A represents the structure represented by the general formulas (BI-1) and (BI-2), and R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted group. Represents a substituted aryl group, or a substituted or unsubstituted aralkyl group, Y represents a divalent alcohol residue, Z represents a divalent carboxylic acid residue, and B and B ′ each independently represents a group — O— (Y—O) _n —R or a group —O— (Y—O) _n —CO—Z—CO—O—R ′ (where R, Y, Z have the same meaning as above). , R ′ represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.), N represents an integer of 1 to 5, and p represents an integer of 5 to 5000. ) In an organic electroluminescent device composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (AI-1) and (AI-2) as a partial structure. Organic electroluminescent element characterized by containing more than seed | species.

(In the general formulas (AI-1) and (AI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group. A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.) In an organic electroluminescent device composed of one or more organic compound layers sandwiched between a pair of electrodes, at least one of which is transparent or translucent,
1 is a charge transporting polyester comprising at least one organic compound layer composed of a repeating unit containing at least one selected from the structures represented by the following general formulas (BI-1) and (BI-2) as a partial structure. Organic electroluminescent element characterized by containing more than seed | species.

(In the general formulas (BI-1) and (BI-2), each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group, or a substituted or unsubstituted aromatic group, A divalent linear hydrocarbon having 1 to 6 carbon atoms or a branched hydrocarbon having 2 to 10 carbon atoms is represented, and l and m represent 0 or 1.)

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