JP2007201192A - Organic electroluminescence device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence device that has an improved luminance, stability, and durability, is allowed to have a larger area, and can be manufactured easily. <P>SOLUTION: The organic electroluminescence device comprises one or a plurality of organic compound layers held by a pair of electrodes in which at least one of them is transparent or translucent. At least one layer of the organic compound layer contains at least one type of charge transporting polyether made of a repetitive unit containing at least one type selected from structures shown by two kinds of formulas (AI-1) and (AI-2) as partial structures; and a radiative low molecule that emits light by the transition from the excitation triplet state of an electron energy level to a base state or the transition to the base state through the excitation triplet state. In the formulas (AI-1) and (AI-2): R<SB>1</SB>indicates a hydrogen atom, an alkyl group having 1-8 carbons, an alkoxy group, or a substituted or unsubstituted aromatic group; T indicates a divalent straight chain hydrocarbon having 1-6 carbons or a branch hydrocarbon having 2-10 carbons; and l and m indicate 0 or 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent element (hereinafter sometimes referred to as an organic EL element), and more particularly to an organic electroluminescent element 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. At present, the one using an inorganic phosphor is the mainstream, but since an AC voltage of 200 V or more is required for driving, there are problems such as high manufacturing cost and insufficient brightness.

  On the other hand, research on EL devices using organic compounds started with a single crystal such as anthracene, but in the case of a single crystal, a film thickness of about 1 mm and a driving voltage of 100 V or more were necessary. For this reason, attempts have been made to reduce the thickness by vapor deposition (see, for example, 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 / 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 element in which a thin film 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 1000 cd is obtained at a low voltage of about 10V. A high luminance of / m ² or more has been reported (for example, see Non-Patent Document 2), and research and development of stacked EL elements have been actively conducted since then. These stacked devices are injected from the electrode through a charge transport layer made of a charge transporting organic compound into a light emitting layer made of a fluorescent organic compound while maintaining the carrier balance of holes and electrons, High-luminance light emission is realized by recombination of the confined holes and electrons.

  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, there is a phenomenon that the hole transporting low molecular weight compound or the fluorescent organic low molecular weight compound formed into a film in an amorphous glass state by vapor deposition is gradually crystallized and finally melted, resulting in a decrease in luminance and dielectric breakdown. It is often observed, and as a result, the lifetime of the device is reduced.

(2) To form a thin film with a film thickness of 0.1 μm or less in a plurality of vapor deposition steps in which a low molecular organic compound is vapor-deposited at the time of device fabrication, in order to obtain pinholes easily and to obtain sufficient performance It is necessary to control the film thickness under strictly controlled conditions. Therefore, productivity is low and it is difficult to increase the area.

(3) Emission from the excited singlet state, that is, fluorescence is used in the luminescent material. 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 is theoretically 25%.

  In order to solve the problem shown in (1) above, a starburst amine capable of obtaining a stable amorphous glass state is used as a hole transport material, or a polymer in which triphenylamine is introduced into the side chain of polyphosphazene is used. There have been reports of EL devices that have been used (for example, see Non-Patent Documents 3 and 4). However, since these materials alone have an energy barrier due to the ionization potential of the hole transport material, they do not satisfy the hole injection property from the anode or the hole injection property to the light emitting layer. In the case of the former starburst amine, it is difficult to purify because of its low solubility, and in the case of the latter polymer, a high current density cannot be obtained and sufficient luminance is obtained. There is also a problem such as not.

  Next, in order to solve the problem shown in (2) above, research and development of an organic electroluminescent device having a single layer structure capable of shortening the process has been promoted, and a conductive polymer such as poly (p-phenylene vinylene). There are proposals for devices using ED and devices in which an electron transport material and a fluorescent dye are mixed in hole transporting polyvinyl carbazole (for example, see Non-Patent Documents 5 and 6). However, it does not reach the stacked organic electroluminescence device using the low molecular weight organic compound. Furthermore, from the viewpoint of manufacturing methods, wet application methods have been studied from the viewpoints of manufacturing simplification, workability, large area, cost, etc., and it has been reported that elements can also be obtained by casting methods ( For example, refer nonpatent literature 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.

Next, in order to solve the problem shown in (3) above, 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 (see, for example, Non-Patent Document 9) was first proposed, and by using a phosphorescent iridium complex, an external quantum efficiency of 7.5% (external extraction efficiency of 20%) was proposed. Assuming%, the internal quantum efficiency is 37.5%), which indicates that it is possible to exceed the value of the external quantum efficiency of 5%, which has conventionally been the upper limit (for example, Non-Patent Document 10). , See 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) Applied Physics Letter, Vol. 51, 913 (1987) Proceedings of the 40th Joint Conference on Applied Physics 30a-SZK-14 (1993) 42nd Polymer Symposium Proceedings 20J21 (1993) Nature, Vol. 357, 477 (1992) Proceedings of the 38th Joint Conference on Applied Physics 31pg-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) Applied Physics Letter, Vol. 75, 4 (1999) International Publication No. 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 electroluminescence 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 polyether 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 electroluminescence device, and the charge transporting poly By combining ether with a light-emitting small molecule that emits light by transition from the excited triplet state to the ground state of the electron energy level or from the ground state via the excited triplet state, The inventors have found that not only the durability and light emission efficiency are excellent but also a highly productive element, and the present invention has been completed.
That is, the organic electroluminescent element of the present invention is

<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,
A charge transporting polyether 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 contains at least one kind and a light emitting small molecule that emits light by a transition from an excited triplet state to a ground state of an electron energy level or through a transition to a ground state via an excited triplet state. It is an organic electroluminescent element.

[In 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 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. ]

<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 polyethers composed of repeating units 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 small molecules 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. It is an organic electroluminescent element as described in <1> characterized.

    <3> The organic electroluminescent element according to <2>, wherein the light emitting layer contains 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 polyethers composed of repeating units 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 small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground state. The organic electroluminescent element according to <1>, wherein

    <5> The organic electroluminescent element as described in <4>, wherein the light emitting layer contains 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 polyethers composed of repeating units 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 small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground state. The organic electroluminescent element according to <1>, wherein

    <7> The organic electroluminescent element according to <6>, wherein the light emitting layer contains 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 includes at least one charge transporting polyether 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; <1> characterized by containing a light-emitting small molecule that emits light by a 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 of description.

    <9> The organic electroluminescent element according to <8>, wherein the light emitting layer contains a charge transporting material.

    <10> A charge transporting polyether 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> The organic electroluminescence device according to <1>, which is a charge transporting polyether represented by the formula:

(In the general formula (AII), A represents at least one selected from the structures represented by the general formulas (AI-1) and (AI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Of the aryl group, or a substituted or unsubstituted aralkyl group, 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, at least one of the organic compound layers is: Excitation of electron energy level with at least one charge transporting polyether comprising a repeating unit containing at least one selected from structures represented by general formulas (BI-1) and (BI-2) as a partial structure An organic electroluminescence device comprising a light-emitting small molecule that emits light by transition from a triplet state to a ground state or by transition to a ground state via an excited triplet state.

[In General Formulas (BI-1) and (BI-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 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 polyethers composed of 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. And
The light emitting layer contains one or more luminescent small molecules 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> characterized in that it is an organic electroluminescent element.

    <13> The organic electroluminescent element according to <12>, wherein the light emitting layer contains 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 polyethers composed of 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. And
The light emitting layer contains one or more luminescent small molecules 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> characterized in that it is an organic electroluminescent element.

    <15> The organic electroluminescent element as described in <14>, wherein the light emitting layer contains 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 polyethers composed of 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. And
The light-emitting layer contains one or more luminescent small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground 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 polyether comprising a repeating unit containing a species as a partial structure, and the light-emitting layer is formed by transition from an excited triplet state of an electron energy level to a ground state or an excited triplet state The organic electroluminescent device according to <11>, which contains a light-emitting small molecule that emits light by transition to a ground state via.

    <19> The organic electroluminescent element as described in <18>, wherein the light emitting layer contains a charge transporting material.

<20> A charge transporting polyether composed of 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): <11> The organic electroluminescence device according to <11>, which is a charge transporting polyether represented by the formula:

(In the general formula (BII), A represents at least one selected from the structures represented by the general formulas (BI-1) and (BI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Of the aryl group, or a substituted or unsubstituted aralkyl group, and p represents an integer of 5 to 5000.)

  As described above, according to the present invention, it is possible to provide an organic electroluminescence device that has sufficient luminance, is excellent in stability and durability, can be increased in area, and can be easily manufactured.

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 polyethers composed of repeating units containing one type as a partial structure, and transition to the ground state through the transition from the excited triplet state to the ground state of the electron energy level or via the excited triplet state It contains a light-emitting small molecule that emits light by the transition of (hereinafter sometimes abbreviated as “light-emitting low molecule”).

The organic EL device of the present invention has a layer containing a light-emitting low molecule and the charge transporting polyether that also functions as a host material of the light-emitting low molecule, so that it has sufficient luminance and is stable. Excellent in durability and durability. Further, by using the charge transporting polyether, the area can be increased and the production can be easily performed.
In particular, in the present invention, since the layer containing the charge transporting polyether and the light emitting low molecule can be formed by a wet coating method, the manufacturing process is greatly simplified compared to the conventional device as described above. Can be

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) A transporting polyether is used. As the charge transporting polyether including such a carbazole structure, a carbazole structure described in JP-A-2005-259441 (so-called 4,4′-dicarbazoly-1,1′- Biphenyl (CBP) -like structure) is also included.
However, since the charge transporting polyether containing a carbazole structure used in the present invention is superior in solubility in a solvent as compared with the charge transporting polyether containing a CBP structure, the film can be formed easily. The uniformity is also good. In addition, there is an advantage that phase separation with the light emitting small molecule to be mixed hardly occurs.

  Next, in the organic electroluminescent device of the present invention, a charge transporting poly- mer 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. The ether will be described.

In the general formulas (AI-1) and (AI-2), R ₁ 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.

  The charge transporting polyether 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). Those are preferably used.

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

  In the general formula (AII), R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. As an alkyl group, a C1-C10 thing is preferable, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group etc. are mentioned. As the aryl group, those having 6 to 20 carbon atoms are preferable, and examples thereof include a phenyl group and a toluyl group. As the aralkyl group, those having 7 to 20 carbon atoms are preferable, and examples thereof include a benzyl group and a phenethyl group. In addition, examples of the substituent of the substituted aryl group and the substituted aralkyl group include a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, and a halogen atom.

  In the general formula (AII), p representing the degree of polymerization is in the range of 5 to 5000, preferably 10 to 3000, and more preferably 15 to 1000.

  When the degree of polymerization p of the charge transporting polyether is less than 5, there is a problem that it is difficult to obtain a strong film due to inferior film formability. On the other hand, when the degree of polymerization p of the charge transporting polyether is higher than 5000, the solubility in a solvent is lowered and the processability is deteriorated.

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

The charge transporting polyether 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 of the present invention is represented by the following structural formula (AIII -1) or (AIII-2) is synthesized by polymerizing a charge transporting monomer represented by, for example, a known method described in the 4th edition, Experimental Chemistry Course Vol. 28 (Maruzen, 1992). Can do. Incidentally, in the structural formula (AIII-1) or _{(AIII-2), R 1} , T, l, m is, R ₁ in the general formula (AI-1) or (AI-2), T, l, m Since these are the same as each other, detailed description is omitted.

  The charge transporting polyether represented by the general formula (AII) can be synthesized as follows.

  1) The charge transporting polyether is a method of subjecting a charge transporting compound (charge transporting monomer) having two hydroxyalkyl groups in the general formulas (AIII-1) and (AIII-2) to heat dehydration condensation. Can be synthesized. In this case, it is desirable that the charge transporting monomer is heated and melted without a solvent and reacted under reduced pressure in order to promote a polymerization reaction due to elimination of water.

  When a solvent is used, a solvent azeotroped with water, for example, trichloroethane, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene, etc. is effective for removing water, and the charge transporting monomer 1 It is used in the range of 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents, relative to equivalents. 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. If the polymerization does not proceed, the solvent may be removed from the reaction system and heated and stirred in a viscous state.

  2) The above charge transporting polyether may be synthesized by a dehydration condensation method using a protonic acid such as p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, trifluoroacetic acid or a Lewis acid such as zinc chloride as an acid catalyst. it can. In this case, the acid catalyst is used in the range of 1/10000 equivalent to 1/10 equivalent, preferably 1/1000 equivalent to 1/50 equivalent, per equivalent of charge transporting monomer. In order to remove water generated during the polymerization, it is preferable to use a solvent azeotropic with water.

  As the solvent, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene and the like are effective, and they are used in the range of 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents with respect to 1 equivalent of the charge transporting monomer. It is done. 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.

3) The above charge transporting polyethers include alkyl isocyanates such as cyclohexyl isocyanate, alkyl isocyanates such as cyclohexyl cyanide, and cyanides such as p-tolyl cyanate and 2,2-bis (4-cyanatophenyl) propane. It can also be synthesized by a method using a condensing agent such as acid ester, dichlorohexylcarbodiimide (DCC), or trichloroacetonitrile. In this case, the condensing agent is used in a range of 1/2 equivalent to 10 equivalents, preferably 1 equivalent to 3 equivalents, relative to 1 equivalent of the charge transporting monomer.

  As the solvent, toluene, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like are effective, and 1 to 100 equivalents, preferably 2 to 50 equivalents, are used with respect to 1 equivalent of the charge transporting monomer. Although reaction temperature can be set arbitrarily, it is preferable to make it react from the room temperature to the boiling point of a solvent.

  Of the synthesis methods 1), 2) and 3), the synthesis method 1) or 3) is preferred because isomerization and side reactions are unlikely to occur. In particular, the synthesis method 3) is more preferable because the reaction conditions are milder.

  If the solvent is not used after completion of the reaction, it is dissolved in a soluble solvent. When a solvent is used, it is dropped as it is in a poor solvent in which alcohols such as methanol and ethanol and charge transporting polymers such as acetone are difficult to dissolve, to precipitate the charge transporting polymer, After separation, wash thoroughly with water or organic solvent and dry.

  Furthermore, if necessary, the reprecipitation treatment may be repeated in which it is dissolved in a suitable organic solvent and dropped into a poor solvent to precipitate the charge transporting polymer.

  The reprecipitation treatment is preferably carried out with efficient stirring using a mechanical stirrer or the like. The solvent for dissolving the charge transporting polymer in the reprecipitation treatment is used in the range of 1 to 100 equivalents, preferably 2 to 50 equivalents, per 1 equivalent of the charge transporting polymer. The poor solvent is used in the range of 1 equivalent to 1000 equivalents, preferably 10 equivalents to 500 equivalents, relative to 1 equivalent of the charge transporting polymer. Furthermore, in the above reaction, a copolymer can be synthesized by using two or more charge transporting monomers, preferably 2 to 5 kinds, more preferably 2 to 3 kinds. By copolymerizing different kinds of charge transporting monomers, it is possible to control electrical characteristics, film formability, and solubility.

  The terminal group of the charge transporting polymer may be a hydroxyl group, that is, R may be a hydrogen atom, as in the case of the charge transporting monomer, but when the polymer physical properties such as solubility, film formability, and mobility are affected, The end group R can be modified to control the physical properties. For example, the terminal hydroxyl group can be alkyl etherified with alkyl sulfate, alkyl iodide or the like.

  The specific reagent can be arbitrarily selected from dimethyl sulfate, diethyl sulfate, methyl iodide, ethyl iodide, etc., and 1 equivalent to 3 equivalents, preferably 1 equivalent to 2 equivalents, per 1 equivalent of the terminal hydroxyl group. Use within the range. In this case, a base catalyst can be used, but the base catalyst can be arbitrarily selected from sodium hydroxide, potassium hydroxide, sodium hydride, sodium metal, etc., and 1 equivalent with respect to 1 equivalent of the terminal hydroxyl group. -3 equivalents, preferably 1 equivalent to 2 equivalents.

  The reaction temperature can be from 0 ° C. to the boiling point of the solvent used. In addition, the solvent used at that time is selected from inert solvents such as benzene, toluene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone. However, a single solvent or a mixed solvent of 2 to 3 types can be used.

  Depending on the reaction, a quaternary ammonium salt such as tetra-n-butylammonium iodide can be used as a phase transfer catalyst. It is also possible to acylate the terminal hydroxyl group using an acid halide to convert the group R into an acyl group. The acid halide is not particularly limited. For example, acryloyl chloride, crotonoyl chloride, methacryloyl chloride, n-butyl chloride, 2-furoyl chloride, benzoyl chloride, cyclohexanecarbonyl chloride, enanthyl chloride, phenylacetyl chloride, o -Toluoyl chloride, m-toluoyl chloride, p-toluoyl chloride, etc. are mentioned, and it is used in the range of 1 to 3 equivalents, preferably 1 to 2 equivalents with respect to 1 equivalent of the terminal hydroxyl group. In this case, a base catalyst can be used, and the base catalyst can be arbitrarily selected from pyridine, dimethylaminopyridine, trimethylamine, triethylamine and the like, and is 1 to 3 equivalents, preferably 1 to 3 equivalents with respect to the acid chloride. Used in the range of 2 equivalents. Examples of the solvent used at that time include benzene, toluene, methyl chloride, tetrahydrofuran, and methyl ethyl ketone.

  The reaction can be carried out from 0 ° C. to the boiling point of the solvent. Preferably, it is performed in the range of 0 ° C to 30 ° C. Furthermore, acylation can also be performed using an acid anhydride such as acetic anhydride. When using a solvent, specifically, an inert solvent such as benzene, toluene or chlorobenzene can be used. The reaction can be carried out from 0 ° C. to the boiling point of the solvent. Preferably, it may be carried out from 50 ° C. to the boiling point of the solvent.

  In addition, a urethane residue (—CONH—R ′) can be introduced at the terminal using monoisocyanate. Specific monoisocyanates include isocyanic acid benzyl ester, isocyanic acid n-butyl ester, isocyanic acid t-butyl ester, isocyanic acid cyclohexyl ester, isocyanic acid 2,6-dimethyl ester, isocyanic acid ethyl ester, isocyanic acid isopropyl ester. Isocyanic acid 2-methoxyphenyl ester, isocyanic acid 4-methoxyphenyl ester, isocyanic acid n-octadecyl ester, isocyanic acid phenyl ester, isocyanic acid i-propyl ester, isocyanic acid m-tolyl ester, isocyanic acid p-tolyl ester, It can be arbitrarily selected from isocyanic acid 1-naphthyl ester and the like, and it is used in the range of 1 equivalent to 3 equivalents, preferably 1 equivalent to 2 equivalents with respect to 1 equivalent of the terminal hydroxyl group.

  Examples of solvents used in this case include benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. Can do.

  The reaction temperature can be from 0 ° C. to the boiling point of the solvent used. If the reaction is difficult to proceed, add a metal compound such as dibutyltin (II) dilaurate, tin (II) octylate, lead naphthenate, or tertiary amines such as triethylamine, trimethylamine, pyridine, dimethylaminopyridine as a catalyst. You can also.

  Next, in the organic electroluminescent element of the present invention, a charge transporting poly- mer 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. The ether will be described.

In the general formulas (BI-1) and (BI-2), R ₁ 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 a hole transporting polyether (charge transporting polyether) 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, Those represented by the general formula (BII) are preferably used.

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

  In general formula (BII), 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), p representing the degree of polymerization of the charge transporting polymer is set in the range of 5 to 5000, preferably 10 to 3000, and more preferably 15 to 1000.
When the degree of polymerization p of the charge transporting polyether is less than 5, there is a problem that it is difficult to obtain a strong film due to inferior film formability. On the other hand, when the degree of polymerization p of the charge transporting polyether is higher than 5000, the solubility in a solvent is lowered and the processability is deteriorated.

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

The charge transporting polyether comprising a repeating unit containing at least one selected from the structure represented by the general formula (BI-1) or the general formula (BI-2) as a partial structure is represented by the following structural formula (BIII-1) or The charge transporting monomer represented by (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 following structural formula (BIII-1) or (BIII-2), T, l, and m are the same as T, l, and m in the general formula (BI-1) and general formula (BI-2), respectively. It is. Further, in the following structural formula (BIII-1) or ^{(BIII-2), R 1} , R 2 are the same as R ₁ in the general formula (BI-1) and the general formula (BI-2).

  The charge transporting polyether represented by the general formula (BII) can be synthesized as follows.

  1) The charge transporting polyether can be synthesized by a method in which the charge transporting compound (charge transporting monomer) having the two hydroxyalkyl groups is subjected to heat dehydration condensation. In this case, it is desirable to heat and melt the charge transporting monomer without solvent and to react under reduced pressure in order to promote the polymerization reaction by dehydration of water. In the case of using a solvent, a solvent azeotropic with water, for example, trichloroethane, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene, etc. is effective for removing water, and 1 equivalent of a charge transporting monomer 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents. 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. If the polymerization does not proceed, the solvent may be removed from the reaction system and heated and stirred in a viscous state.

  2) The charge transporting polyether is synthesized by a dehydration condensation method using a protonic acid such as p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, trifluoroacetic acid or a Lewis acid such as zinc chloride as an acid catalyst. You can also. In this case, the acid catalyst is used in the range of 1/10000 equivalent to 1/10 equivalent, preferably 1/1000 equivalent to 1/50 equivalent, per equivalent of the charge transporting monomer. In order to remove water generated during the polymerization, it is preferable to use a solvent azeotropic with water. As the solvent, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene and the like are effective, and they are used in a range of 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents with respect to 1 equivalent of the charge transporting monomer. It is done. 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.

  3) The above charge transporting polyethers are alkyl isocyanates such as cyclohexyl isocyanate, cyanate esters such as p-tolyl cyanate and 2,2-bis (4-cyanatophenyl) propane, and dichlorocarbodiimide (DCC). It can also be synthesized by a method using a condensing agent such as trichloroacetonitrile. In this case, the condensing agent is used in a range of 1/2 equivalent to 10 equivalents, preferably 1 equivalent to 3 equivalents, relative to 1 equivalent of the charge transporting monomer. As the solvent, toluene, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like are effective, and they are used in the range of 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents, relative to 1 equivalent of the charge transporting monomer. Although reaction temperature can be set arbitrarily, it is preferable to make it react by the boiling point of a solvent from room temperature.

  Of the synthesis methods 1), 2), and 3), the synthesis method 1) or 3) is preferable because isomerization and side reactions hardly occur. In particular, the synthesis method 3) is more preferable because the reaction conditions are mild.

  If the solvent is not used after completion of the reaction, it is dissolved in a soluble solvent. When a solvent is used, it is dropped as it is in a poor solvent in which alcohols such as methanol and ethanol and charge transporting polymers such as acetone are difficult to dissolve, to precipitate the charge transporting polymer, After separation, wash thoroughly with water or organic solvent and dry. Furthermore, if necessary, the reprecipitation treatment may be repeated in which it is dissolved in a suitable organic solvent and dropped into a poor solvent to precipitate the charge transporting polymer.

  The reprecipitation treatment is preferably performed while stirring efficiently with a mechanical stirrer or the like. In the reprecipitation treatment, the solvent for dissolving the charge transporting polymer is used in the range of 1 equivalent to 100 equivalents, preferably 2 equivalents to 50 equivalents, relative to 1 equivalent of the charge transporting polymer. The poor solvent is used in the range of 1 equivalent to 1000 equivalents, preferably 10 equivalents to 500 equivalents, relative to 1 equivalent of the charge transporting polymer. Furthermore, in the above reaction, a copolymer can be synthesized by using two or more charge transporting monomers, preferably 2 to 5 types, more preferably 2 to 3 types. By copolymerizing different kinds of charge transporting monomers, it is possible to control electrical characteristics, film formability, and solubility.

  The terminal group of the charge transporting polymer may be a hydroxyl group, that is, R may be a hydrogen atom, as in the case of the charge transporting monomer, but in the case of affecting the polymer physical properties such as solubility, film formability, and mobility. The end group R can be modified to control the physical properties.

  For example, the terminal hydroxyl group can be alkyl etherified with alkyl sulfate, alkyl iodide or the like. The specific reagent can be arbitrarily selected from dimethyl sulfate, diethyl sulfate, methyl iodide, ethyl iodide and the like, and is 1 equivalent to 3 equivalents, preferably 1 equivalent to 2 equivalents with respect to the terminal hydroxyl group. Use within an equivalent range. In this case, a base catalyst can be used, but the base catalyst can be arbitrarily selected from sodium hydroxide, potassium hydroxide, sodium hydride, sodium metal, etc., and 0.9 equivalent to the terminal hydroxyl group. -3 equivalents, preferably 1 equivalent to 2 equivalents.

The reaction temperature can be from 0 ° C. to the boiling point of the solvent used. In addition, the solvent used at that time is selected from inert solvents such as benzene, toluene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone. However, a single solvent or a mixed solvent of 2 to 3 types can be used.
Depending on the reaction, a quaternary ammonium salt such as tetra-n-butylammonium iodide may be used as a phase transfer catalyst. It is also possible to acylate the terminal hydroxyl group with an acid halide to make the group R an acyl group.

  Although the acid halide is not particularly limited, for example, acryloyl chloride, crotonoyl chloride, methacryloyl chloride, n-butyl chloride, 2-furoyl chloride, benzoyl chloride, cyclohexanecarbonyl chloride, enanthyl chloride, phenylacetyl chloride, o-Toluoyl chloride, m-toluoyl chloride, p-toluoyl chloride and the like can be mentioned, and it is used in the range of 1 to 3 equivalents, preferably 1 to 2 equivalents with respect to the terminal hydroxyl group.

  In this case, a base catalyst can be used, and the base catalyst can be arbitrarily selected from pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and the like, and is 1 to 3 equivalents, preferably 1 to the acid chloride. Used in the range of equivalent to 2 equivalents. Examples of the solvent used at that time include benzene, toluene, methylene chloride, tetrahydrofuran, and methyl ethyl ketone. The reaction can be carried out from 0 ° C. at the boiling point of the solvent used. Preferably, it is used in the range of 0 ° C to 30 ° C.

  Furthermore, acylation can also be performed using an acid anhydride such as acetic anhydride. When using a solvent, specifically, an inert solvent such as benzene, toluene or chlorobenzene can be used. The reaction can be carried out from 0 ° C. to the boiling point of the solvent. Preferably, it may be carried out from 50 ° C. to the boiling point of the solvent. In addition, a urethane residue (—CONH—R ′) can be introduced at the terminal using monoisocyanate. Specific monoisocyanates include isocyanic acid benzyl ester, isocyanic acid n-butyl ester, isocyanic acid t-butyl ester, isocyanic acid cyclohexyl ester, isocyanic acid 2,6-dimethyl ester, isocyanic acid ethyl ester, isocyanic acid isopropyl ester, Isocyanic acid 2-methoxyphenyl ester, isocyanic acid 4-methoxyphenyl ester, isocyanic acid n-octadecyl ester, isocyanic acid phenyl ester, isocyanic acid isopropyl ester, isocyanic acid m-tolyl ester, isocyanic acid p-tolyl ester, isocyanic acid 1 -It can be arbitrarily selected from naphthyl esters and the like, and is used in the range of 1 equivalent to 3 equivalents, preferably 1 equivalent to 2 equivalents with respect to the terminal hydroxyl group. Examples of solvents used in this case include benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like. Can do.

  The reaction temperature can be from 0 ° C. to the boiling point of the solvent used. If the reaction is difficult to proceed, a metal compound such as dibutyltin (II) dilaurate, octyltin (II), lead naphthenate, or a tertiary amine such as triethylamine, trimethylamine, pyridine, dimethylaminopyridine may be added as a catalyst. it can.

Next, the luminescent small molecule will be described.
The light-emitting small molecule used in the present invention includes a compound that emits light by transition from an excited triplet state of an electronic energy level to a ground state in a solid state or from a ground state via an excited triplet state. Used. In the present invention, the “light-emitting small molecule” means a light-emitting molecule that does not have a repeating structure linked by polymerization such as a polymer.

  The compound which emits light by transition to the ground state via the excited triplet state here refers to the excited triplet state of the portion corresponding to the phosphorescent first organic compound disclosed in JP-A-2002-050483. In this case, energy transfer from the portion corresponding to the fluorescent organic luminescent second organic compound to the excited triplet state occurs, and the fluorescent light emission occurs from the second organic compound portion.

  The value of the quantum efficiency of the excited triplet state in the phosphorescent part is preferably 0.1 or more, more preferably 0.3 or more, and still more preferably 0.5 or more. Examples of compounds having high quantum efficiency in the excited triplet state 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 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.

As the transition metal used in the above transition metal complex, in the periodic table, the first transition element series is from Sc of atomic number 21 to Zn of atomic number 30, and the second transition element series is from Y of atomic number 39 to atoms. Up to Cd of number 48, the third transition element series includes from Hf of atomic number 72 to Hg of atomic number 80. In addition, 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 portion of the luminescent small molecule used in the present invention is nonionic. This is because, when the light emitting small molecule is ionic, electrochemiluminescence occurs when a voltage is applied to the light emitting layer containing the light emitting small molecule, and the response speed is very slow, for example, on the order of minutes. This is because it is not preferable for display applications.

Examples of the ligand coordinated to the above transition metal complex and rare earth metal complex include acetylacetonato, 2,2′-bipyridine, 4,4′-dimethyl-2,2′-bipyridine, 1,10 -Phenanthroline, 2-phenylpyridine, porphyrin, phthalocyanine, pyrimidine, quinoline and / or a derivative thereof can be exemplified, but is not limited thereto. One or more kinds of these ligands are coordinated with respect to one complex. In addition, a binuclear complex, a polynuclear complex, or a complex of two or more types of complexes can be used as the complex compound.
In the light-emitting portion of the light-emitting small molecule, the metal atom serving as the central metal of the metal complex is constrained at one or more sites of the ligand. 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. When the metal atom serving as the central metal is an ion, a method of neutralizing the light-emitting moiety is adopted for the above-described reason, and for example, it has a covalent bond sufficient to neutralize the valence of the ion together with the coordination bond Although the method of using an organometallic compound is mentioned, it is not limited to this at all.

The light-emitting small molecule used in the present invention is used by being dispersed in a polymer material. As the polymer material, at least the charge transporting polyester is used. Other polymer materials may be used in combination as necessary. For example, an insulating polymer material or a charge transporting polymer material other than the charge transporting polyester may be used.
Examples of the charge transporting polymer other than the charge transporting polyester include polyvinyl carbazole, polymethyl methacrylate having an aromatic amine in the side chain, polyester having an aromatic amine in the main chain, polyether, or polysilane. However, it is not limited to these. In addition, when dispersed in an insulating polymer material, a hole-transporting host material such as a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an aryl hydrazone derivative, or a porphyrin-based compound, or an oxadiazole derivative, It is desirable to contain an electron transporting host material such as a triazine derivative, a triazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, a fluorenylidenemethane derivative, or the like. Here, examples of the insulating polymer material include, but are not limited to, polystyrene, polyether, polyether, polymethyl methacrylate, and the like.

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 includes at least one kind of the charge transporting polyether and a ground state by a transition from an excited triplet state of an electronic energy level to a ground state or via an excited triplet state. And a light-emitting small molecule that emits light upon transition to.

  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 transporting function, and the light emitting layer having the charge transporting function contains the charge transporting polyether and the light emitting small molecule. To do.
In any of the layer configurations (1) to (3), the light-emitting layer containing a light-emitting low molecule only needs to contain the charge transporting polyether having a function as a host material, and is necessary. Depending on the above, the charge transporting polyether 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 (hole transport property other than the charge transport polyether). Material, 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 charge 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 polyether 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) Can be used as a light emitting layer having a charge transporting ability), and in the case of the layer structure of the organic EL device shown in FIG. 2, any of the hole transporting layer 3 and the electron transporting layer 5 can be used. In the case of the layer structure of the organic EL element shown in FIG. 3, both of them function as a hole transport layer 3 and a light emitting layer 4 (in this case, a light emitting layer having charge transporting ability). In the case of the layer configuration of the organic EL element 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 polyether alone provided with a function (electron transport ability) according to the purpose. In order to adjust the electron mobility for the purpose of further improving the electrical characteristics, the electron transporting material other than the charge transporting polyether is used with respect to the total weight of the material constituting the electron transporting layer 5. It may be formed by mixing and dispersing in the range of 1 to 50% by weight. 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 polyether is not used, the electron transport layer 5 is formed using these electron transporting materials alone.

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 transporting material can be used.
In the case of the layer structure of the organic EL element shown in FIGS. 2 and 3, the hole transport layer 3 is formed of a charge transporting polyether having 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 polyether is mixed in the range of 1 to 50% by weight with respect to the total weight of the material constituting the hole transport layer 3. It may be formed in a dispersed manner.

  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). Among these, the tetraphenylenediamine derivative is used because of its good compatibility with the charge transporting polyether. preferable. Moreover, you may use it by mixing with other general purpose resin etc. When the charge transporting polyether is not used, the hole transport layer 3 is formed by using these hole transporting materials alone.

  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 injects holes from the anode. Any material may be used as long as it has a function, and the same material as the hole transporting material can be used. As a particularly preferable specific example, the following exemplified compound (VII-1) or (VII-2) can be used. Can be mentioned. In the above exemplary compounds (V-4), (VI-7) to (VI-9) and (VII-2), n represents 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 based on the entire material constituting the light emitting layer 4 containing at least the charge transporting polyether as described above. The light emitting low molecule is formed by dispersing in the range of 0.1 to 50% by weight.
In addition to the charge transporting polyether and the light emitting low molecule, the material constituting the light emitting layer 4 may be a charge transporting polymer material other than the charge transporting polyether or an insulating polymer, if necessary. Materials can be used in combination.

  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, the charge transporting polyether provided with a function (hole transporting capability or electron transporting capability) according to the purpose. In the organic compound layer, the light emitting small molecule is dispersed in the range of 0.1 to 50% by weight with respect to the total weight of the material constituting the light emitting layer 6 having a charge transporting ability as the light emitting material. In order to adjust the balance between holes and electrons injected into the organic EL element, a charge transport material other than the charge transport polyether may be dispersed in a range of 10 to 50% by weight.

  As such a charge transport material, when adjusting the electron mobility, the electron transport material is preferably an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, a fluorenylidenemethane derivative. As specific examples, the exemplary compounds (V-1) to (V-4) are exemplified. In addition, it is preferable to use an organic compound that does not exhibit a strong electron interaction with the charge transporting polyether. More preferably, the following exemplified compound (VIII) is used, but it 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 compatibility with the charge transporting polyether.
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 the element from being deteriorated by 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 in accordance with 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 the charge transport 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 polyether, 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 polyether used in the examples was obtained as follows, for example.

(Example A1)
Charge transporting polyether (AIX) as charge transporting material and host material [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 6.9 × 10 ⁴ (styrene equivalent), weight average molecular weight / A number average molecular weight (Mw / Mn) of 2.8] was mixed with 1 part by weight, and 0.1 parts by weight of the following exemplified compound (XIII) as a light-emitting low molecule was mixed to prepare a 10% by weight dichloroethane solution. Filtration 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) as an electron transporting material is prepared as a 5 wt% dichloroethane solution, 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)
Charge transporting material (VI-9) as a hole transporting material [weight average molecular weight (M _w ) measured by GPC (gel permeation chromatography) is 1.04 × 10 ⁵ (in terms of styrene), weight The average molecular weight / number average molecular weight (Mw / Mn) was 1.87] as a 5 wt% chlorobenzene solution, 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 weight of a charge transporting polyether (AIX) as a charge transporting material and host material and 0.1 part by weight of the following exemplary compound (XIII) as a light emitting low molecule are mixed. Prepared as a wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and applied this solution on the hole transport layer by spin coating to form a light emitting layer having a thickness of 0.15 μm and having a charge transport ability. .
After sufficiently drying, charge transporting polyether (AXI) as an electron transporting material [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 1.03 × 10 ⁵ (in terms of styrene)] The weight average molecular weight / number average molecular weight (Mw / Mn) is 3.2] as a 5 wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is spin coated onto the light emitting layer. This was applied 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 A3)
The charge transporting material (VI-9) was prepared as a 5 wt% 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 weight of a charge transporting polyether (AIX) as a charge transporting material and host material and 0.1 part by weight of the following exemplary compound (XIII) as a light emitting low molecule are mixed. Prepared as a wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and applied this solution on the hole transport layer by spin coating to form a light emitting layer having a thickness of 0.15 μm and having a charge transport ability. . 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 polyether (AIX) as a charge transporting and host material, The exemplified compound (XIII) was mixed with 0.1 part by weight, prepared as a 10 wt% 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 produced in the same manner as in Example A3, except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example A7)
A device was fabricated in the same manner as in Example A3 except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Example A8)
Charge transporting polyether (AX) as charge transporting material and host material [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 8.1 × 10 ⁴ (styrene conversion), weight average molecular weight / A device was fabricated in the same manner as in Example A1, except that 3.3] was used as the number average molecular weight (Mw / Mn).

(Example A9)
A device was fabricated in the same manner as in Example A2 except that charge transporting polyether (AX) was used as the charge transporting material and host material.

(Example A10)
A device was produced in the same manner as in Example A3 except that charge transporting polyether (AX) was used as the charge transporting material and host material.

(Example A11)
A device was fabricated in the same manner as in Example A4 except that charge transporting polyether (AX) was used as the charge transporting material and host material.

(Example A12)
A device was fabricated in the same manner as in Example A5 except that charge transporting polyether (AX) was used as the charge transporting material and host material.

(Example A13)
A device was produced in the same manner as in Example A10, except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example A14)
A device was fabricated in the same manner as in Example A10, except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Example A15)
A device was fabricated in the same manner as in Example A1, except that charge transporting polyether (AXI) was used as the charge transporting material and host material.

(Example A16)
A device was fabricated in the same manner as in Example A2, except that charge transporting polyether (AXI) was used as the charge transporting material and host material.

(Example A17)
A device was produced in the same manner as in Example A3 except that charge transporting polyether (AXI) was used as the charge transporting material and host material.

(Example A18)
A device was fabricated in the same manner as in Example A4 except that charge transporting polyether (AXI) was used as the charge transporting material and host material.

(Example A19)
A device was fabricated in the same manner as in Example A5 except that charge transporting polyether (AXI) was used as the charge transporting material and host material.

(Example A20)
A device was produced in the same manner as in Example A17 except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example A21)
A device was fabricated in the same manner as in Example A17, except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Example B1)
Charge transporting polyether (BIX) [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 5.9 × 10 ⁴ (styrene equivalent), weight average molecular weight / A number average molecular weight (Mw / Mn) of 2.8] was mixed with 1 part by weight, and 0.1 parts by weight of the following exemplified compound (XIII) as a light-emitting low molecule was mixed to prepare a 10% by weight dichloroethane solution. Filtration 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) as an electron transporting material is prepared as a 5 wt% dichloroethane solution, 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 wt% 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 weight of charge transporting polyether (BIX) as a charge transporting material and host material and 0.1 part by weight of the following exemplary compound (XIII) as a light emitting low molecule are mixed together. Prepared as a wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and applied this solution on the hole transport layer by spin coating to form a light emitting layer having a thickness of 0.15 μm and having a charge transport ability. .
After sufficiently drying, charge transporting polyether (BXI) [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 8.1 × 10 ⁴ (converted to styrene) as an electron transporting material] The weight average molecular weight / number average molecular weight (Mw / Mn) is 3.0] as a 5 wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and this solution is spin coated on the light emitting layer. This was applied 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 B3)
The charge transporting material (VI-9) was prepared as a 5 wt% 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 weight of charge transporting polyether (BIX) as a charge transporting material and host material and 0.1 part by weight of the following exemplary compound (XIII) as a light emitting low molecule are mixed together. Prepared as a wt% dichloroethane solution, filtered through a 0.1 μm PTFE filter, and applied this solution on the hole transport layer by spin coating to form a light emitting layer having a thickness of 0.15 μm and having a charge transport ability. . 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 a charge transporting polyester (VI-9) as a charge transporting material, 0.5 parts by weight of a charge transporting polyether (BIX) as a charge transporting and host material, The exemplified compound (XIII) was mixed with 0.1 part by weight, prepared as a 10 wt% 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 produced in the same manner as in Example B3 except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example B7)
A device was produced in the same manner as in Example B3 except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Example B8)
Charge transporting polyether (BX) as charge transporting material and host material [weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 7.9 × 10 ⁴ (in terms of styrene), weight average molecular weight / A device was fabricated in the same manner as in Example B1, except that the number average molecular weight (Mw / Mn) was 2.9].

(Example B9)
A device was fabricated in the same manner as in Example B2, except that charge transporting polyether (BX) was used as the charge transporting material and host material.

(Example B10)
A device was fabricated in the same manner as in Example B3 except that charge transporting polyether (BX) was used as the charge transporting material and host material.

(Example B11)
A device was fabricated in the same manner as in Example B4, except that charge transporting polyether (BX) was used as the charge transporting material and host material.

(Example B12)
A device was fabricated in the same manner as in Example B5 except that charge transporting polyether (BX) was used as the charge transporting material and host material.

(Example B13)
A device was produced in the same manner as in Example B10, except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example B14)
A device was produced in the same manner as in Example B10, except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Example B15)
A device was fabricated in the same manner as in Example B1, except that charge transporting polyether (BXI) was used as the charge transporting material and host material.

(Example B16)
A device was fabricated in the same manner as in Example B2, except that charge transporting polyether (BXI) was used as the charge transporting material and host material.

(Example B17)
A device was fabricated in the same manner as in Example B3 except that charge transporting polyether (BXI) was used as the charge transporting material and host material.

(Example B18)
A device was fabricated in the same manner as in Example B4, except that charge transporting polyether (BXI) was used as the charge transporting material and host material.

(Example B19)
A device was fabricated in the same manner as in Example B5 except that charge transporting polyether (BXI) was used as the charge transporting material and host material.

(Example B20)
A device was produced in the same manner as in Example B17 except that the following exemplary compound (XIV) was used as the light-emitting small molecule.

(Example B21)
A device was produced in the same manner as in Example B17 except that the following exemplary compound (XV) was used as the light-emitting small molecule.

(Comparative Example 1)
Using the following exemplified compound (XVI) as a host material and the following exemplified compound (XIII) as a light-emitting small molecule, co-evaporated on a glass substrate formed by etching a 2 mm wide strip-shaped ITO electrode that was dried after washing. Was deposited so that the amount of the compound (XIII) in the film was 5% by weight with respect to the weight of the compound in the whole film to form a light emitting layer having a film 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, the following exemplary compound (XVI) as the host material and the following exemplary compound (XIII) as the light emitting low molecule are used, and the amount of the compound (XIII) in the film is reduced by co-evaporation. Vapor deposition was performed so as to be 5% by weight with respect to the weight of the whole compound to form a light emitting layer having a film 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, the following exemplary compound (XVI) as the host material and the following exemplary compound (XIII) as the light emitting low molecule are used, and the amount of the compound (XIII) in the film is reduced by co-evaporation. Vapor deposition was performed so as to be 5% by weight with respect to the weight of the whole compound to form a light emitting layer having a film 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 following exemplified compound (XVI) as a host material, and 0.05 part by weight of the following exemplified compound (XIII) as a light emitting low molecule Were mixed to prepare a 5% by weight 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.

  In addition, the exemplary compound (XIII), the exemplary compound (XIV), the exemplary compound (XV), the exemplary compound (XVI), and the exemplary compound (XVII) used in Examples / Comparative Examples are shown below.

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 polyether 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 polyether consisting of repeating structural units included as a partial structure has an ionization potential and charge mobility suitable for organic EL devices, and forms a good thin film using a wet process such as spin coating or dipping. Was possible. In addition, a sufficiently high luminance can be obtained by using a light-emitting small molecule that emits light by transition from the excited triplet state to the ground state of the electron energy level or from the ground state via the excited triplet state. It was. Further, in the present invention, since the light emitting layer is used as a light emitting low molecular weight host material 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 polyether of the present invention is superior in solubility in a solvent as compared with other polymer phosphorescent light-emitting host materials, so that the film formation is easy and the uniformity of the formed film is also good. In addition, there is an advantage that phase separation from the light-emitting small molecule to be mixed hardly occurs.

It is the schematic block diagram which showed an example of the laminated constitution of the organic electroluminescent element of this invention. It is the schematic block diagram which showed an example of the laminated constitution of the organic electroluminescent element of this invention. It is the schematic block diagram which showed an example of the laminated constitution of the organic electroluminescent element of this invention. It is the schematic block diagram which showed an example of the laminated constitution of the organic electroluminescent 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 7 which has a charge transport function 7 Back electrode

Claims (20)

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,
A charge transporting polyether 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 contains at least one kind and a light emitting small molecule that emits light by a transition from an excited triplet state to a ground state of an electron energy level or through a transition to a ground state via an excited triplet state. Organic electroluminescent device.

[In 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 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. ] 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 polyethers composed of repeating units 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 small molecules 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. The organic electroluminescent element according to claim 1, wherein   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 polyethers composed of repeating units 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 small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground 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 polyethers composed of repeating units 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 small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground 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 includes at least one charge transporting polyether 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; 2. A light-emitting small molecule that emits 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 as described.   The organic electroluminescent device according to claim 8, wherein the light emitting layer contains a charge transporting material. A charge transporting polyether 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). 2. The organic electroluminescent device according to claim 1, which is a charge transporting polyether.

(In the general formula (AII), A represents at least one selected from the structures represented by the general formulas (AI-1) and (AI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Of the aryl group, or a substituted or unsubstituted aralkyl group, 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, at least one of the organic compound layers is represented by the following general formula ( At least one charge transporting polyether comprising a repeating unit containing at least one selected from the structures represented by BI-1) and (BI-2) as a partial structure, and an excited triplet state of an electron energy level An organic electroluminescent device comprising: a light-emitting small molecule that emits light by a transition from a ground state to a ground state or a transition to a ground state via an excited triplet state.

[In General Formulas (BI-1) and (BI-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 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. ] 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 polyethers composed of 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. And
The light emitting layer contains one or more luminescent small molecules 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. 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 polyethers composed of 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. And
The light emitting layer contains one or more luminescent small molecules 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. 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 polyethers composed of 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. And
The light-emitting layer contains one or more luminescent small molecules that emit light by transition from an excited triplet state to a ground state of an electron energy level or by transition from the excited triplet state to a ground 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 transport polyether which consists of a repeating unit included as a structure are 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 device according to claim 11, further comprising a light-emitting small molecule 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 polyether 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). The organic electroluminescent device according to claim 11, which is a charge transporting polyether.

(In the general formula (BII), A represents at least one selected from the structures represented by the general formulas (BI-1) and (BI-2), and R represents a hydrogen atom, an alkyl group, substituted or unsubstituted. Of the aryl group, or a substituted or unsubstituted aralkyl group, and p represents an integer of 5 to 5000.)

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