High molecular weight compounds and light-emitting diodes containing said high molecular weight compounds

Abstract

The objective of the present invention is to provide a high molecular weight compound having excellent hole injection and transport performance, electron blocking ability, and high stability in a thin film state. Additionally, the invention is to provide a light-emitting diode having high luminous efficiency and a long lifespan, having an organic layer (thin film) formed by the high molecular weight compound. The high molecular weight compound of the present invention comprises repeating units including specific triarylamine structural units and specific linkage structural units, and has a weight average molecular weight of 10,000 or more and less than 1,000,000 in terms of polystyrene.

Description

Technology Field

[0001] The present invention relates to a high molecular weight compound suitable for an organic electroluminescence device (organic EL device), which is a self-luminous element and is a type of light-emitting diode suitable for various display devices, and to the device. Background Technology

[0002] Since organic EL devices are self-luminous devices, they are brighter than liquid crystal devices, offering excellent visibility and enabling clear display, so active research has been conducted.

[0003] Organic EL devices have a configuration in which a thin film (organic layer) of an organic compound is sandwiched between an anode and a cathode. Methods for forming the thin film are broadly classified into vacuum deposition and coating methods. Vacuum deposition is a method of forming a thin film on a substrate by depositing it in a vacuum using mainly low-molecular-weight compounds, and it is a technology that has already been put into practical use. On the other hand, coating is a method of forming a thin film on a substrate using a solution, such as inkjet or printing, using mainly high-molecular-weight compounds; it has high material utilization efficiency, is suitable for large-area and high-precision applications, and is an indispensable technology for future large-area organic EL displays.

[0004] Vacuum deposition methods using low-molecular-weight materials have extremely low material utilization efficiency, and as the substrate size increases, the warping of the shadow mask increases, making uniform deposition on large substrates difficult. It also faces the problem of high manufacturing costs.

[0005] Meanwhile, by applying a solution of polymer materials dissolved in an organic solvent, it is possible to form a uniform film even on large substrates, and thin films can be formed using coating methods such as inkjet printing or printing. Consequently, it is possible to increase the efficiency of material utilization and significantly reduce manufacturing costs for device fabrication.

[0006] Although various organic EL devices using polymer materials have been examined so far, there has been a problem that device characteristics such as luminous efficiency and lifespan are not necessarily sufficient (see, for example, Patent Documents 1 to 5).

[0007] The most important technology for achieving high performance in polymer organic EL devices is the technology to stack the upper layer by coating without disturbing the lower thin film. Since polymer organic EL devices are fabricated by coating a solution in which the material is dissolved in an organic solvent, there is a risk that the lower thin film will be leached into the solvent in which the upper material is dissolved, and thus, compared to vacuum deposition, stacking is difficult.

[0008] There are broadly two types of stacking technologies for polymer organic EL devices. One is a method of imparting cross-linkers to the substrate material. After applying the substrate material, cross-linking is carried out through heat treatment to render it insoluble in organic solvents. The other is a method of selecting the type of solvent used to dissolve the upper layer material. By selecting an organic solvent that does not dissolve the substrate material, the leaching of the substrate when applying the upper layer can be suppressed.

[0009] A fluorene polymer called TFB, which does not have cross-linkers, has been known as a representative hole transport material used in polymer organic EL devices (see Patent Documents 6 to 7). However, TFB has insufficient hole transport and insufficient electron blocking properties, so some electrons escape from the light-emitting layer, and thus, there was a problem in that the improvement of luminous efficiency could not be expected. In addition, there was a problem in that the lifespan of the device could not be expected due to the low film adhesion with adjacent layers. Prior art literature

[0010] Japanese Patent Publication No. 2005-272834 Japanese Patent Publication No. 2007-119763 Japanese Patent Publication No. 2007-162009 Japanese Patent Publication No. 2007-177225 International Publication WO2005 / 049546 International Publication WO99 / 54385 International Publication WO2005 / 059951 The problem to be solved

[0011] The objective of the present invention is to provide a polymer material having excellent hole injection and transport performance, electron blocking ability, and high stability in a thin film state. In addition, the invention is to provide a light-emitting diode having a low driving voltage, high luminous efficiency, and long lifespan, particularly a polymer organic EL device having an organic layer (thin film) formed by the polymer material. means of solving the problem

[0012] The inventors, noting that triarylamines containing a fluorene structure have high hole injection and transport capabilities and can also be expected to have a wide gap, synthesized and examined various high molecular weight compounds having triarylamine structural units containing fluorene structures. As a result, they discovered a high molecular weight compound of a novel structure that, in addition to hole injection and transport capabilities, also has a wide gap, excellent heat resistance, and thin film stability, thereby completing the present invention.

[0013] According to the present invention, a high molecular weight compound is provided comprising a repeating unit represented by the following general formula (3), comprising a triarylamine structural unit represented by the following general formula (1) and a linking structural unit represented by the following general formula (2).

[0014] According to the present invention, a light-emitting diode is provided having a pair of electrodes and at least one organic layer sandwiched between them, wherein the organic layer contains the high molecular weight compound as a constituent material.

[0015] In the light-emitting diode of the present invention, it is suitable for the organic layer to be a hole transport layer, an electron blocking layer, a hole injection layer, or a light-emitting layer.

[0016] That is, the present invention is as follows.

[0017] [1] A high molecular weight compound having a weight average molecular weight of 10,000 or more and less than 1,000,000 in polystyrene equivalent, comprising a triarylamine structural unit represented by the following general formula (1), and a repeating unit represented by the following general formula (3), comprising a linking structural unit represented by the following general formula (2).

[0018]

[0019]

[0020]

[0021] Among the above formulas,

[0022] R1 each independently represents a deuterium atom, a cyano group, a nitro group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group or alkyloxy group having 1 to 8 carbon atoms, a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms, an alkenyl group or aryloxy group having 2 to 6 carbon atoms, and

[0023] R2 each independently represents an alkyl group or alkyloxy group having 1 to 8 carbon atoms, a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms, and

[0024] X represents a hydrogen atom, an amino group, a monovalent aryl group, or a monovalent heteroaryl group, and

[0025] L represents a divalent phenyl group, and

[0026] n represents an integer from 0 to 3, and

[0027] a represents an integer from 0 to 3, and

[0028] b represents an integer from 0 to 4.

[0029] [2] A high molecular weight compound described in [1], in which a and b are 0.

[0030] [3] A high molecular weight compound described in [1] or [2] in which R2 is an alkyl group having 1 to 8 carbon atoms.

[0031] [4] A high molecular weight compound described in any one of [1] to [3], in which X is a hydrogen atom.

[0032] [5] A high molecular weight compound described in any one of [1] to [3], wherein X is a diphenylamino group, a phenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothienyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, an indenocarbazolyl group or an acrridinyl group.

[0033] [6] A light-emitting diode having a pair of electrodes and at least one organic layer sandwiched between them, wherein the organic layer contains a high molecular weight compound as a constituent material as described in any one of [1] to [5].

[0034] [7] A light-emitting diode described in [6], in which the above organic layer is a hole transport layer.

[0035] [8] A light-emitting diode described in [6], in which the above organic layer is an electronic blocking layer.

[0036] [9] The light-emitting diode described in [6], in which the above organic layer is a hole injection layer.

[0037]

[10] A light-emitting diode described in [6], in which the above organic layer is a light-emitting layer.

[0038]

[11] An organic electroluminescent device, a light-emitting diode described in any one of [6] to

[10] .

[0039] The high molecular weight compound of the present invention, having a triarylamine structural unit (a divalent group) represented by the above-described general formula (1) and a linking structural unit (a divalent group) represented by the general formula (2), is, for example, a polymer having the said structural unit as a repeating unit, and suitably has a weight average molecular weight in polystyrene equivalent measured by GPC (gel permeation chromatography) in the range of 10,000 or more and less than 1,000,000. Effects of the invention

[0040] The high molecular weight compound according to the present invention is,

[0041] (1) The injection characteristics of the hole are good, and

[0042] (2) The mobility of the hole is large, and

[0043] (3) It has a wide gap and excellent electron blocking ability,

[0044] (4) The thin film state is stable, and

[0045] (5) It has excellent heat resistance.

[0046] It has the characteristic of.

[0047] An organic EL device in which an organic layer formed by a high molecular weight compound of the present invention, for example, a hole transport layer, an electron blocking layer, a hole injection layer, or a light-emitting layer, is formed between a pair of electrodes,

[0048] (1) High luminous efficiency and power efficiency,

[0049] (2) The practical driving voltage is low, and

[0050] (3) Longevity

[0051] It has the advantage of being... Brief explanation of the drawing

[0052] FIG. 1 is a diagram showing the chemical structures of structural units 1 to 11 suitable as connecting structural units represented by the general formula (2) of the present invention. FIG. 2 is a diagram showing the chemical structures of structural units 12 to 21 suitable as connecting structural units represented by the general formula (2) of the present invention. FIG. 3 is a diagram showing the chemical structures of structural units 22 to 31 suitable as connecting structural units represented by the general formula (2) of the present invention. FIG. 4 is a diagram showing the chemical structures of structural units 32 to 38 suitable as connecting structural units represented by the general formula (2) of the present invention. FIG. 5 is a diagram showing an example of the layer configuration of an organic EL device of the present invention. FIG. 6 is of the high molecular weight compound (compound A) synthesized in Example 1 of the present invention. 1 H-NMR chart as well. FIG. 7 is of the high molecular weight compound (compound B) synthesized in Example 2 of the present invention. 1 H-NMR chart as well. FIG. 8 is of the high molecular weight compound (compound C) synthesized in Example 3 of the present invention. 1 H-NMR chart as well. Specific details for implementing the invention

[0053] <Triarylamine structural unit and linkage structural unit>

[0054] The triarylamine structural unit and the linkage structural unit of the high molecular weight compound of the present invention are both divalent groups and are represented by the following general formulas (1) and (2), respectively.

[0055]

[0056]

[0057] In the above general formulas (1) and (2), R1 each independently represents a hydrogen atom, a deuterium atom, a cyano group, a nitro group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group or alkyloxy group having 1 to 8 carbon atoms, a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms, or an alkenyl group or aryloxy group having 2 to 6 carbon atoms.

[0058] In the above R1, examples of the above alkyl group, alkyloxy group, cycloalkyl group, cycloalkyloxy group, alkenyl group and aryloxy group include the following groups.

[0059] Examples of alkyl groups (1 to 8 carbon atoms) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, neohexyl group, n-heptyl group, isoheptyl group, neoheptyl group, n-octyl group, isooctyl group, neooctyl group, etc.

[0060] Examples of alkyloxy groups (1 to 8 carbon atoms) include methyloxy, ethyloxy, n-propyloxy, isopropyloxy, n-butyloxy, tert-butyloxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, etc.

[0061] Examples of cycloalkyl groups (5 to 10 carbon atoms) include cyclopentyl groups, cyclohexyl groups, 1-adamantyl groups, 2-adamantyl groups, etc.

[0062] Examples of cycloalkyloxy groups (5 to 10 carbon atoms) include cyclopentyloxy groups, cyclohexyloxy groups, cycloheptyloxy groups, cyclooctyloxy groups, 1-adamanthyloxy groups, 2-adamanthyloxy groups, etc.

[0063] Examples of alkenyl groups (with 2 to 6 carbon atoms) include vinyl groups, allyl groups, isopropenyl groups, 2-butenyl groups, etc.

[0064] Examples of aryloxy groups include phenyloxy groups, tolyloxy groups, etc.

[0065] In the above general formulas (1) and (2), a represents an integer from 0 to 3, and b represents an integer from 0 to 4.

[0066] In the high molecular weight compound of the present invention, when a or b is not 0, the R1 is suitable as a deuterium atom, and in the synthetic phase, a and b are most suitable as 0.

[0067] In the above general formula (1), R2 each independently represents an alkyl group or alkyloxy group having 1 to 8 carbon atoms, or a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms.

[0068] In the above R2, examples of the above alkyl group, alkyloxy group, cycloalkyl group, and cycloalkyloxy group include groups similar to those shown in R1.

[0069] In the high molecular weight compound of the present invention, the R2 is preferably an alkyl group having 1 to 8 carbon atoms to increase solubility, and is most suitable as an n-hexyl group or an n-octyl group.

[0070] In the above general formula (2), X represents a hydrogen atom, an amino group, a monovalent aryl group, or a monovalent heteroaryl group.

[0071] In the above X, examples of monovalent aryl groups and monovalent heteroaryl groups include the following groups.

[0072] Examples of aryl groups include phenyl groups, naphthyl groups, anthracenyl groups, phenanthrenyl groups, fluorenyl groups, indenyl groups, pyrenyl groups, perylenyl groups, fluoranthenyl groups, etc.

[0073] Examples of heteroaryl groups include pyridyl, pyrimidinyl, triazinyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, indenocarbazolyl, benzoxazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, naphthyldinyl, phenanthrolinyl, acridinyl, carbolinyl, etc.

[0074] In addition, the above amino group, aryl group, or heteroaryl group may have a substituent. As substituents, in addition to deuterium atoms, cyano groups, nitro groups, etc., the following groups may be used.

[0075] Halogen atoms, e.g., fluorine atoms, chlorine atoms, bromine atoms, iodine atoms; alkyl groups, particularly those having 1 to 8 carbon atoms, e.g., methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, neopentyl groups, n-hexyl groups, isohexyl groups, neohexyl groups, n-heptyl groups, isoheptyl groups, neoheptyl groups, n-octyl groups, isooctyl groups, neooctyl groups; alkyloxy groups, particularly those having 1 to 8 carbon atoms, e.g., methyloxy groups, ethyloxy groups, propyloxy groups; alkenyl groups, e.g., vinyl groups, allyl groups; aryloxy groups, e.g., phenyloxy groups, tolyloxy groups; Aryl groups, e.g., phenyl group, biphenylyl group, terphenylyl group, naphthyl group, anthracenyl group, phenanthrenyl group, fluorenyl group, indenyl group, pyrenyl group, perylenyl group, fluoranthenyl group, triphenylenyl group; heteroaryl groups, e.g., pyridyl group, pyrimidinyl group, triazinyl group, thienyl group, furyl group, pyrrolyl group, quinolyl group, isoquinolyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, indenocarbazolyl group, benzoxazolyl group, benzothiazolyl group, quinoxalinyl group, benzimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothienyl group, carbolinyl group; arylvinyl groups, e.g., styryl group, naphthylvinyl group; Acyl groups, such as acetyl groups and benzoyl groups, can be cited.

[0076] In addition, these substituents may have additional substituents as exemplified above. In addition, while it is preferable for these substituents to exist independently, they may also form rings by being bonded to each other by single bonds, methylene groups that may have substituents, oxygen atoms, or sulfur atoms interposed therebetween.

[0077] For example, the above aryl group or heteroaryl group may have a phenyl group as a substituent, and this phenyl group may also have a phenyl group as a substituent. That is, taking the aryl group as an example, this aryl group may be a biphenylyl group, a terphenylyl group, or a triphenylenyl group.

[0078] In the above general formula (1), L represents a divalent phenyl group, and n represents an integer from 0 to 3. In the present invention, it is preferable that n is 0 in the synthetic phase.

[0079] In addition, the above L may have substituents. Examples of substituents include groups similar to the substituents that the above-mentioned X may have, and these substituents may also have substituents.

[0080] In the present invention, specific examples of the linkage structure unit represented by the general formula (2) described above are shown in FIGS. 1 to 4 as structure units 1 to 38. In addition, in the formulas shown in FIGS. 1 to 4, dashed lines indicate bonding loss to adjacent structure units, and solid lines with free ends extending from the ring indicate that a methyl group is substituted. Although preferred specific examples of linkage structure units have been shown, the linkage structure units used in the present invention are not limited to these structure units.

[0081] High molecular weight compounds

[0082] The high molecular weight compound of the present invention, comprising a repeating unit represented by general formula (3) and a triarylamine structural unit represented by general formula (1) and a linking structural unit represented by general formula (2), as previously explained, has excellent characteristics such as hole injection characteristics, hole mobility, electron blocking ability, thin film stability, and heat resistance. However, in order to further enhance these characteristics and also secure film formation properties, the weight average molecular weight in polystyrene equivalent measured by GPC, for example, is preferably in the range of 10,000 or more and less than 1,000,000, more preferably 10,000 or more and less than 500,000, and even more preferably 10,000 or more and less than 200,000.

[0083] In the high molecular weight compound of the present invention, when the structural unit represented by general formula (1) is represented as I and the linking structural unit represented by general formula (2) is represented as II, it is preferable to include structural unit I and structural unit II in an amount of 50 mol% each, and a binary copolymer containing structural units I and II to satisfy these conditions is most suitable for forming an organic layer of an organic EL device.

[0084] The high molecular weight compounds of the present invention are synthesized by chaining each structural unit by forming CC bonds or CN bonds, respectively, through a Suzuki polymerization reaction or a Hartwig-Buchwald polymerization reaction. Specifically, the high molecular weight compounds of the present invention can be synthesized by preparing a unit compound having each structural unit, appropriately esterifying or halogenating this unit compound with boric acid, and performing a polycondensation reaction using a suitable catalyst.

[0085] For example, as a compound for introducing the structural unit of general formula (1), a triarylamine derivative represented by the following general formula (1a) can be used.

[0086]

[0087] In the formula, Q is a hydrogen atom, a halogen atom, or a boric acid ester group, and R1, R2, and L are all the same as defined in general formula (1).

[0088] That is, in the above general formula (1a), when Q is a hydrogen atom, it is a unit compound for introducing the structural unit of general formula (1), and when Q is a halogen atom or a boric acid ester group, it is a halide or boric acid ester used to synthesize the polymer, respectively. The above halogen atom is preferably Br.

[0089] For example, a copolymer containing 50 mol% of structural unit I represented by general formula (1) and 50 mol% of structural unit II represented by general formula (2) is represented by general formula (4) shown below.

[0090]

[0091] These high molecular weight compounds can be synthesized by the polycondensation reaction of a boric acid esterify and a halide, but it is necessary that the intermediate for introducing structural unit I is a boric acid esterify and the intermediate for introducing structural unit II is a halide, or that the intermediate for introducing structural unit I is a halide and the intermediate for introducing structural unit II is a boric acid esterify. That is, the molar ratio of the halide and the boric acid esterify must be equal.

[0092] The high molecular weight compound of the present invention described above can be dissolved in an aromatic organic solvent such as benzene, toluene, xylene, or anisole to prepare a coating solution, and by coating the coating solution onto a predetermined substrate and heating and drying it, a thin film with excellent properties such as hole injection, hole transport, and electron blocking can be formed. Such a thin film also has good heat resistance and, furthermore, good adhesion to other layers.

[0093] The above high molecular weight compound can be used as a constituent material for the hole injection layer and / or hole transport layer of an organic EL device. Compared to those formed with conventional materials, the hole injection layer or hole transport layer formed by such high molecular weight compound has high hole injection capability, high mobility, high electron blocking capability, can confine excitons generated within the light-emitting layer, and improves the probability of recombination between holes and electrons, thereby enabling high luminous efficiency and lowering the driving voltage, which can realize the advantages of improved durability of the organic EL device.

[0094] In addition, the high molecular weight compound of the present invention having the electrical characteristics as described above has a wider gap than conventional materials and is effective for confining excitons, so it can naturally be suitablely used in electron blocking layers or light-emitting layers.

[0095] Organic EL Device

[0096] An organic EL device having an organic layer formed using the high molecular weight compound of the present invention described above has a structure, for example, as shown in FIG. 5. That is, on a glass substrate (1) (which may be a transparent substrate such as a transparent resin substrate), a transparent anode (2), a hole injection layer (3), a hole transport layer (4), a light-emitting layer (5), an electron transport layer (6), and a cathode (7) are provided.

[0097] Of course, the organic EL device to which the high molecular weight compound of the present invention is applied is not limited to the above layer structure, and a hole blocking layer may be provided between the light-emitting layer (5) and the electron transport layer (6), an electron blocking layer may be provided between the hole transport layer (4) and the light-emitting layer (5), and furthermore, an electron injection layer may be provided between the cathode (7) and the electron transport layer (6). In addition, several layers may be omitted. For example, a simple layer structure may be provided on a substrate (1) with an anode (2), a hole transport layer (4), a light-emitting layer (5), an electron transport layer (6), and a cathode (7). In addition, it is also possible to have a two-layer structure in which layers having the same function are stacked.

[0098] The high molecular weight compound of the present invention is suitably used as a material for forming an organic layer (e.g., a hole injection layer (3), a hole transport layer (4), a light-emitting layer (5), or an electron blocking layer) provided between the anode (2) and the cathode (7), utilizing its characteristics such as hole injection or hole transport.

[0099] In the above organic EL device, the transparent anode (2) may be formed from a known electrode material, or it may be formed by depositing an electrode material with a large work function, such as ITO or gold, on a substrate (1) (a transparent substrate such as a glass substrate).

[0100] In addition, the hole injection layer (3) provided on the transparent anode (2) can be formed using a coating solution in which a high molecular weight compound of the present invention is dissolved in an aromatic organic solvent such as toluene, xylene, or anisole. That is, the hole injection layer (3) can be formed by coating the transparent anode (2) with this coating solution by spin coating, inkjet, etc.

[0101] In addition, in an organic EL device having an organic layer formed using the high molecular weight compound of the present invention, the hole injection layer (3) may be formed using a conventionally known material, such as the following material, without using the high molecular weight compound of the present invention.

[0102] Porphyrin compounds represented by copper phthalocyanine;

[0103] Starburst-type triphenylamine derivative;

[0104] Arylamines having a structure connected by divalent groups that do not contain single bonds or heteroatoms (e.g., triphenylamine trimers and tetramers);

[0105] Acceptor heterocyclic compounds such as hexacyanoazatriphenylene;

[0106] Coating-type polymer materials, e.g., poly(3,4-ethylenedioxythiophene) (PEDOT), poly(styrene sulfonate) (PSS), etc.

[0107] The formation of a layer (thin film) using such materials can be carried out by deposition, spin coating, inkjet coating, etc. The same applies to other layers, and depending on the type of film-forming material, film formation is carried out by deposition or coating methods.

[0108] The hole transport layer (4) provided on the hole injection layer (3) can also be formed by spin coating or inkjet coating using a high molecular weight compound of the present invention, just like the hole injection layer (3).

[0109] In addition, in an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, a hole transport layer (4) may be formed using a conventionally known hole transport material. Representative examples of such hole transport materials are as follows.

[0110] Benzidine derivatives, for example

[0111] N,N'-Diphenyl-N,N'-Di(m-Tolyl)Benzidine (hereinafter abbreviated as TPD);

[0112] N,N'-Diphenyl-N,N'-Di(α-Naphthyl)Benzidine (hereinafter abbreviated as NPD);

[0113] N,N,N',N'-tetrabiphenylbenzidine;

[0114] Amine derivatives, for example

[0115] 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane (hereinafter abbreviated as TAPC);

[0116] Various triphenylamine trimers and tetramers;

[0117] Coating-type polymer materials, etc., also used as hole injection layers.

[0118] The above-described hole transport layer compounds may include the high molecular weight compounds of the present invention and may be formed individually, or two or more may be mixed and formed. In addition, a plurality of layers may be formed using one or more of the above compounds, and a multilayer film in which such layers are stacked may be used as a hole transport layer.

[0119] In addition, in an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, the hole injection layer (3) and the hole transport layer (4) may be combined into a layer, and such hole injection and transport layers may be formed by coating using a polymer material such as PEDOT.

[0120] In addition, regarding the hole transport layer (4) (and the hole injection layer (3) as well), the material normally used for the layer may also be P-doped with trisbromophenylamine hexachlorantimony or radialene derivatives (e.g., see WO2014 / 009310). In addition, the hole transport layer (4) (or hole injection layer (3)) may be formed using a polymer compound having a TPD basic framework.

[0121] In addition, an electron blocking layer (which can be provided between the hole transport layer (4) and the light-emitting layer (5)) can also be formed by spin coating or inkjet coating using the high molecular weight compound of the present invention.

[0122] In addition, in an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, the electron blocking layer may be formed using a known electron blocking compound having an electron blocking action, such as a carbazole derivative or a compound having a triphenylsilyl group and a triarylamine structure. Specific examples of carbazole derivatives and compounds having a triarylamine structure are as follows.

[0123] Examples of carbazole derivatives

[0124] 4,4',4''-tri(N-carbazolyl)triphenylamine (hereinafter abbreviated as TCTA);

[0125] 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene;

[0126] 1,3-bis(carbazole-9-yl)benzene (hereinafter abbreviated as mCP);

[0127] 2,2-bis[4-(carbazole-9-yl)phenyl]adamantan (hereinafter abbreviated as Ad-Cz)

[0128] Examples of compounds having a triarylamine structure

[0129] 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene

[0130] The electron blocking layer may also include the high molecular weight compound of the present invention, and may be formed individually, or may be formed by mixing two or more types. In addition, a plurality of layers may be formed using one or more types of the above compounds, and a multilayer film in which such layers are stacked may be used as the electron blocking layer.

[0131] In an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, the light-emitting layer (5) can be formed using a light-emitting material such as a metal complex of a quinolinol derivative including Alq3, as well as various metal complexes such as zinc, beryllium, and aluminum, anthracene derivatives, bisstyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, and polyparaphenylenevinylene derivatives.

[0132] Additionally, the light-emitting layer (5) may be composed of a host material and a dopant material. In this case, as the host material, in addition to the light-emitting material, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc. may be used, and the high molecular weight compound of the present invention described above may also be used. As the dopant material, quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, etc. may be used.

[0133] This light-emitting layer (5) may also be composed of a single layer using one or more types of light-emitting materials, or a multilayer structure in which multiple layers are stacked.

[0134] In addition, a emitting layer (5) may be formed using a phosphorescent emitting material as the emitting material. As the phosphorescent emitting material, a phosphorescent emitting material of a metal complex such as iridium or platinum may be used. For example, a green phosphorescent emitting material such as Ir(ppy)3, a blue phosphorescent emitting material such as FIrpic or FIr6, and a red phosphorescent emitting material such as Btp2Ir(acac) may be used, and these phosphorescent emitting materials are used by doping a host material capable of hole injection and transport or a host material capable of electron transport.

[0135] In addition, to avoid concentration quenching, it is preferable to dope the host material with a phosphorescent light-emitting material by co-deposition in the range of 1 to 30 weight percent with respect to the entire light-emitting layer.

[0136] In addition, it is also possible to use materials emitting delayed fluorescence, such as CDCB derivatives like PIC-TRZ, CC2TA, PXZ-TRZ, and 4CzIPN, as luminescent materials (see Appl. Phys. Let., 98, 083302(2011)).

[0137] By supporting a high molecular weight compound of the present invention with a fluorescent emitter, a phosphorescent emitter, or a material that emits delayed fluorescence called a dopant to form a light-emitting layer (5), an organic EL device with reduced driving voltage and improved light-emitting efficiency can be realized.

[0138] In an organic EL device having an organic layer formed using the high molecular weight compound of the present invention, the high molecular weight compound of the present invention may be used as a host material for hole injection and transport. In addition, carbazole derivatives such as 4,4'-di(N-carbazolyl)biphenyl (hereinafter abbreviated as CBP), TCTA, and mCP may also be used.

[0139] In addition, in an organic EL device having an organic layer formed using the high molecular weight compound of the present invention, p-bis(triphenylsilyl)benzene (hereinafter abbreviated as UGH2) or 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (hereinafter abbreviated as TPBI) can be used as the electron transport host material.

[0140] In an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, a hole blocking layer (not shown in the drawing) provided between the light-emitting layer (5) and the electron transport layer (6) can be formed using a compound that has a known hole blocking effect. Examples of known compounds having such a hole blocking effect include the following.

[0141] Phenanthroline derivatives such as vasocuproin (hereinafter abbreviated as BCP);

[0142] A metal complex of a quinolinol derivative such as aluminum(III)bis(2-methyl-8-quinolinate)-4-phenylphenolate (hereinafter abbreviated as BAlq);

[0143] Various rare earth complexes;

[0144] Triazole derivatives;

[0145] Triazine derivatives;

[0146] Oxadiazole derivatives, etc.

[0147] These materials can also be used to form the electron transport layer (6) described below, and furthermore, can be used as a hole blocking layer and an electron transport layer.

[0148] These hole-blocking layers can also be formed as a single layer or a multilayer stacked structure, and each layer is formed using one or more of the aforementioned hole-blocking compounds.

[0149] In an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, the electron transport layer (6) is formed using a metal complex of a quinolinol derivative, such as Alq3 and BAlq, in addition to a metal complex of a compound with known electron transport properties, for example, Alq3 and BAlq, as well as various metal complexes, pyridine derivatives, pyrimidine derivatives, triazole derivatives, triazine derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silol derivatives, benzimidazole derivatives, etc.

[0150] This electron transport layer (6) can also be a single layer or a multilayer stacked structure, and each layer is formed using one or more of the electron transport compounds described above.

[0151] In addition, in an organic EL device having an organic layer formed using a high molecular weight compound of the present invention, an electron injection layer (not shown in the drawing) provided as needed can also be formed using a known material, such as an alkali metal salt such as lithium fluoride or cesium fluoride, an alkaline earth metal salt such as magnesium fluoride, a metal oxide such as aluminum oxide, or an organic metal complex such as lithium quinoline.

[0152] As the cathode (7) of an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, an electrode material with a low work function such as aluminum, or an alloy with a lower work function such as magnesium alloy, magnesium indium alloy, or aluminum magnesium alloy can be used as the electrode material.

[0153] As described above, by using the high molecular weight compound of the present invention to form at least one of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron blocking layer, an organic EL device is obtained that has high luminous efficiency and power efficiency, a low practical driving voltage, a low light emission onset voltage, and excellent durability. In particular, this organic EL device can have high luminous efficiency, a reduced driving voltage, improved current resistance, and an improved maximum luminous brightness.

[0154] Examples

[0155] The present invention will be explained below by the following experimental examples.

[0156] In addition, in the following description, the structural unit represented by the general formula (1) of the high molecular weight compound of the present invention is referred to as “structural unit I,” and the connecting structural unit represented by the general formula (2) is referred to as “structural unit II.”

[0157] The synthesized compounds were purified by column chromatography and solvent-based purification. The compounds were identified by NMR analysis.

[0158] Synthesis of Intermediate 1

[0159] In order to prepare the high molecular weight compound of the present invention, intermediate 1 for introducing structural unit I was synthesized.

[0160]

[0161] The following components were added to a nitrogen-substituted reaction vessel, and nitrogen gas was passed through for 30 minutes.

[0162] N,N-Bis(3-bromophenyl)-9,9-dioctyl-9H-fluorene-2-amine: 43.4g

[0163] Bis(pinacolato)diborone: 32.3g

[0164] Potassium acetate: 17.9g

[0165] 1,4-Dioxane: 220ml

[0166] Next, 1.0 g of the dichloromethane adduct of {1,1'-bis(diphenylphosphino)ferrocene}palladium(II) dichloride was added and heated, and stirred at 100°C for 13 hours.

[0167] After cooling to room temperature, water and toluene were added, and the organic layer was collected by performing a separatory operation and washed three times with saturated saline solution. After dehydrating this organic layer with anhydrous sodium sulfate, a prepared product was obtained by concentrating it under reduced pressure. The prepared product was purified by column chromatography (ethyl acetate / n-hexane = 1 / 20) to obtain 22.9 g (yield 45%) of the white powder of intermediate 1.

[0168] <Example 1>

[0169] (Synthesis of high molecular weight compound A)

[0170] The following components were added to a nitrogen-substituted reaction vessel, and nitrogen gas was passed through for 30 minutes.

[0171] N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-9,9-dioctyl-9H-fluorene-2-amine: 5.6g

[0172] 1,3-Dibromobenzene: 1.6g

[0173] Tripotassium phosphate: 7.7g

[0174] Toluene: 9ml

[0175] Water: 5ml

[0176] 1,4-Dioxane: 27ml

[0177] Next, 1.6 mg of palladium acetate (II) and 12.9 mg of tri-o-tolylphosphine were added and heated, and stirred at 85°C for 11 hours. Afterward, 19 mg of phenylboronic acid was added and stirred for 1 hour, followed by the addition of 271 mg of bromobenzene and stirring for 1 hour. 50 ml of toluene and 50 ml of a 5 wt% aqueous solution of N,N-diethyldithiocarbamate were added and heated, and stirred under reflux for 2 hours. After cooling to room temperature, the organic layer was collected by separating the liquids and washed three times with saturated saline solution. The organic layer was dehydrated with anhydrous magnesium sulfate, and the crude polymer was obtained by concentrating under reduced pressure. The crude polymer was dissolved in toluene, silica gel was added for adsorption purification, and the silica gel was removed by filtration. The obtained filtrate was concentrated under reduced pressure, 100 ml of toluene was added to the dried solid to dissolve it, and the mixture was added dropwise to 300 ml of n-hexane. The resulting precipitate was filtered and removed. This operation was repeated three times, and by drying, 3.2 g (yield 70%) of high molecular weight compound A was obtained.

[0178] The average molecular weight and dispersion of high molecular weight compound A, measured by GPC, were as follows.

[0179] Number average molecular weight Mn (polystyrene equivalent): 56,000

[0180] Weight-average molecular weight Mw (polystyrene equivalent): 89,000

[0181] Dispersion (Mw / Mn): 1.6

[0182] In addition, NMR measurements were performed on high molecular weight compound A.1 The H-NMR measurement results are shown in Fig. 6. The structure of high molecular weight compound A was as follows.

[0183]

[0184] As can be understood from the above structural formula, this high molecular weight compound A contained 50 mol% of structural unit I represented by general formula (1) and 50 mol% of structural unit II represented by general formula (2).

[0185] <Example 2>

[0186] (Synthesis of high molecular weight compound B)

[0187] The following components were added to a nitrogen-substituted reaction vessel, and nitrogen gas was passed through for 30 minutes.

[0188] Intermediate 1: 6.6g

[0189] 1,3-Dibromobenzene: 1.9g

[0190] Tripotassium phosphate: 9.1g

[0191] Toluene: 12ml

[0192] Water: 7ml

[0193] 1,4-Dioxane: 36ml

[0194] Next, 1.9 mg of palladium acetate (II) and 15.1 mg of tri-o-tolylphosphine were added and heated, and stirred at 85°C for 11.5 hours. Afterward, 23 mg of phenylboronic acid was added and stirred for 1 hour, followed by the addition of 319 mg of bromobenzene and stirring for 1 hour. 50 ml of toluene and 50 ml of a 5 wt% aqueous solution of N,N-diethyldithiocarbamate were added and heated, and stirred under reflux for 2 hours. After cooling to room temperature, the organic layer was collected by separating the liquids and washed three times with saturated saline solution. The organic layer was dehydrated with anhydrous sodium sulfate, and the crude polymer was obtained by concentrating under reduced pressure. The crude polymer was dissolved in toluene, silica gel was added for adsorption purification, and the silica gel was removed by filtration. The obtained filtrate was concentrated under reduced pressure, 30 ml of toluene was added to the dried solid to dissolve it, and the mixture was added dropwise to 400 ml of n-hexane. The resulting precipitate was filtered and removed. This operation was repeated one more time, and by drying, 1.6 g (yield 30%) of high molecular weight compound B was obtained.

[0195] The average molecular weight and dispersion of polymer compound B measured by GPC were as follows.

[0196] Number average molecular weight Mn (polystyrene equivalent): 38,000

[0197] Weight-average molecular weight Mw (polystyrene equivalent): 50,000

[0198] Dispersion (Mw / Mn): 1.3

[0199] In addition, NMR measurements were performed on high molecular weight compound B. 1 The H-NMR measurement results are shown in Fig. 7. The structure of the high molecular weight compound B was as follows.

[0200]

[0201] As can be understood from the above structural formula, this high molecular weight compound B contained 50 mol% of structural unit I represented by general formula (1) and 50 mol% of structural unit II represented by general formula (2).

[0202] <Example 3>

[0203] (Synthesis of high molecular weight compound C)

[0204] The following components were added to a nitrogen-substituted reaction vessel, and nitrogen gas was passed through for 30 minutes.

[0205] N,N-Bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-9,9-dioctyl-9H-fluorene-2-amine: 5g

[0206] 9-(3,5-Dibromophenyl)-3,6-Diphenyl-9H-Carbazole: 1.6g

[0207] Tripotassium phosphate: 3.4g

[0208] Toluene: 7ml

[0209] Water: 4ml

[0210] 1,4-Dioxane: 21ml

[0211] Next, 1.4 mg of palladium acetate (II) and 11.5 mg of tri-o-tolylphosphine were added and heated, and stirred at 85°C for 12 hours. Afterward, 17 mg of phenylboronic acid was added and stirred for 1 hour, followed by the addition of 242 mg of bromobenzene and stirring for 1 hour. 50 ml of toluene and 50 ml of a 5 wt% aqueous solution of N,N-diethyldithiocarbamate were added and heated, and stirred under reflux for 2 hours. After cooling to room temperature, the organic layer was collected by separating the liquids and washed three times with saturated saline solution. The organic layer was dehydrated with anhydrous sodium sulfate, and the crude polymer was obtained by concentrating under reduced pressure. The crude polymer was dissolved in toluene, silica gel was added for adsorption purification, and the silica gel was removed by filtration. The obtained filtrate was concentrated under reduced pressure, 100 ml of toluene was added to the dried solid to dissolve it, and the mixture was added dropwise to 300 ml of n-hexane. The resulting precipitate was filtered and removed. This operation was repeated three times, and by drying, 1.8 g (yield 30%) of high molecular weight compound C was obtained.

[0212] The average molecular weight and dispersion of high molecular weight compound C, measured by GPC, were as follows.

[0213] Number average molecular weight Mn (polystyrene equivalent): 45,000

[0214] Weight-average molecular weight Mw (polystyrene equivalent): 73,000

[0215] Dispersion (Mw / Mn): 1.6

[0216] In addition, NMR measurements were performed on high molecular weight compound C. 1 The H-NMR measurement results are shown in Fig. 8. The structure of the high molecular weight compound C was as follows.

[0217]

[0218] As can be understood from the above structural formula, this high molecular weight compound C contained 50 mol% of structural unit I represented by general formula (1) and 50 mol% of structural unit II represented by general formula (2).

[0219] <Example 4>

[0220] (Measurement of work function)

[0221] Using high molecular weight compounds A, B, and C synthesized in Examples 1, 2, and 3, a coating film with a thickness of 80 nm was fabricated on an ITO substrate, and the work function was measured using an ionization potential measuring device (Type PYS-202 manufactured by Sumitomo Motors Corporation). The results were as follows.

[0222]

[0223] It can be seen that the high molecular weight compounds A, B, and C of the present invention exhibit suitable energy levels and have good hole transport capabilities compared to the work function of 5.4 eV of general hole transport materials such as NPD and TPD.

[0224] <Example 5>

[0225] (Fabrication and Evaluation of Organic EL Devices)

[0226] An organic EL device with a layered structure as shown in Fig. 5 was fabricated by the following method.

[0227] After cleaning a glass substrate (1) on which an ITO film with a thickness of 50 nm was deposited with an organic solvent, the surface of the ITO was cleaned by UV / ozone treatment. To cover the transparent anode (2) (ITO) provided on the glass substrate (1), a PEDOT / PSS (manufactured by HERAEUS) film with a thickness of 50 nm was deposited by spin coating, and a hole injection layer (3) was formed by drying on a hot plate at 200°C for 10 minutes.

[0228] A coating solution was prepared by dissolving the high molecular weight compound A obtained in Example 1 in toluene at 0.6 wt%. A substrate having a hole injection layer (3) formed as described above was transferred into a glove box replaced with dry nitrogen, and a coating layer with a thickness of 25 nm was formed on the hole injection layer (3) by spin coating using the coating solution, and a hole transport layer (4) was formed by drying on a hot plate at 220°C for 30 minutes.

[0229] As described above, the substrate having the hole transport layer (4) formed thereon was placed in a vacuum deposition machine and the pressure was reduced to 0.001 Pa or less. On the hole transport layer (4), a light-emitting layer (5) with a film thickness of 34 nm was formed by dual deposition of a blue light-emitting material (EMD-1) and a host material (EMH-1) having the following structural formula. In addition, in the dual deposition, the deposition rate ratio was set to EMD-1:EMH-1 = 4:96.

[0230]

[0231] As electron transport materials, compounds with the following structural formulas, ETM-1 and ETM-2, were prepared.

[0232]

[0233] On the light-emitting layer (5) formed above, an electron transport layer (6) with a film thickness of 20 nm was formed by binary deposition using the electron transport materials ETM-1 and ETM-2. In addition, in the binary deposition, the deposition rate ratio was set to ETM-1:ETM-2=50:50.

[0234] Finally, aluminum was deposited to a film thickness of 100 nm to form a cathode (7).

[0235] In this way, a glass substrate having a transparent anode (2), a hole injection layer (3), a hole transport layer (4), a light-emitting layer (5), an electron transport layer (6), and a cathode (7) formed thereon was moved into a glove box filled with dry nitrogen, and another glass substrate for sealing was bonded using a UV-curing resin to form an organic EL device. Characteristic measurements were performed on the fabricated organic EL device at room temperature in the atmosphere. In addition, the light emission characteristics were measured when a DC voltage was applied to the fabricated organic EL device. The above measurement results are shown in Table 2.

[0236] <Example 6>

[0237] An organic EL device was fabricated in exactly the same manner as in Example 5, except that a hole transport layer (4) was formed using a coating solution prepared by dissolving the compound of Example 2 (high molecular weight compound B) in toluene at 0.6 wt% instead of high molecular weight compound A. Characteristic measurements were performed on the fabricated organic EL device in the atmosphere at room temperature. The measurement results of the luminescence characteristics when a DC voltage was applied to the fabricated organic EL device are combined and shown in Table 2.

[0238] <Example 7>

[0239] An organic EL device was fabricated in exactly the same manner as in Example 5, except that a hole transport layer (4) was formed using a coating solution prepared by dissolving the compound of Example 3 (high molecular weight compound C) in toluene at 0.6 wt% instead of high molecular weight compound A. Characteristic measurements were performed on the fabricated organic EL device in the atmosphere at room temperature. The measurement results of the luminescence characteristics when a DC voltage was applied to the fabricated organic EL device are combined and shown in Table 2.

[0240] <Comparative Example 1>

[0241] An organic EL device was fabricated in exactly the same manner as in Example 5, except that a hole transport layer (4) was formed using a coating solution prepared by dissolving the following TFB (hole transport polymer) in toluene at 0.6 wt% instead of high molecular weight compound A.

[0242]

[0243] The TFB (hole transport polymer) is poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine] (American Dye Source, Hole Transport Polymer ADS259BE). Various characteristics of the organic EL device of Comparative Example 1 were evaluated in the same manner as in Example 5, and the results are shown in Table 2.

[0244] In addition, regarding the evaluation of various characteristics, the device lifetime is defined as the luminous brightness at the onset of light emission (initial brightness) of 700 cd / m² 2 When constant current driving was performed, the luminous brightness was 560 cd / m² 2 It was measured as the time until it decayed to (equivalent to 80% when the initial brightness was set to 100%: 80% decay).

[0245]

[0246] As shown in Table 2, both the examples and comparative examples have low practical driving voltages and a current density of 10 mA / cm² 2When a current was applied, the luminous efficiency was 8.65 cd / A for the organic EL device of Example 5, 7.62 cd / A for the organic EL device of Example 6, and 10.34 cd / A for the organic EL device of Example 7, compared to 5.52 cd / A for the organic EL device of Comparative Example 1, showing high efficiency for all. In addition, regarding device lifespan (80% decay), the organic EL device of Example 5 showed an unexpectedly significant improvement in lifespan of 440 hours compared to 5.9 hours for the organic EL device of Comparative Example 1, and the organic EL device of Example 6 showed a lifespan of 9.9 hours and the organic EL device of Example 7 showed a lifespan of 63.9 hours, all showing long lifespans. Industrial applicability

[0247] The high molecular weight compound of the present invention has high hole transport capability and excellent electron blocking capability, and is excellent as a compound for various light-emitting diodes, particularly organic EL devices which are self-luminous devices, and more suitable coating-type organic EL devices. By fabricating coating-type organic EL devices using the said compound, high luminous efficiency and power efficiency can be obtained, and durability can be improved. As a result, it has become possible to expand into a wide range of applications, such as home electronic products and lighting. Explanation of the symbols

[0248] 1: Glass substrate 2: Transparent anode 3: Hole injection layer 4: Precision transport layer 5: Emitting layer 6: Electron transport layer 7: Cathode

Claims

Claim 1 A high molecular weight compound having a weight average molecular weight of 10,000 or more and less than 1,000,000 in polystyrene equivalent, comprising only repeating units represented by the following general formula (3), including a triarylamine structural unit represented by the following general formula (1) and a linking structural unit represented by the following general formula (2). In the formula, R1 each independently represents a deuterium atom; a cyano group; a nitro group; a fluorine atom; a chlorine atom; a bromine atom; an iodine atom; an alkyl group or alkyloxy group having 1 to 8 carbon atoms; a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; or an aryloxy group; R2 each independently represents an alkyl group or alkyloxy group having 1 to 8 carbon atoms; or a cycloalkyl group or cycloalkyloxy group having 5 to 10 carbon atoms; X represents a hydrogen atom, an amino group, a monovalent aryl group or a monovalent heteroaryl group; L represents a divalent phenyl group; n represents an integer from 0 to 3; a represents an integer from 0 to 3; and b represents an integer from 0 to 4. Claim 2 A high molecular weight compound according to claim 1, wherein a and b are 0. Claim 3 A high molecular weight compound according to claim 1, wherein R2 is an alkyl group having 1 to 8 carbon atoms. Claim 4 A high molecular weight compound in which X is a hydrogen atom, in paragraph 1. Claim 5 A high molecular weight compound according to claim 1, wherein X is a diphenylamino group, a phenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothienyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, an indenocarbazolyl group, or an acrridinyl group. Claim 6 A light-emitting diode having a pair of electrodes and at least one organic layer sandwiched between them, wherein the organic layer contains a high molecular weight compound described in any one of claims 1 to 5 as a constituent material. Claim 7 A light-emitting diode in which the organic layer is a hole transport layer, as described in claim 6. Claim 8 In claim 6, the light-emitting diode, wherein the organic layer is an electron blocking layer. Claim 9 A light-emitting diode in which the organic layer is a hole injection layer, as described in claim 6. Claim 10 In claim 6, the light-emitting diode, wherein the organic layer is a light-emitting layer. Claim 11 In paragraph 6, a light-emitting diode, which is an organic electroluminescence device.

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