Organic electroluminescent element and method for manufacturing the same

Abstract

The present invention provides an organic electric field light-emitting element with low driving voltage, high efficiency and high driving stability and a manufacturing method thereof. The organic EL element is an organic electric field light-emitting element having the following characteristics, namely: having one or more light-emitting layers between the anode and the cathode facing each other, at least one light-emitting layer is a light-emitting layer including a vapor-deposited layer containing a first host, a second host and a light-emitting dopant material, the first host is selected from an oligopyridine compound represented by the general formula (1), and the second host is selected from a carbazole compound having two or more carbazole rings, an indolecarbazole compound having an indolecarbazole ring, or a compound having a carbazole ring and an indolecarbazole ring.

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent device (hereinafter referred to as an organic EL device) and a method for producing the same, and more particularly to an organic EL device using an organic electroluminescent device material containing an oligopyridine compound and a method for producing the same. Background Art

[0002] By applying voltage to the organic EL element, holes are injected from the anode into the light-emitting layer, and electrons are injected from the cathode into the light-emitting layer. Then, in the light-emitting layer, the injected holes recombine with the electrons to generate excitons. At this time, according to the statistical law of electron spin, singlet excitons and triplet excitons are generated in a ratio of 1:3. It can be said that the limit of the internal quantum efficiency of the organic EL element using the fluorescent light-emitting type based on the light emission of singlet excitons is 25%. On the other hand, it is known that the internal quantum efficiency of the organic EL element using the phosphorescent light-emitting type based on the light emission of triplet excitons can be increased to 100% when the intersystem crossing (intersystem crossing) is efficiently performed from the singlet excitons.

[0003] However, regarding phosphorescent organic EL elements, extending their lifespan has become a technical challenge.

[0004] Recently, highly efficient organic EL elements utilizing delayed fluorescence are being developed. For example, Patent Document 1 discloses an organic EL element utilizing a triplet-triplet fusion (TTF) mechanism, which is one of the mechanisms of delayed fluorescence. The TTF mechanism utilizes the phenomenon of generating singlet excitons by the collision of two triplet excitons, and it is believed that the internal quantum efficiency can be increased to 40% in theory. However, compared with phosphorescent organic EL elements, the efficiency is low, and therefore further improvement of the efficiency is required.

[0005] Patent document 2 discloses an organic EL element using a thermally activated delayed fluorescence (TADF) mechanism. The TADF mechanism utilizes the following phenomenon: in a material with a small energy difference between the singlet energy level and the triplet energy level, an inverse intersystem crossing from triplet excitons to singlet excitons occurs; it is believed that the internal quantum efficiency can be increased to 100% in theory. However, as with phosphorescent light-emitting elements, further improvement in lifetime characteristics is required.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: WO2010 / 134350A

[0009] Patent Document 2: WO2011 / 070963A

[0010] Patent Document 3: WO2013 / 062075A

[0011] Patent Document 4: US2014 / 0374728A

[0012] Patent Document 5: WO2011 / 136755A

[0013] Patent Document 6: WO2011 / 070963A

[0014] Patent Document 7: JP2006-232813A

[0015] Patent Document 8: KR2014-0028640A

[0016] Patent document 9: CN102503937A

[0017] Patent Documents 3 and 4 disclose the use of a biscarbazole compound as a mixing host.

[0018] Patent Document 5 discloses the use of a host material prepared by premixing a plurality of hosts containing indolocarbazole compounds.

[0019] Patent Document 6 discloses the use of an indolocarbazole compound as a thermally activated delayed fluorescence dopant material.

[0020] Patent Document 7 discloses the use of a bipyridine compound as a host material.

[0021] Patent Document 8 discloses the use of a tripyridine compound as a host material.

[0022] Patent Document 9 discloses the use of a tetraterpene pyridine compound as a host material.

[0023] However, none of them can be said to be sufficient, and further improvements are desired. Summary of the invention

[0024] In order to apply organic EL elements to display elements such as flat panel displays or light sources, it is necessary to improve the luminous efficiency of the elements while fully ensuring the stability during driving. The object of the present invention is to provide an organic EL element with low driving voltage, high efficiency and high driving stability, and a material for an organic electroluminescent element suitable therefor.

[0025] The present inventors have conducted intensive studies and, as a result, have found that an organic EL device having excellent characteristics can be obtained by using a specific oligopyridine compound as a first host, thereby completing the present invention.

[0026] The present invention is an organic EL light-emitting element, which is an organic electric field light-emitting element comprising one or more light-emitting layers between opposing anodes and cathodes, wherein at least one light-emitting layer contains a first main body and a second main body, wherein the first main body is selected from a compound represented by the following general formula (1), and the second main body is selected from a compound represented by the following general formula (2), general formula (3), general formula (4) or general formula (5).

[0027] [Chemistry 1]

[0028]

[0029] Here, L 1 ~L 3 represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a linked aromatic group in which 2 to 10 of these hydrocarbon groups are linked, and R 1 ~R 7 They are independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms. a, b, and c represent the number of repetitions, and a+b≧1. They are independently integers of 0 to 3. p, q, r, s, t, u, and v represent the number of substitutions, and are independently integers of 1 to 3.

[0030] [Chemistry 2]

[0031]

[0032] Here, R 8 With R 9 L independently represents hydrogen, an aromatic hydrocarbon group having 6 to 14 carbon atoms, or a group in which two aromatic hydrocarbon groups are linked together. 4 , L 5 Each of them independently represents a phenylene group.

[0033] [Chemistry 3]

[0034]

[0035] Here, ring C is a heterocyclic ring represented by formula (3a), and ring C is condensed with an adjacent ring at any position, and R 10 ~R 12 are independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms, and L 6represents a single bond, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aromatic heterocyclic group having 3 to 12 carbon atoms, or a linked aromatic group in which 2 to 10 of these groups are linked, Ar 1 It is an aromatic hydrocarbon group having 6 to 10 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms. x, y, and z each independently represent an integer of 0 to 3.

[0036] [Chemistry 4]

[0037]

[0038] Here, L 7 It is an m-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, an aromatic heterocyclic group having 3 to 16 carbon atoms, or a linked aromatic group in which 2 to 10 aromatic rings of these are linked, but it is not a group containing a carbazole ring. 13 Each of them is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 3 to 11 carbon atoms. m is the number of substitutions, which is an integer from 1 to 3. n is the number of repetitions, which is independently an integer from 1 to 4, and at least one n is an integer from 2 to 4.

[0039] [Chemistry 5]

[0040]

[0041] Here, ring D is a heterocyclic ring represented by formula (5a), and ring D is condensed with an adjacent ring at any position, and R 14 ~R 16 are independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms, L 8 is a single bond, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a linked aromatic group in which 2 to 10 of these are linked, Ar 2 It is an aromatic hydrocarbon group having a carbon number of 6 to 30. i, j, and k each independently represent an integer of 0 to 3.

[0042] Preferred embodiments of the general formula (1), general formula (2), general formula (3), general formula (4) or general formula (5) are shown below.

[0043] The general formula (2) is the following formula (6).

[0044] [Chemistry 6]

[0045]

[0046] Here, R 8 , R 9 , L 4 , L 5 It has the same meaning as the general formula (2).

[0047] The general formula (3) is the following formula (7) or formula (8).

[0048] [Chemistry 7]

[0049]

[0050] Here, ring C, R 10 , R 11 ,Ar 1 , x, and y have the same meanings as in the general formula (3).

[0051] The general formula (4) has at least one bond structure represented by the formula (c1) or the formula (c2).

[0052] [Chemistry 8]

[0053]

[0054] Here, R 13 It has the same meaning as the general formula (4).

[0055] The general formula (1) is any one of the following formulas (9) to (11).

[0056] [Chemistry 9]

[0057]

[0058] Here, L 1 ~L 3 , R 1 ~R 7 , and c, p~v have the same meanings as in the general formula (1).

[0059] Preferred embodiments of the organic electroluminescent element are shown below.

[0060] The ratio of the first body to the total of the first body and the second body is more than 20 wt % and less than 55 wt %.

[0061] The luminescent dopant material is an organic metal complex containing at least one metal selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold, or a thermally activated delayed fluorescence luminescent dopant material.

[0062] A hole blocking layer is provided adjacent to the light-emitting layer, and the hole blocking layer contains a compound represented by the general formula (1).

[0063] In addition, the present invention is a method for manufacturing an organic electroluminescent element, which includes the steps of mixing a first host and a second host to form a premix, and then vapor-depositing a host material containing the premix to form a light-emitting layer.

[0064] In the method for manufacturing the organic electroluminescent element, preferably, the difference in 50% weight loss temperature between the first body and the second body is within 20°C.

[0065] In order to improve the device characteristics, the materials used in the organic layer need to have high durability against charges. In particular, in the light-emitting layer, it is important to suppress the leakage of excitons and charges to the peripheral layer. For the leakage suppression of the charges / excitons, it is effective to improve the deviation of the light-emitting area in the light-emitting layer. For this purpose, it is necessary to control the injection amount of the two charges (electrons / holes) into the light-emitting layer or the two charge transfer amount in the light-emitting layer to a preferred range.

[0066] Here, the oligopyridine compound represented by formula (1) used in the present invention has a structure in which a plurality of pyridine rings are bonded, and two or more carbazole rings are bonded to these. The two-charge injection transport energy of the material used in the organic layer is greatly affected by the energy level of the molecular orbital of the material and the size of the intermolecular interaction. Oligopyridine compounds have high electron injection transport energy, but by introducing carbazole rings, the proximity of oligopyridine sites to each other can be suppressed by their steric hindrance effect. In addition, by changing the substituent species or bonding position of the pyridine ring group, the intermolecular interaction of the molecular orbital that has a large impact on the electron injection transport of the light-emitting layer can be controlled at a high level.

[0067] On the other hand, the carbazole compounds represented by general formula (2) to general formula (5) have particularly high hole injection transport energy, and the hole injection transport property can be controlled at a high level by changing the bonding pattern of the carbazole ring or the type / number of substituents for the skeleton. Therefore, by mixing the oligopyridine compound and the carbazole compound for use, the injection amount of the two charges into the organic layer can be adjusted to a preferred range, so that better device characteristics can be expected. In particular, in the case of a delayed fluorescent EL element or a phosphorescent EL element, since it has a minimum excited triplet energy level that is high enough for the excitation energy generated in the enclosed light-emitting layer, there is no energy outflow from the light-emitting layer, the voltage is low, the efficiency is high, and a long life can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic cross-sectional view showing an example of an organic EL element. DETAILED DESCRIPTION

[0069] The organic EL element of the present invention has a structure in which an anode, an organic layer, and a cathode are stacked on a substrate, and at least one of the organic layers contains the material for an organic electroluminescent element.

[0070] The organic EL element has a plurality of organic layers between an anode and a cathode facing each other, at least one of the plurality of layers is a light-emitting layer, and the light-emitting layer may be a plurality of layers. Furthermore, at least one of the light-emitting layers is a light-emitting layer including a vapor-deposited layer containing a first host, a second host, and a light-emitting dopant material.

[0071] An organic electroluminescent element, wherein the first host contained in the light-emitting layer is selected from the compound represented by the general formula (1), and the second host is selected from the compound represented by the general formula (2), general formula (3), general formula (4) or general formula (5).

[0072] The first host is selected from the oligopyridine compounds represented by the general formula (1).

[0073] In the general formula (1), R 1 ~R 7 The alkylene radicals independently represent hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms. Preferably, the alkylene radicals are an aliphatic hydrocarbon group having 1 to 8 carbon atoms, a phenyl group, or an aromatic heterocyclic group having 3 to 12 carbon atoms. More preferably, the alkylene radicals are an aliphatic hydrocarbon group having 1 to 6 carbon atoms, a phenyl group, or a carbazole ring group.

[0074] In the present specification, an aromatic hydrocarbon group, an aromatic heterocyclic group, and a linked aromatic group formed by linking aromatic rings thereof with a single bond are understood to be unsubstituted unless otherwise specified, and may have a substituent. The same applies to an aliphatic hydrocarbon group.

[0075] Specific examples of the aliphatic hydrocarbon group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc. An alkyl group having 1 to 4 carbon atoms is preferred.

[0076] Specific examples of the aromatic hydrocarbon group or aromatic heterocyclic group include aromatic groups generated by removing one H from benzene, naphthalene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. Preferred examples include aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, or benzothiadiazole. More preferred examples include aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, or oxadiazole.

[0077] L 1 ~L 3 Each of them independently represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a linked aromatic group formed by linking 2 to 10 of these groups. Preferred examples of the aromatic hydrocarbon group include divalent groups formed from benzene and naphthalene. Preferred examples of the linked aromatic group include divalent groups formed from biphenyl and terphenyl.

[0078] a, b, and c represent the number of repetitions, and each independently represents an integer of 0 to 3, preferably an integer of 0 or 1. However, a+b≧1.

[0079] p to v represent the number of substitutions, and each independently represents an integer of 1 to 3, and is preferably an integer of 1 or 2.

[0080] A preferred embodiment of the compound represented by the general formula (1) is a compound represented by any one of the general formulas (9) to (11). In the general formulas (9) to (11), the symbols common to the general formula (1) have the same meanings.

[0081] Specific examples of the compound represented by the general formula (1) are shown below, but the compound is not limited to these exemplified compounds.

[0082] [Chemistry 10]

[0083]

[0084] [Chemistry 11]

[0085]

[0086] [Chemistry 12]

[0087]

[0088] [Chemistry 13]

[0089]

[0090] [Chemistry 14]

[0091]

[0092] The second host is selected from the compounds represented by the general formula (2), the general formula (3), the general formula (4) or the general formula (5).

[0093] The general formula (2) which is the second main body and the formula (6) which is a preferred embodiment thereof are described. In the general formula (2) and the formula (6), the common symbols have the same meaning.

[0094] R 8 With R 9 independently represents hydrogen, an aromatic hydrocarbon group having 6 to 14 carbon atoms, or a linked aromatic group formed by linking two aromatic rings of the aromatic hydrocarbon group. Preferably, it is hydrogen or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and more preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms. A preferred embodiment is that R 8 is hydrogen, or R 8 is hydrogen and R 9 It is the above-mentioned aromatic hydrocarbon group or linked aromatic group.

[0095] R 8 With R 9 Specific examples of aromatic hydrocarbon groups and linked aromatic groups include aromatic hydrocarbons such as benzene, naphthalene, anthracene, phenanthrene, fluorene, biphenyl, or aromatic hydrocarbons such as these aromatic hydrocarbons, or aromatic hydrocarbons or linked aromatic hydrocarbons formed by removing one hydrogen from a compound formed by linking two aromatic rings of these aromatic hydrocarbons. Preferably, aromatic hydrocarbons formed by benzene, naphthalene, anthracene, and phenanthrene, or linked aromatic hydrocarbons formed by linking two aromatic hydrocarbons, are included, and more preferably, aromatic hydrocarbons formed by benzene, naphthalene, phenanthrene, or biphenyl are included. Further preferably, R 8 With R 9 It is phenyl.

[0096] R 8 With R 9 It may be hydrogen, in which case one of them may be the aromatic group or the linked aromatic group. 8 is hydrogen and R 9The aromatic group or linked aromatic group may have a substituent, and a preferred substituent is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.

[0097] L 4 , L 5 is phenylene, and the phenylene may be any one of o-phenylene, m-phenylene and p-phenylene. It is preferably p-phenylene or m-phenylene. And, it is preferably L 4 With L 5 Different. In the above case, R 8 With R 9 When it is hydrogen, it is treated as a phenyl group and distinguished from a phenylene group.

[0098] Specific examples of the compounds represented by the general formula (2) and the general formula (6) are shown below, but the compounds are not limited to these exemplified compounds.

[0099] [Chemistry 15]

[0100]

[0101] [Chemistry 16]

[0102]

[0103] [Chemistry 17]

[0104]

[0105] [Chemistry 18]

[0106]

[0107] [Chemistry 19]

[0108]

[0109] Next, the general formula (3) will be described.

[0110] In the general formula (3), ring C is a heterocyclic ring represented by the formula (3a), and ring C is condensed with an adjacent ring at an arbitrary position.

[0111] R 10 ~R 12 It is independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms. It is preferably an aliphatic hydrocarbon group having 1 to 8 carbon atoms, a phenyl group, or an aromatic heterocyclic group having 3 to 9 carbon atoms. It is more preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, a phenyl group, or an aromatic heterocyclic group having 3 to 6 carbon atoms.

[0112] Specific examples of the aliphatic hydrocarbon group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc. An alkyl group having 1 to 4 carbon atoms is preferred.

[0113] Specific examples of the aromatic hydrocarbon group or aromatic heterocyclic group include aromatic groups generated by removing one H from benzene, naphthalene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. Preferred examples include aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, or benzothiadiazole. More preferred examples include aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, or oxadiazole.

[0114] L 6 Each of the following is independently a single bond, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aromatic heterocyclic group having 3 to 12 carbon atoms, or a linked aromatic group formed by linking 2 to 10 of these groups. Except when these groups are divalent groups, preferred examples of the aromatic hydrocarbon group or aromatic heterocyclic group are the same as R 10 The same for these bases.

[0115] Ar 1 is an aromatic hydrocarbon group having 6 to 10 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms. Except for the case where these groups are divalent groups, preferred examples of the aromatic hydrocarbon group or aromatic heterocyclic group are the same as R 10 The same for these bases.

[0116] f, g, and h each independently represent an integer of 0 to 3.

[0117] The compound represented by general formula (3) is preferably a compound represented by formula (7) or formula (8).

[0118] In formula (7) or formula (8), ring B, R 10 ~R 13 ,Ar 1 , x, and y have the same meanings as in the general formula (3).

[0119] Specific examples of the indolocarbazole compound represented by the general formula (3) are shown below, but the indolocarbazole compound is not limited to these.

[0120] [Chemistry 20]

[0121]

[0122] [Chemistry 21]

[0123]

[0124] [Chemistry 22]

[0125]

[0126] [Chemistry 23]

[0127]

[0128] Next, the general formula (4) will be described.

[0129] In the general formula (4), L 7 It is an aromatic hydrocarbon group having 6 to 30 carbon atoms or an aromatic heterocyclic group having 3 to 30 carbon atoms, or a linked aromatic group in which aromatic rings thereof are linked. The linked aromatic group is a group in which 2 to 10 aromatic rings of an aromatic hydrocarbon group or an aromatic heterocyclic group are linked via a single bond.

[0130] L 7 It is an m-valent group, and the aromatic hydrocarbon group, aromatic heterocyclic group or linked aromatic group may have a substituent.

[0131] Here, L 7 It is not a group containing a carbazole ring.

[0132] Specific examples of the aromatic hydrocarbon group or aromatic heterocyclic group include benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, trindene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, tetraphene, tetracene, pleiadene, picene, perylene, pentaphene, pentacene, tetraphenylene, cholanthrylene, helicene, hexaphene, rubicene, coronene, trinaphthylene, heptaphene, pyranthrene, furan, benzofuran, isobenzofuran, xanthene, oxathrene, dioxane, Benzofuran, peri-xanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxathiin, thionaphthene, isothianaphthene, thiophthene, naphtho[2,3-b]thiophene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazan, indolizine, indole, isoindole, indazole, purine, quinolizine, isoquinoline, imidazole, naphthyridine, phthalazine, benzodiazepine A group formed by removing m H from benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carboline, phenotellurazine, phenoselenazine, phenothiazine, phenoxazine, anthyridine, benzothiazole, benzimidazole, benzoxazole, benzisoxazole, benzisothiazole or aromatic compounds in which multiple aromatic rings of these are linked together.

[0133] Furthermore, in the case of a linked aromatic group, the number of links is preferably 2 to 10, more preferably 2 to 7, and the linked aromatic rings may be the same or different. In the above case, in formula (3), the bonding position to the m carbazole groups is not limited, and may be a ring at the terminal part of the linked aromatic ring or a ring at the central part. Here, the aromatic ring is a general term for an aromatic hydrocarbon ring and an aromatic heterocyclic ring.

[0134] Specific examples of the linked aromatic group include groups generated by removing hydrogen from biphenyl, terphenyl, quaterphenyl, binaphthyl, phenyltriphenylene, phenyldibenzofuran, phenyldibenzothiophene, bisdibenzofuran, bisdibenzothiophene and the like.

[0135] L 7 Preferred specific examples of include groups derived from benzene, naphthalene, anthracene, biphenyl, terphenyl, dibenzofuran, dibenzothiophene, phenyldibenzofuran or phenyldibenzothiophene. More preferred examples include groups derived from benzene, biphenyl or terphenyl.

[0136] m represents an integer of 1 to 3. m is preferably 1 or 2, and more preferably 1.

[0137] n is a repetition number, and each independently represents an integer of 1 to 4. Preferably, n is 1 to 3. However, at least one n is an integer of 2 to 4.

[0138] In the general formula (4), it is preferred that at least one bond structure represented by the formula (c1) or the formula (c2) is present in the formula. It is more preferred that all bond structures between carbazole groups are bond structures represented by the formula (c1) or the formula (c2).

[0139] The sum of n (the total number of carbazolyl groups) is an integer of 2-12, preferably 2-9, and more preferably 2-6.

[0140] In the general formula (4), formula (c1) and formula (c2), R 13 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 3 to 11 carbon atoms. Preferably, it is hydrogen, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 3 to 8 carbon atoms, and more preferably, it is hydrogen, an alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group having 5 to 7 carbon atoms.

[0141] Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl, preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl. The alkyl group may be straight chain or branched.

[0142] Specific examples of the cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and methylcyclohexyl, and preferably include cyclohexyl and methylcyclohexyl.

[0143] Specific examples of the carbazole compound represented by the general formula (4) are shown below, but the invention is not limited to these.

[0144] [Chemistry 24]

[0145]

[0146] [Chemistry 25]

[0147]

[0148] [Chemistry 26]

[0149]

[0150] [Chemistry 27]

[0151]

[0152] [Chemistry 28]

[0153]

[0154] [Chemistry 29]

[0155]

[0156] Next, the general formula (5) will be described.

[0157] In the general formula (5), ring D is a heterocyclic ring represented by the formula (5a), and ring D is condensed with an adjacent ring at an arbitrary position.

[0158] R 14 ~R 16 are independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or an aromatic heterocyclic group having 3 to 12 carbon atoms. 10 ~R 12 In the case of these groups, the preferred ranges are the same.

[0159] L 8 are independently a single bond, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a linked aromatic group in which 2 to 10 of these are linked. These aromatic hydrocarbon groups and L of the general formula (3) 6 In the case of these groups, the preferred ranges are the same.

[0160] Ar 2 is an aromatic hydrocarbon group having 6 to 30 carbon atoms. Examples of aromatic hydrocarbon groups are the same as L in the general formula (4). 7 In the case of these groups, the preferred ranges are the same.

[0161] i, j, and k each independently represent an integer of 0 to 3.

[0162] Specific examples of the indolocarbazole compound represented by the general formula (5) are shown below, but the indolocarbazole compound is not limited to these.

[0163] [Chemistry 30]

[0164]

[0165] By using a first host selected from the compound represented by the general formula (1) and a second host selected from the compound represented by the general formula (2), general formula (3), general formula (4) or general formula (5) as the host material of the light-emitting layer, an excellent organic EL element can be provided.

[0166] The first host and the second host may be used by being evaporated from different evaporation sources, but preferably they are premixed before evaporation to form a premix, and the premix is ​​simultaneously evaporated from one evaporation source to form a light-emitting layer. In the above case, the light-emitting dopant material required for forming the light-emitting layer or other hosts used as needed may be mixed in the premix, but if there is a large difference in the temperature at which the desired vapor pressure is achieved, the evaporation may be performed from another evaporation source.

[0167] Regarding the mixing ratio (weight ratio) of the first body and the second body, the proportion of the first body relative to the total of the first body and the second body can be 20% to 60%, preferably more than 20% and less than 55%, and more preferably 40% to 50%.

[0168] Next, the structure of the organic EL element of the present invention will be described with reference to the drawings, but the structure of the organic EL element of the present invention is not limited thereto.

[0169] Figure 1 It is a cross-sectional view showing a structural example of a general organic EL element used in the present invention, 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light-emitting layer, 6 represents an electron transport layer, and 7 represents a cathode. The organic EL element of the present invention may also have an exciton blocking layer adjacent to the light-emitting layer, and may also have an electron blocking layer between the light-emitting layer and the hole injection layer. The exciton blocking layer may also be inserted into either the anode side or the cathode side of the light-emitting layer, or may be inserted into both sides at the same time. In the organic EL element of the present invention, an anode, a light-emitting layer, and a cathode are provided as necessary layers, but in addition to the necessary layers, a hole injection transport layer and an electron injection transport layer may also be provided, and a hole blocking layer may also be provided between the light-emitting layer and the electron injection transport layer. Furthermore, the hole injection transport layer represents either or both of the hole injection layer and the hole transport layer, and the electron injection transport layer represents either or both of the electron injection layer and the electron transport layer.

[0170] Can also be with Figure 1 The opposite structure is that the cathode 7, the electron transport layer 6, the light-emitting layer 5, the hole transport layer 4, and the anode 2 are sequentially stacked on the substrate 1. At this time, the layers can be added or omitted as needed.

[0171] -Substrate-

[0172] The organic EL element of the present invention is preferably supported on a substrate. The substrate is not particularly limited as long as it is a substrate conventionally used in organic EL elements, and for example, a substrate made of glass, transparent plastic, quartz, etc. can be used.

[0173] -anode-

[0174] As the anode material in the organic EL element, a material containing a metal, alloy, conductive compound or a mixture of these with a large work function (4 eV or more) can be preferably used. As specific examples of such electrode materials, metals such as Au; conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO can be listed. In addition, amorphous materials such as IDIXO (In2O3-ZnO) that can be made into transparent conductive films can also be used. The anode can be formed into a thin film by methods such as evaporation or sputtering, and a pattern of the desired shape can be formed by photolithography, or when the pattern accuracy is not very required (about 100 μm or more), the pattern can be formed through a mask of the desired shape during the evaporation or sputtering of the electrode material. Or when using a coatable substance such as an organic conductive compound, a wet film forming method such as printing or coating can also be used. When taking out light from the anode, it is ideal to make the transmittance greater than 10%, and the sheet resistance of the anode is preferably less than several hundred Ω / □. The film thickness also depends on the material, and is usually selected within the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

[0175] -cathode-

[0176] On the other hand, as a cathode material, a material containing a metal (electron injecting metal) with a small work function (less than 4 eV), an alloy, a conductive compound or a mixture of these can be used. As specific examples of such electrode materials, sodium, sodium-potassium alloys, magnesium, lithium, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, indium, lithium / aluminum mixtures, rare earth metals, etc. can be cited. From the perspective of electron injectability and durability to oxidation, etc., a mixture of an electron injecting metal and a second metal as a metal having a larger work function value than the metal and being stable is suitable, such as a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide mixture, a lithium / aluminum mixture, aluminum, etc. The cathode can be made as follows: these cathode materials are formed into a thin film by methods such as evaporation or sputtering. In addition, as a cathode, the sheet resistance is preferably less than hundreds of Ω / □, and the film thickness is usually selected in the range of 10nm to 5μm, preferably 50nm to 200nm. Furthermore, in order to allow the emitted light to pass through, if either the anode or cathode of the organic EL element is transparent or semi-transparent, then the emission brightness is improved, which is advantageous.

[0177] In addition, after the metal is formed in the cathode with a film thickness of 1nm to 20nm, the conductive transparent material listed in the description of the anode is formed thereon, thereby making a transparent or translucent cathode. By applying this method, an element in which both the anode and the cathode are transparent can be made.

[0178] -Luminous layer-

[0179] The light-emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from the anode and the cathode, respectively, and contains an organic light-emitting dopant material and a host.

[0180] The first body and the second body are used in a body.

[0181] The compound represented by the general formula (1) as the first host may be used alone or in combination of two or more. Similarly, the carbazole compound or indolocarbazole compound represented by the general formulae (2) to (5) as the second host may be used alone or in combination of two or more.

[0182] If necessary, one or more known host materials may be used in combination, and the amount used is 50 wt % or less, preferably 25 wt % or less, based on the total amount of the host materials.

[0183] Other materials may also be used for the body.

[0184] The first main body and the second main body may be deposited from different deposition sources, or may be pre-mixed before deposition to form a pre-mixed mixture, thereby simultaneously depositing the first main body and the second main body from one deposition source.

[0185] When the first host and the second host are premixed and used, in order to produce an organic EL element having good characteristics with good reproducibility, it is desirable that the 50% weight loss temperature (T 50 ) is small. The 50% weight loss temperature refers to the temperature at which the weight is reduced by 50% when the temperature is increased from room temperature to 550°C at a rate of 10°C per minute in a thermogravimetric / differential thermal analysis (TG-DTA) measurement under a nitrogen flow reduced pressure (50 Pa). It is believed that gasification due to evaporation or sublimation occurs most strongly near this temperature.

[0186] The difference in the 50% weight loss temperature between the first body and the second body is preferably within 20° C., more preferably within 15° C. As the premixing method, a known method such as pulverization mixing can be used, and it is ideal to mix as uniformly as possible.

[0187] When a phosphorescent dopant is used as a luminescent dopant material, the phosphorescent dopant may be a phosphorescent dopant containing an organic metal complex, wherein the organic metal complex comprises at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold. Specifically, the iridium complex described in Journal of the American Chemical Society, J. Am. Chem. Soc. 2001, 123, 4304 or Japanese Patent Table 2013-53051 may be suitably used, but is not limited thereto.

[0188] The phosphorescent dopant material may be contained in the light emitting layer in one kind or in two or more kinds. The content of the phosphorescent dopant material is preferably 0.1 wt% to 30 wt%, more preferably 1 wt% to 20 wt%, relative to the host material.

[0189] The phosphorescent dopant material is not particularly limited, and specific examples thereof include the following.

[0190] [Chemistry 31]

[0191]

[0192] [Chemistry 32]

[0193]

[0194] When a fluorescent dopant is used as a luminescent dopant material, the fluorescent dopant is not particularly limited, and examples thereof include benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyrrolidine derivatives, cyclopentadiene derivatives, distyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethyl compounds, metal complexes of 8-hydroxyquinoline derivatives or metal complexes of pyrromethene derivatives, rare earth complexes, various metal complexes represented by transition metal complexes, polymer compounds such as polythiophene, polyphenylene, polyphenylene vinylene, and organic silane derivatives. Preferred examples include condensed aromatic derivatives, styryl derivatives, diketopyrrolopyrrole derivatives, oxazine derivatives, pyrromethene metal complexes, transition metal complexes, or lanthanide complexes, and more preferred examples include naphthalene, pyrene, Triphenylene, benzo[c]phenanthrene, benzo[a]anthracene, pentacene, perylene, fluoranthene, acenaphthenefluoranthene, dibenzo[a,j]anthracene, dibenzo[a,h]anthracene, benzo[a]naphthalene, hexacene, naphtho[2,1-f]isoquinoline, α-naphthophenanthridine, phenanthroxazole, quinolino[6,5-f]quinoline, benzonaphthothiophene, etc. These may have an alkyl group, an aryl group, an aromatic heterocyclic group, or a diarylamino group as a substituent.

[0195] The light-emitting layer may contain only one type of fluorescent dopant material or two or more types of fluorescent dopant material. The content of the fluorescent dopant material is preferably 0.1% to 20%, more preferably 1% to 10%, relative to the host material.

[0196] When a thermally activated delayed fluorescence dopant is used as a luminescent dopant material, the thermally activated delayed fluorescence dopant is not particularly limited, and examples thereof include metal complexes such as tin complexes or copper complexes, or indolecarbazole derivatives described in WO2011 / 070963, cyanobenzene derivatives and carbazole derivatives described in Nature 2012, 492, 234, phenazine derivatives, oxadiazole derivatives, triazole derivatives, sulfone derivatives, phenoxazine derivatives, and acridine derivatives described in Nature Photonics 2014, 8, 326.

[0197] The thermally activated delayed fluorescence dopant material is not particularly limited, and specific examples thereof include the following.

[0198] [Chemistry 33]

[0199]

[0200] The thermally activated delayed fluorescent luminescent dopant material may contain only one kind or two or more kinds in the luminescent layer. In addition, the thermally activated delayed fluorescent luminescent dopant may be mixed with a phosphorescent luminescent dopant or a fluorescent luminescent dopant for use. The content of the thermally activated delayed fluorescent luminescent dopant material is preferably 0.1% to 50% relative to the host material, and more preferably 1% to 30%.

[0201] -Injection layer-

[0202] The so-called injection layer is a layer provided between the electrode and the organic layer in order to reduce the driving voltage or increase the luminous brightness. There are hole injection layers and electron injection layers, and they may also exist between the anode and the light-emitting layer or the hole transport layer, and between the cathode and the light-emitting layer or the electron transport layer. The injection layer can be provided as needed.

[0203] -Hole blocking layer-

[0204] The so-called hole blocking layer, in a broad sense, has the function of an electron transport layer, and includes a hole blocking material that has the function of transporting electrons and has a significantly smaller ability to transport holes. It can increase the probability of recombination between electrons and holes in the light-emitting layer by transporting electrons and blocking holes at the same time.

[0205] For the hole blocking layer, a known hole blocking layer material can be used, and preferably contains a compound represented by the general formula (1).

[0206] -Electron blocking layer-

[0207] The electron blocking layer, in a broad sense, has the function of a hole transporting layer and can increase the probability of recombination between electrons and holes in the light-emitting layer by transporting holes and blocking electrons at the same time.

[0208] As the material of the electron blocking layer, a known electron blocking layer material can be used, and the material of the hole transport layer described below can be used as necessary. The film thickness of the electron blocking layer is preferably 3 nm to 100 nm, more preferably 5 nm to 30 nm.

[0209] - Exciton blocking layer -

[0210] The so-called exciton blocking layer is a layer used to block the excitons generated by the recombination of holes and electrons in the light-emitting layer from diffusing to the charge transport layer. By inserting this layer, the excitons can be efficiently sealed in the light-emitting layer, which can improve the luminous efficiency of the element. The exciton blocking layer can be inserted between two adjacent light-emitting layers in an element with two or more adjacent light-emitting layers.

[0211] As the material of the exciton-blocking layer, a known exciton-blocking layer material can be used, for example, 1,3-dicarbazolylbenzene (mCP) or bis(2-methyl-8-hydroxyquinoline)-4-phenylphenol aluminum (III) (BAlq) can be mentioned.

[0212] -Hole transport layer-

[0213] The hole transport layer includes a hole transport material having the function of transporting holes, and the hole transport layer may be provided as a single layer or multiple layers.

[0214] Hole transport materials are materials having either hole injection or transport, or barrier properties of electrons, and may be either organic or inorganic. In the hole transport layer, any one of the known compounds may be selected and used. The hole transport material may include, for example, porphyrin derivatives, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers, etc., preferably porphyrin derivatives, arylamine derivatives and styrylamine derivatives, more preferably arylamine compounds.

[0215] -Electron transport layer-

[0216] The electron transport layer includes a material having a function of transporting electrons, and the electron transport layer may be provided as a single layer or multiple layers.

[0217] As an electron transport material (also serving as a hole blocking material), it is sufficient to have the function of transmitting the electrons injected from the cathode to the light-emitting layer. For the electron transport layer, any one can be selected from the existing known compounds for use, for example, polycyclic aromatic derivatives such as naphthalene, anthracene, and phenanthroline, tris (8-hydroxyquinoline) aluminum (III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, dioxythiopyran derivatives, carbodiimides, fluorenyl methane derivatives, anthraquinone dimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole derivatives, benzothiazole derivatives, indole and carbazole derivatives, etc. can be listed. Furthermore, it is also possible to use polymer materials that introduce these materials into polymer chains or use these materials as the main chain of polymers.

[0218] Example

[0219] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples and can be implemented in various forms without departing from the gist of the present invention.

[0220] Example 1

[0221] On a glass substrate on which an anode made of ITO with a film thickness of 110 nm was formed, a vacuum deposition method was used at a vacuum degree of 4.0×10 -5 Pa and stack each thin film. First, HAT-CN is formed to a thickness of 25nm on ITO as a hole injection layer, and then NPD is formed to a thickness of 30nm as a hole transport layer. Next, HT-1 is formed to a thickness of 10nm as an electron blocking layer. Next, compound 1-1 as the first main body, compound 2-4 as the second main body, and Ir(ppy)3 as a light-emitting dopant are co-deposited from different evaporation sources to form a light-emitting layer with a thickness of 40nm. At this time, co-evaporation is performed under evaporation conditions in which the concentration of Ir(ppy)3 is 10wt% and the weight ratio of the first main body to the second main body is 30:70. Next, ET-1 is formed to a thickness of 20nm as an electron transport layer. Further, LiF is formed to a thickness of 1nm on the electron transport layer as an electron injection layer. Finally, Al is formed to a thickness of 70nm on the electron injection layer as a cathode to produce an organic EL element.

[0222] Example 1 to Example 88

[0223] In Example 1, an organic EL device was produced in the same manner as in Example 1, except that the compounds shown in Table 1 and Table 2 were used as the first host and the second host.

[0224] Embodiment 89 to Embodiment 96

[0225] The first main body and the second main body are mixed in advance to form a premix, and then co-evaporated from one evaporation source.

[0226] In Example 1, an organic EL device was produced in the same manner as in Example 1 except that a premix obtained by weighing the first host (0.30 g) and the second host (0.70 g) and mixing them in a mortar was used.

[0227] Tables 1 to 4 show the evaluation results of the produced organic EL devices.

[0228] In the table, the brightness, driving voltage and luminous efficiency are based on the driving current of 20mA / cm 2 The value at , is the initial characteristic. LT70 is the time it takes for the initial brightness to decay to 70%, indicating the lifespan characteristic.

[0229] [Table 1]

[0230]

[0231] [Table 2]

[0232]

[0233] [Table 3]

[0234]

[0235] [Table 4]

[0236]

[0237] Comparative Example 1

[0238] An organic EL device was prepared in the same manner as in Example 1 except that Compound 1-1 was used alone as a host. The thickness of the light-emitting layer and the concentration of the light-emitting dopant were the same as those in Example 1.

[0239] Comparative Example 2 to Comparative Example 15

[0240] An organic EL device was prepared in the same manner as in Comparative Example 1 except that the compound shown in Table 5 was used alone as a host.

[0241] Comparative Examples 16 to 24

[0242] In Example 1, an organic EL element is prepared in the same manner as in Example 1 except that Compound A is used as the first host and Compound 2-5, Compound 2-6, Compound 3-24, Compound 3-33, Compound 3-45, Compound 4-3, Compound 4-22, Compound 5-3 or Compound 5-19 is used as the second host.

[0243] Comparative Examples 25 to 33

[0244] In Comparative Examples 16 to 24, organic EL devices were produced in the same manner as in Comparative Examples 16 to 24, except that Compound B was used as the first host.

[0245] Comparative Examples 34 to 42

[0246] In Comparative Examples 16 to 24, organic EL devices were produced in the same manner as in Comparative Examples 16 to 24, except that Compound C was used as the first host.

[0247] Tables 5 and 6 show the evaluation results of the produced organic EL devices.

[0248] [Table 5]

[0249]

[0250] [Table 6]

[0251]

[0252] According to Tables 1 to 4, it can be seen that in Examples 1 to 96, the power efficiency and life characteristics are improved, showing good characteristics.

[0253] Embodiment 97

[0254] On a glass substrate on which an anode made of ITO with a film thickness of 110 nm was formed, a vacuum deposition method was used at a vacuum degree of 4.0×10 -5 Pa and stack each thin film. First, HAT-CN is formed to a thickness of 25nm on ITO as a hole injection layer, and then NPD is formed to a thickness of 45nm as a hole transport layer. Secondly, HT-1 is formed to a thickness of 10nm as an electron blocking layer. Secondly, compound 1-1 as the first main body, compound 2-4 as the second main body, and Ir(piq)2acac as a light-emitting dopant are co-deposited from different evaporation sources to form a light-emitting layer with a thickness of 40nm. At this time, co-evaporation is performed under evaporation conditions in which the concentration of Ir(piq)2acac becomes 6.0wt%. Secondly, ET-1 is formed to a thickness of 37.5nm as an electron transport layer. Then, LiF is formed to a thickness of 1nm on the electron transport layer as an electron injection layer. Finally, Al is formed to a thickness of 70nm on the electron injection layer as a cathode to produce an organic EL element.

[0255] Embodiment 98 to Embodiment 182

[0256] In Example 97, an organic EL device was produced in the same manner as in Example 97, except that the compounds shown in Tables 7 to 9 were used as the first host and the second host.

[0257] The evaluation results of the produced organic EL elements are shown in Tables 7 to 9. Here, LT95 is the time taken for the initial luminance to decay to 95%, and indicates the life characteristics.

[0258] [Table 7]

[0259]

[0260] [Table 8]

[0261]

[0262] [Table 9]

[0263]

[0264] Comparative Example 43

[0265] In Example 97, an organic EL device was prepared in the same manner as in Example 97, except that Compound 1-1 was used alone as a host. The thickness of the light-emitting layer and the concentration of the light-emitting dopant were the same as those in Example 97.

[0266] Comparative Examples 44 to 57

[0267] An organic EL device was prepared in the same manner as in Comparative Example 43, except that the compound shown in Table 10 was used alone as a host.

[0268] Comparative Examples 58 to 66

[0269] In Example 97, compound A is used as the first host, and compound 2-5, compound 2-6, compound 3-24, compound 3-33, compound 3-45, compound 4-3, compound 4-22, compound 5-3 or compound 5-19 is used as the second host. Except for this, an organic EL element is prepared in the same manner as in Example 97.

[0270] Comparative Examples 67 to 75

[0271] In Comparative Examples 58 to 66, organic EL devices were produced in the same manner as in Comparative Examples 58 to 66, except that Compound B was used as the first host.

[0272] Comparative Examples 76 to 84

[0273] In Comparative Examples 58 to 66, organic EL devices were produced in the same manner as in Comparative Examples 58 to 66, except that Compound C was used as the first host.

[0274] The evaluation results of the produced organic EL elements are shown in Tables 10 and 11.

[0275] [Table 10]

[0276]

[0277] [Table 11]

[0278]

[0279] According to Tables 7 to 9, it can be seen that in Examples 97 to 182, the power efficiency and life characteristics are improved, showing good characteristics.

[0280] The compounds used in the Examples are shown below.

[0281] [Chemistry 34]

[0282]

[0283] Industrial Applicability

[0284] The organic EL element of the present invention can be driven at a low voltage and can achieve high efficiency and a long life.

Claims

1. An organic electroluminescent element comprising one or more light-emitting layers between an anode and a cathode facing each other, wherein at least one of the light-emitting layers is a light-emitting layer comprising a vapor-deposited layer containing a first host, a second host and a light-emitting dopant material, The first host is selected from the compounds represented by the following general formula (1), The second host is selected from the compounds represented by the following general formula (2) or general formula (4); Here, L 1 ~L 3 represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a linked aromatic group in which 2 to 10 of these hydrocarbon groups are linked, and R 1 ~R 7 independently hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms; a, b, and c represent the number of repetitions, and are independently integers of 0 to 3, and a+b≧1; p, q, r, s, t, u, and v represent the number of substitutions, and are independently integers of 1 to 3; Here, R 8 With R 9 L independently represents hydrogen, an aromatic hydrocarbon group having 6 to 14 carbon atoms, or a group formed by linking two of the aromatic hydrocarbon groups; 4 , L 5 independently represents phenylene; Here, L 7 is an m-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, an aromatic heterocyclic group having 3 to 16 carbon atoms, or a linked aromatic group in which 2 to 10 aromatic rings of these are linked, but is not a group containing a carbazole ring; R 13 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 3 to 11 carbon atoms; m is the number of substitutions, representing an integer from 1 to 3; n is the number of repetitions, representing an integer from 1 to 4, and at least one n is an integer from 2 to 4.

2. The organic electroluminescent element according to claim 1, characterized in that: The compound represented by the general formula (2) is a compound represented by the following formula (6); Here, R 8 , R 9 , L 4 , L 5 It has the same meaning as the general formula (2).

3. The organic electroluminescent element according to claim 1, characterized in that: The general formula (4) has at least one bond structure represented by the formula (c1) or the formula (c2); Here, R 13 Same meaning as general formula (4); Here, R 13 It has the same meaning as the general formula (4).

4. The organic electroluminescent element according to any one of claims 1 to 3, characterized in that: The compound represented by general formula (1) is a compound represented by any one of formulas (9) to (11); Here, L 1 ~L 3 , R 1 ~R 7 , and c, p~v have the same meanings as in the general formula (1).

5. The organic electroluminescent element according to claim 1, characterized in that: The ratio of the first body to the total of the first body and the second body is more than 20 wt % and less than 55 wt %.

6. The organic electroluminescent element according to claim 1, characterized in that: The light-emitting dopant material is an organic metal complex containing at least one metal selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold.

7. The organic electroluminescent element according to claim 1, characterized in that: The luminescent dopant material is a thermally activated delayed fluorescence luminescent dopant material.

8. The organic electroluminescent element according to claim 1, characterized in that: A hole blocking layer is provided adjacent to the light-emitting layer, and the hole blocking layer contains a compound represented by the general formula (1).

9. A method for manufacturing an organic electroluminescent element, characterized in that: The method comprises the steps of mixing a first host and a second host to prepare a premix, and then evaporating a host material containing the premix to form a light-emitting layer when manufacturing the organic electroluminescent element according to claim 1 .

10. The method for manufacturing an organic electroluminescent element according to claim 9, characterized in that: The difference in 50% weight reduction temperature between the first body and the second body is within 20°C.

Images