Organic electroluminescent element

Abstract

This invention provides a high-efficiency, long-life blue-emitting organic electric field (OLED) light-emitting element. The organic EL element comprises one or more light-emitting layers between opposing anodes and cathodes, and at least one light-emitting layer comprises a first host, a second host, and a luminescent dopant. The first host is a carbazole compound or a bicarbazole compound, the second host is an indolecarbazole compound, and the luminescent dopant is a polycyclic aromatic compound represented by general formula (4) or a polycyclic aromatic compound having the structure of general formula (4) as a partial structure. Here, Y... 4 For B, P, P=O, P=S, Al, Ga, As, Si‑R 4 , or Ge‑R 41 X 4 is O, N‑Ar 4 、S or Se.

Description

Technical Field

[0001] This invention relates to an organic electric field light-emitting element (referred to as an organic EL (electroluminescence) element). Background Technology

[0002] By applying a voltage to an organic EL element, holes are injected into the emissive layer from the anode, and electrons are injected into the emissive layer from the cathode. In the emissive layer, the injected holes and electrons recombine to generate excitons. At this point, according to the statistical law of electron spin, singlet and triplet excitons are generated in a 1:3 ratio. For fluorescent organic EL elements utilizing light emission from singlet excitons, the internal quantum efficiency is considered to be limited to 25%. On the other hand, phosphorescent organic EL elements utilizing light emission from triplet excitons have achieved an internal quantum efficiency of up to 100% when intersystem crossings are efficiently performed from singlet excitons.

[0003] However, extending the lifetime of blue phosphorescent organic EL devices remains a technical challenge.

[0004] Recently, high-efficiency organic EL devices utilizing delayed fluorescence have been developed. For example, Patent Document 1 discloses an organic EL device utilizing a triplet-triplet fusion (TTF) mechanism, one of the mechanisms of delayed fluorescence. The TTF mechanism utilizes the phenomenon of generating singlet excitons through the collision of two triplet excitons, and it is believed that the internal quantum efficiency can be theoretically increased to 40%. However, compared with phosphorescent organic EL devices, the efficiency is low, thus requiring further improvement in efficiency.

[0005] Patent document 2 discloses an organic EL device utilizing a thermally activated delayed fluorescence (TADF) mechanism. The TADF mechanism utilizes the phenomenon that, in materials with a small energy difference between singlet and triplet levels, an inverse intersystem crossing occurs from a triplet exciton to a singlet exciton, theoretically increasing the internal quantum efficiency to 100%. However, similar to phosphorescent luminescent devices, further improvements in lifetime characteristics are required.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: WO2010 / 134350

[0009] Patent Document 2: WO2011 / 070963

[0010] Patent Document 3: WO2017 / 138526

[0011] Patent Document 4: WO2018 / 198844

[0012] Patent Document 5: WO2020 / 040298

[0013] Patent document 3 discloses an organic EL element that uses TADF material, represented by the following polycyclic aromatic compounds, as a luminescent dopant, but does not disclose practical lifetime characteristics.

[0014] [Chemistry 1]

[0015]

[0016] Patent document 4 discloses a phosphorescent organic EL element that uses a mixture of an indolocarbazole compound represented by the following compound and a carbazole compound in a light-emitting layer, but does not disclose an organic EL element that has a light-emitting layer mixed with a polycyclic aromatic compound represented by general formula (4) and exhibits practical lifetime characteristics.

[0017] [Chemistry 2]

[0018]

[0019] Patent document 5 discloses an organic EL element in which boron-based compound (a5), TADF compound (a6), and carbazole compound (a7) are mixed in the light-emitting layer, but does not disclose an organic EL element in which a first body represented by general formula (1) or general formula (2) and a second body represented by general formula (3) are mixed and used in the light-emitting layer and exhibit practical lifetime characteristics.

[0020] [Chemistry 3]

[0021] Summary of the Invention

[0022] In order to apply organic EL elements to display elements or light sources such as flat panel displays, it is necessary to ensure stability during driving while improving the luminous efficiency of the elements. The object of this invention is to provide a practically useful organic EL element with high efficiency and long lifespan.

[0023] The present invention is an organic electric field light-emitting element, which includes one or more light-emitting layers between opposing anodes and cathodes. At least one light-emitting layer of the organic electric field light-emitting element includes a host and a light-emitting dopant. The host includes a first host represented by general formula (1) or general formula (2) and a second host represented by general formula (3). The light-emitting dopant includes a polycyclic aromatic compound represented by general formula (4) or a polycyclic aromatic compound having the structure represented by general formula (4) as part of its structure.

[0024] [Chemistry 4]

[0025]

[0026] Here, Y 1 Indicates O, S or N-Ar 1 .

[0027] Ar 1 Independently refers to an aromatic hydrocarbon group having 6 to 18 carbon atoms, substituted or unsubstituted, an aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these aromatic rings.

[0028] R 1 Independently represents deuterium, aliphatic hydrocarbon group with 1 to 10 carbon atoms, substituted or unsubstituted aromatic hydrocarbon group with 6 to 18 carbon atoms, or substituted or unsubstituted aromatic heterocyclic group with 3 to 17 carbon atoms.

[0029] a independently represents an integer from 0 to 4, and b independently represents an integer from 0 to 3.

[0030] [Chemistry 5]

[0031]

[0032] Here, c is an integer from 0 to 5, d is an integer from 0 to 2, and at least one d is 1 or higher. e is an integer from 0 to 2.

[0033] R 2 It can be independently a cyano group, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 18 carbon atoms, whether substituted or unsubstituted.

[0034] L 2 It is an aromatic hydrocarbon group with 6 to 18 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, substituted or unsubstituted.

[0035] Ar 2It is a hydrogen, cyano, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted), or a linked aromatic group consisting of 2 to 3 of these.

[0036] [Chemistry 6]

[0037]

[0038]

[0039] Here, Z 3 The group represented by formula (3a) containing an indolocarbazole ring, * represents the group with L 3 The bond position,

[0040] Ring A is a heterocyclic ring as represented by equation (3b), and it is condensed at any position with the adjacent ring.

[0041] L 3 and L 31 Each is independently an aromatic hydrocarbon group with 6 to 30 carbon atoms, either substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted.

[0042] Ar 3 and Ar 31 Each of these can be independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these.

[0043] R 3 It is independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted).

[0044] f represents an integer from 1 to 3, g represents an integer from 0 to 3, h independently represents an integer from 0 to 4, i represents an integer from 0 to 2, and j represents an integer from 0 to 3.

[0045] [Chemistry 7]

[0046]

[0047] Here, rings C, D, and E are independently aromatic hydrocarbon rings with 6 to 24 carbon atoms or aromatic heterocycles with 3 to 17 carbon atoms.

[0048] Y 4 For B, P, P=O, P=S, Al, Ga, As, Si-R 4 or Ge-R 41 ,

[0049] X 4 Independent of O, N-Ar 4 S or Se,

[0050] R 4 and R 41 They are, independently, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0051] Ar 4 Independently, it is an aromatic hydrocarbon group with 6 to 18 carbon atoms, either substituted or unsubstituted, an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted, or a linked aromatic group consisting of 2 to 8 of these. N-Ar 4 It can bond with any of the C-ring, D-ring, or E-ring to form a heterocycle containing N.

[0052] R 42 Each of these groups independently represents a cyano group, a deuterium group, a diarylamino group with 12–44 carbon atoms, an arylheteroarylamino group with 12–44 carbon atoms, a diheteroarylamino group with 12–10 carbon atoms, an aromatic hydrocarbon group with 6–18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group with 3–17 carbon atoms (substituted or unsubstituted).

[0053] v represents an integer from 0 to 4, and x represents an integer from 0 to 3.

[0054] C ring, D ring, E ring, R 4 R 41 R 42 and Ar 4 At least one hydrogen atom in the atom may be replaced by a halogen or deuterium.

[0055] As a polycyclic aromatic compound having the structure represented by general formula (4) as a part of its structure, examples include polycyclic aromatic compounds represented by formula (5) below, or polycyclic aromatic compounds containing boron represented by formula (6) below.

[0056] [Chemistry 8]

[0057]

[0058] Here, rings F, G, H, I, and J are each an aromatic hydrocarbon ring with 6 to 24 carbon atoms or an aromatic heterocycle with 3 to 17 carbon atoms. At least one hydrogen atom in rings F, G, H, I, and J can be substituted with a halogen or deuterium.

[0059] X 4 Y 4R 42 x and v have the same meaning as in general formula (4), w represents an integer from 0 to 4, y represents an integer from 0 to 3, and z represents an integer from 0 to 2.

[0060] [Chemistry 9]

[0061]

[0062] Here, X 6 Independently represent N-Ar 6 O or S, at least one X 6 Indicates N-Ar 6 Ar 6 Independently representing an aromatic hydrocarbon group having 6 to 18 carbon atoms, substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these aromatic rings, N-Ar 6 Can be with X 6 The aromatic rings are bonded together to form a heterocycle containing N.

[0063] R 6 Independently representing cyano, deuterium, diarylamino with 12 to 44 carbons, aliphatic hydrocarbon with 1 to 10 carbons, substituted or unsubstituted aromatic hydrocarbon with 6 to 18 carbons, or substituted or unsubstituted aromatic heterocyclic group with 3 to 17 carbons.

[0064] k independently represents integers from 0 to 4, l independently represents integers from 0 to 3, and m represents integers from 0 to 2.

[0065] As the first subject, the first subject represented by general formula (1) is preferred; furthermore, Y in general formula (1) is preferred. 1 For N-Ar 1 As a preferred general formula (1), the following formula (7) can be listed.

[0066] [Chemistry 10]

[0067]

[0068] Here, Ar 1 It has the same meaning as general formula (1).

[0069] In addition, another aspect of the present invention is the organic electric field light-emitting element, wherein the light-emitting layer contains a first body represented by general formula (2) and a second body represented by general formula (3).

[0070] As a preferred general formula (2), the following formula (8) can be listed.

[0071] [Chemistry 11]

[0072]

[0073] Here, n is an integer from 1 to 5, and p is an integer from 0 to 1.

[0074] L 8 It represents a group formed from benzene, dibenzofuran, or dibenzothiophene.

[0075] R 81 It represents hydrogen, or a group formed from benzene, dibenzofuran, or dibenzothiophene.

[0076] The difference (ΔEST) between the excited singlet energy (S1) and the excited triplet energy (T1) of the luminescent dopant is preferably 0.20 eV or less, more preferably 0.10 eV or less.

[0077] The light-emitting layer may contain 99.9 wt% to 90 wt% of a host material relative to 0.10 wt% to 10 wt% of the luminescent dopant, and the host material may contain 10 wt% to 90 wt% of a first host material and 90 wt% to 10 wt% of a second host material.

[0078] In addition, the present invention is an organic EL element, which includes one or more light-emitting layers between opposing anodes and cathodes. At least one light-emitting layer of the organic EL element contains an organic light-emitting material as a light-emitting dopant with a difference (ΔEST) between the excitation singlet energy (S1) and the excitation triplet energy (T1) of less than 0.20 eV, and contains a first host and a second host.

[0079] It is believed that the organic EL element of the present invention contains specific luminescent dopants and a variety of specific host materials in the light-emitting layer, and therefore can become an organic EL element with low driving voltage, high luminous efficiency and long life.

[0080] The main reason for the low driving voltage of the organic EL element of the present invention is assumed to be that the carbazole compound as the first host material has the characteristic of easy hole injection, and the indole-carbazole compound as the second host material has the characteristic of easy electron injection, thereby enabling the injection of holes and electrons at a lower voltage to generate excitons.

[0081] Furthermore, the main reason why the organic EL element of the present invention has high luminous efficiency is that carbazole compounds have the characteristic of easily injecting holes, and indolecarbazole compounds have the characteristic of easily injecting electrons, thereby maintaining the balance of holes and electrons in the light-emitting layer.

[0082] The main reason why the organic EL element of the present invention has a long lifespan is that when a voltage is applied to the organic EL element, holes are preferentially injected into the first host containing a carbazole compound and electrons are preferentially injected into the second host containing an indole-carbazole compound, thereby reducing the electrochemical load on the luminescent dopant. Attached Figure Description

[0083] Figure 1 This is a schematic cross-sectional view showing an example of an organic EL element.

[0084] Explanation of symbols

[0085] 1: Substrate

[0086] 2: Anode

[0087] 3: Hole injection layer

[0088] 4: Hole transport layer

[0089] 5: Emissive layer

[0090] 6: Electron transport layer

[0091] 7: Cathode Detailed Implementation

[0092] The organic EL element of the present invention has one or more light-emitting layers between opposing anodes and cathodes, and at least one light-emitting layer contains a first host, a second host, and a light-emitting dopant.

[0093] The first main component is selected from compounds represented by general formula (1) or general formula (2), and the second main component is selected from compounds represented by general formula (3). The luminescent dopant is selected from polycyclic aromatic compounds represented by general formula (4) or polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure. Polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure are also called partially structured polycyclic aromatic compounds.

[0094] The compounds represented by the general formula (1) or general formula (2) that are used as the first subject in this invention will be described.

[0095] In general formula (1), Y 1 Indicates O, S, or N-Ar 1 Preferably, it represents O or N-Ar. 1 More preferably, it represents N-Ar 1 .

[0096] As a preferred embodiment of general formula (1), general formula (7) can be listed. In general formula (1) and formula (7), the common symbols have the same meaning.

[0097] Ar1 Independently refers to an aromatic hydrocarbon group having 6 to 18 carbon atoms, either substituted or unsubstituted, an aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of 2 to 8 of these aromatic rings. Preferably, it is an aromatic hydrocarbon group having 6 to 12 carbon atoms, either substituted or unsubstituted, or a substituted or unsubstituted linked aromatic group consisting of 2 to 4 of these aromatic rings. More preferably, it is phenyl, biphenyl, or terphenyl.

[0098] As Ar 1 Specific examples of unsubstituted aromatic hydrocarbon groups, aromatic heterocyclic groups, or those linked to aromatic groups include benzene, naphthalene, acenaphthene, acenaphthene, azulene, anthracene, 1,2-benzophenanthrene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, thiophene, isothiazole, thiazole, pyridine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalide. The group is formed by removing one hydrogen atom from compounds consisting of azines, tetrazolium, indole, pyridine, pyrimidine, triazine, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromogenone, dibenzofuran, dibenzothiophene, dibenzoselenophene, carbazole, or compounds formed by linking 2 to 8 of these. Preferably, the group is formed by removing one hydrogen atom from compounds consisting of benzene, naphthalene, acenaphthene, acenaphthene, azulene, or compounds formed by linking 2 to 4 of these. More preferably, the group is formed from benzene, biphenyl, or terphenyl.

[0099] In this specification, a linked aromatic group refers to a group in which aromatic rings of an aromatic hydrocarbon group or an aromatic heterocyclic group are linked by single bonds. These linkages can be linear or branched, and the aromatic rings can be the same or different. In cases equivalent to a linked aromatic group, it differs from a substituted aromatic hydrocarbon group or a substituted aromatic heterocyclic group.

[0100] R 1 Independently represented are deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted). Preferably, it is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 15 carbon atoms (substituted or unsubstituted). More preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 12 carbon atoms (substituted or unsubstituted).

[0101] Furthermore, Ar 1 and R 1 Preferably, the group is not generated from pyridine, pyrimidine, or triazine.

[0102] a represents an integer from 0 to 4, and b represents an integer from 0 to 3. Preferably, a is an integer from 0 to 1, and b is an integer from 0 to 1.

[0103] As R 1 Specific examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms include: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or nonyl. Preferably, the following groups are also included: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl.

[0104] As R 1 Specific examples of the Ar group being an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or an unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, are related to the Ar group. 1 The explanations are the same as those used in the previous section.

[0105] In this specification, the substituted aromatic hydrocarbon group, aromatic heterocyclic group, or linked aromatic group may have substituents. Preferred substituents are deuterium, cyano, triarylsilyl, aliphatic hydrocarbon group with 1 to 10 carbon atoms, or diarylamino with 12 to 44 carbon atoms. Here, when the substituent is an aliphatic hydrocarbon group with 1 to 10 carbon atoms, it can be linear, branched, or cyclic. Furthermore, the number of substituents can be 0 to 5, preferably 0 to 2. When calculating the carbon number of aromatic hydrocarbon groups and aromatic heterocyclic groups with substituents, the carbon number of the substituents is not included. However, it is preferable that the total carbon number, including the carbon number of the substituents, meets the aforementioned range.

[0106] Specific examples of the substituents include: cyano, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, diphenylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenoxyamino, dipyreneamino, etc. Preferably, the substituents include: cyano, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, diphenylamino, naphthylphenylamino, or dinaphthylamino.

[0107] In this specification, hydrogen can be understood to be deuterium. That is, in general formulas (1) to (4), etc., the skeleton of carbazole, R 1 Or Ar 1 The H in such substituents can be some or all of deuterium.

[0108] The following are specific examples of compounds represented by general formula (1), but are not limited to these exemplified compounds.

[0109] [Chemistry 12]

[0110]

[0111] [Chemistry 13]

[0112]

[0113] [Chemistry 14]

[0114]

[0115] [Chemistry 15]

[0116]

[0117] [Chemistry 16]

[0118]

[0119] [Chemistry 17]

[0120]

[0121] [Chemistry 18]

[0122]

[0123] [Chemistry 19]

[0124]

[0125] [Chemistry 20]

[0126]

[0127] [Chemistry 21]

[0128]

[0129] [Chemistry 22]

[0130]

[0131] [Chemistry 23]

[0132]

[0133] [Chemistry 24]

[0134]

[0135] [Chemistry 25]

[0136]

[0137] [Chemistry 26]

[0138]

[0139]

[0140] [Chemistry 27]

[0141]

[0142] [Chemistry 28]

[0143]

[0144] [Chemistry 29]

[0145]

[0146] The compounds represented by the general formula (2) will be described.

[0147] In general formula (2), c is an integer from 0 to 5, d is an integer from 0 to 2, and at least one d is 1 or higher. e is an integer from 0 to 2. Preferably, c is an integer from 1 to 2, the sum of the two d is an integer from 1 to 4, and e is an integer from 0 to 1.

[0148] R 2 It is independently a cyano group, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, whether substituted or unsubstituted. Preferably, it is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 12 carbon atoms, whether substituted or unsubstituted, and more preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms, whether substituted or unsubstituted.

[0149] As R 2 Specific examples of R being an aliphatic hydrocarbon group having 1 to 10 carbon atoms are shown in general formula (1). 1 The same applies to these cases.

[0150] As R 2 Specific examples when it is an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, and the Ar 1 The explanations are the same as those used in the previous section.

[0151] L 2 It is an aromatic hydrocarbon group with 6 to 18 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, substituted or unsubstituted. Preferably, it is an aromatic hydrocarbon group with 6 to 12 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 15 carbon atoms, substituted or unsubstituted. More preferably, it is an aromatic hydrocarbon group with 6 to 10 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 12 carbon atoms, substituted or unsubstituted.

[0152] As L 2 Specific examples of Ar in general formula (1) are unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms or unsubstituted aromatic heterocyclic groups having 3 to 17 carbon atoms.1 The same applies to these situations. Furthermore, the prices may sometimes differ. L 2 It can be understood as a base with a 2d+1 valence.

[0153] Ar 2 Independently representing hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted), or a linked aromatic group consisting of 2 to 3 of these. Preferably, it is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms (substituted or unsubstituted), an aromatic heterocyclic group having 3 to 15 carbon atoms (substituted or unsubstituted), or a linked aromatic group consisting of 2 to 3 of these. More preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms (substituted or unsubstituted), an aromatic heterocyclic group having 3 to 12 carbon atoms (substituted or unsubstituted), or a linked aromatic group consisting of 2 to 3 of these.

[0154] Furthermore, Ar 2 L 2 R 2 Preferably, the group is not generated from pyridine, pyrimidine, or triazine.

[0155] Ar 2 Specific examples of R when it is an aliphatic hydrocarbon group with 1 to 10 carbon atoms are the same as those in general formula (1). 1 The same applies to these cases. Additionally, Ar 2 Specific examples of Ar in general formula (1) are aromatic hydrocarbon groups with 6 to 18 carbon atoms, either substituted or unsubstituted, or aromatic heterocyclic groups with 3 to 17 carbon atoms, and are consistent with Ar in general formula (1). 1 The same applies to these cases.

[0156] As a preferred way of general formula (2), formula (8) can be listed.

[0157] In equation (8), n is an integer from 1 to 5, and p is an integer from 0 to 1, preferably an integer from 1 to 2, and p is 0.

[0158] L 8 The group represents a group formed from benzene, dibenzofuran, or dibenzothiophene. R 81 It represents hydrogen, or a group formed from benzene, dibenzofuran, or dibenzothiophene.

[0159] The following are specific examples of compounds represented by general formula (2), but are not limited to these exemplified compounds.

[0160] [Chemistry 30]

[0161]

[0162]

[0163] [Chemistry 31]

[0164]

[0165] [Chemistry 32]

[0166]

[0167]

[0168] [Chemistry 33]

[0169]

[0170] [Chemistry 34]

[0171]

[0172] [Chemistry 35]

[0173]

[0174] [Chemistry 36]

[0175]

[0176] [Chemistry 37]

[0177]

[0178] The compounds represented by the general formula (3) will be described.

[0179] In general formula (3), Z 3 The group represented by formula (3a) containing an indolocarbazole ring, * represents the group with L 3 The bonding positions. Ring A is a heterocyclic ring represented by equation (3b), which is condensed at any position with the adjacent ring.

[0180] f represents an integer from 1 to 3, preferably 1. g represents an integer from 0 to 3, and j represents an integer from 0 to 3. Preferably, g is an integer from 0 to 2, and j is an integer from 0 to 2.

[0181] As a preferred general formula (3), the following formulas (9) or (10) can be listed.

[0182] [Chemistry 38]

[0183]

[0184] In general formulas (3), (9) and (10), the common symbols have the same meaning.

[0185] L3 and L 31 Each group independently represents an aromatic hydrocarbon group with 6 to 30 carbon atoms, either substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted. Preferably, it is an aromatic hydrocarbon group with 6 to 20 carbon atoms, or an aromatic heterocyclic group with 3 to 15 carbon atoms. More preferably, it is a group derived from benzene, naphthalene, pyridine, triazine, dibenzofuran, or carbazole.

[0186] Ar 3 and Ar 31 Each of these is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these. Preferably, the linked aromatic group consists of a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 4 of these. More preferably, the linked aromatic group consists of a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a linked aromatic group consisting of 2 to 3 of these.

[0187] Ar 3 and Ar 31 Phenyl, biphenyl, or terphenyl are preferred. Terphenyl groups can be linear or branched. Additionally, benzene, carbazole, and linked aromatic groups consisting of two to three of these aromatic rings are preferred.

[0188] As L 3 and L 31 Or Ar 3 and Ar 31 Specific examples of unsubstituted aromatic hydrocarbon groups with 6 to 30 carbon atoms or aromatic heterocyclic groups with 3 to 17 carbon atoms include benzene, naphthalene, acenaphthene, acenaphthene, azulene, anthracene, 1,2-benzophenanthrene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, tetraphenylene, pentaphenylene, hexaphenylene, hexabenzophenyl, heptaphenylene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triphenylene ... Zyrazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazolium, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole.

[0189] Among them, L 3 and L 31 It is a base with a valence of g+f or j+1.

[0190] Ar 3 and Ar 31 It can be a linked aromatic group. Regarding linked aromatic groups, in general formula (1), Ar 1 When an aromatic group is linked, the number of carbon atoms in the aromatic hydrocarbon group constituting the linked aromatic group is 6 to 30, otherwise the same.

[0191] Regarding these substituents with substituents, and Ar in general formula (1) 1 The explanation is the same when there are substituents.

[0192] R 3 Each group independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted). Preferably, it is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 15 carbon atoms (substituted or unsubstituted). More preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 12 carbon atoms (substituted or unsubstituted).

[0193] h independently represents an integer from 0 to 4, and i represents an integer from 0 to 2. Preferably, h is an integer from 0 to 1, and i is an integer from 0 to 1.

[0194] R 3 Specific examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms and R 1 The situation is the same, R 3 Specific examples of Ar in general formula (1) are aromatic hydrocarbon groups with 6 to 18 carbon atoms, substituted or unsubstituted, or aromatic heterocyclic groups with 3 to 17 carbon atoms, respectively. 1 The same applies to these cases.

[0195] The following are specific examples of compounds represented by general formula (3), but are not limited to these exemplified compounds.

[0196] [Chemistry 39]

[0197]

[0198]

[0199] [Chemistry 40]

[0200]

[0201]

[0202] [Chemistry 41]

[0203]

[0204] [Chemistry 42]

[0205]

[0206] [Chemistry 43]

[0207]

[0208]

[0209] [Chemistry 44]

[0210]

[0211]

[0212] [Chemistry 45]

[0213]

[0214] [Chemistry 46]

[0215]

[0216] [Chemistry 47]

[0217]

[0218] [Chemistry 48]

[0219]

[0220] [Chemistry 49]

[0221]

[0222] [Transformation 50]

[0223]

[0224] [Chemistry 51]

[0225]

[0226] [Chemistry 52]

[0227]

[0228] [Chemistry 53]

[0229]

[0230] [Chemistry 54]

[0231]

[0232] [Chemistry 55]

[0233]

[0234] [Chemistry 56]

[0235]

[0236] [Chemistry 57]

[0237]

[0238] [Chem.58]

[0239]

[0240] [Chemistry 59]

[0241]

[0242] [Transformation 60]

[0243]

[0244] [Chemistry 61]

[0245]

[0246] [Chemistry 62]

[0247]

[0248] [Chemistry 63]

[0249]

[0250] [Chemistry 64]

[0251]

[0252] The luminescent dopant used in the organic EL element of the present invention is a polycyclic aromatic compound represented by the general formula (4) or a polycyclic aromatic compound having the structure represented by the general formula (4) as part of its structure.

[0253] Polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure are also referred to as partially structured polycyclic aromatic compounds. Preferably, the partially structured polycyclic aromatic compound is the polycyclic aromatic compound represented by formula (5), and more preferably, the boron-containing polycyclic aromatic compound represented by formula (6).

[0254] In general formulas (4) and (5), rings C, D, E, F, G, H, I, and J are each independently an aromatic hydrocarbon ring with 6 to 24 carbon atoms or an aromatic heterocycle with 3 to 17 carbon atoms, preferably an aromatic hydrocarbon ring with 6 to 20 carbon atoms or an aromatic heterocycle with 3 to 15 carbon atoms. Since rings C to J are aromatic hydrocarbon rings or aromatic heterocycles as described above, they are also called aromatic rings.

[0255] Specific examples of the aromatic rings mentioned above include rings containing benzene, naphthalene, acenaphthene, acenaphthene, azulene, anthracene, 1,2-benzophenanthrene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazolium, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. More preferably, it is a benzene ring, a naphthalene ring, an anthracene ring, a triphenylene ring, a phenanthrene ring, a pyrene ring, a pyridine ring, a dibenzofuran ring, a dibenzothiophene ring, or a carbazole ring.

[0256] In general formula (4), Y 4 For B, P, P=O, P=S, Al, Ga, As, Si-R 4 or Ge-R 41 Preferably, it is B, P, P=O or P=S, and more preferably B.

[0257] R 4 and R 41 This refers to an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted). Preferably, it is an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 15 carbon atoms (substituted or unsubstituted). More preferably, it is an aromatic hydrocarbon group having 6 to 10 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 12 carbon atoms (substituted or unsubstituted).

[0258] As R 4 and R 41 When R is an aliphatic hydrocarbon group with 1 to 10 carbon atoms 4 and R 41 Specific examples of aromatic hydrocarbon groups having 6 to 18 carbon atoms, whether substituted or unsubstituted, or aromatic heterocyclic groups having 3 to 17 carbon atoms, are related to R in general formula (1). 1 The same applies to these bases.

[0259] X4 Independently, O and N-Ar respectively 4 S or Se, preferably O or N-Ar 4 Or S, more preferably O or N-Ar 4 .

[0260] Ar 4 Each of these groups is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these groups. Preferably, it represents a substituted or unsubstituted linked aromatic group having 6 to 12 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a linked aromatic group consisting of 2 to 6 of these groups. More preferably, it represents a substituted or unsubstituted linked aromatic group having 6 to 10 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 10 carbon atoms, or a linked aromatic group consisting of 2 to 4 of these groups.

[0261] More preferably, it is phenyl, biphenyl, or terphenyl.

[0262] As Ar 4 Specific examples of aromatic hydrocarbon groups having 6 to 18 carbon atoms that are substituted or unsubstituted, aromatic heterocyclic groups having 3 to 17 carbon atoms that are substituted or unsubstituted, or linked aromatic groups consisting of 2 to 8 of these, are related to Ar in general formula (1). 1 The same applies to these bases.

[0263] N-Ar 4 It can also bond with aromatic rings selected from C, D, or E rings to form heterocycles containing N. Additionally, C, D, E, and R rings... 4 R 41 R 42 and Ar 4 At least one hydrogen atom in the atom may be replaced by a halogen or deuterium.

[0264] R 42Substituents representing the C, D, and E rings can independently represent cyano, deuterium, a diarylamino group with 12-44 carbon atoms, an arylheteroarylamino group with 12-44 carbon atoms, a diheteroarylamino group with 12-44 carbon atoms, an aliphatic hydrocarbon group with 1-10 carbon atoms, an aromatic hydrocarbon group with 6-18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group with 3-17 carbon atoms (substituted or unsubstituted). Preferably, they are diarylamino groups with 12-36 carbon atoms, arylheteroarylamino groups with 12-36 carbon atoms, diheteroarylamino groups with 6-12 carbon atoms (substituted or unsubstituted), or aromatic heterocyclic groups with 3-15 carbon atoms (substituted or unsubstituted). More preferably, it is a diarylamino group with 12 to 24 carbons, an arylheteroarylamino group with 12 to 24 carbons, a diheteroarylamino group with 12 to 24 carbons, an aromatic hydrocarbon group with 6 to 10 carbons that has been substituted or not substituted, or an aromatic heterocyclic group with 3 to 12 carbons that has been substituted or not substituted.

[0265] As R 42 Specific examples when referring to aliphatic hydrocarbon groups with 1 to 10 carbon atoms, and R 1 The situation is the same.

[0266] As R 42 Specific examples when referring to substituted or unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms, or substituted or unsubstituted aromatic heterocyclic groups having 3 to 17 carbon atoms, are related to Ar. 1 The same applies to the case where the group is derived from benzene, naphthalene, acenaphthene, acenaphthene, azulene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazolium, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimazole, benzotriazole, benzoisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. More preferably, the group derived from benzene or naphthalene is also preferred.

[0267] As R 42Specific examples of diarylamino, arylheteroarylamino, diheteroarylamino, or aliphatic hydrocarbon groups having 12 to 44 carbon atoms can be listed as follows: diphenylamino, diphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenanthylamino, dipyreneamino, dibenzofuranylphenylamino, dibenzofuranylbiphenylamino, dibenzofuranylnaphthylamino, dibenzofuranylanthrylamino, dibenzofuranylphenanthylamino, dibenzofuranylpyreneamino, bisdibenzofuranylamino, carbazoylphenylamino, carbazoylnaphthylamino, carbazoylanthrylamino, carbazoylphenanthylamino, carbazoylpyreneamino, dicarbazoylamino, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or nonyl. Preferably, the following are examples: diphenylamino, diphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenoxyamino, or dipyreneamino. More preferably, the following are examples: diphenylamino, diphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, dibenzofuranylphenylamino, or carbazoleylphenylamino.

[0268] v represents an integer from 0 to 4, preferably an integer from 0 to 2, and more preferably 0 to 1. x represents an integer from 0 to 3, preferably an integer from 0 to 2, and more preferably 0 to 1.

[0269] Polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure will be described. The polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure can be regarded as condensates of the compound represented by general formula (4) or analogues thereof, and are therefore also called partially structured polycyclic aromatic compounds.

[0270] As a partial structural polycyclic aromatic compound, there are compounds represented by formula (5) or formula (6).

[0271] In general formulas (4), (5) and (6), the common symbols have the same meaning.

[0272] In equation (5), w represents an integer from 0 to 4, y represents an integer from 0 to 3, and z represents an integer from 0 to 2. Preferably, w is 0 or 2, y is 0 or 1, and z is 0 or 1.

[0273] In equation (5), rings F to J are as described above.

[0274] The F ring, G ring and C ring and D ring in general formula (4) have the same meaning, the H ring, J ring and E ring have the same meaning, and the I ring is a common structure, so it becomes a tetravalent base (when z = 0).

[0275] In equation (6), X 6Independently represent N-Ar 6 O or S, at least one X 6 Indicates N-Ar 6 Preferably, it represents O or N-Ar. 5 More preferably, it represents N-Ar 5 Ar 6 Ar of general formula (4) 4 They have the same meaning. N-Ar 6 It can also bond with the aromatic ring to form a heterocycle containing N. In this case, Ar 3 It can be directly bonded to the aromatic ring, or it can be bonded via a linker group.

[0276] R 6 Independently representing cyano, deuterium, diarylamino with 12 to 44 carbons, aliphatic hydrocarbon with 1 to 10 carbons, substituted or unsubstituted aromatic hydrocarbon with 6 to 18 carbons, or substituted or unsubstituted aromatic heterocyclic group with 3 to 17 carbons.

[0277] Its specific examples are similar to R. 42 The same applies to these cases.

[0278] k independently represents an integer from 0 to 4, l independently represents an integer from 0 to 3, and m independently represents an integer from 0 to 2. Preferably, k independently represents an integer from 0 to 2, l represents an integer from 0 to 2, and m is an integer from 0 to 1.

[0279] The following descriptions of some structural polycyclic aromatic compounds refer to equations (5) and (6).

[0280] Equation (5) includes the structure represented by general equation (4) and a portion thereof. From another perspective, although there are two structures represented by general equation (4), they become a structure sharing a common I-ring. That is, the structure represented by general equation (4) is set as a partial structure.

[0281] Similarly, formula (6) becomes a structure with a common central benzene ring, which can be understood as including the structure represented by general formula (4) and a part of its structure.

[0282] The partial structure of the polycyclic aromatic compounds described in this invention has the structure represented by general formula (4) as a partial structure. It is preferable to have a structure lacking any one of the C-rings to E-rings in general formula (4) as another partial structure. Furthermore, it is preferable to have one structure represented by general formula (4) as a partial structure and one to three of the other partial structures. The bond between the structure represented by general formula (4) and the other partial structures can be a bond based on the condensation or formation of one or more rings, or a bond based on one or more interlocking bonds.

[0283] As a preferred embodiment of the general formula (4), general formula (5) or formula (6), or a partial structure of polycyclic aromatic compounds, there are the following formulas (4-a) to (4-h).

[0284] [Chemistry 65]

[0285]

[0286] The partial structure of polycyclic aromatic compounds represented by formula (4-a) corresponds, for example, to compounds represented by formula (4-64) described later. That is, formula (4-a) is a structure in which the central benzene ring has two general formulas (4), and can be understood as a compound containing a structural unit of general formula (4) and containing one of the partial structures.

[0287] The partial structure of polycyclic aromatic compounds represented by formula (4-b) corresponds, for example, to compounds represented by formula (4-65) described later. That is, formula (4-b) is a structure with two general formulas (4) in the central benzene ring, and can be understood as a compound containing a structural unit of general formula (4) and containing one of the aforementioned partial structures. If explained using general formula (4), then X 4 One is N-Ar 4 It becomes a ring structure that bonds with another aromatic ring to form a ring (condensed ring structure).

[0288] The partial structure of polycyclic aromatic compounds represented by formula (4-c) corresponds, for example, to compounds represented by formula (4-66) described later. That is, if explained using general formula (4), the structure has three unit structures represented by general formula (4) because it contains a benzene ring as the E ring. In other words, it can be understood as a compound having a unit structure represented by general formula (4) as a partial structure, and comprising two structures obtained by removing one benzene ring from general formula (4), i.e., the partial structure. Furthermore, X 4 For N-Ar 4 It becomes a ring structure that forms with another adjacent ring bond.

[0289] [Chemistry 66]

[0290]

[0291] In addition, some of the structural polycyclic aromatic compounds represented by formulas (4-d), (4-e), (4-f), and (4-g) correspond to compounds represented by formulas (4-67), (4-68), (4-69), and (4-70) as described later.

[0292] That is, a compound having two or three unit structures represented by general formula (4) in one compound, which are benzene rings that are C-rings (or D-rings). That is, it can be understood as a compound having a unit structure represented by general formula (4) as a partial structure, and containing a structure obtained by removing a benzene ring from general formula (4), namely the partial structure.

[0293] The partial structure of polycyclic aromatic compounds represented by formula (4-h) corresponds, for example, to compounds represented by formulas (4-71), (4-72), (4-73), (4-74), and (4-75) described later. That is, if explained using general formula (4), it refers to a partial structure of polycyclic aromatic compounds where the C ring is a naphthalene ring and the ring is shared, and which in a compound has two unit structures represented by general formula (4). In other words, it can be understood as a compound having a unit structure represented by general formula (4) as a partial structure, and comprising one or two structures obtained by removing one C ring (naphthalene ring) from general formula (4), i.e., the partial structure.

[0294] In equations (4-a) to (4-h), X 4 and Y 4 R has the same meaning as general formula (4). 6 k, l, and m have the same meaning as in equation (6). s is 0 to 1, preferably 0.

[0295] Some of the structural polycyclic aromatic compounds of the present invention may refer to the following compounds: compounds of multiple general formula (4) having one or two rings (C ring to E ring) in the structural unit of general formula (4) and linked together, and containing at least one structural unit of general formula (4).

[0296] The number of compounds forming the general formula (4) is 2 to 5, preferably 2 to 3. The number of rings (C-rings to E-rings) can be one, two, or three.

[0297] The following examples show specific examples of polycyclic aromatic compounds represented by general formula (4), general formula (5) or formula (6) and other partially structured polycyclic aromatic compounds, but are not limited to these exemplified compounds.

[0298] [Chemistry 67]

[0299]

[0300] [Chemistry 68]

[0301]

[0302]

[0303] [Chemistry 69]

[0304]

[0305]

[0306] [Chemistry 70]

[0307]

[0308] [Chemistry 71]

[0309]

[0310] [Chemistry 72]

[0311]

[0312] [Chemistry 73]

[0313]

[0314] [Chemistry 74]

[0315]

[0316] [Chemistry 75]

[0317]

[0318] [Chemistry 76]

[0319]

[0320] [Chemistry 77]

[0321]

[0322] [Chemistry 78]

[0323]

[0324] [Chemistry 79]

[0325]

[0326] [Chemistry 80]

[0327]

[0328] [Chemistry 81]

[0329]

[0330] [Chemistry 82]

[0331]

[0332] [Chemistry 83]

[0333]

[0334] [Chemistry 84]

[0335]

[0336] In the organic EL element of the present invention, the ΔEST of the organic light-emitting material used as a light-emitting dopant is preferably 0.20 eV or less. More preferably, it is 0.15 eV or less, and even more preferably, it is 0.10 eV or less.

[0337] ΔEST represents the difference between the excited singlet energy (S1) and the excited triplet energy (T1). Here, the conditions for measuring S1 and T1 depend on the methods described in the examples.

[0338] An excellent organic EL element can be provided by using a material selected from the polycyclic aromatic compounds or partially structured polycyclic aromatic compounds represented by the general formula (3) as a luminescent dopant, and using a material selected from the compounds represented by the general formula (1) or general formula (2) as a first host, and using a material selected from the compounds represented by the general formula (3) as a second host.

[0339] In other embodiments of the invention, a compound with a ΔEST of 0.20 eV or less is used as a luminescent dopant in conjunction with the first and second bodies. In this case, the compound used as the luminescent dopant does not need to be the polycyclic aromatic compound material, as long as it is a compound with a ΔEST of 0.20 eV or less, preferably 0.15 eV or less, and more preferably 0.10 eV or less. Such compounds are known from numerous documents such as Patent Document 2 and are known as delayed fluorescence luminescent materials (TADF), and therefore can be selected from these.

[0340] Next, the structure of the organic EL element of the present invention will be described with reference to the accompanying drawings, but the structure of the organic EL element of the present invention is not limited thereto.

[0341] Figure 1This is a cross-sectional view showing a typical organic EL element structure used in this invention. 1 represents the substrate, 2 represents the anode, 3 represents the hole injection layer, 4 represents the hole transport layer, 5 represents the light-emitting layer, 6 represents the electron transport layer, and 7 represents the cathode. The organic EL element of this invention may also have an exciton blocking layer adjacent to the light-emitting layer. Furthermore, an electron blocking layer may also be present between the light-emitting layer and the hole injection layer. The exciton blocking layer may be inserted into either the anode side or the cathode side of the light-emitting layer, or simultaneously into both sides. In the organic EL element of this invention, an anode, a light-emitting layer, and a cathode are essential layers. However, in addition to these essential layers, a hole injection transport layer and an electron injection transport layer may also be present, and a hole blocking layer may also be present between the light-emitting layer and the electron injection transport layer. Furthermore, the hole injection transport layer refers to either or both of the hole injection layer and the hole transport layer, and the electron injection transport layer refers to either or both of the electron injection layer and the electron transport layer.

[0342] It can also be with Figure 1 In the opposite structure, where the cathode 7, electron transport layer 6, light-emitting layer 5, hole transport layer 4, and anode 2 are sequentially stacked on the substrate 1, layers can be added or omitted as needed.

[0343] -Substrate-

[0344] 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 that has been used in organic EL elements before, such as a substrate containing glass, transparent plastic, quartz, etc.

[0345] -anode-

[0346] As the anode material in an organic electroluminescent (EL) element, materials containing metals, alloys, conductive compounds, or mixtures thereof with a high work function (4 eV or higher) are preferably used. Specific examples of such electrode materials include metals such as Au; conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. Alternatively, amorphous materials such as IDIXO (In2O3-ZnO) that can be formed 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 then patterned into the desired shape using photolithography. Alternatively, when pattern precision is not critical (around 100 μm or higher), a mask of the desired shape can be used during the evaporation or sputtering of the electrode material to form the pattern. Alternatively, when using a coatable substance such as an organic conductive compound, wet film formation methods such as printing or coating can be used. In the case of extracting light from the anode, it is ideal to have a transmittance greater than 10%, and the sheet resistance of the anode is preferably less than several hundred Ω / Y. The film thickness also depends on the material, and is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

[0347] -cathode-

[0348] On the other hand, as cathode materials, materials containing metals (called electron-injecting metals), alloys, conductive compounds, or mixtures thereof with low work functions (below 4 eV) can be used. Specific examples of such electrode materials include: sodium, sodium-potassium alloys, magnesium, lithium, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / alumina (Al₂O₃) mixtures, indium, lithium / aluminum mixtures, rare earth metals, etc. Among these, in terms of electron injection performance and durability against oxidation, mixtures of electron-injecting metals and a second metal that is stable and has a work function greater than that are suitable, such as magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / alumina (Al₂O₃) mixtures, lithium / aluminum mixtures, aluminum, etc. Cathodes can be fabricated by forming thin films from these cathode materials through methods such as vapor deposition or sputtering. Furthermore, as a cathode, the sheet resistance is preferably several hundred Ω / Y or less, and the film thickness is typically selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. 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 translucent, the luminous brightness will be increased, which is advantageous.

[0349] Furthermore, after forming the metal on the cathode with a film thickness of 1 nm to 20 nm, a conductive transparent material listed in the description of the anode is formed on it, thereby making a transparent or semi-transparent cathode. By applying the method described above, an element in which both the anode and cathode are permeable can be made.

[0350] -Emitting Layer-

[0351] The light-emitting layer is a layer that emits light after excitons are generated by the recombination of holes and electrons injected from the anode and cathode, respectively, and the light-emitting layer contains a light-emitting dopant and a host.

[0352] Regarding the luminescent dopant and the substrate, for example, the luminescent dopant can be used at 0.10% to 10% and the substrate at 99.9% to 90%. Preferably, the luminescent dopant is 1.0% to 5.0% and the substrate is 99% to 95%, more preferably, the luminescent dopant is 1.0% to 3.0% and the substrate is 99% to 97%.

[0353] Unless otherwise specified, % in this specification refers to mass.

[0354] As the main body in the light-emitting layer, a first main body represented by general formula (1) or general formula (2) and a second main body represented by general formula (3) are used. Regarding the first main body and the second main body, for example, 10% to 90% of the first main body and 90% to 10% of the second main body can be used. Preferably, the first main body is 30% to 70% and the second main body is 70% to 30%, more preferably the first main body is 40% to 60% and the second main body is 60% to 40%.

[0355] Furthermore, as other entities besides those mentioned above, one or more existing entities may be used in combination, and the amount used relative to the total amount of the entity material may be set to 50% or less, preferably 25% or less.

[0356] The host material is a compound possessing hole transport capability, electron transport capability, and a high glass transition temperature, preferably having a T1 greater than that of the luminescent dopant. Specifically, the T1 of the host material is preferably 0.010 eV or more higher than that of the luminescent dopant, more preferably 0.030 eV or more higher, and even more preferably 0.10 eV or more higher. Furthermore, a TADF-active compound can be used as the host material, preferably one where the difference (ΔEST) between the excited singlet energy (S1) and the excited triplet energy (T1) is 0.20 eV or less.

[0357] Existing entities that can be considered as other entities are known from a large number of patent documents, etc., and can therefore be selected from these. Specific examples of entities are not particularly limited, and examples include various metal complexes represented by metal complexes of indole derivatives, carbazole derivatives, indole-carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, phenylenediamine derivatives, arylamine derivatives, styrene-anthracene derivatives, fluorene derivatives, stilbene derivatives, triphenylene derivatives, carborane derivatives, porphyrin derivatives, phthalocyanine derivatives, 8-hydroxyquinoline derivatives, or metal complexes of metal phthalocyanines, benzoxazole, or benzothiazole derivatives; poly(N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylidene derivatives, polyfluorene derivatives, and other polymeric compounds.

[0358] When using multiple substrates, each substrate can be vapor-deposited from different vapor deposition sources, or a premix can be prepared by pre-mixing before vapor deposition, thereby allowing multiple substrates to be vapor-deposited simultaneously from a single vapor deposition source.

[0359] Ideally, premixing methods should be those that can mix as uniformly as possible. Examples of such methods include pulverizing and mixing, heating and melting under reduced pressure or inert gas environments such as nitrogen, or sublimation, but these methods are not the only ones that can be used.

[0360] As the luminescent dopant in the luminescent layer, the polycyclic aromatic compound material or an organic luminescent material with a ΔEST of 0.20 eV or less can be used. Preferably, the polycyclic aromatic compound material with a ΔEST of 0.20 eV or less is used.

[0361] The polycyclic aromatic compound material can be used as a luminescent dopant in the luminescent layer. Preferably, it is a partially structured polycyclic aromatic compound represented by formula (5), and more preferably, it is a boron-containing partially structured polycyclic aromatic compound represented by formula (6). The ΔEST of the polycyclic aromatic compound material is preferably 0.20 eV or less.

[0362] The luminescent layer may contain two or more luminescent dopants. For example, it may be the polycyclic aromatic compound material and luminescent dopants containing other compounds. In this case, the luminescent dopant containing other compounds is preferably ΔEST of 0.20 eV or less, but is not limited thereto.

[0363] When the luminescent layer contains two or more luminescent dopants, the first dopant may be the polycyclic aromatic compound material, and the second dopant may also use existing compounds as other luminescent dopants. Preferably, the content of the first dopant is 0.05% to 50% relative to the host material, and the content of the second dopant is 0.050% to 50% relative to the host material, and the total content of the first and second dopants relative to the host material does not exceed 50%.

[0364] Other luminescent dopants are known from numerous patent documents and can be selected from these. Specific examples of dopants are not particularly limited, but can include: phenanthrene, anthracene, pyrene, tetraphenylene, pentaphenylene, perylene, naphthylpyrene, dibenzopyrene, rubrene, and condensation ring derivatives such as 1,2-benzophenanthrene; benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bis(styrene)-anthracene derivatives or bis(styrene)-phenylene derivatives, bis(styrene)-aryl derivatives, diazabenzodiinden derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives, dibenzofuran derivatives, coumarin derivatives, dicyandiamide derivatives, etc. Methylpyran derivatives, dicyanomethylenethiaran derivatives, polymethimide derivatives, anthocyanin derivatives, oxobenzanthracene derivatives, xanthracene derivatives, rhodamine derivatives, fluorescein derivatives, piperanium derivatives, 2-hydroxyquinoline (carbostyril) derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazopyrene derivatives, pyrrolemethylene derivatives, violetone derivatives, pyrrolopyrrole derivatives, squaric acid lactone derivatives, violetanone derivatives, phenazine derivatives, acridineone derivatives, deazaflavin derivatives, fluorene derivatives, and benzo[a]fluorene derivatives, etc.

[0365] The organic light-emitting dopant and the first or second host can be deposited from different evaporation sources, or they can be premixed before evaporation to form a premix, thereby depositing the light-emitting dopant and the first or second host simultaneously from a single evaporation source.

[0366] -Injection Layer-

[0367] An injection layer is a layer placed between the electrode and the organic layer to reduce the driving voltage or increase the luminous brightness. There are hole injection layers and electron injection layers, which can exist between the anode and the luminescent layer or hole transport layer, and between the cathode and the luminescent layer or electron transport layer. The injection layer can be added as needed.

[0368] -hole blocking layer-

[0369] In a broad sense, a hole blocking layer functions as an electron transport layer. It comprises hole-blocking materials that can transport electrons but have a significantly lower hole-transporting capacity. By transporting electrons and blocking holes, it increases the recombination probability of electrons and holes in the luminescent layer. Existing hole-blocking materials can be used in the hole blocking layer. To leverage the properties of the luminescent dopant, a material used as a second host can also be used as the hole blocking layer material. Furthermore, multiple hole-blocking materials can be used in combination.

[0370] -Electron blocking layer-

[0371] In a broad sense, an electron blocking layer functions as a hole transport layer, increasing the probability of electron-hole recombination in the luminescent layer by transporting holes and blocking electrons. Existing electron blocking layer materials can be used as the electron blocking layer material. To leverage the properties of the luminescent dopant, materials used as the primary host can also be used as the electron blocking layer material.

[0372] The thickness of the electron blocking layer is preferably 3nm to 100nm, and more preferably 5nm to 30nm.

[0373] -Exciton blocking layer-

[0374] An exciton blocking layer is used to prevent excitons generated by the recombination of holes and electrons in the light-emitting layer from diffusing into the charge transport layer. By inserting this layer, excitons can be efficiently sealed into the light-emitting layer, thereby improving the luminous efficiency of the device. In devices with two or more adjacent light-emitting layers, the exciton blocking layer can be inserted between two adjacent light-emitting layers.

[0375] Existing exciton blocking layer materials can be used as the material for the exciton blocking layer.

[0376] As layers adjacent to the light-emitting layer, there are hole blocking layers, electron blocking layers, exciton blocking layers, etc. In the absence of these layers, hole transport layers, electron transport layers, etc. become adjacent layers.

[0377] -Hole transport layer-

[0378] The hole transport layer contains hole transport material with the function of transporting holes, and the hole transport layer can be a single layer or multiple layers.

[0379] The hole transport material is any material that possesses either hole injection or transport or electron barrier properties, and can be either organic or inorganic. In the hole transport layer, any compound can be selected from existing compounds. Examples of such hole transport materials include porphyrin derivatives, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, phenylenediamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrene-anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymeric oligomers, particularly thiophene oligomers. Porphyrin derivatives, arylamine derivatives, and styrene-anthracene derivatives are preferred, and arylamine compounds are more preferred.

[0380] -Electron transport layer-

[0381] The electron transport layer contains materials that can transport electrons, and the electron transport layer can be a single layer or multiple layers.

[0382] As an electron transport material (and sometimes a hole blocking material), it only needs to have the function of transmitting electrons injected from the cathode to the light-emitting layer. The electron transport layer can be any compound selected from existing compounds, such as polycyclic aromatic derivatives of naphthalene, anthracene, phenanthroline, tris(8-hydroxyquinoline)aluminum(III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiamethane dioxide derivatives, carbodiimide, fluorenemethane derivatives, anthraquinone dimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole derivatives, benzothiazole derivatives, indolecarbazole derivatives, etc. Furthermore, polymers incorporating these materials into polymer chains or using them as the backbone of polymers can also be used.

[0383] There are no particular limitations on the film-forming methods for each layer when manufacturing the organic EL element of the present invention; either dry or wet processes can be used.

[0384] Example

[0385] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0386] The following examples and comparative examples show the compounds used.

[0387] [Chemistry 85]

[0388]

[0389] The S1 and T1 of compounds (4-2) and (4-110) were determined.

[0390] S1 and T1 are determined in the following manner.

[0391] On a quartz substrate, vacuum evaporation is used at a vacuum degree of 10. -4 Under conditions below Pa, a vapor deposition film with a thickness of 100 nm is formed by co-deposition of compound (2-30) as the host and compound (4-2) or compound (4-110) as the luminescent dopant from different vapor deposition sources. At this time, co-deposition is carried out under vapor deposition conditions where the concentration of compound (4-2) or compound (4-110) is 3%.

[0392] Regarding S1, the emission spectrum of the vapor-deposited film is measured, and a tangent line is drawn at the starting point of the short wavelength side of the emission spectrum. The wavelength value λedge[nm] at the intersection of the tangent line and the horizontal axis is substituted into the following equation (i) to calculate S1.

[0393] S1[eV]=1239.85 / λedge (i)

[0394] Regarding T1, the phosphorescence spectrum of the vapor-deposited film is measured, and a tangent line is drawn at the starting point of the short wavelength side of the phosphorescence spectrum. The wavelength value λedge[nm] at the intersection of the tangent line and the horizontal axis is substituted into equation (ii) to calculate T1.

[0395] T1[eV]=1239.85 / λedge (ii)

[0396] The measurement results are shown in Table 1.

[0397] [Table 1]

[0398] compound S1(eV) T1(eV) S1-T1(eV) 4-2 2.79 2.61 0.18 4-110 2.71 2.67 0.04

[0399] Example 1

[0400] On a glass substrate with an ITO-containing anode having a film thickness of 70 nm, a vacuum evaporation method was used to deposit the film at a vacuum degree of 4.0 × 10⁻⁶. -5Pa is used to stack the thin films. First, on ITO, HAT-CN is formed to a thickness of 10 nm as a hole injection layer, and then HT-1 is formed to a thickness of 25 nm as a hole transport layer. Next, compound (1-77) is formed to a thickness of 5 nm as an electron blocking layer. Next, compound (1-77) as the first host, compound (3-3) as the second host, and compound (4-110) as the luminescent dopant are co-deposited from different evaporation sources to form a luminescent layer to a thickness of 30 nm. At this time, co-deposition is performed under evaporation conditions where the concentration of compound (4-110) is 2% and the weight ratio of the first host to the second host is 50:50. Next, compound (HB1) is formed to a thickness of 5 nm as a hole blocking layer. Next, ET-1 is formed to a thickness of 40 nm as an electron transport layer. Furthermore, on the electron transport layer, lithium fluoride (LiF) is formed to a thickness of 1 nm as an electron injection layer. Finally, aluminum (Al) is formed on the electron injection layer to a thickness of 70 nm as a cathode to fabricate an organic EL device.

[0401] Examples 2 to 16

[0402] Organic EL elements were fabricated in the same manner as in Example 1, except that the luminescent dopant, the first host, the second host, and the weight ratio of the first host to the second host were set as shown in Table 2.

[0403] Comparative Example 1

[0404] On a glass substrate with an ITO-containing anode having a film thickness of 70 nm, a vacuum evaporation method was used to deposit the film at a vacuum degree of 4.0 × 10⁻⁶. -5 Pa is used to stack various thin films. First, on ITO, HAT-CN is formed to a thickness of 10 nm as a hole injection layer, and then HT-1 is formed to a thickness of 25 nm as a hole transport layer. Next, compounds (2-30) are formed to a thickness of 5 nm as an electron blocking layer. Next, compounds (1-77) as the first host and compounds (4-110) as luminescent dopants are co-deposited from different evaporation sources to form a luminescent layer to a thickness of 30 nm. At this time, co-deposition is performed under evaporation conditions where the concentration of compound (4-110) is 2%. Next, compound (HB1) is formed to a thickness of 5 nm as a hole blocking layer. Next, ET-1 is formed to a thickness of 40 nm as an electron transport layer. Furthermore, lithium fluoride (LiF) is formed to a thickness of 1 nm on the electron transport layer as an electron injection layer. Finally, aluminum (Al) is formed to a thickness of 70 nm on the electron injection layer as a cathode, thereby fabricating an organic EL device.

[0405] Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 7, Comparative Example 8, Comparative Example 9

[0406] An organic EL element was fabricated in the same manner as in Comparative Example 1, except that the luminescent dopant and the first host (without a second host) were set to the compounds shown in Table 2.

[0407] Comparative Example 5, Comparative Example 6, Comparative Example 10

[0408] The luminescent dopant, the first host, and the second host are the compounds shown in Table 2. Otherwise, the organic EL element is fabricated in the same manner as in Example 1.

[0409] [Table 2]

[0410] dopant First subject Second subject Example 1 4-110 1-77(50％) 3-3(50％) Example 2 4-110 1-77(30％) 3-3(70％) Example 3 4-110 1-77(70％) 3-3(30％) Example 4 4-110 1-132(50％) 3-3(50％) Example 5 4-110 2-14(50％) 3-1(50％) Example 6 4-110 2-30(50％) 3-3(50％) Example 7 4-110 2-22(50％) 3-77(50％) Example 8 4-110 2-27(50％) 3-111(50％) Example 9 4-2 1-77(50％) 3-3(50％) Example 10 4-110 1-77(50％) 3-162(50％) Example 11 4-110 1-89(50％) 3-3(50％) Example 12 4-110 1-77(70％) 3-24(30％) Example 13 4-110 1-77(70％) 3-43(30％) Example 14 4-110 2-30(70％) 3-188(30％) Example 15 4-110 1-77(70％) 3-77(30％) Example 16 4-110 1-153(70％) 3-79(30％) Comparative Example 1 4-110 1-77 - Comparative Example 2 4-110 3-3 - Comparative Example 3 4-110 2-30 Comparative Example 4 4-110 mCBP - Comparative Example 5 4-110 mCBP (50%) 3-3(50％) Comparative Example 6 4-110 mCBP (50%) 3-162(50％) Comparative Example 7 4-2 1-77 Comparative Example 8 4-2 3-3 Comparative Example 9 4-2 mCBP Comparative Example 10 4-2 mCBP (50%) 3-162(50％)

[0411] Table 3 shows the voltage, maximum emission wavelength, external quantum efficiency, and lifetime of the organic EL devices fabricated in the examples and comparative examples. The voltage, maximum emission wavelength, and external quantum efficiency are based on a luminance of 500 cd / m². 2 The value at that time represents the initial characteristics. Lifespan is defined as the initial brightness of 500 cd / m². 2 The time until the brightness decays to 50% of the initial brightness is measured.

[0412] [Table 3]

[0413]

[0414] According to Table 3, the organic EL element of the embodiment of the present invention has the characteristics of high efficiency and long lifespan, and it is known to emit blue light according to the maximum emission wavelength.

Claims

1. An organic electric field light-emitting element comprising one or more light-emitting layers between opposing anodes and cathodes, characterized in that: at least one light-emitting layer comprises a host and a luminescent dopant, the host comprising a first host having hole transport capability as represented by general formula (7) or general formula (2), and a second host having electron transport capability as represented by general formula (3), the luminescent dopant comprising a polycyclic aromatic compound represented by general formula (4) or a polycyclic aromatic compound having the structure represented by said general formula (4) as a partial structure, The luminescent dopant in the luminescent layer is 0.10%–10% by mass, the host is 99.9%–90% by mass, and the first host in the host is 30%–70% by mass, while the second host is 70%–30% by mass. Here, Ar 1 Independently representing an aromatic hydrocarbon group having 6 to 18 carbon atoms, substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these aromatic rings; Here, c is an integer from 0 to 5, d is an integer from 0 to 2, and at least one d is 1 or higher; e is an integer from 0 to 2. R 2 It can be independently a cyano group, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 18 carbon atoms, whether substituted or unsubstituted. L 2 It is an aromatic hydrocarbon group with 6 to 18 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, substituted or unsubstituted; Ar 2 It is a hydrogen, cyano, an aliphatic hydrocarbon group having 1 to 10 carbons, an aromatic hydrocarbon group having 6 to 18 carbons that has been substituted or not substituted, an aromatic heterocyclic group having 3 to 17 carbons that has been substituted or not substituted, or a linked aromatic group consisting of 2 to 3 of these. Here, Z 3 is an indolocarbazole ring-containing group represented by formula (3a), For bonding to L 3 the bonding position of L Ring A is a heterocyclic ring as represented by equation (3b), and it is condensed at any position with the adjacent ring; L 3 and L 31 Each is independently an aromatic hydrocarbon group with 6 to 30 carbon atoms, either substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted. Ar 3 and Ar 31 Each is independently an aromatic hydrocarbon group with 6 to 30 carbon atoms that has been substituted or unsubstituted, an aromatic heterocyclic group with 3 to 17 carbon atoms that has been substituted or unsubstituted, or a linked aromatic group consisting of 2 to 8 of these. R 3 It is independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted). f represents 1, g represents integers from 0 to 3, h independently represents integers from 0 to 4, i represents integers from 0 to 2, and j represents integers from 0 to 3; Here, rings C, D, and E are independently aromatic hydrocarbon rings with 6 to 24 carbon atoms or aromatic heterocycles with 3 to 17 carbon atoms. Y 4 For B, P, P=O, P=S, Al, Ga, As, Si-R 4 or Ge-R 41 , X 4 independently O, N-Ar 4 , S or Se, R 4 and R 41 They are, independently, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. Ar 4 Independently, it is an aromatic hydrocarbon group with 6 to 18 carbon atoms, either substituted or unsubstituted, an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted, or a linked aromatic group consisting of 2 to 8 of these. N-Ar 4 It can bond with any of the C-ring, D-ring, or E-ring to form a heterocycle containing N. R 42 Each of these groups independently represents a cyano group, a deuterium group, a diarylamino group with 12–44 carbon atoms, an arylheteroarylamino group with 12–44 carbon atoms, a diheteroarylamino group with 12–10 carbon atoms, an aromatic hydrocarbon group with 6–18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group with 3–17 carbon atoms (substituted or unsubstituted). v represents an integer from 0 to 4, and x represents an integer from 0 to 3; C ring, D ring, E ring, R 4 R 41 R 42 and Ar 4 At least one hydrogen atom in the atom may be replaced by a halogen or deuterium.

2. The organic electroluminescent element according to claim 1, wherein Polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure are polycyclic aromatic compounds represented by the following formula (5). Here, rings F, G, H, I, and J are each independently an aromatic hydrocarbon ring with 6 to 24 carbon atoms, or an aromatic heterocycle with 3 to 17 carbon atoms. At least one hydrogen atom in the F ring, G ring, H ring, I ring, and J ring can be substituted with halogen or deuterium; X 4 Y 4 R 42 x and v have the same meaning as in general formula (4), w represents an integer from 0 to 4, y represents an integer from 0 to 3, and z represents an integer from 0 to 2.

3. The organic electroluminescent device according to claim 1, wherein Polycyclic aromatic compounds having the structure represented by general formula (4) as a partial structure are boron-containing polycyclic aromatic compounds represented by the following formula (6). Here, X 6 Independently represent N-Ar 6 O or S, at least one X 6 Indicates N-Ar 6 ; Ar 6 Independently representing an aromatic hydrocarbon group having 6 to 18 carbon atoms, substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these aromatic rings, N-Ar 6 Can be with X 6 The bonded aromatic rings are bonded together to form a heterocycle containing N; R 6 Independently representing cyano, deuterium, diarylamino with 12 to 44 carbons, aliphatic hydrocarbon group with 1 to 10 carbons, substituted or unsubstituted aromatic hydrocarbon group with 6 to 18 carbons, or substituted or unsubstituted aromatic heterocyclic group with 3 to 17 carbons. k independently represents integers from 0 to 4, l independently represents integers from 0 to 3, and m represents integers from 0 to 2.

4. The organic electroluminescent device according to claim 1, wherein The first subject is represented by the general formula (7).

5. The organic electroluminescent device according to claim 1, wherein The light-emitting layer contains a first subject represented by general formula (2) and a second subject represented by general formula (3).

6. The organic electric field light-emitting element according to claim 1, wherein the general formula (2) is the following formula (8). Here, n is an integer from 1 to 5, and p is an integer from 0 to 1. L 8 This indicates a group formed from benzene, dibenzofuran, or dibenzothiophene; R 81 represents hydrogen, or a group derived from benzene, dibenzofuran, or dibenzothiophene.

7. The organic electroluminescent device according to claim 1, wherein The difference ΔEST between the excited singlet energy (S1) and the excited triplet energy (T1) of the luminescent dopant is less than 0.20 eV.

8. The organic electroluminescent device according to claim 7, wherein The ΔEST is below 0.10 eV.

9. An organic electric field light-emitting element comprising one or more light-emitting layers between opposing anodes and cathodes, characterized in that: at least one light-emitting layer comprises a first body represented by general formula (7) or general formula (2) and a second body represented by general formula (3), and contains a luminescent dopant with a ΔEST of 0.20 eV or less. The luminescent dopant in the luminescent layer is 0.10%–10% by mass, the host is 99.9%–90% by mass, and the first host in the host is 30%–70% by mass, while the second host is 70%–30% by mass. Here, Ar 1 Independently representing an aromatic hydrocarbon group having 6 to 18 carbon atoms, substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a linked aromatic group consisting of 2 to 8 of these aromatic rings; Here, c is an integer from 0 to 5, d is an integer from 0 to 2, and at least one d is 1 or higher; e is an integer from 0 to 2. R 2 It can be independently a cyano group, an aliphatic hydrocarbon group with 1 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 18 carbon atoms, whether substituted or unsubstituted. L 2 It is an aromatic hydrocarbon group with 6 to 18 carbon atoms, substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, substituted or unsubstituted; Ar 2 It is a hydrogen, cyano, an aliphatic hydrocarbon group having 1 to 10 carbons, an aromatic hydrocarbon group having 6 to 18 carbons that has been substituted or not substituted, an aromatic heterocyclic group having 3 to 17 carbons that has been substituted or not substituted, or a linked aromatic group consisting of 2 to 3 of these. Here, Z 3 is an indolocarbazole ring-containing group represented by formula (3a), For bonding to L 3 the bonding position of L Ring A is a heterocyclic ring as represented by equation (3b), and it is condensed at any position with the adjacent ring; L 3 and L 31 Each is independently an aromatic hydrocarbon group with 6 to 30 carbon atoms, either substituted or unsubstituted, or an aromatic heterocyclic group with 3 to 17 carbon atoms, either substituted or unsubstituted. Ar 3 and Ar 31 Each is independently an aromatic hydrocarbon group with 6 to 30 carbon atoms that has been substituted or unsubstituted, an aromatic heterocyclic group with 3 to 17 carbon atoms that has been substituted or unsubstituted, or a linked aromatic group consisting of 2 to 8 of these. R 3 It is independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms (substituted or unsubstituted), or an aromatic heterocyclic group having 3 to 17 carbon atoms (substituted or unsubstituted). f represents 1, g represents an integer from 0 to 3, h independently represents an integer from 0 to 4, i represents an integer from 0 to 2, and j represents an integer from 0 to 3.

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