Boron-containing compound, light-emitting material, and light-emitting device using the same

Abstract

The present invention provides a compound represented by formula (I) (in the formula: R1, R2, R3, R4, R5 and R6 represent a substituted or unsubstituted alkyl group; m's independently represent an integer of 0-4; n's independently represent an integer of 0-3; Y represents N-R7, O or S; Z represents N-R8, O or S; and R7 and R8 independently represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, provided that when R7 is a substituted or unsubstituted aryl group, the aryl group may be bonded to ring A1 to form a fused ring, and when R8 is a substituted or unsubstituted aryl group, the aryl group may be bonded to ring A2 to form a fused ring), etc.

Description

[Technical field]

[0001] The present invention relates to a boron-containing compound, a light-emitting material, and a light-emitting device using the same. More specifically, the present invention relates to a boron-containing compound having excellent light-emitting properties, a light-emitting material, and a light-emitting device using the same. [Background technology]

[0002] For example, Patent Document 1 proposes the following boron-containing compound as a light-emitting material.

[0003] [ka]

[0004] [ka]

[0005] [ka] [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US2020 / 0270278A1 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a novel boron-containing compound having excellent light-emitting properties, a light-emitting material, and a light-emitting device using the same. [Means for solving the problem]

[0008] As a result of intensive research aimed at solving the above problems, the present invention has been completed, which includes the following aspects.

[0009] That is, the present invention provides [1] A compound represented by formula (I):

[0010] [ka]

[0011] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4, Each n is independently an integer of 0 to 3, Y is NR 7 , O or S; Z is NR 8 , O or S; R 7 and R 8 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, R 7 is a substituted or unsubstituted aryl group, the aryl group may be linked to the A1 ring to form a fused ring, and R 8 When is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A2 to form a fused ring.

[0012] [2] The compound according to [1], which is represented by formula (II):

[0013] [ka]

[0014] In formula (II), R 1 , R 2 , R3 , R 4 , R 5 , R 6 , R 9 and R 10 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4; and Each n is independently an integer of 0 to 3.

[0015] [3] A light-emitting material comprising the compound according to [1] or [2].

[0016] [4] A light-emitting device containing the light-emitting material according to [3]. Effect of the Invention

[0017] The boron-containing compound of the present invention is useful as a light-emitting material. The light-emitting material of the present invention may emit delayed fluorescence. A light-emitting device containing the light-emitting material of the present invention may achieve excellent light-emitting efficiency. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a diagram showing an example of the PL spectrum of the light-emitting material of the present invention. [Diagram 2] FIG. 2 is a graph showing an example of the current density-external quantum efficiency characteristics of a light-emitting element of the present invention. [Diagram 3] FIG. 2 is a diagram showing an example of the voltage-current density characteristics of a light-emitting element of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The boron-containing compound of the present invention is a compound represented by formula (I), preferably a compound represented by formula (II).

[0020] [ka]

[0021] In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4, Each n is independently an integer of 0 to 3, Y is NR 7 , O or S; Z is NR 8 , O or S; R 7 and R 8 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, R 7 is a substituted or unsubstituted aryl group, the aryl group may be linked to the A1 ring to form a fused ring, and R 8 When is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A2 to form a fused ring.

[0022] [ka]

[0023] In formula (II), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 9 and R 10 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4; and Each n is independently an integer of 0 to 3.

[0024] In the present invention, the term "unsubstituted" means that only the core group is present. When the term "substituted" is not used and only the name of the core group is used, it means "unsubstituted" unless otherwise specified. On the other hand, the term "substituted" means that any hydrogen atom of the core group is replaced with a group (substituent) having the same or different structure as the core group. Therefore, a "substituent" is another group bonded to the core group. The number of substituents may be one or more. The two or more substituents may be the same or different. Terms such as "C1-6" indicate that the number of carbon atoms in the parent group is 1 to 6. This number of carbon atoms does not include the number of carbon atoms in the substituent. For example, a butyl group having an ethoxy group as a substituent is classified as a C2 alkoxy C4 alkyl group.

[0025] The "substituent" is not particularly limited as long as it is chemically permissible and has the effect of the present invention. Examples of groups that can be the "substituent" are shown below. C1-6 alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl, n-pentyl, and n-hexyl groups; C2-6 alkenyl groups such as vinyl group, 1-propenyl group, 2-propenyl group (allyl group), 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-methyl-2-propenyl group, and 2-methyl-2-propenyl group; C2-6 alkynyl groups, such as an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, or a 1-methyl-2-propynyl group;

[0026] C3-6 cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group; Phenyl group, naphthyl group; 3-6 membered heterocyclyl groups;

[0027] C1-6 alkoxy groups, such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an s-butoxy group, an i-butoxy group, or a t-butoxy group; C6-10 aryloxy groups such as phenoxy and naphthoxy groups; 5- to 6-membered heteroaryloxy groups, such as thiazolyloxy groups and pyridyloxy groups;

[0028] C1-6 alkoxycarbonyl groups, such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, or a t-butoxycarbonyl group;

[0029] halogeno groups such as fluoro, chloro, bromo, and iodo groups; C1-6 haloalkyl groups such as a chloromethyl group, a chloroethyl group, a trifluoromethyl group, a 1,2-dichloro-n-propyl group, a 1-fluoro-n-butyl group, and a perfluoro-n-pentyl group; C1-6 haloalkoxy groups, such as a trifluoromethoxy group, a 2-chloro-n-propoxy group, or a 2,3-dichlorobutoxy group;

[0030] Formylamino group; C1-6 alkylcarbonylamino groups, such as an acetylamino group, a propanoylamino group, a butyrylamino group, or an i-propylcarbonylamino group; C1-6 alkoxycarbonylamino groups, such as a methoxycarbonylamino group, an ethoxycarbonylamino group, an n-propoxycarbonylamino group, or an i-propoxycarbonylamino group; Unsubstituted or substituted aminocarbonyl groups, such as an aminocarbonyl group, a dimethylaminocarbonyl group, a phenylaminocarbonyl group, or an N-phenyl-N-methylaminocarbonyl group;

[0031] C1-6 alkylthio groups, such as a methylthio group, an ethylthio group, an n-propylthio group, an i-propylthio group, an n-butylthio group, an i-butylthio group, an s-butylthio group, or a t-butylthio group; C1-6 haloalkylthio groups, such as a trifluoromethylthio group and a 2,2,2-trifluoroethylthio group; C1-6 alkylsulfonyl groups such as a methylsulfonyl group, an ethylsulfonyl group, or a t-butylsulfonyl group; C1-6 haloalkylsulfonyl groups such as a trifluoromethylsulfonyl group or a 2,2,2-trifluoroethylsulfonyl group;

[0032] Cyano group;Nitro group;

[0033] In addition, any hydrogen atom in these "substituents" may be substituted with a group of a different structure. In that case, examples of the substituent include a C1-6 alkyl group, a C1-6 haloalkyl group, a C1-6 alkoxy group, a C1-6 haloalkoxy group, a halogeno group, a cyano group, and a nitro group.

[0034] The above-mentioned "3- to 6-membered heterocyclyl group" includes 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms as ring-constituting atoms. The heterocyclyl group may be either a monocyclic or polycyclic ring. As for the polycyclic heterocyclyl group, as long as at least one ring is a heterocyclic ring, the remaining rings may be any of saturated alicyclic rings, unsaturated alicyclic rings, and aromatic rings. Examples of the "3- to 6-membered heterocyclyl group" include 3- to 6-membered saturated heterocyclyl groups, 5- to 6-membered heteroaryl groups, and 5- to 6-membered partially unsaturated heterocyclyl groups. Examples of the 3- to 6-membered saturated heterocyclyl group include an aziridinyl group, an epoxy group, a pyrrolidinyl group, a tetrahydrofuranyl group, a thiazolidinyl group, a piperidyl group, a piperazinyl group, a morpholinyl group, a dioxolanyl group, and a dioxanyl group. Examples of the 5-membered heteroaryl group include a pyrrolyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a triazolyl group, an oxadiazolyl group, a thiadiazolyl group, and a tetrazolyl group. Examples of the 6-membered heteroaryl group include a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, and a triazinyl group.

[0035] In formula (I) or (II), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 The alkyl group in may be a straight chain or a branched chain. The number of carbon atoms constituting the alkyl group is preferably 1 to 6. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an i-propyl group, an i-butyl group, an s-butyl group, an t-butyl group, an i-pentyl group, a neopentyl group, a 2-methylbutyl group, a 2,2-dimethylpropyl group, and an i-hexyl group.

[0036] Examples of the substituent on the "alkyl group" include halogeno groups such as fluoro, chloro, bromo and iodo groups; hydroxyl groups; C1-6 alkoxy groups such as methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy, i-butoxy and t-butoxy groups; C1-6 haloalkoxy groups such as 2-chloro-n-propoxy, 2,3-dichlorobutoxy and trifluoromethoxy groups; phenyl groups; phenyl groups substituted with halogeno groups, C1-6 haloalkyl groups or C1-6 haloalkoxy groups, such as 4-chlorophenyl, 4-trifluoromethylphenyl and 4-trifluoromethoxyphenyl groups; or cyano groups.

[0037] In formula (I), R 7 and R 8 In the above formula, examples of the aryl group include a phenyl group and a naphthyl group. Examples of the substituent on the "phenyl group" or "naphthyl group" include halogeno groups such as fluoro, chloro, bromo, and iodo groups; C1-6 alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl, n-pentyl, and n-hexyl groups; C1-6 haloalkyl groups such as chloromethyl, chloroethyl, trifluoromethyl, 1,2-dichloro-n-propyl, and 1-fluoro-n-butyl groups; hydroxyl groups; C1-6 alkoxy groups such as methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy, i-butoxy, and t-butoxy groups; C1-6 haloalkoxy groups such as 2-chloro-n-propoxy, 2,3-dichlorobutoxy, and trifluoromethoxy groups; and cyano groups.

[0038] R 7 When is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A1 to form a fused ring. R 8 When is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A2 to form a fused ring.

[0039] Specific examples of the boron-containing compound of the present invention include the following: However, these are merely examples, and the present invention is not limited to the exemplified compounds.

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] The boron-containing compound of the present invention can be obtained by combining known synthesis reactions (eg, coupling reactions, substitution reactions, etc.).

[0045] For example, BBCz-R, which is one of the compounds represented by formula (I), can be obtained, for example, as follows.

[0046] (Example 1) [ka]

[0047] In a 300 mL Schlenk flask, t-BuOK (2.24 g, 20.0 mmol), dehydrated DMF (180 ml), and 3,6-di-t-butyl-carbazole (5.58 g, 20.0 mmol) were added and stirred at room temperature for 30 minutes. 2-Bromo-1,3-difluorobenzene (5.78 g, 30.0 mmol) was added to the mixture and refluxed for 24 hours. The resulting liquid was poured into water, and then dichloromethane was added for extraction. Magnesium sulfate was added to the resulting organic layer to dry it, then it was filtered and concentrated with a rotary evaporator. The concentrate was separated and purified by silica gel column chromatography (n-hexane / chloroform = 4 / 1) to obtain 4.51 g (50% yield) of white solid BCz-Br. 1 H-NMR(400MHz,CDCl3,δ): 8.13 (d, J = 1.4 Hz, 2H), 7.48-7.45 (m, 1H), 7.43 (dd, J = 8.8, 2.0 Hz, 2H), 7.31-7.26 (m, 2H), 6.99-6.94 (m, 2H), 1.45 (s, 18H)

[0048] In a 300 mL Schlenk flask, t-BuOK (2.81 g, 25.0 mmol), dehydrated DMF (180 ml), and 2,8-di-t-butyl-5,11-dihydroindolo[3,2-b]carbazole (3.69 g, 10.0 mmol) were added and stirred at room temperature for 30 minutes. BCz-Br (11.30 g, 25.0 mmol) was added to the mixture and refluxed for 24 hours. The resulting liquid was poured into water, and then dichloromethane was added for extraction. Magnesium sulfate was added to the resulting organic layer to dry it, then it was filtered and concentrated with a rotary evaporator. The concentrate was separated and purified by silica gel column chromatography (n-hexane / chloroform = 3 / 1) to obtain 4.82 g (yield 39%) of a white solid of 2BCz-INCz-Br. 1 H-NMR(400MHz,CDCl3,δ): 8.21-8.18 (m, 6H), 7.85 (s, 2H), 7.78-7.70 (m, 6H), 7.59-7.53 (m, 6H), 7.32 (d, J = 8.8 Hz, 2H), 7.20 (dd, J = 8.5, 6.0 Hz, 4H), 1.52 (s, 19H), 1.49 (d, J = 2.0 Hz, 36H).

[0049] 2BCz-INCz-Br (1.11 g, 0.90 mmol) and dehydrated t-butylbenzene (120 ml) were added to a 300 ml Schlenk flask. The flask was then purged with nitrogen. To this, n-butyllithium (1.7 ml, 1.6 M, 2.70 mmol) was added little by little at 0°C, and the mixture was stirred at room temperature for 4 hours. To this, boron tribromide (0.30 mL, 2.70 mol) was added little by little at 0°C, and the mixture was stirred at room temperature overnight. Next, N,N-diisopropylethylamine (0.70 mL, 4.05 mmol) was added at 0°C, and the mixture was stirred at 170°C for 24 hours. The resulting liquid was returned to room temperature and poured into water. Then, extraction was performed by adding chloroform. The resulting organic layer was filtered. The filtrate was washed with water. Then, magnesium sulfate was added to dry the mixture, and the mixture was concentrated using a rotary evaporator. The concentrate was separated and purified by silica gel column chromatography (n-hexane / chloroform=9 / 1) to obtain 0.054 g (yield 5%) of black crystals of BBCz-R. 1 H-NMR(400MHz,CDCl3,δ): 8.67 (d, J = 1.8 Hz, 2H), 8.46 (d, J = 8.8 Hz, 2H), 8.43-8.31 (m, 12H), 8.10 (t, J = 8.2 Hz, 2H), 7.74 (dd, J = 8.5, 2.0 Hz, 2H), 7.51 (dd, J = 8.5, 1.8 Hz, 2H), 1.58 (s, 18H), 1.32 (s, 18H), 1.09 (s, 18H)

[0050] The synthesized compounds can be purified by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., recrystallization or crystallization using a solvent, etc. The compounds can be identified by NMR analysis, etc.

[0051] The boron-containing compound of the present invention can be used as a light-emitting material. The light-emitting material of the present invention can provide a light-emitting device such as an organic photoluminescence device or an organic electroluminescence device. The boron-containing compound of the present invention has a function of assisting the emission of other light-emitting materials (host materials), and can be used by doping other light-emitting materials.

[0052] The organic photoluminescence element of the present invention comprises a substrate and a light-emitting layer containing the light-emitting material of the present invention. The light-emitting layer can be obtained by a coating method such as spin coating, a printing method such as ink-jet printing, a vapor deposition method, or the like.

[0053] The organic electroluminescence element of the present invention has an organic layer between an anode and a cathode. In the present invention, the term "organic layer" means a layer located between the anode and the cathode and substantially made of an organic material, and these layers may contain inorganic materials within a range that does not impair the performance of the light-emitting element of the present invention.

[0054] The structure of the organic electroluminescent element of the present invention in one embodiment can be one that is composed of an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode in this order on a substrate, or one that further has an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, it is possible to omit some organic layers, and for example, it is also possible to sequentially have an anode, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode on a substrate, or an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode. The light emitting material of the present invention may be doped not only into the light emitting layer, but also into the hole injection layer, the hole transport layer, the electron blocking layer, the hole blocking layer, the electron transport layer, or the electron injection layer.

[0055] The substrate is a support for the light-emitting element, and a silicon plate, a quartz plate, a glass plate, a metal plate, a metal foil, a resin film, a resin sheet, etc. are used. In particular, a glass plate or a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. When using a synthetic resin substrate, attention must be paid to the gas barrier property. If the gas barrier property of the substrate is too low, the light-emitting element may be deteriorated by the outside air passing through the substrate. For this reason, it is preferable to provide a dense silicon oxide film or the like on one or both sides of the synthetic resin substrate to ensure the gas barrier property.

[0056] An anode is provided on the substrate. A material with a large work function is generally used for the anode. Examples of materials for the anode include metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium oxide, tin oxide, ITO, zinc oxide, In2O3-ZnO, and IGZO; metal halides such as copper iodide; carbon black; and conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. The formation of the anode is usually performed by a sputtering method, a vacuum deposition method, or the like. In addition, in the case of metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, the anode can also be formed by dispersing them in an appropriate binder resin solution and applying them on the substrate. Furthermore, in the case of conductive polymers, a thin film can be formed directly on the substrate by electrolytic polymerization, or a conductive polymer can be applied on the substrate to form the anode.

[0057] The anode can be formed by laminating two or more different materials. The thickness of the anode varies depending on the required transparency. When transparency is required, it is desirable to set the visible light transmittance to usually 60% or more, preferably 80% or more, and in this case, the thickness is usually 10 to 1000 nm, preferably 10 to 200 nm. When opaqueness is sufficient, the anode may have a thickness approximately equal to that of the substrate. The sheet resistance of the anode is preferably several hundred Ω / □ or more.

[0058] As the hole injection layer provided as required, in addition to porphyrin compounds such as copper phthalocyanine, naphthalenediamine derivatives, starburst-type triphenylamine derivatives, triphenylamine trimers and tetramers such as arylamine compounds having a structure in which three or more triphenylamine structures are linked in the molecule by single bonds or divalent groups not containing heteroatoms, acceptor heterocyclic compounds such as hexacyanoazatriphenylene, and coating-type polymer materials can be used. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0059] The hole transport material used in the hole transport layer, which is provided as necessary, is preferably one that has a high efficiency of hole injection from the anode and can efficiently transport the injected holes. For this purpose, it is preferable that the material has a small ionization potential, is highly transparent to visible light, has a large hole mobility, is stable, and is unlikely to generate impurities that become traps during production or use. In addition to the above general requirements, when considering application to in-vehicle displays, it is preferable that the element has a high heat resistance. Therefore, a material having a Tg value of 70°C or more is desirable.

[0060] Examples of the hole transport layer that may be provided as necessary include triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers. More specifically, examples of the compound include compounds containing m-carbazolylphenyl groups, N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (hereinafter abbreviated as TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)-benzidine (hereinafter abbreviated as NPD), benzidine derivatives such as N,N,N',N'-tetrabiphenylylbenzidine, 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (hereinafter abbreviated as TAPC), various triphenylamine trimers and tetramers, and carbazole derivatives. These can be used alone or in combination of two or more. The hole transport layer may be a film having a single layer structure or a film having a laminate structure. In addition, a coating type polymer material such as poly(3,4-ethylenedioxythiophene) (hereinafter abbreviated as PEDOT) / poly(styrenesulfonate) (hereinafter abbreviated as PSS) can be used as the hole injection / transport layer. These materials can be formed into thin films by known methods such as deposition, spin coating, and inkjet printing.

[0061] In addition, in the hole injection layer or hole transport layer, materials that are usually used in the layer can be further doped with trisbromophenylaminehexachloroantimony P, or polymer compounds having a PD structure in their partial structure, etc. Carbazole derivatives such as CBP, TCTA, and mCP can be used as hole injection / transport host materials.

[0062] Preferred compounds (hi1) to (hi7) that can be used as the hole injection material are listed below.

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] Preferred compounds (ht1) to (ht38) that can be used as the hole transport material are listed below.

[0071] [ka]

[0072] [ka]

[0073]

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[0075]

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[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] As the electron blocking layer provided as necessary, compounds having an electron blocking effect can be used, such as carbazole derivatives such as 4,4',4"-tri(N-carbazolyl)triphenylamine (hereinafter abbreviated as TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (hereinafter abbreviated as mCP), and 2,2-bis(4-carbazol-9-ylphenyl)adamantane (hereinafter abbreviated as Ad-Cz), and compounds having a triphenylsilyl group and a triarylamine structure, such as 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene. These can be used alone or in combination of two or more. The electron blocking layer may be a film of a single layer structure or a film of a laminate structure. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0110] Preferred compounds (es1) to (es5) that can be used as the electron blocking material are listed below.

[0111] [ka]

[0112]

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[0113]

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[0114]

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[0115]

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[0116] The light-emitting layer is a layer having a function of emitting light by generating excitons by recombination of holes and electrons injected from the anode and cathode, respectively. The light-emitting layer may be formed by using the light-emitting material of the present invention alone, or may be formed by doping the light-emitting material of the present invention into a host material. Examples of the host material include metal complexes of quinolinol derivatives such as tris(8-hydroxyquinoline)aluminum (hereinafter abbreviated as Alq3), anthracene derivatives, bisstyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, polyparaphenylenevinylene derivatives, compounds having a bipyridyl group and an ortho-terphenyl structure, mCP, thiazole derivatives, benzimidazole derivatives, and polydialkylfluorene derivatives. The light-emitting layer may contain a known dopant. Examples of the dopant include quinacridone, coumarin, rubrene, anthracene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, and aminostyryl derivatives. In addition, phosphorescent emitters such as green phosphorescent emitters such as Ir(ppy)3, blue phosphorescent emitters such as FIrpic and FIr6, and red phosphorescent emitters such as Btp2Ir(acac) may be used. These may be used alone or in combination of two or more. The light-emitting layer may be a film having a single layer structure or a film having a laminated structure. These materials can be formed into thin films by known methods such as vapor deposition, spin coating, and inkjet printing. When a host material is used, the amount of the light-emitting material of the present invention that can be contained in the light-emitting layer has a lower limit of preferably 0.1 mass %, more preferably 1 mass %, and an upper limit of preferably 50 mass %, more preferably 20 mass %, and even more preferably 10 mass %.

[0117] Preferred compounds (el1) to (el40) that can be used as the host material of the light-emitting layer are listed below.

[0118] [ka]

[0119]

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[0123]

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[0157]

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[0158] Examples of the hole blocking layer that may be provided as necessary include compounds having a hole blocking effect, such as compounds having a bipyridyl group and an ortho-terphenyl structure, phenanthroline derivatives such as bathocuproine (hereinafter abbreviated as BCP), metal complexes of quinolinol derivatives such as aluminum (III) bis(2-methyl-8-quinolinato)-4-phenylphenolate (hereinafter abbreviated as BAlq), various rare earth complexes, oxazole derivatives, triazole derivatives, and triazine derivatives. These materials may also serve as materials for the electron transport layer. These materials may be used alone or in combination of two or more. The hole blocking layer may be a film having a single layer structure or a film having a laminate structure. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet.

[0159] Preferred compounds (hs1) to (hs11) that can be used as the hole blocking material are listed below. [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167] [ka]

[0168] [ka]

[0169] [ka]

[0170] As the electron transport layer provided as required, in addition to metal complexes of quinolinol derivatives such as Alq3 and BAlq, various metal complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silole derivatives, etc. can be used. These can be used alone or in combination of two or more. The electron transport layer may be a film of a single layer structure or a film of a laminate structure. These materials can be formed into a thin film by known methods such as a vapor deposition method, a spin coating method, and an inkjet method.

[0171] The electron injection layer, which is provided as needed, can be made of an alkali metal salt such as lithium fluoride or cesium fluoride, an alkaline earth metal salt such as magnesium fluoride, or a metal oxide such as aluminum oxide, but can be omitted in the preferred selection of the electron transport layer and the cathode.

[0172] In the electron injection layer or electron transport layer, a material that is further doped with N-type metal such as cesium in addition to the materials normally used for the layer can be used.

[0173] Preferred compounds (et1) to (et30) that can be used as the electron transporting material are listed below.

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] [ka]

[0183]

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[0184]

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[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198]

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[0199]

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[0200]

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[0201]

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[0202]

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[0203]

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[0204] Preferred compounds (ei1) to (ei4) that can be used as the electron injection material are listed below.

[0205] [ka]

[0206] [ka]

[0207] [ka]

[0208] [ka]

[0209] Preferred compounds (st1) to (st5) that can be used as the stabilizing material are listed below.

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215] A material with a small work function is generally used for the cathode. Examples of the cathode material include sodium, sodium-potassium alloy, lithium, tin, magnesium, magnesium / copper mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, indium, calcium, aluminum, silver, lithium / aluminum mixture, magnesium-silver alloy, magnesium-indium alloy, and aluminum-magnesium alloy. A transparent or semi-transparent cathode can be obtained by using a transparent conductive material. The thickness of the cathode is usually 10 to 5000 nm, preferably 50 to 200 nm. The sheet resistance of the cathode is preferably several hundred Ω / □ or more.

[0216] In order to protect the cathode made of a low work function metal, it is preferable to further laminate a metal layer having a high work function and stable against the atmosphere, such as aluminum, silver, nickel, chromium, gold, or platinum, on the cathode, since this increases the stability of the element. In addition, in order to improve the contact between the cathode and an adjacent organic layer (e.g., an electron transport layer or an electron injection layer), a cathode interface layer may be provided between the two. Examples of materials used for the cathode interface layer include aromatic diamine compounds, quinacridone compounds, naphthacene derivatives, organic silicon compounds, organic phosphorus compounds, compounds having an N-phenylcarbazole skeleton, and N-vinylcarbazole polymers.

[0217] The light-emitting device of the present invention can be applied to any of a single element, an element having a structure in which elements are arranged in an array, and an element having a structure in which anodes and cathodes are arranged in an XY matrix.

[0218] The effects of the embodiments of the present invention will be described below.

[0219] The light emission characteristics were evaluated using a source meter (Keithley: 2400 series), a spectroradiometer (Konica Minolta: CS-2000), a spectrofluorometer (JASCO: FP-8600), and a 100 mmΦ integrating sphere (JASCO: ILF-835).

[0220] (Example 2) A toluene solution of BBCz-R was prepared in a nitrogen atmosphere glove box. The PL spectrum of this solution was measured. The results are shown in Figure 1.

[0221] BBCz-R: [ka]

[0222] (Example 3) On a glass substrate with an indium tin oxide (ITO) anode, a 10-nm-thick 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) film, a 50-nm-thick 1,1-bis[4-[N,N-di(p-tolyl)amino]phenyl]cyclohexane (TAPC) film, a 10-nm-thick mCBP film, a 20-nm-thick 2 wt% BBCz-R:mCBP film, a 10-nm-thick 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF) film, and a 40-nm-thick 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene (B3PyPB) film were deposited in this order by vacuum deposition (5.0 × 10 -4 The laminate was laminated at a pressure of 100 Pa or less.

[0223] Next, a 1 nm-thick 8-hydroxyquinolitritium film and a 100 nm-thick aluminum film were laminated in this order by vacuum deposition to form a cathode, thereby obtaining an organic electroluminescence device. The characteristics of the organic electroluminescence device were measured. The light emission characteristics are shown in Table 1. Figure 2 shows the current density-external quantum efficiency characteristics. Figure 3 shows the voltage-current density characteristics.

[0224] [Table 1]

[0225] The light-emitting device using BBCz-R showed a high maximum external quantum efficiency of 22%. The FWHM (Full Width at Half Maximum), which indicates the spread of the emission spectrum, was a narrow value of 26 nm. The chromaticity coordinates on the CIE (Commission Internationale de l'Eclairage) xy chromaticity diagram were (0.67, 0.33), and the color was close to pure red.

[0226] As described above, high light-emitting properties were obtained by using the light-emitting material made of the compound represented by formula (I).

Claims

1. A compound represented by formula (I): 【Chemistry 1】 In formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4, n is independently an integer of 0 to 3, Y is N-R 7 , O or S; Z is N-R 8 , O or S; R 7 and R 8 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, R 7 is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A to form a fused ring, R 8 When is a substituted or unsubstituted aryl group, the aryl group may be linked to ring A2 to form a fused ring.

2. The compound according to claim 1 , represented by formula (II): 【Chemistry 2】 In formula (II), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 9 and R 10 each independently represents a substituted or unsubstituted alkyl group, m is independently an integer of 0 to 4, Each n is independently an integer of 0 to 3.

3. R in formula (I) 7 and R 8 The compound according to claim 1 or 2, wherein the substituted or unsubstituted aryl group is a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.

4. In formulas (I) and (II), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 are each independently a substituted or unsubstituted C1-6 alkyl group.

5. A light-emitting material comprising the compound according to any one of claims 1 to 4.

6. A light-emitting device comprising the light-emitting material according to claim 5 .

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