Compound, light-emitting element material, light-emitting element using same, photoelectric conversion material, and photoelectric conversion element using same

Abstract

The purpose of the present invention is to provide a light-emitting element material with which it is possible to obtain a light-emitting element having excellent element efficiency and durability, and a photoelectric conversion material with which it is possible to obtain a photoelectric conversion element having high photoelectric conversion efficiency for green light. The present invention is a compound having a specific structure which has a pyrromethene structure, an aromatic ring structure, and a condensed ring structure.

Description

Compound, light-emitting element material, light-emitting element using the same, photoelectric conversion material, and photoelectric conversion element using the same

[0001] The present invention relates to a compound, a light-emitting device material, a light-emitting device using the same, a photoelectric conversion material, and a photoelectric conversion device using the same.

[0002] Organic thin-film light-emitting devices emit light when electrons injected from a cathode and holes injected from an anode recombine in an emissive layer sandwiched between the two electrodes. These devices have the advantages of being thin, requiring low driving voltage, high brightness, and capable of emitting multicolor light. In particular, by combining a host material and a dopant material in the emissive layer, it is possible to obtain a light-emitting device that emits light in the three primary colors of blue, green, and red with high efficiency.

[0003] Pyrromethene boron complexes having various structures have been reported as dopant materials capable of providing light-emitting devices with high brightness and high color purity (see, for example, Patent Document 1). In recent years, aiming for higher device efficiency, light-emitting devices that combine a TADF (thermally activated delayed fluorescence) material with a pyrromethene boron complex have been investigated (see, for example, Patent Documents 2 and 3).

[0004] In recent years, the Internet of Things (IoT) and big data have been attracting attention, and sensing technology for acquiring the various data that supports them is becoming increasingly important. There are various sensing technologies, but optical sensing in particular is a highly useful sensing technology, as it allows for a wide range of applications, such as changing the sensing target by selecting the target wavelength.

[0005] Optical sensors generally include a photoelectric conversion element that converts light into electrical energy and a light-emitting element, and sense an object by irradiating the object with light from the light-emitting element and receiving the light transmitted through or reflected from the object with the photoelectric conversion element. Such optical sensors can acquire biometric information such as fingerprints, vein patterns, and blood oxygen levels by using, for example, green, red, or near-infrared light. Furthermore, by forming the substrate, light-emitting element, and light-receiving element primarily from organic materials, it is possible to construct a thin and flexible device (see, for example, Non-Patent Document 1).

[0006] Pyrromethene compounds have been investigated as photoelectric conversion materials for use in such photoelectric conversion elements (see, for example, Patent Documents 4 to 7). Pyrromethene compounds generally have a high absorption coefficient, and are characterized in that the absorption wavelength region can be designed to a desired range by selecting a substituent.

[0007] "Science Advances", 2016, Vol. 2, p. e1501856

[0008] International Publication No. WO 2009 / 116456 International Publication No. WO 2016 / 056559 International Publication No. WO 2019 / 013063 JP 2020-72270 A International Publication No. WO 2015 / 119039 JP 2008-109097 A International Publication No. WO 2017 / 018351

[0009] As described above, light-emitting devices using pyrromethene boron complexes as dopant materials have been proposed to date, but have had problems such as insufficient device efficiency and durability. The present invention aims to provide a light-emitting device material that can provide a light-emitting device with excellent device efficiency and durability. Furthermore, the pyrromethene compounds described in Patent Documents 4 to 7 have high wavelength selectivity but have a problem of insufficient photoelectric conversion efficiency. Therefore, the present invention aims to provide a photoelectric conversion material that can provide a photoelectric conversion device with high green light photoelectric conversion efficiency.

[0010] The present invention is a compound having a structure represented by the following general formula (1).

[0011]

[0012] In the above general formula (1), A is a monovalent group having a structure represented by the following general formula (2).

[0013]

[0014] In the above general formula (2), R １ ~R ４ may be the same or different and represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group. ５ and R ６ may be the same or different and represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a carbamoyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group. １ and Z ２ may be the same or different and represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a hydroxyl group, a halogen atom, or a cyano group. L represents the bonding site to L in general formula (1).

[0015] In the above general formula (1), L is a divalent aromatic hydrocarbon group having a structure represented by the following general formula (3) or (4): A represents the bonding site to A in general formula (1).

[0016]

[0017] In the above general formulas (3) and (4), R ２１ ~R ２５and R ３１ ~R ３７ may be the same or different, and are each a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted siloxanyl group, or R ２２ and R ２３ Or R ２３ and R ２４ The ring structure formed between R ２１ is not a hydrogen atom.

[0018] In the above general formula (3), R ２１ ~R ２５ is a single bond, R in general formula (1) is bonded to that single bond. ２１ ~R ２５ When R does not have a single bond ２１ ~R ２５ At least one of R is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, ２２ and R ２３ Or R ２３ and R ２４ and R in general formula (1) is bonded to the substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, or ring structure.

[0019] In the above general formula (4), R ３１ ~R ３７ is a single bond, R in general formula (1) is bonded to that single bond. ３１ ~R ３７ When R does not have a single bond ３１ ~R３７ at least one of the groups is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or has a ring structure formed between an adjacent group, and R in general formula (1) is bonded to the substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, or ring structure.

[0020] In the above general formula (1), R is a monovalent group having a structure represented by the following general formula (5).

[0021]

[0022] In the general formula (5), X is CR Ｘ１ R Ｘ２ , N.R. Ｘ１ or a divalent heteroatom. １ ~X ８ One of the X's is a carbon atom and is the bonding site of X in general formula (1). １ ~X ８ may be the same or different, and CR Ｘ１ R Ｘ２ , N.R. Ｘ１ Alternatively, R may represent a divalent heteroatom, forming a ring structure between two adjacent substituents. Ｘ１ and R Ｘ２ may be the same or different and represent a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group.

[0023] The compound of the present invention can provide a light-emitting device material that can provide a light-emitting device excellent in device efficiency and durability, and a photoelectric conversion material that can provide a photoelectric conversion device with high photoelectric conversion efficiency for green light.

[0024] Preferred embodiments of the compound, light-emitting device material, light-emitting device using the same, photoelectric conversion material, and photoelectric conversion device using the same according to the present invention will be described in detail below. However, the present invention is not limited to the following embodiments and can be practiced with various modifications depending on the purpose and application.

[0025] The compound of the present invention has a structure represented by the following general formula (1).

[0026]

[0027] In the above general formula (1), A is a monovalent group having a structure represented by the following general formula (2), L is a divalent aromatic hydrocarbon group having a structure represented by the following general formula (3) or (4), and R is a monovalent group having a structure represented by the following general formula (5).

[0028] In the present invention, by arranging a fused ring represented by R at a specific position of a pyrromethene boron complex having a specific substituent represented by A via an aromatic hydrocarbon group having a specific structure represented by L, intramolecular rotation can be suppressed to improve the light-emitting properties of the light-emitting device, and the bulky structure can increase the distance between the pyrromethene boron complex molecules, thereby improving the device efficiency and durability. Furthermore, by suppressing intermolecular interactions, the photoelectric conversion efficiency of the photoelectric conversion device can be improved.

[0029]

[0030] In the above general formula (2), R １ ~R ４may be the same or different, and represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group. Among these, from the viewpoint of further improving the element efficiency and durability, a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group is preferable. Among these, R １ and R ４ may be the same or different, and are preferably substituted or unsubstituted alkyl groups or substituted or unsubstituted cycloalkyl groups. ２ and R ３ may be the same or different, and are preferably substituted or unsubstituted alkyl groups or substituted or unsubstituted cycloalkyl groups. By selecting these groups, the absorption peak wavelength of the compound of the present invention can be easily adjusted to a range of 490 nm to 580 nm, thereby efficiently absorbing green light and increasing the photoelectric conversion efficiency of the photoelectric conversion element.

[0031] In the above general formula (2), R ５ and R ６ may be the same or different, and represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a carbamoyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group. Among these, from the viewpoint of thermal stability, R ５ and R ６ may be the same or different and are preferably a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted cycloalkyl group.

[0032] In the above general formula (2), Z １ and Z ２ may be the same or different and represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a hydroxyl group, a halogen atom, or a cyano group. By selecting these groups, the thermal stability of the light-emitting device material can be improved. Among these, a fluorine atom is preferred from the viewpoint of device efficiency. In general formula (2), Z １ and Z ２ are preferably all fluorine atoms.

[0033] In the above general formula (2), L represents the bonding site to L in general formula (1).

[0034]

[0035] In the above general formulas (3) and (4), R ２１ ~R ２５ and R ３１ ~R ３７ may be the same or different, and are each a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted siloxanyl group, or R ２２ and R ２３ Or R ２３ and R ２４and represents a ring structure formed between the group R and the group R. By selecting these groups, it is possible to improve the device efficiency. Among these, from the viewpoint of thermal stability, a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkoxy group, a halogen atom, a substituted or unsubstituted amino group, a cyano group, or R ２２ and R ２３ Or R ２３ and R ２４ From the viewpoint of further improving durability, a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group is more preferred. ２１ is not a hydrogen atom. ２１ If is hydrogen, the intramolecular rotation cannot be suppressed, resulting in a decrease in the efficiency and durability of the device.

[0036] In the above general formula (3), R ２１ ~R ２５ is a single bond, R in general formula (1) is bonded to that single bond. ２１ ~R ２５ When R does not have a single bond ２１ ~R ２５ At least one of R is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, ２２ and R ２３ Or R ２３ and R ２４ and R in general formula (1) is bonded to the substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, or ring structure. ３１ ~R ３７ is a single bond, R in general formula (1) is bonded to that single bond. ３１ ~R３７ When R does not have a single bond ３１ ~R ３７ At least one of the groups is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or has a ring structure formed between adjacent groups, and R in general formula (1) is bonded to either the substituted or unsubstituted aryl group, the substituted or unsubstituted heteroaryl group, or the ring structure. That is, R in general formula (1) is bonded to a ring structure (including an aromatic ring). By bonding R in general formula (1) to a ring structure, thermal stability and film stability can be improved. From the viewpoint of further improving durability, in general formula (3), R ２１ ~R ２５ or in general formula (4), R ３１ ~R ３７ It is preferable that either of these is a single bond.

[0037]

[0038] In the general formula (5), X is CR Ｘ１ R Ｘ２ , N.R. Ｘ１ or a divalent heteroatom. Ｘ１ R Ｘ２ , N.R. Ｘ１ Alternatively, it is preferably an oxygen atom. １ ~X ８ One of the X's is a carbon atom and is the bonding site of X in general formula (1). １ ~X ８ may be the same or different, and CR Ｘ１ R Ｘ２ , N.R. Ｘ１ Alternatively, R may represent a divalent heteroatom, forming a ring structure between two adjacent substituents. Ｘ１ and R Ｘ２may be the same or different, and represent a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group or a substituted or unsubstituted siloxanyl group.Among these, from the viewpoint of thermal stability, a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a halogen atom, a cyano group are preferred.

[0039] In the description of the present invention, "unsubstituted" means that the atoms bonded to the target basic skeleton or group are only hydrogen atoms or deuterium atoms. Furthermore, when the target group has a substituent, examples of the substituent include an alkyl group, a halogen atom, an aryl group, and a heteroaryl group. Furthermore, the preferred range of the number of carbon atoms shown for each group does not include the carbon atoms of the substituent.

[0040] In the description of the present invention, hydrogen in all groups may be deuterium.

[0041] The alkyl group refers to a saturated aliphatic hydrocarbon group, which may or may not have a substituent, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group. The number of carbon atoms in the alkyl group is not particularly limited, but from the viewpoints of availability and cost, it is preferably in the range of 1 to 20, more preferably 1 to 8.

[0042] The cycloalkyl group refers to a saturated alicyclic hydrocarbon group, such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group, which may or may not have a substituent. The number of ring carbon atoms is not particularly limited, but is preferably in the range of 3 to 20.

[0043] The aryl group refers to an aromatic hydrocarbon group such as a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthracenyl group, a benzophenanthryl group, a benzanthracenyl group, a chrysenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, a benzofluoranthenyl group, a dibenzoanthracenyl group, a perylenyl group, or a helicenyl group, which may or may not have a substituent. Among these, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group, or a triphenylenyl group is preferred. The number of ring carbon atoms is not particularly limited, but is preferably in the range of 6 to 40, more preferably 6 to 30. Furthermore, in a phenyl group, when two adjacent carbon atoms in the phenyl group each have a substituent, the substituents may form a ring structure together.

[0044] Examples of heteroaryl groups include pyridyl, furanyl, thiophenyl, quinolinyl, isoquinolinyl, pyrazinyl, pyrimidyl, pyridazinyl, triazinyl, naphthyridinyl, cinnolinyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothiophenyl, indolyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, benzocarbazolyl, and carbolinyl groups.

[0039] Heteroaryl groups include cyclic aromatic groups having one or more atoms other than carbon in the ring, such as indolocarbazolyl groups, benzofurocarbazolyl groups, benzothienocarbazolyl groups, dihydroindenocarbazolyl groups, benzoquinolinyl groups, acridinyl groups, dibenzoacridinyl groups, benzimidazolyl groups, imidazopyridyl groups, benzoxazolyl groups, benzothiazolyl groups, and phenanthrolinyl groups, which may or may not have a substituent. The number of ring atoms in the heteroaryl group is not particularly limited, but is preferably in the range of 3 to 40, more preferably 3 to 30.

[0045] The alkoxy group refers to a group in which an aliphatic hydrocarbon group, such as a methoxy group, an ethoxy group, or a propoxy group, is bonded via an ether bond, and this aliphatic hydrocarbon group may or may not have a substituent. The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably in the range of 1 to 20.

[0046] An alkylthio group is an alkoxy group in which the oxygen atom of the ether bond is replaced with a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. The number of carbon atoms in the alkylthio group is not particularly limited, but is preferably in the range of 1 to 20.

[0047] The aryloxy group refers to a group, such as a phenoxy group, to which an aromatic hydrocarbon group is bonded via an ether bond, and the aromatic hydrocarbon group may or may not have a substituent. The number of ring carbon atoms of the aryloxy group is not particularly limited, but is preferably in the range of 6 to 40.

[0048] An arylthio group is an aryloxy group in which the oxygen atom of the ether bond is substituted with a sulfur atom. The aromatic hydrocarbon group in the arylthio group may or may not have a substituent. The number of ring carbon atoms in the arylthio group is not particularly limited, but is preferably in the range of 6 to 40.

[0049] The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as a vinyl group, an allyl group, or a butadienyl group, which may or may not have a substituent. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0050] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group, which may or may not have a substituent. The number of ring carbon atoms is not particularly limited, but is preferably in the range of 3 to 20.

[0051] The alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as an ethynyl group, which may or may not have a substituent. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0052] The amino group may or may not have a substituent.

[0053] The nitro group is -NO ２ Here, it is the nitrogen atom that bonds to the other functional groups.

[0054] The silyl group refers to a group to which a substituted or unsubstituted silicon atom is bonded, and examples thereof include alkylsilyl groups such as trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, propyldimethylsilyl, and vinyldimethylsilyl, and arylsilyl groups such as phenyldimethylsilyl, tert-butyldiphenylsilyl, triphenylsilyl, and trinaphthylsilyl. The substituent on the silicon may be further substituted. The number of carbon atoms in the silyl group is not particularly limited, but is preferably in the range of 1 to 30.

[0055] The siloxanyl group refers to a silicon compound group bonded via an ether bond, such as a trimethylsiloxanyl group, etc. The substituent on the silicon may be further substituted.

[0056] A carbonyl group is a group represented by -C(=O)-, where the carbon atom is bonded to another functional group.

[0057] A carboxyl group is a group in which a hydroxyl group is bonded to a carbonyl group.

[0058] An alkoxycarbonyl group is a group in which an alkoxy group or an aryloxy group is bonded to a carbonyl group.

[0059] A carbamoyl group is a functional group in which an amino group is bonded to a carbonyl group.

[0060] The halogen atom refers to an atom selected from fluorine, chlorine, bromine and iodine.

[0061] A cyano group is a group whose structure is represented by -C≡N, where it is the carbon atom that bonds to other functional groups.

[0062] Examples of A having the structure represented by general formula (2) are shown below, but are not limited to these: where L represents the bonding site to L in general formula (1).

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] Examples of L having a structure represented by general formula (3) or (4) are shown below, but are not limited to these, where A represents the bonding site to A in general formula (1), and R represents the bonding site to R in general formula (1).

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] Examples of R having the structure represented by general formula (5) are shown below, but are not limited to these: where L represents the bonding site to L.

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083] The pyrromethene boron complex having the structure represented by general formula (1) is composed of the above A, L and R.

[0084] The pyrromethene boron complex having the structure represented by general formula (1) can be produced by referring to the methods described in, for example, J. Org. Chem., vol. 64, No. 21, pp. 7813-7819 (1999), Angew. Chem., Int. Ed. Engl., vol. 36, pp. 1333-1335 (1997), Org. Lett., vol. 12, pp. 296 (2010), etc.

[0085] The obtained pyrromethene boron complex is preferably purified by organic synthesis techniques such as recrystallization or column chromatography, and then further purified by heating under reduced pressure, generally known as sublimation purification, to remove low-boiling components and improve purity. The heating temperature in sublimation purification is not particularly limited, but is preferably 330°C or lower, and more preferably 300°C or lower, from the viewpoint of preventing thermal decomposition of the pyrromethene boron complex.

[0086] The purity of the pyrromethene boron complex is preferably 99% by weight or more from the viewpoint of stabilizing the light-emitting device characteristics and photoelectric conversion characteristics.

[0087] From the viewpoint of improving color purity, it is preferable that the emission spectrum of light emitted by the pyrromethene boron complex having the structure represented by general formula (1) upon irradiation with excitation light is sharp. Furthermore, top-emission elements, which are mainstream in display devices and lighting devices, can achieve high brightness and high color purity due to the resonance effect of the microcavity structure, and a sharp emission spectrum makes this resonance effect more pronounced, which is advantageous for improving efficiency. From this viewpoint, the half-width of the emission spectrum is preferably 45 nm or less, and more preferably 35 nm or less.

[0088] <Light-Emitting Device Material> The light-emitting device material of the present invention comprises the compound of the present invention. That is, it refers to a material comprising a pyrromethene boron complex having a structure represented by general formula (1) and used in any layer of a light-emitting device. In other words, the light-emitting device material refers to the use of the compound of the present invention, i.e., the pyrromethene boron complex having a structure represented by general formula (1) described above. Examples of light-emitting device materials include materials used in the hole injection layer, hole transport layer, light-emitting layer, electron transport layer, and / or protective film (cap layer) of an electrode, which will be described later. Among these, the light-emitting device material is preferably used in the light-emitting layer because of its high device efficiency and durability.

[0089] <Light-Emitting Element> Next, an embodiment of the light-emitting element of the present invention will be described. The light-emitting element of the present invention has a light-emitting layer containing the light-emitting element material of the present invention between an anode and a cathode, and emits light when exposed to electrical energy.

[0090] The light-emitting device of the present invention may be either a bottom-emission type or a top-emission type. Among these, the light-emitting device material of the present invention has a narrow half-width of the emission spectrum and high device efficiency, and therefore can be preferably used for a top-emission type light-emitting device. That is, the light-emitting device of the present invention is preferably a top-emission type organic electroluminescent device. In a top-emission type light-emitting device, the narrower the half-width, the higher the device efficiency due to the resonance effect of the microcavity. Therefore, it is possible to achieve both color purity and device efficiency at a higher level.

[0091] The layer configuration between the anode and the cathode in such a light-emitting element may be a configuration consisting of only a light-emitting layer, or may be a laminate configuration such as 1) light-emitting layer / electron transport layer, 2) hole transport layer / light-emitting layer, 3) hole transport layer / light-emitting layer / electron transport layer, 4) hole injection layer / hole transport layer / light-emitting layer / electron transport layer, 5) hole transport layer / light-emitting layer / electron transport layer / electron injection layer, 6) hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer, 7) hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer, or 8) hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer.

[0092] Furthermore, a tandem type may be used in which a plurality of the above-described laminated structures are laminated via an intermediate layer. Examples of the intermediate layer include an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, and an intermediate insulating layer, and known material structures can be used. Specific preferred examples of the tandem type include laminated structures having two or more light-emitting layers between an anode and a cathode, and one or more charge-generating layers between the respective light-emitting layers, such as 9) hole transport layer / light-emitting layer / electron transport layer / charge generation layer / hole transport layer / light-emitting layer / electron transport layer, and 10) hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / charge generation layer / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer.

[0093] Each of the above layers may be a single layer or multiple layers, and may be doped. In addition to the above layers, a protective layer may be provided, which can further improve the device efficiency by optical interference effects.

[0094] Specific examples of the configuration of the light-emitting element are given below, but the configuration of the present invention is not limited to these.

[0095] (Substrate) It is preferable to form the light-emitting element on a substrate in order to maintain the mechanical strength of the light-emitting element, minimize thermal deformation, and provide barrier properties that prevent water vapor and oxygen from penetrating the light-emitting layer. The substrate is not particularly limited, but examples include glass plates, ceramic plates, resin films, thin resin films, and thin metal plates. Among these, glass substrates are preferably used because of their transparency and ease of processing. In particular, for bottom-emission light-emitting elements that extract light through the substrate, highly transparent glass substrates are preferred. Furthermore, flexible displays and foldable displays are becoming increasingly common, primarily in mobile devices such as smartphones, and for these applications, resin films and thin resin films obtained by curing varnish are preferably used. Heat-resistant films are used as resin films, and specific examples include polyimide films and polyethylene naphthalate films.

[0096] Furthermore, various wirings, circuits, and switching elements using TFTs for driving the organic EL may be provided on the surface of the substrate.

[0097] (Anode) The anode is preferably formed on the substrate. Various wirings, circuits, and switching elements may be interposed between the substrate and the anode. The material used for the anode is not particularly limited as long as it can efficiently inject holes into the organic layer. In the case of a bottom-emission light-emitting element, it is preferably a transparent or semi-transparent electrode, and in the case of a top-emission light-emitting element, it is preferably a reflective electrode.

[0098] Examples of materials constituting a transparent or translucent electrode include conductive metal oxides such as zinc oxide, tin oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, aluminum, and chromium; and conductive polymers such as polythiophene, polypyrrole, and polyaniline. However, when using a metal, it is preferable to make the film thickness thin so that light can be semi-transmitted. Among these, indium tin oxide (ITO) is more preferable from the viewpoints of transparency and stability.

[0099] The material for the reflective electrode is preferably one that does not absorb any light and has high reflectivity, and examples thereof include metals such as aluminum, silver, and platinum.

[0100] Two or more of these electrode materials may be used, or a plurality of materials may be laminated.

[0101] The thickness of the anode is not particularly limited, but is preferably from several nm to several hundred nm.

[0102] The method for forming the anode can be selected optimally depending on the material used, and examples thereof include sputtering, vapor deposition, inkjet printing, etc. For example, sputtering is preferably used when the anode is made of a metal oxide, and vapor deposition is preferably used when the anode is made of a metal.

[0103] (Cathode) The cathode is formed on the surface opposite to the anode with the organic layer sandwiched therebetween, and is preferably formed in contact with the electron transport layer or the electron injection layer. The material used for the cathode is not particularly limited as long as it can efficiently inject electrons into the light emitting layer, but in the case of a bottom emission type light emitting element, it is preferably a reflective electrode, and in the case of a top emission type light emitting element, it is preferably a semi-transparent electrode.

[0104] Preferred materials for the cathode include metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium; alloys or multilayer laminates of these metals with low work function metals such as lithium, sodium, potassium, calcium, and magnesium; and conductive metal oxides such as zinc oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Among these, aluminum, silver, and magnesium are preferred as the main component from the viewpoints of electrical resistance, ease of film formation, film stability, and device efficiency. Furthermore, a cathode made of magnesium and silver is preferred because it facilitates electron injection into the electron transport layer and electron injection layer, thereby enabling a reduction in driving voltage.

[0105] The thickness of the cathode is not particularly limited, but is preferably from several nm to several μm.

[0106] The cathode can be formed by an optimum method selected depending on the material used, and examples thereof include sputtering, vapor deposition, etc. For example, when the cathode is made of metal, the vapor deposition method is preferably used.

[0107] (Protective Layer) For cathode protection, it is preferable to laminate a protective layer (cap layer) on the cathode. The material constituting the protective layer is not particularly limited, but examples thereof include metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, alloys using these metals, inorganic substances such as silica, titania, and silicon nitride, and organic polymer compounds such as polyvinyl alcohol, polyvinyl chloride, and hydrocarbon polymer compounds. However, in the case of a top-emission light-emitting element, it is preferable that the material used for the protective layer be selected from materials that are optically transparent in the visible light region.

[0108] (Hole injection layer) The hole injection layer is inserted between the anode and the hole transport layer to facilitate hole injection. The hole injection layer may be a single layer or may be a laminate of multiple layers. The presence of the hole injection layer between the hole transport layer and the anode allows the device to be driven at a lower voltage and improves durability. Furthermore, the carrier balance of the device is improved, thereby improving device efficiency.

[0109] A preferred example of the hole injection material constituting the hole injection layer is an electron-donating hole injection material (donor material). These materials have a shallower HOMO level than the hole transport layer and a work function close to that of the anode, and therefore can reduce the energy barrier with the anode. Specific examples include aromatic amine-based materials such as benzidine derivatives, starburst arylamines such as 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine (m-MTDATA) and 4,4',4"-tris(1-naphthyl(phenyl)amino)triphenylamine (1-TNATA), heterocyclic compounds such as carbazole derivatives, pyrazoline derivatives, stilbene compounds, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, phthalocyanine derivatives, and porphyrin derivatives, polycarbonates and styrene derivatives having the above-mentioned monomers in their side chains, polythiophenes such as PEDOT / PSS, polyaniline, polyfluorene, polyvinylcarbazole, and polysilane polymers. Two or more of these may be used. Furthermore, a plurality of materials may be laminated to form the hole injection layer.

[0110] Another preferred example of the hole injection material is an electron-accepting hole injection material (acceptor material). The hole injection layer may be composed of an acceptor material alone, or may be composed of the donor material doped with the acceptor material. The acceptor material is a material that forms a charge-transfer complex with the adjacent hole transport layer when used alone, or with the donor material when used as a dopant. The use of such a material is more preferred because it contributes to improving the conductivity of the hole injection layer and reducing the driving voltage of the device, thereby further improving the device efficiency and durability. Examples of acceptor materials include metal oxides such as molybdenum oxide, vanadium oxide, tungsten oxide, and ruthenium oxide, charge-transfer complexes such as tris(4-bromophenyl)aminium hexachloroantimonate (TBPAH), 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN6), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), tetracyanoquinodimethane derivatives, radialene derivatives, n-type organic semiconductor compounds such as fluorinated copper phthalocyanine, and fullerenes. When the hole-injection layer contains an acceptor compound, the hole-injection layer may be a single layer, or may be configured by laminating multiple layers.

[0111] (Hole Transport Layer and Electron Blocking Layer) The hole transport layer is a layer that transports holes injected from the anode to the light-emitting layer, and the electron blocking layer is a layer that efficiently blocks the movement of electrons. Both the hole transport layer and the electron blocking layer may be configured as a single layer or a laminate of multiple layers. Furthermore, it is preferable that the hole transport material used in the hole transport layer and the electron blocking layer has high hole injection efficiency and efficiently transports the injected holes. To this end, it is preferable that the material has an appropriate ionization potential, high hole mobility, excellent stability, and is unlikely to generate impurities that become traps.

[0112] Substances that satisfy these conditions include, but are not limited to, heterocyclic compounds such as benzidine derivatives, aromatic amine materials called starburst arylamines, carbazole derivatives, pyrazoline derivatives, stilbene compounds, hydrazone compounds, benzofuran derivatives, dibenzofuran derivatives, thiophene derivatives, benzothiophene derivatives, dibenzothiophene derivatives, fluorene derivatives, spirofluorene derivatives, oxadiazole derivatives, phthalocyanine derivatives, and porphyrin derivatives, as well as polymers such as polycarbonates and styrene derivatives having the above-mentioned monomers in their side chains, polythiophenes, polyanilines, polyfluorenes, polyvinylcarbazoles, and polysilanes. Two or more of these may be used.

[0113] (Light-emitting layer) The light-emitting layer is a layer that emits light by excitation energy generated by the recombination of holes and electrons. The light-emitting layer may be composed of a single material, but from the viewpoint of color purity, it is preferable to have a first compound and a second compound that is a dopant that exhibits strong light emission. Suitable examples of the first compound include, for example, a host material that is responsible for charge transfer and a TADF material.

[0114] A light-emitting device material having a structure represented by general formula (1) is preferably used as a second compound that is a dopant in the light-emitting layer because it can achieve a narrow half-width of the emission spectrum and high color purity, and its bulky structure increases the distance between molecules and prevents concentration quenching. That is, in the light-emitting device of the present invention, the light-emitting layer preferably has a first compound and a second compound that is a dopant, and the second compound is the light-emitting device material of the present invention. From the viewpoint of further suppressing concentration quenching, the content of the second compound in the light-emitting layer is preferably 5 wt% or less, more preferably 2 wt% or less. On the other hand, from the viewpoint of more efficient energy transfer, the content of the second compound in the light-emitting layer is preferably 0.1 wt% or more, more preferably 0.5 wt% or more.

[0115] The host material is not particularly limited, and examples thereof include compounds having a fused aryl ring such as naphthacene, pyrene, anthracene, and fluoranthene, and derivatives thereof, aromatic amine derivatives such as N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine, metal chelated oxinoid compounds such as tris(8-quinolinato)aluminum(III), bisstyryl derivatives such as distyrylbenzene derivatives, tetraphenylbutadiene derivatives, indene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, pyrrolopyrrole derivatives, thiadiazolopyridine derivatives, dibenzofuran derivatives, carbazole derivatives, indolocarbazole derivatives, triazine derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polymers such as polythiophene derivatives. Two or more of these host materials may be used, or two or more host materials may be laminated. Among these, carbazole derivatives, anthracene derivatives, and naphthacene derivatives are preferred.

[0116] The dopant material may contain a fluorescent material other than the pyrromethene boron complex having the structure represented by general formula (1). Specific examples include compounds having fused aryl rings such as naphthacene, pyrene, anthracene, and fluoranthene, and derivatives thereof; compounds having heteroaryl rings and derivatives thereof; distyrylbenzene derivatives; aminostyryl derivatives; tetraphenylbutadiene derivatives; stilbene derivatives; aldazine derivatives; pyrromethene derivatives; diketopyrrolo[3,4-c]pyrrole derivatives; coumarin derivatives; azole derivatives and metal complexes thereof; and aromatic amine derivatives. Furthermore, molecules utilizing the multiple resonance effect by containing boron and nitrogen in the same molecule may also be used. Two or more of these may also be used.

[0117] The dopant material may also contain a phosphorescent material. The phosphorescent material is preferably a metal complex compound containing at least one metal selected from the group consisting of iridium (Ir), ruthenium (Ru), palladium (Pd), platinum (Pt), osmium (Os), and rhenium (Re), and from the viewpoint of highly efficient luminescence, an iridium complex or a platinum complex is more preferable. The ligand preferably has a nitrogen-containing heteroaryl group such as a phenylpyridine skeleton, a phenylquinoline skeleton, or a carbene skeleton, but is not limited thereto.

[0118] The dopant material preferably consists solely of a light emitting device material having a structure represented by general formula (1).

[0119] In addition to the host material or dopant material, the light-emitting layer may further contain a third component for adjusting the carrier balance in the light-emitting layer or for stabilizing the layer structure of the light-emitting layer. However, it is preferable to select a material as the third component that does not cause an interaction between the host material and the dopant material.

[0120] Delayed fluorescent materials are materials that promote reverse intersystem crossing from the triplet excited state to the singlet excited state by reducing the energy gap between the singlet excited state and the triplet excited state, thereby improving the probability of generating singlet excitons. By utilizing delayed fluorescence due to this TADF mechanism, the theoretical internal efficiency can be increased to 100%. Furthermore, when Förster-type energy transfer occurs from the singlet excited state of a first compound having delayed fluorescence to the singlet excited state of a second compound, fluorescence emission from the singlet excited state of the second compound is observed. Here, when the second compound is a fluorescent material with a sharp emission spectrum, a light-emitting device with superior device efficiency and color purity can be obtained. Thus, when the light-emitting layer contains a delayed fluorescent material, device efficiency is further improved, contributing to lower power consumption of the display. The delayed fluorescent material may be a material that exhibits delayed fluorescence from a single material, or may be a material that exhibits delayed fluorescence from multiple materials, such as when forming an exciplex complex.

[0121] The delayed fluorescent compound may be a single material or multiple materials, and known materials can be used. Specific examples include benzonitrile derivatives, triazine derivatives, disulfoxide derivatives, carbazole derivatives, indolocarbazole derivatives, dihydrophenazine derivatives, thiazole derivatives, and oxadiazole derivatives. Examples of such delayed fluorescent compounds include, but are not limited to, the following. Two or more of these may be contained.

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] The first compound is preferably a delayed fluorescent compound. The second compound is preferably a pyrromethene boron complex having a structure represented by the general formula (1). When the first compound is a delayed fluorescent compound, the light-emitting layer preferably further contains a third compound having a singlet energy greater than that of the first compound. This allows the third compound to confine the energy of the light-emitting material within the light-emitting layer, enabling efficient light emission. The lowest excited triplet energy of the third compound is preferably greater than that of the first compound.

[0130] The third compound is preferably an organic compound having high charge transport ability and a high glass transition temperature. The third compound is not particularly limited, but examples include the following. Two or more of these may be contained.

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140] (Electron Transport Layer and Hole Blocking Layer) The electron transport layer is a layer that receives electrons injected from the cathode and further transports the electrons, while the hole blocking layer is a layer that efficiently blocks the movement of holes. The electron transport material used in the electron transport layer and the hole blocking layer is preferably a substance that has high electron affinity, high electron mobility, excellent stability, and is unlikely to generate impurities that become traps. Furthermore, from the viewpoint of suppressing film quality deterioration due to crystallization, a compound with a molecular weight of 400 or more is preferred.

[0141] Examples of electron transport materials include polycyclic aromatic derivatives, styryl aromatic ring derivatives, quinone derivatives, phosphorus oxide derivatives, and various metal complexes such as quinolinol complexes of tris(8-quinolinolato)aluminum(III), benzoquinolinol complexes, hydroxyazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes. From the perspective of reducing the driving voltage and further improving device efficiency, it is preferable to use a compound having a heteroaryl group containing electron-accepting nitrogen. Here, electron-accepting nitrogen refers to a nitrogen atom that forms a multiple bond with an adjacent atom. Heteroaryl groups containing electron-accepting nitrogen have a large electron affinity, which facilitates electron injection from the cathode and allows for further reduction in driving voltage. Furthermore, the increased supply of electrons to the light-emitting layer increases the recombination probability, thereby further improving device efficiency. Examples of compounds having a heteroaryl group structure containing electron-accepting nitrogen include pyridine derivatives, triazine derivatives, pyrazine derivatives, pyrimidine derivatives, quinoline derivatives, quinoxaline derivatives, quinazoline derivatives, naphthyridine derivatives, benzoquinoline derivatives, phenanthroline derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, triazole derivatives, oxadiazole derivatives, thiadiazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, phenanthroimidazole derivatives, oligopyridine derivatives such as bipyridine and terpyridine, etc. Two or more of these may be used.

[0142] Furthermore, it is more preferable that the electron transport material has a condensed polycyclic aromatic skeleton, since the glass transition temperature is improved, the electron mobility is large, and the driving voltage can be reduced. As such a condensed polycyclic aromatic skeleton, a quinolinol complex, a triazine derivative, a fluoranthene skeleton, an anthracene skeleton, a pyrene skeleton, or a phenanthroline skeleton is preferable.

[0143] The electron transport layer may contain a donor material. Here, the donor material is a compound that improves the electron injection barrier, thereby facilitating electron injection from the cathode or the electron injection layer into the electron transport layer, and further improving the electrical conductivity of the electron transport layer. Preferred examples of the donor material include alkali metals such as Li, inorganic salts containing alkali metals such as LiF, complexes of alkali metals and organic substances such as lithium quinolinol, alkaline earth metals, inorganic salts containing alkaline earth metals, complexes of alkaline earth metals and organic substances, rare earth metals such as Eu and Yb, inorganic salts containing rare earth metals, and complexes of rare earth metals and organic substances. Two or more of these may be used. Among these, metallic lithium, rare earth metals, and lithium quinolinol (Lq) are preferred.

[0144] (Charge Generation Layer) The charge generation layer in the present invention is a layer that generates or separates charges upon application of a voltage and injects the charges into adjacent layers. The charge generation layer may be formed of a single layer or may be a laminate of multiple layers. In general, a layer that easily generates electrons as charges is called an n-type charge generation layer, and a layer that easily generates holes is called a p-type charge generation layer. The charge generation layer preferably consists of a double layer, and a p-n junction charge generation layer consisting of an n-type charge generation layer and a p-type charge generation layer is more preferred. In a light-emitting element, a p-n junction charge generation layer generates charges upon application of a voltage or separates charges into holes and electrons, and injects these holes and electrons into the light-emitting layer via a hole transport layer and an electron transport layer. Specifically, in a light-emitting element in which multiple light-emitting layers are stacked, the p-type charge generation layer functions as an intermediate layer, or a charge generation layer. The n-type charge generation layer supplies electrons to the first light-emitting layer located on the anode side, and the p-type charge generation layer supplies holes to the second light-emitting layer located on the cathode side. Therefore, it is possible to further improve the device efficiency in a light-emitting element having a plurality of stacked light-emitting layers, reduce the driving voltage, and further improve the durability of the element. That is, it is preferable that the light-emitting element of the present invention has two or more light-emitting layers between the anode and the cathode, and has one or more charge-generating layers between the respective light-emitting layers.

[0145] The n-type charge generation layer is composed of an n-type dopant and an n-type host, and conventional materials can be used for these. For example, the donor materials exemplified as materials for the electron transport layer are preferably used as the n-type dopant. Among these, alkali metals or their salts, and rare earth metals are preferred, with metallic lithium, lithium fluoride (LiF), lithium quinolinol (Liq), and metallic ytterbium being more preferred. Furthermore, the n-type host is preferably one of the materials exemplified as electron transport materials. Among these, triazine derivatives, phenanthroline derivatives, and oligopyridine derivatives are preferred, with phenanthroline derivatives and terpyridine derivatives being more preferred, and phenanthroline derivatives represented by the following general formula (6) being even more preferred. That is, the light-emitting element of the present invention preferably contains a phenanthroline derivative represented by general formula (6) in the charge generation layer.

[0146]

[0147] In the above general formula (6), Ar １ is selected from the group consisting of p-valent aromatic hydrocarbon groups and p-valent aromatic heterocyclic groups, where p is a natural number from 1 to 3. ８ ~R １４ may be the same or different and represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a heterocyclic group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. １ In the above, the substitution positions of the p phenanthrolyl groups are arbitrary positions.

[0148] The aromatic hydrocarbon group is, for example, an aryl group when it is monovalent. From the viewpoints of ease of synthesis and sublimation, the aromatic hydrocarbon group is preferably a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, or a group obtained by removing at least a portion of the hydrogen atoms from these groups. The number of ring carbon atoms in the aromatic hydrocarbon group is preferably in the range of 6 to 40, more preferably 6 to 30. Furthermore, when there are substituents on each of two adjacent carbon atoms, the substituents may form a ring structure together.

[0149] The aromatic heterocyclic group refers to a cyclic aromatic group having one or more atoms other than carbon in the ring, and is, for example, a heteroaryl group when it is monovalent. The number of ring atoms of the aromatic heterocyclic group is not particularly limited, but is preferably in the range of 3 to 40, more preferably 3 to 30.

[0150] The aromatic hydrocarbon group or aromatic heterocyclic group may further have a substituent other than the phenanthryl group.

[0151] From the viewpoint of sublimation property and thin film formability, p is preferably 2.

[0152] An example of the phenanthroline derivative represented by the general formula (6) is shown below.

[0153]

[0154] The p-type charge generating layer is composed of a p-type dopant and a p-type host, and conventional materials can be used for these. For example, the p-type dopant can be an acceptor material exemplified as the material for the hole injection layer, iodine, FeCl ３ , FeF ３ , SbCl ５ Specifically, HAT-CN6, F4-TCNQ, tetracyanoquinodimethane derivatives, radialene derivatives, iodine, FeCl ３ , FeF ３ , SbCl ５and the like. Two or more of these may be contained. Among these, radialene derivatives such as HAT-CN6, (2E,2'E,2''E)-2,2',2''-(cyclopropane-1,2,3-triylidene)tris(2-(perfluorophenyl)-acetonitrile), and (2E,2'E,2''E)-2,2',2''-(cyclopropane-1,2,3-triylidene)tris(2-(4-cyanoperfluorophenyl)-acetonitrile) are more preferred. A thin film of a p-type dopant may be formed, and its film thickness is preferably 10 nm or less. Furthermore, arylamine derivatives are preferred as p-type hosts.

[0155] (Electron Injection Layer) The electron injection layer is a layer that assists the injection of electrons from the cathode to the electron transport layer, and is preferably formed between the cathode and the electron transport layer. Examples of electron injection materials used in the electron injection layer include compounds having a heteroaryl ring structure containing electron-accepting nitrogen and the donor materials described above. Two or more of these may be contained. Among these, triazine derivatives, phenanthroline derivatives, and oligopyridine derivatives are preferred, with phenanthroline derivatives and terpyridine derivatives being more preferred, and the phenanthroline derivative represented by the general formula (6) being even more preferred. That is, the light-emitting device of the present invention preferably has an electron injection layer between the cathode and the electron transport layer, and the electron injection layer preferably contains the phenanthroline derivative represented by the general formula (6).

[0156] Furthermore, inorganic insulating or semiconducting materials can also be used for the electron injection layer, which can prevent short circuits in the light emitting element and improve the electron injection properties.

[0157] Such an insulator is preferably a metal compound such as an alkali metal chalcogenide, an alkaline earth metal chalcogenide, an alkali metal halide, an alkaline earth metal halide, etc. Two or more of these may be used.

[0158] (Method for manufacturing light-emitting element) The method for forming each of the layers constituting the light-emitting element may be either a dry process or a wet process, and examples thereof include resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, coating, inkjet printing, etc. Among these, resistance heating evaporation is preferred from the viewpoint of element characteristics.

[0159] The thickness of the organic layer is not limited because it depends on the resistance value of the light-emitting substance, but is preferably 1 to 1,000 nm. The thickness of each of the light-emitting layer, electron transport layer, hole-blocking layer, hole transport layer, electron blocking layer, and charge-generating layer is preferably 1 nm to 200 nm, more preferably 5 nm to 100 nm.

[0160] (Characteristics of Light-Emitting Element) The light-emitting element according to the embodiment of the present invention has a function of converting electrical energy into light. While direct current is primarily used as the electrical energy, pulsed current or alternating current can also be used. There are no particular limitations on the current value and voltage value, and the required characteristic values ​​vary depending on the purpose of the element. However, from the viewpoint of the power consumption and lifespan of the element, it is preferable that high brightness can be obtained at a low voltage.

[0161] In order to further enhance color purity, the light emitting device according to the embodiment of the present invention preferably has a half-width of 45 nm or less, more preferably 35 nm or less, in the fluorescent emission spectrum when energized.

[0162] (Use of Light-Emitting Device) The light-emitting device according to the embodiment of the present invention is suitably used as a display device such as a display that displays in a matrix and / or segment system.

[0163] The light-emitting element according to the embodiment of the present invention is also preferably used as a backlight for various devices. Backlights are primarily used for the purpose of improving the visibility of display devices such as non-self-luminous displays, and are used in display devices such as liquid crystal displays, clocks, audio devices, automobile panels, display boards, and signs. In particular, the light-emitting element of the present invention is preferably used as a backlight for liquid crystal displays, particularly for personal computers, which are being considered for thinning, and can provide a backlight that is thinner and lighter than conventional ones.

[0164] The light-emitting element according to the embodiment of the present invention is preferably used as a variety of lighting devices. The light-emitting element according to the embodiment of the present invention can achieve both high device efficiency and high color purity, and furthermore, can be made thin and lightweight, so that a lighting device that combines low power consumption, vivid luminous color, and high designability can be realized.

[0165] <Photoelectric Conversion Material> The photoelectric conversion material of the present invention comprises the compound of the present invention. That is, the photoelectric conversion material comprises a pyrromethene boron complex represented by general formula (1), and represents a material used as a material constituting a photoelectric conversion layer in a photoelectric conversion element having a photoelectric conversion layer between an anode and a cathode. In other words, the photoelectric conversion material refers to the use of the compound of the present invention, i.e., the pyrromethene boron complex represented by the above-mentioned general formula (1).

[0166] The photoelectric conversion material of the present invention may be composed only of the compound having the structure represented by general formula (1) of the present invention, but may further contain other photoelectric conversion materials in order to further increase the photoelectric conversion efficiency.

[0167] Next, the photoelectric conversion element of the present invention will be described. The photoelectric conversion element of the present invention is a photoelectric conversion element that has a photoelectric conversion layer between an anode and a cathode, converts light into electrical energy, and contains the photoelectric conversion material of the present invention in the photoelectric conversion layer.

[0168] The photoelectric conversion layer preferably contains two or more types of photoelectric conversion materials, and for example, it is preferable to combine the photoelectric conversion material having the structure represented by general formula (1) of the present invention with another photoelectric conversion material. The photoelectric conversion material to be combined is preferably an organic semiconductor exhibiting p-type or n-type semiconductor properties.

[0169] Examples of n-type semiconductors include 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI), N,N'-dioctyl-3,4,9,10-naphthyltetracarboxylic diimide (PTCDI-CH); 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-o Examples of suitable materials include oxazole derivatives such as oxadiazole (PBD) and 2,5-di(1-naphthyl)-1,3,4-oxadiazole (BND), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), phenanthroline derivatives, phosphine oxide derivatives, fullerene compounds, carbon nanotubes (CNT), and derivatives of poly-p-phenylene vinylene polymers with cyano groups introduced therein (CN-PPV). Two or more of these may be used. Among these, fullerene compounds are preferred because of their high charge separation rate and electron transfer rate. Examples of fullerene compounds include unsubstituted fullerenes such as C60, C70, C76, C78, ​​C82, C84, C90, and C94, as well as [6,6]-phenyl C61 butyric acid methyl ester ([6,6]-PCBM), [5,6]-phenyl C61 butyric acid methyl ester ([5,6]-PCBM), [6,6]-phenyl C61 butyric acid hexyl ester ([6,6]-PCBH), [6,6]-phenyl C61 butyric acid dodecyl ester ([6,6]-PCBD), phenyl C71 butyric acid methyl ester (PC70BM), and phenyl C85 butyric acid methyl ester (PC84BM).

[0170] Examples of p-type semiconductors include oligothiophene compounds such as terthiophene, quarterthiophene, sexithiophene, and octithiophene, phenylene vinylene compounds, p-phenylene compounds, polyfluorene compounds, phthalocyanine derivatives such as H2 phthalocyanine (H2Pc), copper phthalocyanine (CuPc), and zinc phthalocyanine (ZnPc), porphyrin derivatives, triarylamine derivatives such as N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine (TPD) and N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine (NPD), and carbazole derivatives such as 4,4'-di(carbazol-9-yl)biphenyl (CBP). Two or more of these may be used.

[0171] As described above, by combining a photoelectric conversion material having a structure represented by general formula (1) with an organic semiconductor having different HOMO-LUMO levels, excitons generated by absorbing light are efficiently charge-separated and charge-dissociated at the interface between the different materials, thereby further increasing the photoelectric conversion efficiency.

[0172] When the photoelectric conversion layer contains two or more types of photoelectric conversion materials, these materials may be mixed or stacked, but from the viewpoint of rectification, stacking is preferred. In the case of stacking, it is preferable that the layer containing the material exhibiting p-type semiconductor characteristics is located on the anode side, and the layer containing the material exhibiting n-type semiconductor characteristics is located on the cathode side. Furthermore, in the case of stacking, a mixed layer (i-layer) may be present at the stacking interface. This configuration is called a p-i-n structure, in which the i-layer is primarily responsible for charge separation, and the p-layer and n-layer are primarily responsible for hole transport and electron transport, respectively, thereby further improving photoelectric conversion efficiency. In the case of a mixture, it is preferable that the materials combined with the photoelectric conversion material having a structure represented by general formula (1) are compatible at the molecular level or phase-separated at the nanolevel. In the case of phase separation, the domain size of the phase-separated structure is preferably 1 nm or more and 50 nm or less.

[0173] The thickness of the photoelectric conversion layer is preferably 10 nm to 500 nm, more preferably 20 nm to 100 nm. When the photoelectric conversion layer has a laminated structure, the thickness of the layer containing the photoelectric conversion material having the structure represented by general formula (1) and the thickness of the laminated layer, out of the total thickness of the photoelectric conversion layer, are each preferably 5 nm to 495 nm, more preferably 10 nm to 50 nm. When a mixed layer (i-layer) is present at the laminate interface, the thickness of the i-layer is preferably 1 nm to 100 nm, more preferably 5 nm to 50 nm.

[0174] In the photoelectric conversion element, it is preferable that the anode and / or cathode have optical transparency. The optical transparency of the electrode is not particularly limited as long as it is sufficient for incident light to reach the photoelectric conversion layer and generate an electromotive force. Here, optical transparency is defined as the transmitted light intensity (W / m ２ ) / incident light intensity (W / m ２ ) × 100 (%). The thickness of the light-transmitting electrode may be in a range that provides both light transparency and conductivity, and although it differs depending on the electrode material, a thickness of 20 nm to 300 nm is preferred. The other electrode does not necessarily need to be light-transmitting as long as it is conductive, and there are no particular restrictions on its thickness.

[0175] As for the electrode materials, it is preferable to use a conductive material with a large work function for one electrode and a conductive material with a small work function for the other electrode.

[0176] An electrode made of a conductive material with a large work function serves as an anode. Examples of conductive materials with a large work function include metals such as gold, platinum, chromium, and nickel, as well as transparent metal oxides such as indium, tin, and molybdenum, and composite metal oxides such as indium tin oxide (ITO) and indium zinc oxide (IZO). Here, the conductive material used for the anode preferably forms an ohmic junction with the photoelectric conversion layer. Furthermore, as described below, when a hole transport layer is provided between the anode and the photoelectric conversion layer, the conductive material used for the anode preferably forms an ohmic junction with the hole transport layer. The anode can be formed using an optimal method depending on the material used for the anode, and examples include sputtering, vapor deposition, and inkjet printing. For example, sputtering is preferably used when forming an anode using a metal oxide, and vapor deposition is preferably used when forming an anode using a metal.

[0177] An electrode using a conductive material with a small work function serves as a cathode. Examples of conductive materials with a small work function that are preferably used include alkali metals such as lithium, alkaline earth metals such as magnesium and calcium, tin, silver, aluminum, and alloys thereof. A laminate using two or more of these may also be used. Here, the conductive material used for the cathode preferably forms an ohmic junction with the photoelectric conversion layer. Furthermore, as described below, when an electron transport layer is provided between the cathode and the photoelectric conversion layer, the conductive material used for the cathode preferably forms an ohmic junction with the electron transport layer. Furthermore, by introducing a metal fluoride such as lithium fluoride or cesium fluoride into the interface between the cathode and the electron transport layer, it is also possible to improve the extraction current.

[0178] In order to maintain the mechanical strength of the photoelectric conversion element, suppress thermal deformation, and impart barrier properties that suppress the intrusion of water vapor and oxygen into the photoelectric conversion layer, it is preferable to form the photoelectric conversion element on a substrate. Examples of the substrate include a glass plate, a ceramic plate, a resin film, a resin thin film obtained by curing varnish, and a thin metal plate. Among these, a glass substrate is preferably used from the viewpoint of transparency and ease of processing. Furthermore, flexible displays and foldable displays are becoming increasingly common, mainly in mobile devices such as smartphones, and resin films and resin thin films are suitable for this application, for example, heat-resistant films such as polyimide films and polyethylene naphthalate films.

[0179] The photoelectric conversion element of the present invention may have a hole transport layer between the anode and the photoelectric conversion layer. Examples of materials for forming the hole transport layer include the above-mentioned oligothiophene compounds, phenylene vinylene compounds, p-phenylene compounds, polyfluorene compounds, phthalocyanine derivatives such as H2 phthalocyanine (H2Pc), copper phthalocyanine (CuPc), and zinc phthalocyanine (ZnPc), porphyrin derivatives, triarylamine derivatives such as N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine (TPD) and N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine (NPD), carbazole derivatives such as 4,4'-di(carbazol-9-yl)biphenyl (CBP), and metal oxides exhibiting p-type semiconductor properties such as molybdenum oxide and tungsten oxide. The thickness of the hole transport layer is preferably 1 nm to 200 nm, and more preferably 5 nm to 100 nm.

[0180] Furthermore, the photoelectric conversion element of the present invention may have a hole extraction layer between the anode and the hole transport layer. Examples of materials for forming the hole extraction layer include charge transfer complexes such as tris(4-bromophenyl)aminium hexachloroantimonate (TBPAH), 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN6), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), tetracyanoquinodimethane derivatives, radialene derivatives, and fluorinated copper phthalocyanine.

[0181] The photoelectric conversion element of the present invention may also have an electron transport layer between the photoelectric conversion layer and the cathode. Examples of materials for forming the electron transport layer include the n-type organic semiconductors described above, as well as polycyclic aromatic derivatives, styryl aromatic ring derivatives, quinone derivatives, phosphorus oxide derivatives, and various metal complexes such as quinolinol complexes of tris(8-quinolinolato)aluminum(III), benzoquinolinol complexes, hydroxyazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes. From the perspective of further improving electron transport efficiency, it is preferable to use a compound having a heteroaryl group containing electron-accepting nitrogen. Here, electron-accepting nitrogen refers to a nitrogen atom that forms a multiple bond with an adjacent atom. Heteroaryl groups containing electron-accepting nitrogen have a large electron affinity, making them more likely to transport electrons, further contributing to improved photoelectric conversion efficiency.

[0182] Examples of compounds having a heteroaryl group structure containing electron-accepting nitrogen include pyridine derivatives, triazine derivatives, pyrazine derivatives, pyrimidine derivatives, quinoline derivatives, quinoxaline derivatives, quinazoline derivatives, naphthyridine derivatives, benzoquinoline derivatives, phenanthroline derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, triazole derivatives, oxadiazole derivatives, thiadiazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, phenanthroimidazole derivatives, and oligopyridine derivatives such as bipyridine and terpyridine. Two or more of these may be used. Furthermore, electron transport materials having a condensed polycyclic aromatic skeleton are more preferred because they have an improved glass transition temperature and high electron mobility. Examples of such condensed polycyclic aromatic skeletons include quinolinol complexes, triazine derivatives, fluoranthene skeletons, anthracene skeletons, pyrene skeletons, and phenanthroline skeletons.

[0183] The electron transport layer may contain an electron donor material. Here, the electron donor material is a compound that improves the electrical conductivity of the electron transport layer. Preferred examples of the electron donor material include alkali metals such as Li, inorganic salts containing alkali metals such as LiF, complexes of alkali metals and organic substances such as lithium quinolinol, alkaline earth metals, inorganic salts containing alkaline earth metals, complexes of alkaline earth metals and organic substances, rare earth metals such as Eu and Yb, inorganic salts containing rare earth metals, and complexes of rare earth metals and organic substances. Two or more of these may be used. Among these, metallic lithium, rare earth metals, and lithium quinolinol (Liq) are preferred.

[0184] The thickness of the electron transport layer is preferably from 1 nm to 200 nm, and more preferably from 5 nm to 100 nm.

[0185] The method for forming each of the layers constituting the photoelectric conversion element may be either a dry process or a wet process, and examples thereof include resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, coating, inkjet printing, etc. Among these, resistance heating evaporation is preferred from the viewpoint of element characteristics.

[0186] The photoelectric conversion element of the present invention has a function of converting light into electrical energy. From the viewpoint of highly efficient photoelectric conversion of green light having different wavelengths, the photoelectric conversion element of the present invention preferably has an absorption peak wavelength of 490 nm or more and 580 nm or less, and more preferably has an absorption peak wavelength of 500 nm or more and 570 nm or less, in the absorption spectrum of the photoelectric conversion layer.

[0187] The photoelectric conversion element of the present invention can be applied to various electronic devices and optical sensing devices that utilize its ability to selectively and efficiently photoelectrically convert green light. For example, it can be used as an optical sensor, optical switch, or imaging element, and can acquire biometric information such as fingerprints, veins, pulse waves, and blood oxygen levels with high sensitivity. It can also be used in a display device that includes the photoelectric conversion element of the present invention and an organic light-emitting element, and performs fingerprint authentication using the light from the organic light-emitting element. For example, by configuring some of the pixels of an organic EL display that displays in a matrix and / or segment format with the photoelectric conversion element of the present invention, the organic EL display can be endowed with fingerprint authentication functionality. That is, green light emitted from the organic light-emitting element of the organic EL display is reflected and scattered by a finger touching the display, and the light is received and photoelectrically converted by the photoelectric conversion element of the present invention, thereby enabling fingerprint information to be acquired with high accuracy.

[0188] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0189] First, the evaluation methods used in each of the examples and comparative examples will be described below.

[0190] ( １ H-NMR) The pyrromethene boron complexes obtained in Examples 1 to 3 were analyzed in deuterated chloroform solution using a superconducting FTNMR EX-270 (manufactured by JEOL Ltd.). １ The structure was identified by H-NMR measurement.

[0191] (Purity Measurement and Mass Analysis) The pyrromethene boron complexes obtained in Examples 1 to 3 were subjected to liquid chromatographic purity measurement and mass analysis using an ultra-high performance liquid chromatograph Nexera X2 (manufactured by Shimadzu Corporation) and a mass spectrometer LCMS-2020 (manufactured by Shimadzu Corporation). The liquid chromatography area percentage value was used as an index of purity.

[0192] (Absorption spectrum) The pyrromethene boron complexes obtained in Examples 1 to 3 were dissolved in toluene at a concentration of 10 －５ The absorption spectrum of the diluted solution of 100 mol / L was measured using a spectrophotometer (U-3010) manufactured by Hitachi High-Tech Science Corporation, and the peak wavelength was determined.

[0193] (Emission spectrum) The pyrromethene boron complexes obtained in Examples 1 to 3 were dissolved in toluene at a concentration of 10 －５ The emission spectrum of the diluted solution of 100 mol / L was measured using a FluoroMax-4P spectrophotometer manufactured by Horiba Ltd., and the peak wavelength and half-width were determined.

[0194] (Light-emitting device characteristics) The light-emitting devices obtained in each example and comparative example were subjected to a current density of 0.1 mA / cm ２ A voltage was applied so that the emission spectrum was measured using a spectroradiometer CS-1000 manufactured by Konica Minolta, Inc. From the obtained emission spectrum, the external quantum efficiency EQE was calculated on the assumption that Lambertian radiation was performed, and was used as an index of device efficiency.

[0195] Furthermore, the light-emitting devices obtained in Examples 1 to 13 and Comparative Examples 1 to 4 were tested at 1000 cd / m ２ The emission spectrum was measured in the same manner, and the peak wavelength and half-width were calculated.

[0196] In addition, the light-emitting devices obtained in Examples 14 to 19 and Comparative Examples 5 to 8 were subjected to a current density of 10 mA / cm ２ The emission spectrum was measured in the same manner when a voltage was applied so that the peak wavelength and half width were calculated.

[0197] (Durability) The light-emitting devices obtained in Examples 1 to 13 and Comparative Examples 1 to 4 were tested to have an initial luminance of 1000 cd / m ２ The luminance of the light-emitting element was measured using a photodiode while applying a voltage so as to obtain a current density of 0.01g / cm2, and the time required for the luminance to reach 90% of the initial luminance (LT90) was measured and used as an index of durability.

[0198] In addition, the light-emitting devices obtained in Examples 14 to 19 and Comparative Examples 5 to 8 were subjected to a current density of 10 mA / cm ２ The luminance of the light-emitting element was measured using a photodiode while applying a voltage so that the luminance reached 90% of the initial luminance, and the time (LT90) until the luminance reached 90% of the initial luminance was measured and used as an index of durability.

[0199] In each example and comparative example, the structures of the compounds used in the hole injection layer, hole transport layer, hole blocking layer, host material, TADF material, electron blocking layer, electron transport layer, charge generation layer, and electron injection layer are shown below.

[0200]

[0201] Example 1 (Synthesis of Compound D-1) Compound D-1 was synthesized according to the following reaction scheme.

[0202]

[0203] 10.45 g of D-1A and 5.99 g of 2,4-dimethylpyrrole were placed in a reaction vessel, and 1 L of dichloromethane and 5 drops of trifluoroacetic acid were added. The mixture was stirred at room temperature for 18 hours. 10.99 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was then added and stirred at room temperature for 6.5 hours. The mixture was then filtered and the solvent was distilled off. 1 L of dichloromethane and 16.3 mL of diisopropylethylamine were added to the resulting reaction product and stirred at room temperature for 5 minutes. 11.3 mL of boron trifluoride diethyl ether complex was added and stirred at room temperature for 1 hour, after which water was added and stirred. The organic layer was separated and washed with saturated saline. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The resulting reaction product was purified by silica gel chromatography to obtain a red powder. 60 mL of butyl acetate was added to the resulting powder and heated and stirred at 140°C for 30 minutes, then allowed to cool, and the precipitated solid was filtered. This procedure was repeated three more times to obtain 0.98 g of a red powder. １ Analysis by H-NMR and LC-MS confirmed that the red powder was a pyrromethene boron complex, Compound D-1. １ H-NMR (CDCl ３ (d = ppm)): １ H-NMR (CDCl ３　 (d=ppm)): 8.12-8.10 (m, 2H), 7.99 (t, 2H), 7.74 (d, 1H), 7.65 (d, 1H), 7.51-7.25 (m, 9H), 5.95 (s, 2H), 2.53 (s, 6H), 1.58 (s, 6H).

[0204] The luminescence characteristics of Compound D-1 in solution are shown below: Absorption spectrum (solvent: toluene): λmax 508 nm Fluorescence spectrum (solvent: toluene): λmax 521 nm, half width 23 nm.

[0205] To further increase the purity, sublimation purification was carried out. The metal container containing Compound D-1 was placed in a glass tube, and 1 × 10 －３ Compound D-1 was sublimated by heating at 250°C under a pressure of 10 Pa. The solid adhering to the wall of the glass tube was collected, and its molecular weight and purity were measured by the above-mentioned methods, revealing that the molecular weight was 566 and the purity was 99%.

[0206] (Fabrication of Light-Emitting Device) A glass substrate (manufactured by Geomatec Co., Ltd., 11 Ω / □, sputtered product) on which a 165 nm ITO transparent conductive film was deposited as an anode was cut into a size of 38 × 46 mm and etched. The resulting substrate was ultrasonically cleaned with "Semicoclean 56" (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, then washed with ultrapure water, and dried.

[0207] This substrate was subjected to UV-ozone treatment for 1 hour immediately before fabricating the element, and then placed in a vacuum deposition apparatus. The pressure inside the apparatus was reduced to 5×10 －４ The chamber was evacuated to a pressure of 10 Pa or less. Using a resistance heating method, first, 10 nm of HAT-CN6 was deposited as a hole injection layer, and 50 nm of HT-1 was deposited as a hole transport layer. Next, as an emitting layer, H-1 was deposited as a host material and Compound D-1 was deposited as a dopant material to a thickness of 20 nm so that the doping concentration was 1.0 wt %. Furthermore, ET-1 was used as an electron transport layer, and 2E-1 was used as a donor material, and a thickness of 30 nm was stacked such that the deposition rate ratio of ET-1 to 2E-1 was 1:1. Next, 0.5 nm of 2E-1 was deposited as an electron injection layer, and then 1000 nm of magnesium and silver were co-deposited to form a cathode, and a 5 mm x 5 mm square light-emitting device was fabricated.

[0208] The fluorescent element characteristics of this light-emitting device were evaluated by the above-mentioned method, and the emission peak wavelength was 524 nm, the half-value width was 25 nm, and the external quantum efficiency was 3.1%. Furthermore, the durability was evaluated by the above-mentioned method, and the LT90 was 61 hours.

[0209] Example 2 (Synthesis of Compound D-2) Compound D-2 was synthesized according to the following reaction scheme.

[0210]

[0211] 11.1 g of D-2A and 6.9 g of 2,4-dimethylpyrrole were placed in a reaction vessel, and 1 L of dichloromethane and 5 drops of trifluoroacetic acid were added. The mixture was stirred at room temperature for 1 hour. Water was then added and the mixture was stirred. The organic layer was separated and washed with saturated saline. This organic layer was dried over magnesium sulfate, filtered, and the solvent was removed by distillation. 234 mL of dichloromethane and 7.73 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) were added to the resulting red solid and stirred at room temperature for 2.5 hours. 40.0 mL of diisopropylethylamine was then added and the mixture was stirred at room temperature for 5 minutes. 40.0 mL of boron trifluoride diethyl ether complex was then added and the mixture was stirred at room temperature for 16 hours. Water was then added and the mixture was stirred. The organic layer was separated and washed with saturated saline. This organic layer was dried over magnesium sulfate, filtered, and the solvent was removed by distillation. The resulting reaction product was purified by silica gel chromatography to obtain a red powder. 35 mL of butyl acetate was added to the obtained powder, which was then heated and stirred at 140°C for 30 minutes, allowed to cool, and the precipitated solid was filtered. This procedure was repeated 9 more times to obtain 0.75 g of a red powder. １ Analysis by H-NMR and LC-MS confirmed that the red powder was compound D-2, a pyrromethene boron complex. １ H-NMR (CDCl ３ (d = ppm)): １ H-NMR (CDCl ３　 (d=ppm)): 8.08 (d, 1H), 8.04 (d, 1H), 7.92 (d, 1H), 7.78 (d, 1H), 7.74 (d, 1H) ), 7.58 (d, 1H), 7.54-7.36 (m, 7H), 6.00 (s, 2H), 2.57 (s, 6H), 1.24 (s, 6H).

[0212] The luminescence characteristics of compound D-2 in solution are shown below: Absorption spectrum (solvent: toluene): λmax 507 nm Fluorescence spectrum (solvent: toluene): λmax 520 nm, half-width 23 nm.

[0213] The metal container containing Compound D-2 was placed in a glass tube, and a 1×10 －３Compound D-2 was sublimated by heating at 230°C under a pressure of 10 Pa. The solid adhering to the wall of the glass tube was collected, and its molecular weight and purity were measured by the above-mentioned methods, revealing that the molecular weight was 540 and the purity was 99%.

[0214] (Fabrication of Light-Emitting Device) A light-emitting device was fabricated and evaluated in the same manner as in Example 1, except that Compound D-2 was used as the dopant material instead of Compound D-1. The results are shown in Table 1.

[0215] Example 3 (Synthesis of Compound 3) Compound D-3 was synthesized according to the following reaction scheme.

[0216]

[0217] 7.41 g of D-3A and 3.3 g of 2,4-dimethylpyrrole were placed in a reaction vessel, and 330 mL of toluene and 10 drops of trifluoroacetic acid were added. The mixture was stirred at 80°C for 10 hours. 4.12 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was then added, followed by stirring at room temperature for 15 hours and then at 80°C for 1 hour. The mixture was then filtered. 14.1 mL of diisopropylethylamine was added to the resulting reaction solution and stirred at room temperature for 5 minutes. 10.4 mL of boron trifluoride diethyl ether complex was added and stirred at room temperature for 23 hours, after which water was added and stirred. The organic layer was separated and washed with saturated saline. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The resulting reaction product was purified by silica gel chromatography to obtain a red powder. 260 mL of butyl acetate was added to the resulting powder, and the mixture was heated and stirred at 140°C for 30 minutes, then allowed to cool. The precipitated solid was filtered, yielding 3.62 g of a red powder. The resulting powder １ Analysis by H-NMR and LC-MS confirmed that the red powder was a pyrromethene boron complex, Compound D-3. １ H-NMR (CDCl ３ (d = ppm)): １ H-NMR (CDCl ３　(d=ppm)): 7.91 (d, 2H), 7.87 (t, 2H), 7.69 (d, 1H), 7.41-7.35 (m, 3H), 7.22 (s, 2H), 7.15-7.08 (m, 3H), 7.02 (s, 1H), 6.79 (d, 2H), 6.70 (d, 1H), 5.93 (s, 2H), 2.53 (s, 6H), 2.16 (s, 6H), 1.33 (s, 6H).

[0218] The emission characteristics of compound D-3 in solution are shown below: Absorption spectrum (solvent: toluene): λmax 504 nm Fluorescence spectrum (solvent: toluene): λmax 516 nm, half-width 21 nm.

[0219] To further increase the purity, sublimation purification was carried out. The metal container containing Compound D-3 was placed in a glass tube, and 1 × 10 －３ Compound D-3 was sublimated by heating at 290°C under a pressure of 10 Pa. The solid adhering to the wall of the glass tube was collected, and its molecular weight and purity were measured by the above-mentioned methods, revealing that the molecular weight was 666 and the purity was 99%.

[0220] Example 4 (Synthesis of Compound D-14) Compound D-14 was synthesized according to the following reaction scheme.

[0221]

[0222] 2.0 g of D-14A and 90 mL of toluene were placed in a flask and purged with nitrogen. 1.4 g of 3-ethyl-2,4-dimethylpyrrole was added to the reaction solution, and the atmosphere was purged with nitrogen again. 2 g of methanesulfonic anhydride was added to the reaction solution, and the mixture was heated and stirred at 80°C for 4 hours under a nitrogen stream. The reaction solution was cooled to room temperature, water was added, and the mixture was stirred to extract an organic layer. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off to obtain D-14B.

[0223] 120 mL of toluene was added to D-14B in a flask and the atmosphere was replaced with nitrogen. 4 mL of diisopropylethylamine and 2.8 mL of boron trifluoride diethyl ether complex were added and stirred at room temperature for 30 minutes, after which water was added and stirred to extract an organic layer. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The resulting reaction product was purified by silica gel chromatography to obtain an orange powder. Further, butyl acetate was added to the obtained powder, and the mixture was heated and stirred at 140°C for several minutes, and then allowed to cool. This operation was repeated several times, and the precipitated solid was filtered and dried in vacuo to obtain 1.8 g of an orange powder. １ The results of H-NMR analysis are as follows, and it was confirmed that the orange powder obtained above was Compound D-14 having a pyrromethene skeleton. １ H-NMR (CDCl ３ (d = ppm)): １ H-NMR (CDCl ３　 (d=ppm)): 8.13-8.00 (m, 2H), 8.00 (t, 2H), 7.76 (d, 1H), 7.66 (d, 1H), 7.52-7 .17 (m, 9H), 5.92 (s, 1H), 2.52 (s, 6H), 2.26 (q, 2H), 1.58 (s, 6H), 0.99 (t, 3H).

[0224] The emission characteristics of compound D-14 in solution are shown below: Absorption spectrum (solvent: toluene): λmax 519 nm Fluorescence spectrum (solvent: toluene): λmax 534 nm, half-width 26 nm.

[0225] To further increase the purity, sublimation purification was carried out. The metal container containing Compound D-14 was placed in a glass tube, and 1 × 10 －３ Compound D-14 was sublimated by heating at 230°C under a pressure of 10 Pa. The solid adhering to the wall of the glass tube was collected, and its molecular weight and purity were measured by the above-mentioned methods, revealing that the molecular weight was 594 and the purity was 99%.

[0226] (Fabrication of Light-Emitting Device) A light-emitting device was fabricated and evaluated in the same manner as in Example 1, except that compound D-14 was used as the dopant material instead of compound D-1. The results are shown in Table 1. Example 5 (Synthesis of Compound D-15) Compound D-15 was synthesized according to the following reaction scheme.

[0227]

[0228] 9.7 g of D-15A and 430 mL of toluene were placed in a flask and purged with nitrogen. 4 g of 3-ethyl-2,4-dimethylpyrrole was added to the reaction solution, and the atmosphere was purged with nitrogen again. 7.5 g of methanesulfonic anhydride was added to the reaction solution, and the mixture was heated and stirred at 80°C for 4 hours under a nitrogen stream. The reaction solution was cooled to room temperature, water was added, and the mixture was stirred to extract an organic layer. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off to obtain D-15B.

[0229] 300 mL of toluene was added to D-15B in a flask and the atmosphere was replaced with nitrogen. 29 mL of diisopropylethylamine and 15 mL of boron trifluoride diethyl ether complex were added and stirred at room temperature for 30 minutes, after which water was added and stirred to extract an organic layer. This organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The resulting reaction product was purified by silica gel chromatography to obtain an orange powder. Further, butyl acetate was added to the obtained powder, and the mixture was heated and stirred at 140°C for several minutes, and then allowed to cool. This operation was repeated several times, and the precipitated solid was filtered and dried in vacuo to obtain 3.0 g of an orange powder. １ The results of H-NMR analysis are as follows, and it was confirmed that the orange powder obtained above was Compound D-15 having a pyrromethene skeleton. １ H-NMR (CDCl ３ (d = ppm)): １ H-NMR (CDCl ３　 (d=ppm)): 8.08 (d, 1H), 8.05 (d, 1H), 7.93 (d, 1H), 7.77 (d, 1H), 7.73 (d, 1H), 7.5 8-7.36 (m, 8H), 5.95 (s, 1H), 2.61 (s, 6H), 2.30 (q, 2H), 1.24 (s, 6H), 0.97 (t, 3H).

[0230] The emission characteristics of compound D-15 in solution are shown below: Absorption spectrum (solvent: toluene): λmax 518 nm Fluorescence spectrum (solvent: toluene): λmax 531 nm, half width 24 nm.

[0231] To further increase the purity, sublimation purification was carried out. The metal container containing Compound D-14 was placed in a glass tube, and 1 × 10 －３ Compound D-14 was sublimated by heating at 235°C under a pressure of 10 Pa. The solid adhering to the wall of the glass tube was collected, and its molecular weight and purity were measured by the above-mentioned methods, revealing that the molecular weight was 568 and the purity was 99%.

[0232] (Fabrication of Light-Emitting Device) A light-emitting device was fabricated and evaluated in the same manner as in Example 1, except that Compound D-15 was used as the dopant material instead of Compound D-1. The results are shown in Table 1.

[0233] The structures of compounds D-4 to D-13 and compounds C-1 to C-5 used in the examples and comparative examples are shown below.

[0234]

[0235]

[0236] Examples 6 to 15 and Comparative Examples 1 to 5 Light-emitting device materials and light-emitting devices were prepared in the same manner as in Example 1, except that the compounds shown in Table 1 were used as the dopant material instead of Compound D-1. The evaluation results are shown in Table 1.

[0237]

[0238] In comparison with Comparative Examples 1 to 5, Examples 1 to 15 had improved device efficiency (external quantum efficiency) and durability (LT90).

[0239] (Evaluation of Thermally Activated Delayed Fluorescence Device) Example 16 (Fabrication of Light-Emitting Device) A glass substrate (manufactured by Geomatec Co., Ltd., 11 Ω / □, sputtered product) on which a 165 nm ITO transparent conductive film had been deposited was cut into a size of 38 mm x 46 mm and etched. The obtained substrate was subjected to ultrasonic cleaning for 15 minutes using "Semicoclean" (registered trademark) 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before fabricating the device, and then placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was adjusted to 5 x 10 －４ The chamber was evacuated to a pressure of 10 Pa or less. Using a resistance heating method, first, 10 nm of HAT-CN6 was deposited as a hole injection layer, followed by 30 nm of HT-1 as a hole transport layer. Next, as an emitting layer, a host material H-1, a compound D-1, and a compound H-2 (TADF material) were deposited in a weight ratio of 79.0:1.0:20 to a thickness of 30 nm. Subsequently, 10 nm of ET-1 was deposited as a hole blocking layer, and 40 nm of ET-2 was deposited as an electron transport layer. Next, 0.5 nm of 2E-1 was deposited as an electron injection layer, and then 100 nm of magnesium and silver were co-deposited to form a cathode, and a 5 mm x 5 mm square light-emitting device was fabricated.

[0240] The obtained light-emitting device was evaluated by the above-mentioned method, and found to have an emission peak wavelength of 524 nm, a half-value width of 27 nm, an external quantum efficiency of 15.0%, and an LT90 of 61 hours.

[0241] Examples 16 to 22 and Comparative Examples 6 to 9 Light-emitting devices were fabricated in the same manner as in Example 14, except that the compounds shown in Table 2 were used as the dopant material in place of pyrromethene boron complex D-1. The evaluation results are shown in Table 2.

[0242]

[0243] In Examples 16 to 22, the external quantum efficiency and device durability (LT90) were improved while maintaining a small full width at half maximum compared to Comparative Examples 5 to 8. Furthermore, the external quantum efficiency was further improved compared to Examples 1 to 13. This shows that the use of a thermally activated delayed fluorescence material can further improve device efficiency.

[0244] Example 23 A glass substrate (manufactured by Geomatec Co., Ltd., 11 Ω / □, sputtered product) on which a 165 nm ITO transparent conductive film had been deposited was cut into a size of 38 mm x 46 mm and etched. The resulting substrate was ultrasonically cleaned for 15 minutes using "Semicoclean" 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) and then washed with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before fabricating the element, and then placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was adjusted to 5 x 10 －４ The chamber was evacuated to a pressure of 100 Pa or less. Using a resistance heating method, first, HAT-CN6 was deposited to a thickness of 5 nm as a hole injection layer, followed by HT-1 at a thickness of 50 nm as a hole transport layer. Next, H-1 was deposited to a thickness of 10 nm as a hole blocking layer, and a host material H-1 and compound D-1 were deposited to a thickness of 20 nm as an emitting layer at a weight ratio of 99.5:0.5. Further, ET-1 was deposited to a thickness of 10 nm as an electron blocking layer, and compound ET-3 was deposited to a thickness of 35 nm as an electron transport layer. Subsequently, compound ET-3, an n-type host, and metallic lithium, an n-type dopant, were deposited to a thickness of 10 nm at a deposition rate ratio of 99:1 as an n-type charge generation layer. Further, HAT-CN6 was deposited to a thickness of 10 nm as a p-type charge generation layer. A 50 nm hole transport layer, a 10 nm hole blocking layer, and a 20 nm emitting layer were formed thereon in the same manner as above. Further, ET-2 was deposited to a thickness of 10 nm as an electron blocking layer, and ET-3 was deposited to a thickness of 35 nm as an electron transport layer, followed by deposition of 2E-1 to a thickness of 0.5 nm as an electron injection layer, followed by co-deposition of magnesium and silver to a thickness of 1000 nm as a cathode, to fabricate a tandem light-emitting device measuring 5 mm × 5 mm.

[0245] The resulting light-emitting device was evaluated by the above-mentioned method, and found to have an emission peak wavelength of 524 nm, a half-value width of 24 nm, an external quantum efficiency of 4.9%, and an LT90 of 74 hours.

[0246] Example 24 (Fabrication of a Photoelectric Conversion Element) A glass substrate on which a 125 nm thick ITO transparent conductive film had been deposited was subjected to ultrasonic cleaning using "Semicoclean" 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.). Immediately before fabricating the element, this substrate was subjected to UV-ozone treatment for 30 minutes, and then placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was adjusted to 3×10. －３The chamber was evacuated to approximately Pa. First, N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (40 nm) was deposited as a hole transport layer. Next, compound D-1 (15 nm) and fullerene (15 nm) were deposited in this order as a photoelectric conversion layer. After opening to the atmosphere, the deposition source was reinstalled, and after reducing the pressure, Liq (5 nm) was deposited as an electron transport layer and aluminum (41 nm) as a cathode in this order to prepare a photoelectric conversion element.

[0247] (Photoelectric conversion efficiency characteristics) The photoelectric conversion efficiency of the obtained photoelectric conversion elements was measured using a spectral sensitivity measurement device (Hyper Monolight System, SM-250 model, manufactured by Bunko Keiki Co., Ltd.) (applied voltage, photoelectric conversion efficiency, maximum absorption wavelength) = (-3 V, 9.0%, 510 nm).

[0248] Example 25 A photoelectric conversion element was produced in the same manner as in Example 24, except that compound D-14 was used in place of compound D-1 in the photoelectric conversion layer. The obtained photoelectric conversion element was evaluated by the above-mentioned method, and the following measurement results were obtained: (applied voltage, photoelectric conversion efficiency, maximum absorption wavelength) = (-3 V, 9.2%, 521 nm).

[0249] As shown in Examples 24 and 25, Compound D-1 and Compound D-14 can efficiently convert green light into electrical energy.

Claims

1. A compound having a structure represented by general formula (1): 【Chemistry 1】 In the above general formula (1), A is a monovalent group having a structure represented by the following general formula (2). 【Chemistry 2】 In the above general formula (2), R １ ~R ４ may be the same or different, and each represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group. ５ and R ６ may be the same or different and each represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted cycloalkyl group. １ and Z ２ may be the same or different and represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a hydroxyl group, a halogen atom, or a cyano group. L represents a bonding site with L in general formula (1). In the above general formula (1), L is a divalent aromatic hydrocarbon group having a structure represented by the following general formula (3) or (4): A represents a bonding site with A in general formula (1). 【Chemistry 3】 In the above general formulas (3) to (4), R ２１ ~R ２５ and R ３１ ~R ３７ may be the same or different, and are each a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted siloxanyl group, or R ２２ and R ２３ Or R ２３ and R ２４ Here, R represents a ring structure formed between ２１ is not a hydrogen atom. In the above general formula (3), R ２１ ~R ２５ When any of R is a single bond, R in general formula (1) bonds to that single bond. ２１ ~R ２５ When R does not have a single bond, ２１ ~R ２５ At least one of R is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, ２２ and R ２３ Or R ２３ and R ２４ and R in general formula (1) bonds to the substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, or ring structure. In the above general formula (4), R ３１ ~R ３７ When any of R is a single bond, R in general formula (1) bonds to that single bond. ３１ ~R ３７ When R does not have a single bond, ３１ ~R ３７ at least one of the groups is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or has a ring structure formed with an adjacent group, and R in general formula (1) is bonded to either the substituted or unsubstituted aryl group, the substituted or unsubstituted heteroaryl group, or the ring structure. In the above general formula (1), R is a monovalent group having a structure represented by the following general formula (5). 【Chemistry 4】 In the above general formula (5), X is CR Ｘ１ R Ｘ２ , N.R. Ｘ１ or a divalent heteroatom. １ ~X ８ Among them, one is a carbon atom which is a bonding site with in general formula (1). １ ~X ８ may be the same or different, CR Ｘ１ R Ｘ２ , N.R. Ｘ１ or a divalent heteroatom, which may form a ring structure between two adjacent substituents. Ｘ１ and R Ｘ２ may be the same or different, and represent a single bond, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted siloxanyl group.

2. In the general formula (5), X is CR Ｘ１ R Ｘ２ , N.R. Ｘ１ or an oxygen atom.

3. In the general formula (2), R １ and R ４ The compound according to claim 1 or 2, wherein may be the same or different and are a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group.

4. In the general formula (2), R ２ and R ３ The compound according to any one of claims 1 to 3, wherein may be the same or different and are a substituted or unsubstituted alkyl group or a substituted or unsubstituted cycloalkyl group.

5. In the general formula (3), R ２１ ~R ２５ or in the general formula (4), R ３１ ~R ３７ The compound according to any one of claims 1 to 4, wherein either one of is a single bond.

6. In the general formula (2), Z １ and Z ２ The compound according to any one of claims 1 to 5, wherein each of

7. A light-emitting device material comprising the compound according to claim 1 .

8. A light-emitting device which emits light by electrical energy, comprising a light-emitting layer containing the light-emitting device material according to claim 7 between an anode and a cathode.

9. The light-emitting device according to claim 8 , wherein the light-emitting layer comprises a first compound and a second compound that is a dopant, and the second compound is the light-emitting device material according to claim 7 .

10. The light-emitting device according to claim 8 , wherein the first compound is a delayed fluorescent compound.

11. The light-emitting device according to claim 10 , wherein the light-emitting layer further comprises a third compound having a singlet energy greater than the singlet energy of the first compound.

12. 12. The light-emitting device according to claim 8, further comprising two or more light-emitting layers between an anode and a cathode, and one or more charge-generating layers between each of the light-emitting layers.

13. The light-emitting device according to claim 12 , wherein the charge generating layer contains a phenanthroline derivative having a structure represented by the following general formula (6): 【Chemistry 5】 (In the above general formula (6), Ar １ represents a p-valent aromatic hydrocarbon group or a p-valent aromatic heterocyclic group, and p represents a natural number from 1 to 3. ８ ~R １５ may be the same or different and represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.

14. 14. The light-emitting device according to claim 8, further comprising an electron injection layer between the cathode and the electron transport layer, the electron injection layer containing the phenanthroline derivative represented by the general formula (6).

15. The light-emitting device according to any one of claims 8 to 14, which is a top-emission type organic electroluminescent device.

16. A photoelectric conversion material comprising the compound according to any one of claims 1 to 6.

17. A photoelectric conversion element having a photoelectric conversion layer between an anode and a cathode, for converting light into electrical energy, the photoelectric conversion layer containing the photoelectric conversion material according to claim 16.

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