Triazine Compounds

Abstract

SOLUTION: Compounds represented by a formula (1) are useful as materials for organic devices such as organic electrolytic light emitting devices. (X is heteroarylene; Y1 is a group represented by a formula (1-a); Y2 is a group represented by a formula (1-b); A1, A2, A3, and A4 are substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl, and at least one of A1 and A2 or at least one of A3, and A4 is a group with N as a bonding position; Z1, Z2, and Z3 are CH or N, at least one of which is N; and * denotes a bonding position. At least one hydrogen in the compounds represented by the formula (1) may be replaced by cyano, halogen, or deuterium.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a triazine compound, an organic electroluminescent device using the same, and a display device and a lighting device. [Background technology]

[0002] Display devices using electroluminescent light-emitting elements have been the subject of extensive research because of their potential for power saving and thinning, and organic electroluminescent devices made from organic materials have also been actively investigated because they can be easily made lighter and larger. In particular, there has been active research into the development of organic materials that have the luminescence properties of blue and green, which are one of the three primary colors of light, and organic materials that have the ability to transport charges such as holes and electrons (potential to become semiconductors or superconductors), regardless of whether they are polymeric or low-molecular-weight compounds.

[0003] An organic EL device has a structure consisting of a pair of electrodes consisting of an anode and a cathode, and one or more layers containing organic compounds disposed between the pair of electrodes. The layers containing organic compounds include a light-emitting layer and a charge transport / injection layer that transports or injects charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

[0004] Currently, three types of light-emitting materials are used for the light-emitting layer: fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. For example, improved azaborine derivatives have been reported as fluorescent materials (Patent Document 1), noble metal complexes with multidentate ligands have been developed as phosphorescent materials (Patent Document 2), and carbazonitrile compounds have been developed as thermally activated delayed fluorescence (TADF) materials (Non-Patent Document 1).

[0005] In devices using either material, a material with a high lowest excited singlet energy level or lowest excited triplet energy level is used in the layer adjacent to the emitting layer or as the host to prevent energy leakage from the emitting layer or surrounding layers, which would lead to a decrease in efficiency. Patent Document 3 describes that good device performance was obtained by using, as the host of the emitting layer, a compound having at least two donor moieties and at least two acceptor moieties, where the donor moieties and acceptor moieties are present in equal numbers in the same molecule. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2015 / 102118 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-239225 [Patent Document 3] US Patent Application Publication No. 2020 / 0020867 [Non-patent literature]

[0007] [Non-Patent Document 1] Nature Vol.492 13 December 2012 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, various materials have been developed for use in organic EL devices, but in order to increase the options for materials for organic EL devices, it is desirable to develop materials made of compounds different from conventional ones. Also, Patent Document 1 reports a boron-containing polycyclic aromatic compound and an organic EL device using the same, but in order to further improve device characteristics, there is a demand for materials for the emitting layer and peripheral layers that can improve the luminous efficiency and device life. [Means for solving the problem]

[0009] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that novel triazine compounds have a high lowest excited singlet energy level and high electron transport properties. They have also found that an excellent organic EL device can be obtained by, for example, using such a triazine compound as a host material or as a material for a layer adjacent to an emitting layer, and disposing an emitting layer between a pair of electrodes, the emitting layer containing a compound having a lower lowest excited triplet energy than the emitting layer as a dopant, thereby completing the present invention. Specifically, the present invention provides the following triazine compounds, as well as materials for organic devices containing the following triazine compounds.

[0010] <1> A compound represented by formula (1); [ka] In formula (1), X is a substituted or unsubstituted heteroarylene; Y 1 is a group represented by formula (1-a), Y 2 is a group represented by formula (1-b),

[0011] [ka]

[0012] A 1 and A 2 each independently represents a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl; A 3 and A 4 each independently represents a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted diarylamino, a substituted or unsubstituted diheteroarylamino, or a substituted or unsubstituted arylheteroarylamino; A 1 and A 2 Neither of or A 3and A 4 At least one of the above is a group having N as the bonding position, Z 1 , Z 2 and Z 3 are each independently CH or N, but Z 1 , Z 2 and Z 3 At least one of them is N, * indicates the bond position, At least one hydrogen atom in the compound represented by formula (1) may be replaced by cyano, halogen, or deuterium.

[0013] <2> Groups bonding to N are each independently substituted or unsubstituted N-carbazolyl, substituted or unsubstituted N-azacarbazolyl, substituted or unsubstituted N-benzimidazolyl, substituted or unsubstituted N-imidazoimidazolyl, substituted or unsubstituted N-indoloindolyl, substituted or unsubstituted N-indolocarbazolyl, substituted or unsubstituted N-benzofurocarbazolyl, substituted or unsubstituted N-benzothienocarbazolyl, or substituted or unsubstituted N-indenocarbazolyl. <1> The compound described in

[0014] <3> A 1 and A 2 are all groups with N as the bonding position <1> or <2> The compound described in <4> The heteroarylene for X is a divalent group formed by removing any two hydrogen atoms bonded to a ring atom of carbazole, azacarbazole, benzimidazole, imidazoimidazole, indoloindole, indolocarbazole, benzofurocarbazole, benzothienocarbazole, or indenocarbazole. <1> ~ <3> The compound according to any one of claims 1 to 4.

[0015] <5> Z 1 , Z 2 and Z 3 But both are N <1> ~ <4> The compound according to any one of the preceding claims. <6> A 1and A 2 are both unsubstituted N-carbazolyl, and A 3 and A 4 are both unsubstituted N-carbazolyl or unsubstituted phenyl <1> ~ <5> The compound according to any one of the preceding claims.

[0016] <7> Represented by one of the following formulas <1> The compound described in [ka]

[0017] <8> <1> ~ <7> 1. A material for an organic device, comprising the compound according to any one of claims 1 to 9. <9> The organic layer is disposed between a pair of electrodes consisting of an anode and a cathode, and the organic layer is <1> ~ <7> 1. An organic electroluminescent device comprising the compound according to any one of claims 1 to 9. <10> the organic layer is an emitting layer; <9> The organic electroluminescent device according to claim 1. <11> the light-emitting layer contains the compound as a host material and further contains a dopant material; <10> The organic electroluminescent device according to claim 1. <12> the organic layer is an electron transport layer; <9> The organic electroluminescent device according to claim 1. <13> <9> ~ <12> A display device or a lighting device comprising the organic electroluminescent device according to any one of the preceding claims. [Effects of the Invention]

[0018] According to a preferred embodiment of the present invention, an organic EL device is produced using the novel triazine compound, for example, as a host material in an emitting layer, as a component of the host material, or as a component of a layer adjacent to the emitting layer, thereby providing an organic EL device having excellent quantum efficiency and device life. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view showing an organic EL element according to an embodiment of the present invention. [Figure 2]FIG. 1 is an energy level diagram showing the energy relationship among the host, assisting dopant, and emitting dopant of a TAF element using a common fluorescent dopant. [Figure 3] 1 is an energy level diagram showing an example of the energy relationship between a host, an assisting dopant, and an emitting dopant in an organic electroluminescent element according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In addition, in this specification, "hydrogen" in the explanation of structural formulas means "hydrogen atom (H)". Similarly, "carbon atom (C)" may be referred to as "carbon". In this specification, the term "adjacent groups" refers to two groups bonded to two adjacent atoms (two atoms directly bonded by a covalent bond) in a structural formula.

[0021] In this specification, "Me" represents methyl, "Et" represents ethyl, "nBu" represents n-butyl (normal butyl), "tBu" represents t-butyl (tertiary butyl), "iBu" represents isobutyl, "secBu" represents secondary butyl, "nPr" represents n-propyl (normal propyl), "iPr" represents isopropyl, "tAm" represents t-amyl, "2EH" represents 2-ethylhexyl, "tOct" represents t-octyl, "Ad" represents 1-adamantyl, "Ph" represents phenyl, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Tf" represents trifluoromethanesulfonyl, "TMS" represents trimethylsilyl, and "D" represents deuterium. In this specification, the organic electroluminescent device may be referred to as an organic EL device.

[0022] In this specification, chemical structures and substituents are sometimes represented by the number of carbon atoms. However, when a chemical structure is substituted with a substituent or when a substituent is further substituted with a substituent, the number of carbon atoms refers to the number of carbon atoms in each of the chemical structure and the substituent, and does not refer to the total number of carbon atoms in the chemical structure and the substituent, or the total number of carbon atoms in the substituent and the substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent B of carbon number Y" is substituted with "substituent A of carbon number X," and the carbon number Y is not the total number of carbon atoms in substituents A and B. Also, for example, "substituent B of carbon number Y substituted with substituent A" means that "substituent B of carbon number Y" is substituted with "substituent A (with no carbon number restriction)," and the carbon number Y is not the total number of carbon atoms in substituents A and B.

[0023] <Explanation of rings and substituents> First, the rings and substituents used in this specification will be described in detail below.

[0024] As used herein, the "aryl ring" includes, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 16 carbon atoms, more preferably an aryl ring having 6 to 12 carbon atoms, and particularly preferably an aryl ring having 6 to 10 carbon atoms.

[0025] Specific examples of the "aryl ring" include a monocyclic benzene ring, a bicyclic bicyclic bicyclic naphthalene ring and an indene ring, a tricyclic terphenyl ring (m-terphenyl, o-terphenyl, p-terphenyl) and a fused tricyclic acenaphthylene ring, a fluorene ring, a phenalene ring, a phenanthrene ring, and an anthracene ring, fused tetracyclic triphenylene ring, a pyrene ring, a naphthacene ring, and a chrysene ring, fused pentacyclic perylene ring and a pentacene ring, etc. Furthermore, the fluorene ring, benzofluorene ring, and indene ring each include a structure in which a fluorene ring, a benzofluorene ring, a cyclopentane ring, etc. are spiro-bonded. The fluorene ring, benzofluorene ring, and indene ring also include rings in which two of the two hydrogen atoms of the methylene in the structure are replaced by alkyl such as methyl as the first substituent described below, resulting in a dimethylfluorene ring, a dimethylbenzofluorene ring, a dimethylindene ring, and the like.

[0026] As used herein, examples of the "heteroaryl ring" include heteroaryl rings having 2 to 30 carbon atoms, preferably heteroaryl rings having 2 to 25 carbon atoms, more preferably heteroaryl rings having 2 to 20 carbon atoms, still more preferably heteroaryl rings having 2 to 15 carbon atoms, and particularly preferably heteroaryl rings having 2 to 10 carbon atoms. Furthermore, examples of the "heteroaryl ring" include heterocyclic rings containing, as ring-constituting atoms other than carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, phosphorus, selenium, etc.

[0027] Specific examples of the "heteroaryl ring" include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, an isoindole ring, a 1H-indazole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a 1H-benzotriazole ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinazoline ring, a quinoxaline ring, a phthalazine ring, a naphthyridine ring, a purine ring, a pteridine ring, a carbazole ring, an acridine ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, a phenazasiline ... Examples thereof include an azine ring, a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a furazan ring, a thianthrene ring, an indolocarbazole ring, a benzoindolocarbazole ring, a dibenzoindolocarbazole ring, a naphthobenzofuran ring, a dioxin ring, a dihydroacridine ring, a xanthene ring, a thioxanthene ring, a dibenzodioxin ring, a benzoselenophene ring, a dibenzoselenophene ring, an azacarbazole ring, an azadibenzothiophene ring, an azadibenzofuran ring, an azadibenzoselenophene ring, an azatriphenylene ring, an imidazoimidazole ring, an indoloindole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, an indenocarbazole ring, and a selenophenocarbazole ring. In addition, dihydroacridine rings, xanthene rings, thioxanthene rings, and indenocarbazole rings are also preferably those in which two of the two hydrogen atoms of the methylene in the structure are replaced by alkyl such as methyl as the first substituent described below, resulting in a dimethyldihydroacridine ring, dimethylxanthene ring, or dimethylthioxanthene ring. Bicyclic rings such as bipyridine rings, phenylpyridine rings, and pyridylphenyl rings, and tricyclic rings such as terpyridyl rings, bispyridylphenyl rings, and pyridylbiphenyl rings are also examples of "heteroaryl rings." Furthermore, "heteroaryl rings" also include pyran rings.

[0028] In this specification, a substituent may be substituted with an additional substituent. For example, a specific substituent may be described as "substituted or unsubstituted." This means that the specific substituent is substituted with at least one additional substituent, or is not substituted. In the same sense, the term "optionally substituted" may also be used. In this specification, the specific substituent may be referred to as a "first substituent," and the additional substituent may be referred to as a "second substituent."

[0029] In this specification, unless otherwise specified, the term "substituent" may refer to any group selected from substituent group Z. For example, when a group that is described as "substituted or unsubstituted" is substituted, the group may be substituted with at least one group selected from substituent group Z.

[0030] In the present specification, the substituent group Z is an aryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl; heteroaryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl; diarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl (two aryls may be bonded to each other via a linking group); diheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl (two heteroaryls may be bonded to each other via a linking group); arylheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl (the aryl and heteroaryl may be bonded to each other via a linking group); diarylboryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl (two aryls may be bonded via a single bond or a linking group); alkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, and cycloalkyl; cycloalkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl; alkoxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl; aryloxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, and cycloalkyl; and It consists of substituted silyl. The aryl as the second substituent in each group of the substituent group Z may be further substituted with an aryl, heteroaryl, alkyl, or cycloalkyl; similarly, the heteroaryl as the second substituent may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl.

[0031] In this specification, "aryl" refers to, for example, aryl having 6 to 30 carbon atoms, and preferably aryl having 6 to 20 carbon atoms, aryl having 6 to 16 carbon atoms, aryl having 6 to 12 carbon atoms, or aryl having 6 to 10 carbon atoms.

[0032] Specific examples of "aryl" include monovalent groups obtained by removing one hydrogen atom from the above-mentioned "aryl ring." For example, the monocyclic ring system is phenyl, the bicyclic ring system is biphenylyl (2-biphenylyl, 3-biphenylyl, or 4-biphenylyl), the fused bicyclic ring system is naphthyl (1-naphthyl or 2-naphthyl), the tricyclic ring system is terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, or p-terphenyl-4-yl), the fused tricyclic ring system is acenaphthylene-(1-, 3-, 4-, or 5-), -)yl, fluoren-(1-, 2-, 3-, 4-, or 9-)yl, phenalen-(1- or 2-)yl, phenanthrene-(1-, 2-, 3-, 4-, or 9-)yl, or anthracene-(1-, 2-, or 9-)yl, the tetracyclic ring systems quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl fluorene-4-yl, m-quaterphenyl-4-yl, or m-quaterphenyl), fused tetracyclic ring systems such as triphenylene-(1- or 2-)yl, pyrene-(1-, 2-, or 4-)yl, or naphthacene-(1-, 2-, or 5-)yl, or fused pentacyclic ring systems such as perylene-(1-, 2-, or 3-)yl, or pentacene-(1-, 2-, 5-, or 6-)yl. Other examples include monovalent radicals of spirofluorene.

[0033] The aryl as the second substituent also includes a structure in which the aryl is substituted with at least one group selected from the group consisting of aryl such as phenyl (specific examples are the groups described above), alkyl such as methyl (specific examples are the groups described below), and cycloalkyl such as cyclohexyl or adamantyl (specific examples are the groups described below). An example of such a group is a group in which the 9-position of the fluorenyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl.

[0034] The "arylene" is, for example, an arylene having 6 to 30 carbon atoms, and preferably an arylene having 6 to 20 carbon atoms, an arylene having 6 to 16 carbon atoms, an arylene having 6 to 12 carbon atoms, or an arylene having 6 to 10 carbon atoms. Specific examples of "arylene" include divalent groups obtained by removing one hydrogen atom from the above-mentioned "aryl" (monovalent group).

[0035] The "heteroaryl" is, for example, a heteroaryl having 2 to 30 carbon atoms, and preferably a heteroaryl having 2 to 25 carbon atoms, a heteroaryl having 2 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, or a heteroaryl having 2 to 10 carbon atoms. The "heteroaryl" contains, in addition to carbon, one or more, preferably 1 to 5, heteroatoms selected from oxygen, sulfur, nitrogen, etc. as ring-constituting atoms.

[0036] Specific examples of "heteroaryl" include monovalent groups obtained by removing one hydrogen atom from the above-mentioned "heteroaryl ring." For example, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenazasilinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzo Examples include furanyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, benzoselenophenyl, dibenzoselenophenyl, azacarbazolyl, azadibenzothiophenyl, azadibenzofuranyl, azadibenzoselenophenyl, azatriphenylenyl, imidazoimidazolyl, indoloindolyl, benzofurocarbazolyl, benzothienocarbazolyl, indenocarbazolyl and selenophenocarbazolyl, benzophosphoryl, dibenzophosphoryl, a monovalent radical of a benzophospholeoxide ring, a monovalent radical of a dibenzophospholeoxide ring, furazanyl, thianthrenyl, indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl, and oxazolinyl. Other examples include a monovalent group of spiro[fluorene-9,9'-xanthene] and a monovalent group of spirobi[silafluorene].

[0037] The heteroaryl as the second substituent also includes a structure in which the heteroaryl is substituted with at least one group selected from the group consisting of aryl such as phenyl (specific examples are the groups described above), alkyl such as methyl (specific examples are the groups described below), and cycloalkyl such as cyclohexyl or adamantyl (specific examples are the groups described below). An example of such a group is a carbazolyl group as the second substituent, where the 9-position is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl. Also included in the heteroaryl group as the second substituent are groups in which a nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl, or carbazolyl is further substituted with phenyl or biphenylyl.

[0038] The "heteroarylene" is, for example, a heteroarylene having 2 to 30 carbon atoms, and preferably a heteroarylene having 2 to 25 carbon atoms, a heteroarylene having 2 to 20 carbon atoms, a heteroarylene having 2 to 15 carbon atoms, or a heteroarylene having 2 to 10 carbon atoms. Furthermore, the "heteroarylene" is, for example, a divalent group such as a heterocycle containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms. Specific examples of "heteroarylene" include divalent groups obtained by removing one hydrogen atom from the above-mentioned "heteroaryl" (monovalent group).

[0039] "Diarylamino" is an amino substituted with two aryls, and the details of the aryls can be found in the above explanation of "aryl". "Diheteroarylamino" refers to an amino group substituted with two heteroaryls, and the details of this heteroaryl can be found in the above description of "heteroaryl". "Arylheteroarylamino" refers to an amino group substituted with an aryl and a heteroaryl, and the details of the aryl and heteroaryl can be found in the above descriptions of "aryl" and "heteroaryl".

[0040] The two aryls in the diarylamino as the first substituent may be bonded to each other via a linking group, the two heteroaryls in the diheteroarylamino as the first substituent may be bonded to each other via a linking group, and the aryl and heteroaryl in the arylheteroarylamino as the first substituent may be bonded to each other via a linking group. Here, the expression "bonded via a linking group" means that, for example, the two phenyls in diphenylamino form a bond via a linking group, as shown below. This explanation also applies to diheteroarylamino and arylheteroarylamino formed by aryls or heteroaryls.

[0041] [ka]

[0042] Specific examples of the linking group include >O and >NR X ,>C(-R X )2, >Si(-R X )2, >S, >CO, >CS, >SO, >SO2, and >Se. X are each independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl, or heteroaryl. X )2, >Si(-R X )2, in R X is a single bond or a linking group X Y They may be bonded via X to form a ring. Y As >O, >NR Y ,>C(-R Y )2, >Si(-R Y )2, >S, >CO, >CS, >SO, >SO2, and >Se, and R Y are each independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl, or heteroaryl, provided that X Y >C(-R Y)2 and >Si(-R Y )2, two R Y do not bond to form a ring. Further examples of the linking group include alkenylene. Any hydrogen atom in the alkenylene can be independently selected from R X and R X are each independently alkyl, cycloalkyl, substituted silyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, substituted silyl, or aryl.

[0043] In this specification, unless otherwise specified, when "diarylamino," "diheteroarylamino," or "arylheteroarylamino" is simply described, it is assumed that the following explanation is added: "two aryls of the diarylamino may be bonded to each other via a linking group," "two heteroaryls of the diheteroarylamino may be bonded to each other via a linking group," and "aryl and heteroaryls of the arylheteroarylamino may be bonded to each other via a linking group," respectively.

[0044] A "diarylboryl" is a boryl substituted with two aryls. For details of the aryl, see the above description of the "aryl." The two aryls may be bonded via a single bond or a linking group (e.g., -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >C(-R)2, >Si(-R)2, or >Se). Here, the R of -CR=CR-, the R of >NR, the R of >C(-R)2, and the R of >Si(-R)2 are aryl, heteroaryl, diarylamino, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen atom in the R may be further substituted with an aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. Adjacent Rs may be bonded to form a ring, forming a cycloalkylene, arylene, or heteroarylene. For details of the substituents listed here, the above-mentioned explanations of "aryl," "arylene," "heteroaryl," "heteroarylene," and "diarylamino," as well as the below-mentioned explanations of "alkyl," "alkenyl," "alkynyl," "cycloalkyl," "cycloalkylene," "alkoxy," and "aryloxy" can be cited. Furthermore, when "diarylboryl" is simply described in this specification, unless otherwise specified, it is assumed that the explanation that "the two aryls of the diarylboryl may be bonded to each other via a single bond or a linking group" is also added.

[0045] The "alkyl" may be either straight-chain or branched-chain, for example, a straight-chain alkyl having 1 to 24 carbon atoms or a branched-chain alkyl having 3 to 24 carbon atoms, and is preferably an alkyl having 1 to 18 carbon atoms (branched-chain alkyl having 3 to 18 carbon atoms), an alkyl having 1 to 12 carbon atoms (branched-chain alkyl having 3 to 12 carbon atoms), an alkyl having 1 to 6 carbon atoms (branched-chain alkyl having 3 to 6 carbon atoms), an alkyl having 1 to 5 carbon atoms (branched-chain alkyl having 3 to 5 carbon atoms), or an alkyl having 1 to 4 carbon atoms (branched-chain alkyl having 3 to 4 carbon atoms).

[0046] Specific examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1,1,2,2-tetramethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-ethylbutyl, 1,1-dimethylbutyl, 3,3-dimethylbutyl, 1,1-diethylbutyl, 1-ethyl-1-methylbutyl, 1-propyl-1-methylbutyl, 1,1,3-trimethylbutyl, 1-ethyl-1,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, t-pentyl (t-amyl), 1-methylpentyl, 2-propylpentyl, 1,1-dimethylpentyl, 1-ethyl-1-methylpentyl, 1-propyl-1 -methylpentyl, 1-butyl-1-methylpentyl, 1,1,4-trimethylpentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 1,1-dimethylhexyl, 1-ethyl-1-methylhexyl, 1,1,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-heptyl, 1-methylheptyl, 1-hexylheptyl, 1,1-dimethylheptyl, 2,2-dimethylhexyl Examples of the alkyl group include methylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, t-octyl (1,1,3,3-tetramethylbutyl), 1,1-dimethyloctyl, n-nonyl, n-decyl, 1-methyldecyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-eicosyl.

[0047] An "alkylene" is a divalent group obtained by removing any hydrogen from an "alkyl", such as methylene, ethylene, or propylene.

[0048] For "alkenyl," the explanation of "alkyl" above can be referred to. It is a group in which a C═C single bond in the "alkyl" structure is replaced with a C═C double bond, and also includes groups in which not only one but two or more single bonds are replaced with double bonds (also called alkadiene-yl or alkanetriene-yl).

[0049] "Alkenylene" is a divalent group obtained by removing any hydrogen from "alkenyl", and examples include vinylene.

[0050] For "alkynyl," the explanation of "alkyl" above can be referred to. It is a group in which a C≡C single bond in the "alkyl" structure is replaced with a C≡C triple bond, and also includes groups in which not only one but two or more single bonds are replaced with triple bonds (also called alkadiyn-yl or alkanetriyn-yl).

[0051] The "cycloalkyl" is, for example, a cycloalkyl having 3 to 24 carbon atoms, and preferably a cycloalkyl having 3 to 20 carbon atoms, a cycloalkyl having 3 to 16 carbon atoms, a cycloalkyl having 3 to 14 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, a cycloalkyl having 5 to 10 carbon atoms, a cycloalkyl having 5 to 8 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, or a cycloalkyl having 5 carbon atoms.

[0052] Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyl (particularly methyl) substituted derivatives thereof having 1 to 5 carbon atoms or 1 to 4 carbon atoms, norbornenyl, bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, and decahydroazulenyl.

[0053] "Cycloalkylene" is, for example, cycloalkylene having 3 to 24 carbon atoms, and preferably cycloalkylene having 3 to 20 carbon atoms, cycloalkylene having 3 to 16 carbon atoms, cycloalkylene having 3 to 14 carbon atoms, cycloalkylene having 3 to 12 carbon atoms, cycloalkylene having 5 to 10 carbon atoms, cycloalkylene having 5 to 8 carbon atoms, cycloalkylene having 5 to 6 carbon atoms, cycloalkylene having 5 carbon atoms, etc. A specific example of "cycloalkylene" is a structure in which one hydrogen atom is removed from the above-mentioned "cycloalkyl" (monovalent group) to form a divalent group.

[0054] "Cycloalkenyl" refers to a group having a structure in which at least one pair of single bonds between two carbon atoms in the above-mentioned "cycloalkyl" has become a double bond (for example, a group in which -CH-CH- is replaced with -CH=CH-), and does not fall under the category of aryl. Specific examples include 1-cyclohexenyl and 1-cyclopentenyl.

[0055] "Alkoxy" is a group represented by "Alk-O- (Alk is alkyl)", and the above explanation of "alkyl" can be cited for details of the alkyl.

[0056] "Aryloxy" is a group represented by "Ar-O-(Ar is aryl)", and the above explanation of "aryl" can be cited for details of the aryl.

[0057] The "substituted silyl" is, for example, a silyl substituted with at least one of aryl, alkyl, and cycloalkyl, and is preferably triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, or alkyldicycloalkylsilyl.

[0058] "Triarylsilyl" is a silyl group substituted with three aryl groups, and the details of the aryl groups can be found in the above description of "aryl." Specific examples of "triarylsilyl" include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl.

[0059] "Trialkylsilyl" is a silyl group substituted with three alkyl groups, and the details of this alkyl can be found in the above explanation of "alkyl". Specific examples of the "trialkylsilyl" include trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-s-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldiethylsilyl, isopropyldiethylsilyl, n-butyldiethylsilyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, s-butyldi-n-propylsilyl, t-butyldi-n-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, and t-butyldiisopropylsilyl.

[0060] "Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyl groups, and the details of this cycloalkyl can be found in the above description of "cycloalkyl". Specific "tricycloalkylsilyl" includes, for example, tricyclopentylsilyl or tricyclohexylsilyl.

[0061] "Dialkylcycloalkylsilyl" is a silyl group substituted with two alkyls and one cycloalkyl, and the details of the alkyl and cycloalkyl can be found in the explanations of "alkyl" and "cycloalkyl" above.

[0062] "Alkyldicycloalkylsilyl" is a silyl group substituted with one alkyl and two cycloalkyl, and the details of the alkyl and cycloalkyl can be found in the explanations of "alkyl" and "cycloalkyl" above.

[0063] <When two groups bonded to the same atom are bonded to each other> In the present specification, when it is stated that two groups bonded to the same atom may be bonded to each other to form a ring, they may be bonded by a single bond or a linking group (collectively also referred to as a linking group), and examples of the linking group include -CH2-CH2-, -CHR-CHR-, -CR2-CR2-, -CH=CH-, -CR=CR-, -C≡C-, -N(-R)-, -O-, -S-, -C(-R)2-, -Si(-R)2-, or -Se-, for example, the following structure. R of -CHR-CHR-, R of -CR-CR-, R of -CR=CR-, R of -N(-R)-, R of -C(-R)-, and R of -Si(-R)- are each independently hydrogen, aryl optionally substituted with alkyl or cycloalkyl, heteroaryl optionally substituted with alkyl or cycloalkyl, alkyl optionally substituted with cycloalkyl, alkenyl optionally substituted with alkyl or cycloalkyl, alkynyl optionally substituted with alkyl or cycloalkyl, or cycloalkyl optionally substituted with alkyl or cycloalkyl. Two adjacent Rs may be bonded to form a ring, forming a cycloalkylene, arylene, or heteroarylene.

[0064] [ka]

[0065] As the linking group, a single bond and -CR=CR-, -N(-R)-, -O-, -S-, -C(-R)2-, -Si(-R)2-, and -Se- are preferred, a single bond and -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R)2- as linking groups are more preferred, a single bond and -CR=CR-, -N(-R)-, -O-, and -S- as linking groups are even more preferred, and a single bond is most preferred.

[0066] The position at which two Rs are bonded by the bonding group is not particularly limited as long as it is a position where bonding is possible, but it is preferable that they are bonded at the most adjacent positions. For example, when the two groups are phenyl, it is preferable that they are bonded at positions ortho (2nd position) relative to the bonding position (1st position) of "C" or "Si" in the phenyl (see the structural formula above).

[0067] 1. Compounds of the Present Invention The triazine compound of the present invention is represented by formula (1).

[0068] [ka]

[0069] In formula (1), Y 1 is a group represented by formula (1-a), and Y 2 is a group represented by formula (1-b). 1 and / or Y 2 As the bond position, it has an electron-accepting substituent (acceptor structure) such as triazinyl to which multiple electron-donating substituents (donor structure) such as heteroaryl are bonded. Specifically, in formula (1), A 1 and A 2 Neither of or A 3 and A 4 At least one of the above is a group having N as the bonding position.

[0070] [ka] * indicates the bond position.

[0071] In formula (1-a), A 1 and A 2 are each independently a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl. 3 and A 4are each independently substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, or substituted or unsubstituted arylheteroarylamino.

[0072] A 1 , A 2 , A 3 or A 4 The aryl in the substituted or unsubstituted aryl represented by A is preferably phenyl. 1 , A 2 , A 3 or A 4 The heteroaryl in the substituted or unsubstituted heteroaryl represented by the formula (I) is preferably carbazolyl (particularly N-carbazolyl), azacarbazolyl (particularly N-azacarbazolyl), benzimidazolyl (particularly N-benzimidazolyl), imidazoimidazolyl (particularly N-imidazoimidazolyl), N-indoloindolyl (particularly N-indoloindolyl), N-indolocarbazolyl (particularly N-indolocarbazolyl), N-benzofurocarbazolyl (particularly N-benzofurocarbazolyl), N-benzothienocarbazolyl (particularly N-benzothienocarbazolyl), or N-indenocarbazolyl (particularly N-indenocarbazolyl), and more preferably N-carbazolyl.

[0073] A 1 , A 2 , A 3 or A 4When the aryl or heteroaryl in is substituted, the substituent is preferably aryl or heteroaryl, more preferably phenyl, carbazolyl (particularly N-carbazolyl), azacarbazolyl (particularly N-azacarbazolyl), benzimidazolyl (particularly N-benzimidazolyl), imidazoimidazolyl (particularly N-imidazoimidazolyl), N-indoloindolyl (particularly N-indoloindolyl), N-indolocarbazolyl (particularly N-indolocarbazolyl), N-benzofurocarbazolyl (particularly N-benzofurocarbazolyl), N-benzothienocarbazolyl (particularly N-benzothienocarbazolyl), or N-indenocarbazolyl (particularly N-indenocarbazolyl), and even more preferably phenyl or N-carbazolyl. The position of the substituent is not particularly limited. The number of the substituents is preferably 0 to 2, and more preferably 0 to 1. 1 , A 2 , A 3 or A 4 It is particularly preferred that each independently be unsubstituted phenyl or unsubstituted N-carbazolyl.

[0074] A 3 or A 4 In the substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, or substituted or unsubstituted arylheteroarylamino represented by the formula (I), when the diarylamino, diheteroarylamino, and arylheteroarylamino are substituted, the substituent is preferably phenyl. The number of substituents is preferably 0 to 2, more preferably 0 to 1. It is preferable that the diarylamino, diheteroarylamino, and arylheteroarylamino are all unsubstituted. Of these, a preferred example is unsubstituted diphenylamino.

[0075] In equation (1), A 1 and A 2 and / or A 3 and A 4are groups with N as the bonding site. As shown in the examples, the compound represented by formula (1) having a substituent in which multiple electron-donating nitrogen-substituted groups are substituted on an electron-accepting substituent such as triazinyl has an extremely high lowest excited singlet energy level compared to a compound that does not have such a substituent.

[0076] The group bonding to N is preferably a group having an electron-donating structure as a whole, and is preferably, for example, substituted or unsubstituted N-carbazolyl, substituted or unsubstituted N-azacarbazolyl, substituted or unsubstituted N-benzimidazolyl, substituted or unsubstituted N-imidazoimidazolyl, substituted or unsubstituted N-indoloindolyl, substituted or unsubstituted N-indolocarbazolyl, substituted or unsubstituted N-benzofurocarbazolyl, substituted or unsubstituted N-benzothienocarbazolyl, or substituted or unsubstituted N-indenocarbazolyl.

[0077] The group bonding to N is more preferably any of the following groups: The following groups may have 1 to 2 substituents selected from the group consisting of unsubstituted phenyl and unsubstituted N-carbazolyl.

[0078] [ka]

[0079] In the above formula (Aa-2), W is NH, NMe, NPh, O, S, or C(Me)2. The two dotted lines in formula (Aa-2) bond the ends of the dotted lines to two adjacent ring-constituting carbon atoms of the six-membered ring located inside the ring.

[0080] The group having N as the bonding position is particularly preferably a group represented by formula (Aa-1).

[0081] In formula (1), at least A 1 and A 2are preferably groups bonding to N. That is, the compound of the present invention preferably has a triazinyl substituted with two substituted or unsubstituted heteroaryls bonding to N. A 1 , A 2 , A 3 and A 4 may each be a group having N as the bonding position.

[0082] In formula (1-b), Z 1 , Z 2 and Z 3 are independently CH or N, but Z 1 , Z 2 and Z 3 At least one of the groups represented by formula (1-b) is N. 3 and A 4 A triazinyl having as a substituent 3 and A 4 Pyridyl having as a substituent, or A 3 and A 4 Z is a pyrimidinyl having Z as a substituent. 1 , Z 2 and Z 3 are preferably both N.

[0083] In formula (1), X is a substituted or unsubstituted heteroarylene. The heteroaryl ring constituting the arylene is preferably any one selected from the group consisting of an indole ring, a carbazole ring, a benzothiophene ring, a benzofuran ring, a benzoselenophene ring, a dibenzothiophene ring, a dibenzofuran ring, a dibenzoselenophene ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an azacarbazole ring, an azadibenzothiophene ring, an azadibenzofuran ring, an azadibenzoselenophene ring, an azatriphenylene ring, an imidazole ring, a benzimidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, an isoxazole ring, an isothiazole ring, a triazole ring, a thiadiazole ring, an oxadiazole ring, an imidazoimidazole ring, an indoloindole ring, an indolocarbazole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, an indenocarbazole ring, and a selenophenocarbazole ring. Among these, electron-donating heteroaryl rings are preferred, and more specifically, a carbazole ring, an azacarbazole ring, a benzimidazole ring, an imidazoimidazole ring, an indoloindole ring, an indolocarbazole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, or an indenocarbazole ring is more preferred. The bonding positions are not particularly limited, but for example, the carbazole ring is preferably a divalent group bonding to the 3rd and 9th positions or the 2nd and 9th positions, and more preferably a divalent group bonding to the 3rd and 9th positions. Furthermore, the indolocarbazole ring is preferably a divalent group bonding to two N atoms. The heteroaryl ring constituting the heteroarylene in X is particularly a carbazole ring. It is preferable that

[0084] When the heteroarylene in X is substituted, the substituents include aryl or Heteroaryl is preferred, with phenyl, carbazolyl (particularly N-carbazolyl), azacarbazolyl (particularly N-azacarbazolyl), benzimidazolyl (particularly N-benzimidazolyl), imidazoimidazolyl (particularly N-imidazoimidazolyl), N-indoloindolyl (particularly N-indoloindolyl), N-indolocarbazolyl (particularly N-indolocarbazolyl), N-benzofurocarbazolyl (particularly N-benzofurocarbazolyl), N-benzothienocarbazolyl (particularly N-benzothienocarbazolyl), or N-indenocarbazolyl (particularly N-indenocarbazolyl) being even more preferred, with phenyl or N-carbazolyl being even more preferred.

[0085] The position of the substituent on the heteroarylene in X is not particularly limited. is preferably 0 to 2, more preferably 0 to 1. X is an unsubstituted heteroarylene. It is particularly preferred that

[0086] At least one hydrogen atom in the compound represented by formula (1) may be replaced by deuterium, cyano, or halogen. Halogen is fluorine, chlorine, bromine, or iodine, preferably fluorine, chlorine, or bromine, and more preferably fluorine or chlorine.

[0087] Specific examples of the compound of the present invention include compounds represented by any of the following structural formulas.

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091]

change

[0092]

change

[0093]

change

[0094]

change

[0095]

change

[0096]

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[0097]

change

[0098]

change

[0099]

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[0100]

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[0101]

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[0102] 2. Method for producing triazine compounds The compound represented by formula (1) can be produced by applying known reactions such as Suzuki coupling and Negishi coupling to a compound having a reactive group at a desired position on the nitrogen-containing six-membered ring in formula (1) and a compound having a reactive group at a desired position as starting materials. Examples of reactive groups in these compounds include halogens and boronic acids.

[0103] 3. Organic Devices The triazine compound according to the present invention can be used as a material for organic devices, such as organic electroluminescent devices, organic field-effect transistors, and organic thin-film solar cells.

[0104] 3-1. Organic electroluminescent device The organic EL element according to this embodiment will be described in detail below with reference to the drawings: Figure 1 is a schematic cross-sectional view showing the organic EL element according to this embodiment.

[0105] <Structure of organic electroluminescent device> The organic EL device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, a hole transport layer 104 provided on the hole injection layer 103, an emitting layer 105 provided on the hole transport layer 104, an electron transport layer 106 provided on the emitting layer 105, an electron injection layer 107 provided on the electron transport layer 106, and a cathode 108 provided on the electron injection layer 107.

[0106] The organic EL element 100 may be fabricated in the reverse order, for example, to have a substrate 101, a cathode 108 provided on the substrate 101, an electron injection layer 107 provided on the cathode 108, an electron transport layer 106 provided on the electron injection layer 107, an emitting layer 105 provided on the electron transport layer 106, a hole transport layer 104 provided on the emitting layer 105, a hole injection layer 103 provided on the hole transport layer 104, and an anode 102 provided on the hole injection layer 103.

[0107] Not all of the above layers are essential, and the minimum structural unit is a configuration consisting of an anode 102, an emitting layer 105, and a cathode 108. The hole injection layer 103, the hole transport layer 104, the electron transport layer 106, and the electron injection layer 107 are layers that may be optionally provided. Furthermore, each of the above layers may consist of a single layer or multiple layers.

[0108] The layers constituting the organic EL element may be configured as follows: "substrate / anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode" as described above, as well as "substrate / anode / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode", "substrate / anode / hole injection layer / light-emitting layer / electron transport layer / electron injection layer / cathode", "substrate / anode / hole injection layer / hole transport layer / light-emitting ... transport The configuration may be, for example, "substrate / anode / light-emitting layer / electron transport layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron transport layer / cathode," "substrate / anode / hole injection layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole injection layer / light-emitting layer / electron transport layer / cathode," "substrate / anode / light-emitting layer / electron transport layer / cathode," or "substrate / anode / light-emitting layer / electron injection layer / cathode."

[0109] The organic EL device may further include one or both of an electron blocking layer (electron blocking layer) and a hole blocking layer (hole blocking layer). The electron blocking layer has a LUMO shallower than that of the light-emitting layer and a HOMO close to that of the light-emitting layer or the hole transport layer, and is disposed between the light-emitting layer and the hole transport layer. Since electrons remain in the light-emitting layer and do not leak into the hole transport layer, it is possible to prevent a shortened lifetime due to deterioration of the hole transport layer and a decrease in efficiency due to a decrease in recombination efficiency. The hole blocking layer has a HOMO deeper than that of the light-emitting layer and a LUMO close to that of the light-emitting layer or the hole transport layer, and is disposed between the light-emitting layer and the electron transport layer. Since holes remain in the light-emitting layer and do not leak into the electron transport layer, it is possible to prevent a shortened lifetime due to deterioration of the electron transport layer and a decrease in efficiency due to a decrease in recombination efficiency. The hole injection / transport layer may also function as the electron blocking layer. The electron injection / transport layer may also function as the hole blocking layer.

[0110] The organic EL device may further include a high T1 layer. The high T1 layer has a higher T1 than the host compound, assisting dopant compound, or emitting dopant compound used in the emissive layer, and is disposed between the emissive layer and the hole-transporting layer and / or between the emissive layer and the electron-blocking layer. The T1 energy value varies depending on the device's light-emitting mechanism, but it has a higher T1 than the compound used in the host. By having a high T1 layer around the emissive layer, triplet energy can be trapped and converted into singlet energy, which would not normally lead to light emission in fluorescent molecules, resulting in high efficiency. The hole-injection / transporting layer or electron-blocking layer may also function as a high T1 layer. The electron-injection / transporting layer or hole-blocking layer may also function as a high T1 layer.

[0111] The triazine compound of the present invention is preferably used as a material for organic electroluminescent devices. Generally, compounds having a donor structure can be used as a hole-transporting host material in the light-emitting layer and as a hole-transporting layer, while compounds having an acceptor structure can be used as an electron-transporting host material in the electron-transporting layer. Compounds having both a donor structure and an acceptor structure can be used in both the hole-transporting layer and the host and electron-transporting layer in the light-emitting layer. For donor and acceptor structures, see, for example, Advanced Functional Materials 2020, 2008332. More specifically, donor structures include triarylamine structures and carbazole structures, while acceptor structures include triazine structures, pyrimidine structures, and pyridine structures. The triazine compound of the present invention can be used as a host material in the light-emitting layer, a hole-transporting layer material, an electron-transporting layer material, or the like.

[0112] <Substrate in organic electroluminescent device> The substrate 101 is a support for the organic EL device 100 and is typically made of quartz, glass, metal, plastic, or the like. The substrate 101 may be formed into a plate, film, or sheet shape depending on the purpose, and may be, for example, a glass plate, a metal plate, a metal foil, a plastic film, or a plastic sheet. Among these, glass plates and plates made of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. For glass substrates, soda-lime glass or alkali-free glass may be used, and the thickness may be sufficient to maintain mechanical strength. Furthermore, to improve gas barrier properties, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one side. Providing a gas barrier film is particularly preferred when a synthetic resin plate, film, or sheet with poor gas barrier properties is used as the substrate 101.

[0113] <Anode in organic electroluminescent device> The anode 102 serves to inject holes into the light-emitting layer 105. When at least one of the hole injection layer 103 and the hole transport layer 104 is provided between the anode 102 and the light-emitting layer 105, holes are injected into the light-emitting layer 105 via these layers.

[0114] Materials for forming the anode 102 include inorganic and organic compounds. Examples of inorganic compounds include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO), etc.), metal halides (copper iodide, etc.), copper sulfide, carbon black, ITO glass, and NESA glass. Examples of organic compounds include polythiophenes such as poly(3-methylthiophene), and conductive polymers such as polypyrrole and polyaniline. In addition, materials can be appropriately selected from those used as anodes in organic EL devices.

[0115] <Hole injection layer and hole transport layer in organic electroluminescent device> The hole injection layer 103 serves to efficiently inject holes migrating from the anode 102 into the light-emitting layer 105 or the hole transport layer 104. The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 via the hole injection layer 103 to the light-emitting layer 105. The hole injection layer 103 and the hole transport layer 104 are each formed by laminating or mixing one or more types of hole injection / transport materials. Alternatively, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injection / transport material.

[0116] The hole injection / transport material must be able to efficiently inject and transport holes from the positive electrode between electrodes to which an electric field is applied, and it is desirable that the hole injection efficiency be high and the injected holes be efficiently transported. To this end, it is preferable that the material has a low ionization potential, a high hole mobility, and excellent stability, and that impurities that become traps are unlikely to be generated during production or use. It is also preferable to use the triazine compound of the present invention as a material for the hole transport layer.

[0117] As materials for forming the hole injection layer 103 and the hole transport layer 104, any compound can be selected from compounds conventionally used as charge transport materials for holes in photoconductive materials, p-type semiconductors, and known compounds used in hole injection layers and hole transport layers of organic EL devices. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (polymers having an aromatic tertiary amino group in the main chain or side chain, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine, N 4 ,N 4' -diphenyl-N 4 ,N 4' -bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N 4 ,N 4 ,N 4' ,N 4'-tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine, triphenylamine derivatives such as 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives Examples of the material include conductors (for example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. Among polymers, polycarbonates and styrene derivatives having the above-mentioned monomers in their side chains, polyvinylcarbazole, and polysilanes are preferred, but there are no particular limitations on the material as long as it is a compound that can form a thin film required for fabricating a light-emitting device, can inject holes from the anode, and can transport holes.

[0118] It is also known that the conductivity of organic semiconductors is strongly influenced by their doping. Such organic semiconductor matrix materials consist of compounds with good electron-donating or electron-accepting properties. Strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known for doping with electron-donating substances (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes via an electron transfer process in the electron-donating base material (hole-transporting material). The conductivity of the base material varies considerably depending on the number and mobility of holes. Known matrix materials with hole transport properties include benzidine derivatives (such as TPD) or starburst amine derivatives (such as TDATA), as well as certain metal phthalocyanines (e.g., zinc phthalocyanine (ZnPc)) (see JP 2005-167175 A).

[0119] The hole injection layer material and the hole transport layer material described above can also be used as hole layer materials in the form of a polymer compound obtained by polymerizing a reactive compound substituted with a reactive substituent as a monomer, or a crosslinked polymer thereof, or a pendant polymer compound obtained by reacting a main-chain polymer with the reactive compound, or a crosslinked pendant polymer thereof.

[0120] <Light-emitting layer in organic electroluminescent device> The light-emitting layer 105 is a layer that emits light by recombining holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material for the light-emitting layer 105 may be a compound that emits light upon excitation by the recombination of holes and electrons (light-emitting compound), and is preferably a compound that can be formed into a stable thin film and exhibits strong luminescence (fluorescence) efficiency in a solid state. The triazine compound of the present invention is also preferably used as a material for the light-emitting layer.

[0121] The light-emitting layer may be a single layer or may consist of multiple layers, each formed from materials for the light-emitting layer (host material, dopant material). The host material and the dopant material may each be one type or a combination of multiple types. The dopant material may be contained entirely or partially in the host material. As a doping method, the layer can be formed by co-evaporation with the host material, but it may also be mixed with the host material in advance and then vapor-deposited simultaneously, or mixed with the host material together with an organic solvent in advance and then formed into a film by a wet film-forming method.

[0122] The amount of the host material used varies depending on the type of host material and may be determined according to the properties of the host material. The amount of the host material used is preferably 50 to 99.999% by mass, more preferably 80 to 99.95% by mass, and even more preferably 90 to 99.9% by mass, based on the total mass of the materials for the light-emitting layer.

[0123] The amount of dopant material used varies depending on the type of dopant material and may be determined according to the properties of the dopant material. The amount of dopant material used is preferably 0.001 to 50% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass, based on the total mass of the materials for the light-emitting layer. The above ranges are preferable in that, for example, concentration quenching can be prevented. Furthermore, from the viewpoint of durability, it is also preferable that some or all of the hydrogen atoms in the dopant material are deuterated.

[0124] As the dopant material, an emitting dopant and an assisting dopant material may be used. It is preferable to use a thermally activated delayed fluorescent material as the assisting dopant material. In an organic electroluminescent device using an assisting dopant material, a low concentration of the emitting dopant material is preferred in terms of preventing concentration quenching. A high concentration of the assisting dopant material is preferred in terms of the efficiency of the thermally activated delayed fluorescent mechanism. Furthermore, in an organic electroluminescent device using a thermally activated delayed fluorescent assisting dopant material, a low concentration of the emitting dopant material is preferred compared to the amount of the assisting dopant material in terms of the efficiency of the thermally activated delayed fluorescent mechanism of the assisting dopant material.

[0125] When an assisting dopant material is used, the amounts of the host material, assisting dopant material, and emitting dopant material used are approximately 40 to 99 mass%, 59 to 1 mass%, and 20 to 0.001 mass%, respectively, based on the total mass of the materials for the light-emitting layer, preferably 60 to 95 mass%, 39 to 5 mass%, and 10 to 0.01 mass%, respectively, and more preferably 70 to 90 mass%, 29 to 10 mass%, and 5 to 0.05 mass%, respectively.

[0126] <Host material> Examples of host materials include fused ring derivatives of anthracene and pyrene, which have long been known as light emitters, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, fluorene derivatives, benzofluorene derivatives, N-phenylcarbazole derivatives, and carbazonitrile derivatives.

[0127] From the viewpoint of promoting TADF generation in the light-emitting layer without inhibiting it, the triplet energy of the host material is preferably higher than that of the dopant or assisting dopant having the highest triplet energy in the light-emitting layer. Specifically, the triplet energy of the host material is preferably 0.01 eV or more, more preferably 0.03 eV or more, and even more preferably 0.1 eV or more. A TADF-active compound may also be used as the host material.

[0128] The host material may be one kind or a combination of two or more kinds. In the case of a combination of two or more kinds, a combination of a hole-transporting host material and an electron-transporting host material is preferred.

[0129] The triazine compound of the present invention can be preferably used as a host material. The triazine compound of the present invention may be used as a sole host material, a hole-transporting host material, or an electron-transporting host material. The triazine compound of the present invention is preferably used as a sole host material or an electron-transporting host material.

[0130] It is also preferable to use a hole-transporting host material in the hole-transporting layer adjacent to the light-emitting layer and an electron-transporting host material in the electron-transporting layer adjacent to this light-emitting layer. This is because carrier leakage and energy leakage from the light-emitting layer to the adjacent layer are less likely to occur, resulting in a highly efficient organic EL device. The host material (hole-transporting host material) in the light-emitting layer and the material of the hole-transporting layer may be the same or different. Furthermore, the host material (electron-transporting host material) in the light-emitting layer and the material of the electron-transporting layer may be the same or different.

[0131] [Hole-transporting host material (HH)] Preferred examples of the hole-transporting host material (HH) include the triazine compound of the present invention, as well as a compound represented by formula (HH-1) and a compound having a partial structure represented by formula (HH-1).

[0132] [ka]

[0133] In formula (HH-1), Q is >O, >S, or >NA; In the formula (HH-1), one carbon atom adjacent to the carbon atom to which Q is bonded in each of the two phenyl groups may be bonded to each other via L, L is a single bond, >O, >S or >C(-A)2; A is hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy or aryloxy, and two As in >C(-A)2 may be bonded to each other to form an aryl, heteroaryl or cycloalkyl.

[0134] When the hole-transporting host material contains a structure represented by formula (HH-1) as a partial structure, it may contain one of the partial structures 1, but it is also preferable to contain two or more of them. When two or more partial structures are contained, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded so that any rings contained in the partial structures are shared, or may be bonded so that any rings contained in the partial structures are fused to each other. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

[0135] The hole-transporting host material is preferably a compound containing one or more partial structures selected from the group consisting of a triarylamine structure, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a fused polycyclic ring containing phenoxazine or phenothiazine. The hole-transporting host material may contain one such partial structure 1, but preferably contains two or more. When two or more partial structures are contained, the two or more partial structures may be the same or different.

[0136] Specific examples of the hole-transporting host material include the following compounds.

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] Of the above, HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92 and HH-1-106 to HH-1-108 are preferred.

[0151] [Electron-transporting host material (EH)] Examples of the electron-transporting host material (EH) include the triazine compound of the present invention, a compound represented by formula (EH-1), and a compound having a partial structure represented by formula (EH-1). [ka]

[0152] In formula (EH-1), Each J is independently =C(-A)- or =N-, and at least three J's are =C(-A)-; Z is -O-, -S-, -C(=O)-, -P(=O)(-A)-, -P(=S)(-A)-, -N(-A)-, -B(-A)- or -S(=O)2-; J adjacent to the carbon atom to which Z is bonded and A to which Z is bonded may be bonded to each other via L, L is a single bond, >O, >S or >C(-A)2; A is hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, triarylsilyl, alkoxy or aryloxy, and two A's in >C(-A)2 may be bonded to each other to form an aryl, heteroaryl or cycloalkyl; When all J's are =C(-A)-, then either one of A or Z contains a heteroatom.

[0153] For aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, triarylsilyl, alkoxy, or aryloxy represented by A in formula (EH-1), the explanation for A in formula (HH-1) can be referred to. When two As in formula (EH-1) bond to each other to form an aryl, heteroaryl, or cycloalkyl, the explanation for the aryl, heteroaryl, or cycloalkyl can also be referred to in formula (HH-1).

[0154] When the electron-transporting host material contains a structure represented by formula (EH-1) as a partial structure, it may contain one such partial structure, but it is also preferable to contain two or more such partial structures. When two or more such partial structures are contained, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded so that any rings contained in the partial structures are shared, or may be bonded so that any rings contained in the partial structures are fused to each other. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

[0155] Specific examples of the electron transporting host material include the following compounds. [ka]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] Another preferred example of the electron-transporting host material (a compound having a partial structure represented by formula (EH-1)) is a polycyclic aromatic compound represented by the following formula (EH-1b), or a multimer of a polycyclic aromatic compound having a plurality of structures represented by the following formula (EH-1b). [ka]

[0165] In formula (EH-1b), R 1 , R 2 , R 3 , R 4 and R 5(Hereinafter referred to as “R 1 and the like) are each independently hydrogen or a substituent selected from the group Z of substituents. In formula (EH-1b), X 1 and X 2 are each independently >NR (amine nitrogen), >O, >C(-R)2, >S or >Se, and X 1 and X 2 are never both >C(-R)2, R in the >NR and >C(-R)2 each independently represents hydrogen or a substituent selected from the substituent group Z, and R in the >NR and >C(-R)2 each independently may be bonded to at least one of the ring a, ring b, and ring c via a linking group or a single bond. Y 1 , Y 2 , Y 3 , Y 4 , Y 5 and Y 6 (hereinafter, "Y 1 each independently represents ═C(—R)— or ═N— (pyridinic nitrogen), and at least one represents ═N— (pyridinic nitrogen); Each R in the =C(-R)- is independently hydrogen or a substituent selected from the substituent group Z. R 1 , R 2 , R 3 , R 4 and R 5 , and the Y 1 ~Y 6 Adjacent groups among R in =C(-R)- may be bonded to each other to form an aryl ring or a heteroaryl ring together with at least one ring of ring a, ring b, and ring c, and the formed ring may be substituted with at least one group selected from substituent group Z. At least one hydrogen atom in the compounds and structures represented by formula (EH-1b) may be replaced with cyano, halogen, or deuterium.

[0166] In formula (EH-1b), R 1, R 2 , R 3 , R 4 and R 5 are all hydrogen atoms, or R 3 and R 4 are both hydrogen and R 1 , R 2 and R 5 Preferably, one or more selected from the group consisting of are substituents other than hydrogen, and the rest are hydrogen. The substituents are preferably alkyl, aryl which may be substituted with alkyl or heteroaryl, heteroaryl which may be substituted with alkyl or aryl, or diarylamino which may be substituted with alkyl or aryl. In this case, the alkyl is preferably an alkyl having 1 to 6 carbon atoms (e.g., methyl, t-butyl), the aryl is preferably phenyl or biphenyl, and the heteroaryl is preferably triazinyl, carbazolyl (e.g., 2-carbazolyl, 3-carbazolyl, 9-carbazolyl), pyrimidinyl, pyridinyl, dibenzofuranyl, or dibenzothienyl. Specific examples include phenyl, biphenyl, diphenyltriazinyl, carbazolyltriazinyl, monophenylpyrimidinyl, diphenylpyrimidinyl, carbazolyltriazinyl, pyridinyl, dibenzofuranyl, and dibenzothienyl.

[0167] Y 1 etc. are each independently =C(-R)- or =N-, and at least one is =N-. Y 1 ~Y 6 Any of the groups may be =N-. Preferably, Y 1 and Y 6 =N-(a ring is a pyrimidine ring), Y 1 or Y 6 =N-(a ring is a pyridine ring), Y 2 and Y 5 =N-(ring b and ring c are pyridine rings), Y 3 and Y 4 =N-(ring b and ring c are pyridine rings), Y 2 ~Y 5is =N-(ring b and ring c are pyrimidine rings), Y 1 , Y 3 , Y 4 and Y 6 is =N-(a ring is a pyrimidine ring, b ring and c ring are pyridine rings), Y 1 , Y 2 , Y 5 and Y 6 is =N-(a ring is a pyrimidine ring, b ring and c ring are pyridine rings), Y 1 ~Y 6 is =N-(a ring, b ring and c ring are pyrimidine rings), Y 2 or Y 5 is =N-(ring b or ring c is a pyridine ring).

[0168] In addition to the above =N- arrangement, X 1 and X 2 is preferably >O, and a polycyclic aromatic compound containing a partial structure represented by any of the following formulas is preferred. [ka]

[0169] In particular, polycyclic aromatic compounds containing a partial structure represented by formula (EH-1b-N1) have a higher E S1 , high E T1 , small ΔE S1T1 It has. Specific examples of the polycyclic aromatic compound represented by formula (EH-1b) are shown below.

[0170] [ka]

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] Of the above, EH-1-1 to EH-1-4, EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 to EH-1-59, EH-1-61, EH-1-66, EH-1-68, EH-1-71, EH-1-72, EH-1-90, EH-1-100, EH-1-101, EH-1-104, EH-1-115, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130 are preferred.

[0177] [Combination of hole-transporting host material and electron-transporting host material] The combination of a hole-transporting host material and an electron-transporting host material is selected depending on the HOMO, LUMO and excited triplet energy of the hole-transporting host material, the electron-transporting host material and the dopant material. With regard to the HOMO and LUMO, a combination is selected in which the HOMO(HH) of the hole-transporting host material is shallower than the HOMO(EH) of the electron-transporting host material and the LUMO(EH) of the electron-transporting host material is deeper than the LUMO(HH) of the hole-transporting host material. More specifically, a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.10 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.10 eV or more is preferred, a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.20 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.20 eV or more is more preferred, and a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.25 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.25 eV or more is even more preferred.

[0178] The hole-transporting host material and the electron-transporting host material may be combined to form an association called an exciplex. It is generally known that exciplexes are easily formed between a material with a relatively deep LUMO level and a material with a shallow HOMO level. The interaction between the hole-transporting host material and the electron-transporting host material, specifically, whether an exciplex is formed, can be determined by forming a single-layer film consisting of only the hole-transporting host material and the electron-transporting host material under the same conditions as for forming the light-emitting layer, measuring the emission spectrum (fluorescence or phosphorescence spectrum), and comparing the obtained emission spectrum with the emission spectrum of each of the hole-transporting host material and the electron-transporting host material alone. This can be determined by the spectrum of a mixed film containing the hole-transporting host material and the electron-transporting host material exhibiting an emission wavelength different from both the spectrum of the film of the hole-transporting host material and the spectrum of the film of the electron-transporting host material. Specifically, a difference of 10 nm or more in the peak wavelength of the spectrum can be used as an indicator.

[0179] Specific examples of combinations of hole-transporting host materials and electron-transporting host materials that do not form exciplexes include the following combinations. In order to satisfy the physical properties of the HOMO, LUMO, and excited triplet energy described above, the hole-transporting host material is preferably a compound having carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, more preferably a compound having carbazole, dibenzofuran, or dibenzothiophene as a partial structure, and even more preferably a compound having carbazole as a partial structure. Similarly, the electron-transporting host material is preferably a compound having pyridine, triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, and even more preferably a compound having triazine.

[0180] More specifically, the hole-transporting host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, and HH-1-106 to HH-1-108, and the electron-transporting host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-5, EH-1-6, EH-1-7, EH-1-8, EH-1-9, EH-1-10, EH-1-11, EH-1-12, EH-1-13, EH-1-14, EH-1-15, EH-1-16, EH-1-17, EH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, and HH-1-106 to HH-1-108. It is preferable that the polyisoprene is selected from the group consisting of EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 to EH-1-59, EH-1-61, EH-1-71, EH-1-72, EH-1-90, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130. Preferred examples of combinations include Compound HH-1-1 and Compound EH-1-22, Compound HH-1-1 and Compound EH-1-23, Compound HH-1-1 and Compound EH-1-24, Compound HH-1-2 and Compound EH-1-22, Compound HH-1-2 and Compound EH-1-23, Compound HH-1-2 and Compound EH-1-24, or Compound HH-1-1 and Compound EH-1-128.

[0181] Specific examples of combinations of hole-transporting host materials and electron-transporting host materials that form exciplexes include the following combinations. In order to satisfy the physical properties of HOMO, LUMO, and excited triplet energy, the hole-transporting host material is preferably a compound having carbazole, triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, more preferably a compound having triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, and even more preferably a compound having triarylamine as a partial structure. Similarly, the electron-transporting host material is preferably a compound having pyridine, triazine, phosphine oxide, or benzofuropyridine as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, and even more preferably a compound having phosphine oxide or triazine.

[0182] More specifically, the hole-transporting host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-11, HH-1-12, HH-1-17, HH-1-18, HH-1-23, and HH-1-24, and the electron-transporting host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-21 to EH-1-25, EH- It is preferable that the compound is selected from the group consisting of EH-1-51 to EH-1-57, EH-1-59, EH-1-66, EH-1-68, EH-1-90, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130. Preferred examples of combinations include Compound HH-1-1 and Compound EH-1-21, Compound HH-1-2 and Compound EH-1-21, Compound HH-1-12 and Compound EH-1-117, Compound HH-1-1 and Compound EH-1-130, Compound HH-1-33 and Compound EH-1-117, Compound HH-1-48 and Compound EH-1-117, or Compound HH-1-49 and Compound EH-1-117.

[0183] Other specific combinations of hole-transporting host materials and electron-transporting host materials are described in Organic Electronics 66 (2019) 227-24, Advanced Functional Materals 25 (2015) 361-366, Advanced Materials 26 (2014) 4730-4734, ACS Applied Materials and Interfaces 8 (2016) 32984-32991, ACS Applied Materials and Interfaces 2016, 8, 9806-9810, ACS Applied Materials and Interfaces 2016, 8, 32984-32991, Journal of Materials Chemistry C, 2018, 6, 8784-8792, Angewante Chemie International Edition. 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684 and Synthetic Metals, 201, 2015, 49 can be referenced.

[0184] <Dopant materials> Known compounds can be used as the dopant material, and can be selected from a variety of materials depending on the desired emission color. Specific examples include fused ring derivatives of phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and chrysene, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, and tetraphenylbutadiene. derivatives, cyclopentadiene derivatives, bisstyryl derivatives such as bisstyryl anthracene derivatives and distyrylbenzene derivatives (JP Patent Publication No. 245087 / 1999), bisstyrylarylene derivatives (JP Patent Publication No. 247278 / 1990), diazaindacene derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives such as phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, and phenylisobenzofuran Coumarin derivatives such as dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives, and 3-benzoxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, xanthene derivatives, and rhodamine derivatives. conductors, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives, and benzofluorene derivatives.

[0185] As the emitting dopant material, it is also preferable to use a boron-containing polycyclic aromatic compound described in WO 2015 / 102118, WO 2020 / 162600, paragraphs 0097 to 0269 of JP 2021-077890 A, etc. The polycyclic aromatic compound having a boron atom may be a phosphor or a TADF material (thermally activated delayed phosphor). The polycyclic aromatic compound having a boron atom is preferably a blue-emitting compound.

[0186] Preferred examples of the boron-containing polycyclic aromatic compound include compounds represented by the following formula (12), formula (13) or formula (14). [ka]

[0187] ring A, ring B, ring C and ring D are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; Y is B (boron), X 1 , X 2 , X 3 and X 4 are each independently >O, >NR, >S, or >Se, and R of the >NR is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, or a substituted or unsubstituted alkyl, and R of the >NR may be bonded to the A ring, the B ring, the C ring, and / or the D ring via a linking group or a single bond; R 1 and R 2 are each independently hydrogen, alkyl having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, or diarylamino (wherein aryl has 6 to 12 carbon atoms), Z 1 and Z 2 are each independently any substituent selected from the substituent group Z, and Z 1may be bonded to ring A via a linking group or a single bond, and Z 2 may be bonded to the ring C via a linking group or a single bond, and At least one hydrogen atom in the compound represented by formula (12) may be replaced by cyano, halogen, or deuterium.

[0188] Substituents when the aryl or heteroaryl rings in rings A, B, C and D of formula (12) are substituted, and Z 1 , Z 2 Examples of the substituent include a substituent selected from the group Z of substituents.

[0189] X in equation (12) 1 , X 2 , X 3 and X 4 are each independently >O, >NR, >S, or >Se, and each R in the >NR is independently an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, or an alkyl having 1 to 6 carbon atoms. In the compound represented by formula (12), from the viewpoint of high TADF properties, Z 1 and Z 2 is preferably diphenylamino which may have a substituent or N-carbazolyl which may have a substituent, and more preferably diphenylamino which may have a substituent. The diphenylamino which may have a substituent is preferably unsubstituted diphenylamino or diphenylamino which has at least one alkyl having 1 to 4 carbon atoms, and more preferably unsubstituted diphenylamino or diphenylamino which has at least one methyl at the m-position or o-position relative to N. From the viewpoint of ease of synthesis and emission wavelength, the aryl ring or heteroaryl ring in ring A, ring B, ring C and ring D is Z 1 and Z 2 It is preferred that the group has no substituents other than Z or has only alkyl having 1 to 6 carbon atoms as other substituents. 1 and Z 2 It is more preferred that there are no substitutions other than: Examples of compounds represented by formula (12) are shown below.

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] In formula (13) and formula (14), A 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B 21 Ring, C 11 ring, and C 31 each ring is independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; Y 11 , Y 21 , Y 31 is B (boron), X 11 , X 12 , X 21 , X 22 , X 31 , and X 32 are each independently >O, >NR, >S, or >Se, and R of the >NR is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, or a substituted or unsubstituted alkyl, and R of the >NR is connected to A by a linking group or a single bond. 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B21 Ring, C 11 ring, and / or C 31 may be attached to a ring, At least one hydrogen atom in the compounds represented by formula (13) and formula (14) may be replaced by cyano, halogen, or deuterium.

[0195] A in Equation (13) and Equation (14) 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B 21 Ring, C 11 ring, and C 31 In the above, the substituents when the aryl or heteroaryl ring is substituted and Z 1 , Z 2 Examples of the substituent include a substituent selected from the group Z of substituents.

[0196] X in Equation (13) and Equation (14) 11 , X 12 , X 21 , X 22 , X 31 , and X 32 are each independently >O, >NR, >S, or >Se, and each R in the >NR is independently an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, or an alkyl having 1 to 6 carbon atoms.

[0197] Examples of the compound represented by formula (13) or formula (14) are shown below. [ka]

[0198] [ka]

[0199] <Thermally activated delayed phosphor (assisting dopant)> The term "thermally activated delayed fluorescent substance" refers to a compound that can absorb thermal energy to undergo reverse intersystem crossing from an excited triplet state to an excited singlet state, and then radiatively deactivate from the excited singlet state to emit delayed fluorescence. However, the term "thermally activated delayed fluorescent substance" also includes compounds that undergo a higher-order triplet state during the excitation process from the excited triplet state to the excited singlet state. Examples include a paper by Monkman et al. of Durham University (NATURE COMMUNICATIONS,7:13680,DOI: 10.1038 / ncomms13680), a paper by Hosokai et al. of the National Institute of Advanced Industrial Science and Technology (Hosokai et al., Sci. Adv. 2017;3: e1603282), a paper by Sato et al. of Kyoto University (Scientific Reports,7:4820,DOI:10.1038 / s41598-017-05007-7), and an academic presentation by Sato et al., also of Kyoto University (98th Annual Meeting of the Chemical Society of Japan, presentation number: 2I4-15, Mechanism of highly efficient light emission in organic electroluminescence using DABNA as the emissive molecule, Kyoto University Graduate School of Engineering). In the present invention, when a sample containing a target compound is measured for its fluorescence lifetime at 300 K, if a slow fluorescent component is observed, the target compound is determined to be a "thermally activated delayed fluorescent substance." Here, a slow fluorescent component refers to a component with a fluorescence lifetime of 0.1 μsec or longer. The fluorescence lifetime can be measured using, for example, a fluorescence lifetime measurement device (manufactured by Hamamatsu Photonics, C11367-01).

[0200] In the following description, an organic electroluminescent device that uses a thermally activated delayed fluorescent substance as an assisting dopant may be referred to as a "TAF device" (TADF Assisting Fluorescence device). The "host compound" in a TAF element means a compound whose excited singlet energy level, determined from the shoulder on the short-wavelength side of the peak of the fluorescence spectrum, is higher than that of the thermally activated delayed fluorescent substance serving as the assisting dopant and the emitting dopant.

[0201] Figure 2 shows the energy level diagram of the emitting layer of a TAF device using a common fluorescent dopant as the emitting dopant (ED). In the diagram, the ground state energy level of the host is E(1,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the host is E(1,S,Sh), the excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the host is E(1,T,Sh), the ground state energy level of the assisting dopant is E(2,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the assisting dopant is E(2,S,Sh), and the excited triplet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the assisting dopant is E(2,T,Sh). The excited triplet energy level obtained from the shoulder on the short wavelength side of the spectrum is E(2,T,Sh), the ground state energy level of the emitting dopant is E(3,G), the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the emitting dopant is E(3,S,Sh), the excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the emitting dopant is E(3,T,Sh), the hole is h+, the electron is e-, and fluorescence resonance energy transfer is FRET (Fluorescence Resonance Energy Transfer). In a TAF element, when a general fluorescent dopant is used as the emitting dopant (ED), the energy upconverted by the assisting dopant is transferred to the excited singlet energy level E(3,S,Sh) of the emitting dopant and emits light. However, some of the excited triplet energy E(2,T,Sh) on the assisting dopant transfers to the excited triplet energy level E(3,T,Sh) of the emitting dopant, or intersystem crossing occurs on the emitting dopant from the excited singlet energy level E(3,S,Sh) to the excited triplet energy level E(3,T,Sh), followed by thermal decay to the ground state E(3,G). This pathway results in a waste of energy, as some of the energy is not used for light emission.

[0202] In contrast, in the organic electroluminescent device of this embodiment, the energy transferred from the assisting dopant to the emitting dopant can be efficiently utilized for light emission, thereby achieving high luminous efficiency. This is presumably due to the following luminescence mechanism.

[0203] A preferred energy relationship in the organic electroluminescent device of this embodiment is shown in Figure 3. In the organic electroluminescent device of this embodiment, the compound having a boron atom as the emitting dopant has a high excited triplet energy level E(3,T,Sh). Therefore, even if the excited singlet energy upconverted by the assisting dopant undergoes intersystem crossing to the excited triplet energy level E(3,T,Sh) in the emitting dopant, it is either upconverted on the emitting dopant or recovered to the excited triplet energy level E(2,T,Sh) on the assisting dopant (thermally activated delayed fluorescent material). Therefore, the generated excited energy can be used for emission without waste. Furthermore, by dividing the upconversion and emission functions into two types of molecules each specializing in each function, the residence time of the high energy is reduced, which is expected to reduce the burden on the compound.

[0204] In this embodiment, known host compounds can be used, such as compounds having at least one of a carbazole ring and a furan ring. Among them, it is preferable to use a compound in which at least one of a furanyl group and a carbazolyl group is bonded to at least one of an arylene group and a heteroarylene group. Specific examples include mCP and mCBP.

[0205] The triplet energy level E(1,T,Sh), determined from the shoulder on the short-wavelength side of the peak of the phosphorescence spectrum of the host compound, is preferably higher than the triplet energy levels E(2,T,Sh) and E(3,T,Sh) of the emitting dopant or assisting dopant having the highest triplet energy level in the emitting layer, from the viewpoint of promoting TADF generation without inhibiting it. Specifically, the triplet energy level E(1,T,Sh) of the host compound is preferably higher than E(2,T,Sh) and E(3,T,Sh) by 0.01 eV or more, more preferably by 0.03 eV or more, and even more preferably by 0.1 eV or more. A TADF-active compound may also be used as the host compound.

[0206] The thermally activated delayed phosphor (TADF compound) used in the TAF element is preferably a donor-acceptor type thermally activated delayed phosphor (DA type TADF compound) designed to localize the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) within the molecule using an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor, thereby causing efficient reverse intersystem crossing.

[0207] In this specification, the term "electron-donating substituent" (donor) refers to a substituent or partial structure in which the HOMO orbital is localized in the thermally activated delayed fluorescent substance molecule, and the term "electron-accepting substituent" (acceptor) refers to a substituent or partial structure in which the LUMO orbital is localized in the thermally activated delayed fluorescent substance molecule.

[0208] In general, thermally activated delayed fluorescent materials using donors and acceptors have large spin-orbit coupling (SOC) due to their structure, and small exchange interaction between HOMO and LUMO, resulting in a low ΔE S1T1On the other hand, thermally activated delayed fluorescent materials using donors or acceptors exhibit large structural relaxation in the excited state (in some molecules, the stable structure differs between the ground state and the excited state, so when an external stimulus causes a transition from the ground state to the excited state, the structure subsequently changes to the stable structure in the excited state), giving a wide emission spectrum, which may reduce color purity when used as a light-emitting material.

[0209] As the thermally activated delayed phosphor in the TAF element, for example, a compound in which a donor and an acceptor are bonded directly or via a spacer can be used.As the electron donating group (donor structure) and electron accepting group (acceptor structure) used in the thermally activated delayed phosphor of the present invention, for example, the structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used. Donor structures include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridinediamine, tetramethyl-dihydroindenoacridine, and diphenyl-dihydrodibenzazasiline.Acceptor structures include sulfonyldibenzene, benzophenone, phenylenebis(phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthracenone, anthracenedione, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorene dicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thianthrene tetraoxide, and tris(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence in the TAF element is preferably a compound having at least one partial structure selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole, and benzophenone.

[0210] The compound used as the assisting dopant in the light-emitting layer of the TAF element is preferably a thermally activated delayed phosphor, the emission spectrum of which at least partially overlaps with the absorption peak of the emitting dopant.

[0211] <Phosphorescent materials (assisting dopants)> In the light-emitting layer, a phosphorescent material may be used as an assisting dopant. The phosphorescent material utilizes the intramolecular spin-orbit interaction (heavy atom effect) of a metal atom to obtain light emission from triplets. For example, a luminescent metal complex can be used as such a phosphorescent material. Examples of the luminescent metal complex include compounds represented by the following formula (B-1) and formula (B-2).

[0212] [ka]

[0213] In formula (B-1), M is at least one selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu, n is an integer of 1 to 3, and each "XY" is independently a bidentate ligand. In formula (B-2), M is at least one selected from the group consisting of Pt, Re, and Cu, and "WXYZ" is a tetradentate ligand. In the formula (B-1), M is preferably Ir and n is preferably 3 from the viewpoints of efficiency and life. In the formula (B-2), M is preferably Pt from the viewpoint of efficiency and life. The ligand (XY) in formula (B-1) has at least one ligand selected from the group consisting of: The ligand (WXYZ) in formula (B-2) has at least one ligand selected from the group consisting of:

[0214] [ka]

[0215] During the ceremony, --- binds to the central metal M, Y is independently BR e , N.R. e , PR e , O, S, Se, C=O, S=O, SO2, CR e R f , SiRe R f , or GeR e R f and Each aromatic carbon atom CH in the ring may be independently substituted with N; R e and R f may be optionally fused or linked to form a ring, R a , R b , R c , and R d may each independently be unsubstituted or substituted with from 1 to the maximum possible number of substitutions, R a , R b , R c , R d , R e , and R f are each independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, or a combination thereof; However, R a , R b , R c , and R d Any two adjacent substituents in may be fused or linked to form a ring or to form a multidentate ligand.

[0216] Examples of the compound represented by formula (B-1) include Ir(ppy)3, Ir(ppy)2(acac), Ir(mppy)3, Ir(PPy)2(m-bppy), BtpIr(acac), Ir(btp)2(acac), Ir(2-phq)3, Hex-Ir(phq)3, Ir(fbi)2(acac), and fac-Tris(2-(3-p-xylyl)phenyl)pyridine. iridium(III), Eu(dbm)3(Phen), Ir(piq)3, Ir(piq)2(acac), Ir(Fliq)2(acac), Ir(Flq)2(acac), Ru(dtb-bpy)3·2(PF6), Ir(2-phq)3, Ir(BT)2(acac), Ir(DMP)3 , Ir(Mphq)3IR(phq)2tpy, fac-Ir(ppy)2Pc, Ir(dp)PQ2, Ir(Dpm)(Piq)2, Hex-Ir(piq)2(acac), Hex-Ir(piq)3, Ir(dmpq)3, Ir(dmpq)2(acac), FPQIrpic, etc.

[0217] Other examples of the compound represented by formula (B-1) include the following compounds: [ka]

[0218] [ka]

[0219] [ka]

[0220] In addition, iridium complexes described in JP 2006-089398 A, JP 2006-080419 A, JP 2005-298483 A, JP 2005-097263 A, and JP 2004-111379 A, ​​U.S. Patent Application Publication No. 2019 / 0051845, or Advanced Materials, 26: 7116-7121, NPG Asia Materials 13, 53 (2021), Applied Physics Letters, 117, 253301 (2020), Light-Emitting Diode - An Outlook On the Empirical Features and Its Recent Technological Advancements, Chapter 5 Platinum complexes described may also be used.

[0221] <Electron injection layer and electron transport layer in organic electroluminescent device> The electron injection layer 107 plays a role of efficiently injecting electrons moving from the cathode 108 into the light-emitting layer 105 or the electron transport layer 106. The electron transport layer 106 plays a role of efficiently transporting electrons injected from the cathode 108 or electrons injected from the cathode 108 via the electron injection layer 107 to the light-emitting layer 105. The electron transport layer 106 and the electron injection layer 107 are each formed by laminating or mixing one or more electron transport / injection materials, or by a mixture of an electron transport / injection material and a polymer binder.

[0222] The electron injection / transport layer is a layer responsible for injecting electrons from the cathode and transporting them. It is desirable for the layer to have high electron injection efficiency and efficiently transport the injected electrons. To achieve this, it is preferable for the material to have high electron affinity, high electron mobility, excellent stability, and be less likely to generate trapping impurities during manufacture and use. However, considering the balance between hole and electron transport, if a material primarily serves to efficiently block holes from the anode from flowing to the cathode without recombining, it can have the same effect of improving luminous efficiency as a material with high electron transport ability, even if it does not have a particularly high electron transport ability. Therefore, the electron injection / transport layer in this embodiment may also function as a layer that can efficiently block the movement of holes.

[0223] The material (electron transport material) for forming the electron transport layer 106 or the electron injection layer 107 can be arbitrarily selected from compounds conventionally used as electron transport compounds in photoconductive materials and known compounds used in electron injection layers and electron transport layers of organic EL devices. It is also preferable to use the triazine compound of the present invention as a material for an electron transport layer.

[0224] Materials used in the electron transport layer or electron injection layer preferably contain at least one selected from the group consisting of aromatic or heteroaromatic ring compounds composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon, and phosphorus; pyrrole derivatives and their fused ring derivatives; and metal complexes containing electron-accepting nitrogen. Specific examples include fused ring aromatic derivatives such as naphthalene and anthracene; styryl aromatic derivatives such as 4,4'-bis(diphenylethenyl)biphenyl; perinone derivatives; coumarin derivatives; naphthalimide derivatives; quinone derivatives such as anthraquinone and diphenoquinone; phosphine oxide derivatives; arylnitrile derivatives; and indole derivatives. Metal complexes containing electron-accepting nitrogen include, for example, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. These materials can be used alone or in combination with other materials.

[0225] Specific examples of other electron transport compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (e.g., 1,3-bis[(4-t-butylphenyl)1,3,4-oxadiazolyl]phenylene), thiophene derivatives, triazole derivatives (e.g., N-naphthyl-2,5-diphenyl-1,3,4-triazole), thiadiazole derivatives, metal complexes of oxine derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, and the like. Examples of the compound include benzoquinolin-2-yl-9,9'-spirobifluorene, benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(2,2':6',2"-terpyridin-4'-yl)benzene, naphthyridine derivatives (bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphine oxide derivatives, and bisstyryl derivatives.

[0226] Furthermore, metal complexes having an electron-accepting nitrogen atom can also be used, and examples thereof include hydroxyazole complexes such as quinolinol metal complexes and hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

[0227] The above-mentioned materials may be used alone or in combination with other materials.

[0228] Among the above-mentioned materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO-based derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metal complexes are preferred.

[0229] The electron transport layer or the electron injection layer may further contain a substance capable of reducing the material forming the electron transport layer or the electron injection layer. Various substances can be used as this reducing substance as long as they have a certain level of reducing ability. For example, at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, rare earth metal oxides, rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, and rare earth metal organic complexes can be suitably used.

[0230] Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (2.28 eV), Rb (2.16 eV), and Cs (1.95 eV), and alkaline earth metals such as Ca (2.9 eV), Sr (2.0-2.5 eV), and Ba (2.52 eV), with substances with a work function of 2.9 eV or less being particularly preferred. Among these, more preferred reducing substances are alkali metals such as K, Rb, and Cs, with Rb or Cs being even more preferred, and Cs being the most preferred. These alkali metals have particularly high reducing ability, and adding a relatively small amount of these metals to the material forming the electron transport layer or electron injection layer can improve the luminance and extend the life of the organic EL device. Furthermore, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more of these alkali metals is also preferred, and in particular, a combination containing Cs is preferred, such as a combination of Cs and Na, Cs and K, Cs and Rb, or Cs, Na and K. By including Cs, the reducing ability can be efficiently exerted, and by adding Cs to the material forming the electron transport layer or electron injection layer, the luminance of the organic EL device can be improved and the lifetime can be extended.

[0231] <Cathode in organic electroluminescent device> The cathode 108 serves to inject electrons into the light-emitting layer 105 through the electron injection layer 107 and the electron transport layer 106 .

[0232] The material for the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but materials similar to those for the anode 102 can be used. Among these, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium, and magnesium, or alloys thereof (e.g., magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys such as lithium fluoride / aluminum alloys), are preferred. To increase electron injection efficiency and improve device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low-work-function metals are effective. However, these low-work-function metals are generally unstable in air. To address this issue, a method has been proposed in which a trace amount of lithium, cesium, or magnesium is doped into the organic layer to create a highly stable electrode. Other dopants that can be used include inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide, and cesium oxide. However, these are not limited to these.

[0233] Further, for electrode protection, preferred examples include lamination of metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, inorganic materials such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon polymer compounds, etc. The method for producing these electrodes is not particularly limited as long as electrical conduction can be achieved, and may include resistance heating, electron beam evaporation, sputtering, ion plating, and coating.

[0234] <Method for producing organic electroluminescent device> Each layer constituting an organic EL device can be formed by forming the material to be formed into a thin film using methods such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, spin coating or casting, and coating. There are no particular limitations on the film thickness of each layer formed in this way, and it can be set appropriately depending on the properties of the material, but it is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a quartz oscillator film thickness measuring device or the like. When forming a thin film using vapor deposition, the vapor deposition conditions vary depending on the type of material, the desired crystal structure and association structure of the film, etc. Vapor deposition conditions are generally a boat heating temperature of +50 to +400°C, a vacuum degree of 10 -6 ~10 -3 It is preferable to appropriately set the pressure, the deposition rate, the substrate temperature, and the film thickness in the range of 0.01 to 50 nm / sec, -150 to +300° C., and 2 nm to 5 μm.

[0235] When applying a DC voltage to the organic EL element obtained in this way, the anode should be set to + and the cathode to -. When a voltage of about 2 to 40 V is applied, light emission can be observed from the transparent or semi-transparent electrode side (anode or cathode, or both). This organic EL element also emits light when a pulse current or an AC current is applied. The waveform of the applied AC current can be any waveform.

[0236] Next, as an example of a method for producing an organic EL element, a method for producing an organic EL element comprising an anode, a hole injection layer, a hole transport layer, an emitting layer composed of a host material and a dopant material, an electron transport layer, an electron injection layer, and a cathode will be described.

[0237] <Vapor deposition method> An anode is prepared by forming a thin film of an anode material on a suitable substrate by vapor deposition or the like, and then forming thin films of a hole injection layer and a hole transport layer on the anode. A host material and a dopant material are co-deposited on the anode to form a thin film to serve as an emissive layer. An electron transport layer and an electron injection layer are then formed on the emissive layer, and a thin film of a cathode material is then formed by vapor deposition or the like to serve as a cathode, thereby obtaining the desired organic EL device. It is also possible to reverse the order of fabrication of the organic EL device described above, by fabricating the layers in the order of cathode, electron injection layer, electron transport layer, emissive layer, hole transport layer, hole injection layer, and anode.

[0238] <Wet film formation method> The wet film formation method is carried out by preparing a liquid organic layer-forming composition from a low molecular weight compound capable of forming each organic layer of an organic EL device, and using this. If there is no suitable organic solvent that can dissolve this low molecular weight compound, the organic layer-forming composition may be prepared from a reactive compound obtained by substituting a reactive substituent on the low molecular weight compound, such as another monomer having a solubility function as a reactive compound, or a polymer compound polymerized together with a main-chain polymer.

[0239] In wet film formation, a coating film is generally formed through a coating step in which an organic layer-forming composition is applied to a substrate and a drying step in which the solvent is removed from the applied organic layer-forming composition. When the polymer compound has a crosslinkable substituent (also called a crosslinkable polymer compound), the drying step further crosslinks the polymer to form a crosslinked polymer. Depending on the coating process, methods using a spin coater are called spin coating methods; methods using a slit coater are called slit coating methods; methods using a printing plate are called gravure, offset, reverse offset, or flexographic printing methods; methods using an inkjet printer are called inkjet methods; and methods spraying the composition in a mist are called spray methods. Drying methods include air drying, heating, and vacuum drying. The drying process may be performed once or multiple times using different methods and conditions. Different methods, such as baking under reduced pressure, may also be used in combination.

[0240] Wet film formation methods are film formation methods that use solutions, such as some printing methods (inkjet methods), spin coating or casting methods, and coating methods. Unlike vacuum deposition methods, wet film formation methods do not require expensive vacuum deposition equipment and can form films under atmospheric pressure. In addition, wet film formation methods allow for large-area and continuous production, which leads to reduced manufacturing costs.

[0241] On the other hand, compared to vacuum deposition, wet deposition can be difficult to layer. When using wet deposition to create layered films, it is necessary to prevent the dissolution of the lower layer by the composition of the upper layer, and methods such as controlled solubility compositions, crosslinking of the lower layer, and orthogonal solvents (solvents that are not soluble in each other) are used. However, even with these techniques, it can be difficult to use wet deposition for all film application.

[0242] Therefore, a common method for fabricating organic EL devices is to use a wet film-forming method for only some layers and a vacuum deposition method for the remaining layers.

[0243] For example, the procedure for producing an organic EL element by partially applying a wet film formation method is shown below. (Step 1) Formation of the anode by vacuum deposition (Step 2) Forming a film by a wet film formation method using a composition for forming a hole injection layer containing a material for the hole injection layer (Step 3) Forming a film by a wet film formation method using a composition for forming a hole transport layer containing a material for the hole transport layer (Step 4) Forming a film by a wet film formation method using a composition for forming an emitting layer containing a host material and a dopant material (Step 5) Formation of the electron transport layer by vacuum deposition (Step 6) Formation of the electron injection layer by vacuum deposition (Step 7) Cathode deposition by vacuum evaporation Through this procedure, an organic EL element consisting of an anode, a hole injection layer, a hole transport layer, a light-emitting layer made of a host material and a dopant material, an electron transport layer, an electron injection layer, and a cathode is obtained. Of course, the electron transport layer and the electron injection layer may also be formed by a wet film formation method using layer-forming compositions containing the electron transport layer material and the electron injection layer material, respectively. In this case, it is preferable to use a method to prevent dissolution of the underlying light-emitting layer or a method to form the layer from the cathode side, in the reverse order of the above procedure.

[0244] <Other film formation methods> The organic layer-forming composition can be formed into a film by laser thermal imaging (LITI), a method in which a compound attached to a substrate is heated and vapor-deposited with a laser, and the organic layer-forming composition can be used as the material applied to the substrate.

[0245] <Optional process> Before and after each film-forming step, appropriate treatment steps, cleaning steps, and drying steps may be added as appropriate. Examples of treatment steps include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent, and heat treatment. Furthermore, a series of steps for preparing a bank may also be included.

[0246] Photolithography can be used to fabricate the banks. Positive and negative resist materials can be used as bank materials for photolithography. Patternable printing methods such as inkjet printing, gravure offset printing, reverse offset printing, and screen printing can also be used. In these cases, permanent resist materials can also be used.

[0247] <Composition for forming organic layer used in wet film formation method> The organic layer-forming composition is obtained by dissolving a low-molecular-weight compound capable of forming each organic layer of an organic EL device, or a polymer compound obtained by polymerizing such a low-molecular-weight compound, in an organic solvent. For example, the light-emitting layer-forming composition contains at least one polycyclic aromatic compound (or a polymer compound thereof) as a dopant material as a first component, at least one host material as a second component, and at least one organic solvent as a third component. The first component functions as a dopant component for the light-emitting layer obtained from the composition, and the second component functions as a host component for the light-emitting layer. The third component functions as a solvent that dissolves the first and second components in the composition, and upon application, the controlled evaporation rate of the third component itself provides a smooth and uniform surface profile.

[0248] <Organic solvents> The organic layer-forming composition contains at least one organic solvent. By controlling the evaporation rate of the organic solvent during film formation, it is possible to control and improve film-forming properties, the presence or absence of defects in the coating film, surface roughness, and smoothness. Furthermore, when forming a film using an inkjet method, it is possible to control meniscus stability at the pinhole of the inkjet head and control and improve ejection properties. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, it is possible to improve the electrical properties, luminescence properties, efficiency, and lifespan of an organic EL device having an organic layer obtained from the organic layer-forming composition.

[0249] After film formation, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, or heating. When heating is performed, from the viewpoint of improving coating film-forming properties, it is preferable to perform the heating at a temperature not higher than 30°C above the glass transition temperature (Tg) of at least one of the solutes. Furthermore, from the viewpoint of reducing residual solvent, it is preferable to perform the heating at a temperature not lower than 30°C below the glass transition temperature (Tg) of at least one of the solutes. Even if the heating temperature is lower than the boiling point of the organic solvent, the organic solvent can be sufficiently removed because the film is thin. Furthermore, drying may be performed multiple times at different temperatures, or multiple drying methods may be used in combination.

[0250] (2) Specific examples of organic solvents Examples of organic solvents used in the organic layer-forming composition include, but are not limited to, alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, monocyclic ketone solvents, solvents having a diester skeleton, and fluorine-containing solvents. The solvents may be used alone or in combination.

[0251] <Optional ingredients> The composition for forming the organic layer may contain optional components, such as a binder and a surfactant, to the extent that the properties of the composition are not impaired.

[0252] <Composition and Properties of the Organic Layer-Forming Composition> The content of each component in the composition for forming an organic layer is determined taking into consideration the good solubility, storage stability, and film-forming properties of each component in the composition for forming an organic layer, as well as the good film quality of the coating film obtained from the composition for forming an organic layer, good ejection properties when an inkjet method is used, and good electrical properties, light-emitting properties, efficiency, and lifespan of an organic EL element having an organic layer produced using the composition.

[0253] The composition for forming an organic layer can be produced by appropriately selecting the above-mentioned components by a known method, such as stirring, mixing, heating, cooling, dissolving, dispersing, etc. After preparation, the composition may be appropriately subjected to filtration, degassing (also called degassing), ion exchange treatment, inert gas substitution / filling treatment, etc.

[0254] <Application examples of organic electroluminescent devices> The present invention can also be applied to a display device equipped with an organic EL element or a lighting device equipped with an organic EL element. A display device or lighting device including an organic EL element can be manufactured by a known method, for example, by connecting the organic EL element according to this embodiment to a known driving device, and can be driven appropriately using a known driving method such as DC driving, pulse driving, or AC driving.

[0255] Examples of display devices include panel displays such as color flat panel displays, and flexible displays such as flexible color organic electroluminescent (EL) displays (see, for example, JP-A-10-335066, JP-A-2003-321546, and JP-A-2004-281086). Examples of display methods include matrix and segment methods. Note that matrix display and segment display may coexist on the same panel.

[0256] In a matrix display, pixels are arranged two-dimensionally, such as in a grid or mosaic pattern, and a collection of pixels displays characters and images. The shape and size of the pixels are determined by the application. For example, images and text displayed on computers, monitors, and televisions typically use square pixels with sides of 300 μm or less. Large displays such as display panels use pixels on the order of millimeters. For monochrome displays, pixels of the same color are simply arranged, while for color displays, red, green, and blue pixels are displayed side by side. These types are typically known as delta and stripe types. The matrix can be driven by either line-sequential or active matrix methods. While line-sequential driving has the advantage of being simpler, active matrix methods can sometimes be superior in terms of operating characteristics, so the choice must be made based on the application.

[0257] In the segment type, a pattern is formed to display predetermined information, and a predetermined area is illuminated. Examples include the time and temperature displays on digital clocks and thermometers, the operating status displays on audio equipment and induction cookers, and panel displays on automobiles.

[0258] Examples of lighting devices include lighting devices for indoor lighting and backlights for liquid crystal display devices (see, for example, JP 2003-257621 A, JP 2003-277741 A, JP 2004-119211 A, etc.). Backlights are primarily used to improve the visibility of non-self-luminous display devices, and are used in liquid crystal display devices, clocks, audio devices, automobile panels, display boards, signs, etc. In particular, for backlights for liquid crystal display devices, particularly for personal computers where thinning is an issue, considering that conventional systems use fluorescent lamps and light guide plates and therefore make thinning difficult, backlights using the light-emitting elements according to this embodiment are characterized by their thinness and light weight.

[0259] 3-2. Other organic devices The triazine compound according to the present invention can be used to produce not only the above-mentioned organic electroluminescent device but also an organic field effect transistor or an organic thin film solar cell. [Example]

[0260] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. First, synthesis examples of triazine compounds will be described below.

[0261] Synthesis example (1) Synthesis of Compound (1-1): 9,9'-(6-(9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-3-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) [ka]

[0262] Synthesis of 9,9'-(6-chloro-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1-a) [ka]

[0263] Under a nitrogen atmosphere, sodium hydride (6.5 g, 274 mmol) was added in portions to a solution of 9H-carbazole (45.7 g, 274 mmol) in tetrahydrofuran (1000 mL) and stirred at room temperature for 30 minutes. Then, a solution of cyanuric chloride (25 g, 137 mmol) in tetrahydrofuran (500 mL) was added dropwise and stirred at room temperature for 3 hours. After the reaction was completed, water (1000 mL) was added, and the resulting crystals were filtered and washed with water, acetone, and methanol. The resulting crystals were slurry-washed twice with toluene (100 mL), and the combined filtrate was concentrated. The resulting crystals were slurry-washed twice with Solmix and then dried to yield 9,9'-(6-chloro-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (34.1 g, 76.7 mmol).

[0264] Synthesis of 3-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole (1-b) [ka]

[0265] Under a nitrogen atmosphere, sodium hydride (0.41 g, 45.0 mmol) was added in portions to a solution of 3-bromo-9H-carbazole (10.2 g, 41.6 mmol) in tetrahydrofuran (100 mL) and stirred at room temperature for 30 minutes. Then, a solution of 2-chloro-4,6-diphenyl-1,3,5-triazine (10.0 g, 37.4 mmol) in tetrahydrofuran (50 mL) was added dropwise and stirred at room temperature for 3 hours. After the reaction was completed, water (100 mL) was added, and the resulting crystals were filtered and washed with water, acetone, and methanol. The resulting crystals were dried to give 3-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole (19.6 g, 41.2 mmol).

[0266] Synthesis of 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazole (1-1c) [ka]

[0267] A flask containing 3-bromo-9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazole (10.0 g, 21.0 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (5.6 g, 22.0 mmol), potassium acetate (3.4 g, 42.0 mmol), palladium acetate (0.094 g, 0.42 mmol), SPhos (2-dicyclohexylphosphino-2,6-biphenyl) (0.04 g, 0.84 mmol), and cyclopentyl methyl ether (100 mL) was heated to reflux under a nitrogen atmosphere for 8 hours. After completion of the reaction, the reaction solution was cooled to room temperature, water (100 mL) was added, and the resulting crystals were filtered. The obtained crystals were washed with water, acetone, and methanol, and then dried to obtain 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazole (8.7 g, 16.6 mmol).

[0268] Synthesis of 9,9'-(6-(9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-3-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1-1) [ka]

[0269] A flask containing 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazole (2.0 g, 4.4 mmol), 9,9'-(6-chloro-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (2.3 g, 4.4 mmol), potassium carbonate (1.8 g, 13.1 mmol), tetrakis(triphenylphosphine)palladium (0.51 g, 0.44 mmol), tetrabutylammonium bromide (0.42 g, 1.31 mmol), dimethoxyethane (100 mL), and water (10 mL) was heated to reflux under a nitrogen atmosphere for 8 hours. After completion of the reaction, the reaction solution was cooled to room temperature, water (100 mL) was added, and the resulting crystals were filtered. The resulting crystals were washed with water, acetone, and methanol, followed by two slurry washes with tetrahydrofuran (50 ml). The crystals were dried and purified by sublimation (380°C) to give 9,9'-(6-(9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-3-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (0.26 g, 0.32 mmol).

[0270] The structure of the compound obtained was confirmed by NMR measurement and LC-MS. 1 H-NMR (500MHz, CDCl3): δ=7.45-7.62(m,9H), 7.65-7.75(m,7H), 8.15(d,4H), 8.28(d ,1H), 8.82(d,4H), 9.02(d,1H), 9.15(d,4H), 9.22(d,1H), 9.38(d,1H), 9.52(s,1H). LC-MS: m / z = 808 [M+H].

[0271] Synthesis example (2) Synthesis of Compound (1-21): 9,9'-(6-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) [ka]

[0272] Synthesis of 9,9'-(6-(3-bromo-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1-c) [ka]

[0273] Under a nitrogen atmosphere, sodium hydride (0.32 g, 13.5 mmol) was added in portions to a solution of 3-bromo-9H-carbazole (3.0 g, 12.4 mmol) in tetrahydrofuran (100 mL) and stirred at room temperature for 30 minutes. Then, a solution of 9,9'-(6-chloro-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (5.0 g, 11.2 mmol) in tetrahydrofuran (50 mL) was added dropwise and stirred at room temperature for 3 hours. After the reaction was completed, water (100 mL) was added, and the resulting crystals were filtered and washed with water, acetone, and methanol. The resulting crystals were dried to give 9,9'-(6-(3-bromo-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (7.1 g, 10.9 mmol).

[0274] Synthesis of 9,9'-(6-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1-d) [ka]

[0275] A flask containing 9,9'-(6-(3-bromo-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (10.0 g, 15.3 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (4.1 g, 16.0 mmol), potassium acetate (2.5 g, 30.7 mmol), palladium acetate (0.069 g, 0.31 mmol), SPhos (2-dicyclohexylphosphino-2,6-biphenyl) (0.03 g, 0.61 mmol), and cyclopentyl methyl ether (100 mL) was heated to reflux under a nitrogen atmosphere for 8 hours. After completion of the reaction, the reaction solution was cooled to room temperature, water (100 mL) was added, and the resulting crystals were filtered. The obtained crystals were washed with water, acetone, and methanol, and then dried to give 9,9'-(6-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (7.5 g, 10.6 mmol).

[0276] Synthesis of 9,9'-(6-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1-21) [ka]

[0277] A flask containing 9,9'-(6-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (2.0 g, 2.8 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (0.76 g, 2.8 mmol), potassium carbonate (1.1 g, 8.3 mmol), tetrakistriphenylphosphine palladium (0.32 g, 0.28 mmol), tetrabutylammonium bromide (0.27 g, 0.83 mmol), dimethoxyethane (50 ml), and water (5 ml) was heated to reflux under a nitrogen atmosphere for 8 hours. After completion of the reaction, the reaction solution was cooled to room temperature, water (50 ml) was added, and the resulting crystals were filtered. The resulting crystals were washed with water, acetone, and methanol, followed by two slurry washes with tetrahydrofuran (50 ml). The crystals were dried and purified by sublimation (380°C) to give 9,9'-(6-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (0.1 g, 0.12 mmol).

[0278] The structure of the compound obtained was confirmed by NMR measurement and LC-MS. 1 H-NMR (500MHz, CDCl3): δ=7.45-7.56(m,10H), 7.60-7.66(m,6H), 8.15(d,4H), 8.38(d d,1H), 8.85(d,4H), 8.94(d,1H), 9.04(d,1H), 9.05(d,4H), 9.16(d,1H), 9.55(s,1H). LC-MS: m / z = 808 [M+H].

[0279] Synthesis example (3) Synthesis of Compound (1-11): 9,9',9'',9''-((9H-carbazole-3,9-diyl)bis(1,3,5-triazine-6,2,4-triyl))tetrakis(9H-carbazole) [ka]

[0280] Synthesis of 9,9',9'',9'''-((9H-carbazole-3,9-diyl)bis(1,3,5-triazine-6,2,4-triyl))tetrakis(9H-carbazole) (1-11). [ka]

[0281] In a manner similar to that of Synthesis Examples (1) and (2), 9,9',9'',9'''-((9H-carbazole-3,9-diyl)bis(1,3,5-triazine-6,2,4-triyl))tetrakis(9H-carbazole) (0.1 g, 1.0 mmol) was obtained from 9,9'-(6-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaboran-2-yl)-9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (2.0 g, 2.8 mmol) and 9,9'-(6-chloro-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (1.3 g, 2.8 mmol).

[0282] The structure of the compound obtained was confirmed by NMR measurement and LC-MS. 1 H-NMR (500MHz, CDCl3): δ=7.45-7.62(m,8H), 7.61-7.75(m,5H), 8.15(d,4H), 8.28- 8.38(m,2H), 8.80-8.87(m,8H), 8.93-9.06(m,10H), 9.15-9.22(m,1H), 9.55(s,1H). LC-MS: m / z = 986 [M+H].

[0283] By appropriately changing the starting compounds, other compounds of the present invention can be synthesized in accordance with the methods of the above synthesis examples.

[0284] Next, the preparation and evaluation of an organic EL device will be described. However, the application of the compound of the present invention is not limited to the examples shown below, and the film thickness and constituent materials of each layer can be appropriately changed depending on the basic physical properties of the compound used.

[0285] <Comparative Example 1-1> A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) on which a 200 nm thick ITO film was formed by sputtering and polished to 50 nm was used as a transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available evaporation system (manufactured by Showa Vacuum Co., Ltd.), and molybdenum evaporation boats containing HAT-CN, HTL-1, TcTa, CzTP, new-DABNA, ETL-1, and ET7, and tungsten evaporation boats containing LiF and aluminum were attached.

[0286] The following layers were formed in order on the ITO film of the transparent support substrate. -4 The pressure was reduced to 100 Pa, and HAT-CN was heated and evaporated to a thickness of 5 nm to form a hole injection layer. Next, HTL-1 was heated and evaporated to a thickness of 90 nm to form hole transport layer 1, and TcTa was heated and evaporated to a thickness of 10 nm to form hole transport layer 2. Next, CzTP and new-DABNA were simultaneously heated and evaporated to a thickness of 20 nm to form an emitting layer. The evaporation rate was adjusted so that the weight ratio of CzTP to new-DABNA was approximately 99:1. Next, ETL-1 was heated and evaporated to a thickness of 20 nm to form electron transport layer 1, and ET7 was heated and evaporated to a thickness of 10 nm to form electron transport layer 2. The evaporation rate for each layer was 0.01–1 nm / s. Next, LiF was heated and evaporated at a evaporation rate of 0.01–0.1 nm / s to a thickness of 1 nm, and then aluminum was heated and evaporated to a thickness of 100 nm to form a cathode, completing the organic EL device. At this time, the deposition rate of aluminum was adjusted to 1 to 10 nm / sec.

[0287] <Examples 1-1 to 1-3, Examples 2-1 to 2-3, Examples 3-1 to 3-3, Comparative Examples 1-2 to 1-5, and Comparative Examples 2-1 to 2-3> Each device was fabricated by changing the host or electron transport layer 1 of Comparative Example 1-1 to each material listed in Table 1.

[0288] [Table 1]

[0289] The chemical structures of the compounds used in the examples and comparative examples are shown below.

[0290] [ka]

[0291] [ka]

[0292] <Evaluation of organic EL elements> A DC voltage was applied to the fabricated organic EL device with the ITO electrode as the anode and the aluminum electrode as the cathode, and the brightness was 1000 cd / m 2 External quantum efficiency (EQE) and LT50 (initial luminance 1000 cd / m 2 500 cd / m when continuously driven at a current density of 2 The time it took for the reaction to become

[0293] The external quantum efficiency was measured as follows. The device was made to emit light by applying a voltage using an Advantest R6144 voltage / current generator. The spectral radiance in the visible light region was measured perpendicular to the light-emitting surface using a TOPCON SR-3AR spectroradiometer. Assuming the light-emitting surface is a perfectly diffusing surface, the measured spectral radiance value for each wavelength component was divided by the wavelength energy and multiplied by π to obtain the number of photons at each wavelength. The number of photons was then integrated over the entire observed wavelength range to obtain the total number of photons emitted from the device. The applied current value was divided by the elementary charge to obtain the number of carriers injected into the device. The total number of photons emitted from the device divided by the number of carriers injected into the device was then used to obtain the external quantum efficiency. The evaluation results are shown in Table 2.

[0294] [Table 2]

[0295] From Table 2, in the example using the triazine compound represented by formula (1), Y 1 and Y 2 a compound that does not have both X and Y (CzTP), a compound that does not have a heteroarylene group that is X (BTB), or a compound that does not have Y 1 or Y 2 It can be seen that high efficiency and long life were obtained compared to the example using a compound (CPCBPTz) that does not have one of the above. Furthermore, even when compared to the examples using similar compounds (Comparative Examples 1-4, 1-5, 2-2, and 2-3) that have a structure in which two heteroaryls are bonded to a triazinyl but in which the heteroaryls are not groups that bond to N, the examples using the triazine compound represented by formula (1) (Examples 1-1 to 1-3 and 2-1 to 1-3) also achieved high efficiency and long life.

[0296] Examples 3-1 to 3-3, which used the triazine compound represented by formula (1) as the host material in the light-emitting layer (electron-transporting host material: host 2) and the material in the electron-transporting layer, had higher efficiency and longer life than the other examples. [Explanation of symbols]

[0297] 100 Organic electroluminescent device 101 Substrate 102 Anode 103 Hole injection layer 104 Hole transport layer 105 Light-emitting layer 106 Electron transport layer 107 Electron injection layer 108 Cathode

Claims

1. A compound represented by formula (1); 【Chemistry 1】 In formula (1), X is a substituted or unsubstituted heteroarylene; The heteroarylene represented by X is a divalent group obtained by removing any two hydrogen atoms bonded to a ring atom of carbazole, benzofurocarbazole, benzothienocarbazole, or indenocarbazole, Y 1 is a group represented by formula (1-a), Y 2 is a group represented by formula (1-b), 【Chemistry 2】 A 1 and A 2 each independently represents a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl; A 3 and A 4 each independently represents a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted diarylamino, a substituted or unsubstituted diheteroarylamino, or a substituted or unsubstituted arylheteroarylamino; A 1 and A 2 Either of the above or A 3 and A 4 At least one of the above is a group having N as the bonding position, Z 1 , Z 2 and Z 3 are each independently CH or N, but Z 1 , Z 2 and Z 3 at least one of them is N, * indicates the bond position, At least one hydrogen atom in the compound represented by formula (1) may be replaced by cyano, halogen, or deuterium.

2. The compound according to claim 1, wherein the groups bonding to N are each independently substituted or unsubstituted N-carbazolyl, substituted or unsubstituted N-azacarbazolyl, substituted or unsubstituted N-benzimidazolyl, substituted or unsubstituted N-imidazoimidazolyl, substituted or unsubstituted N-indoloindolyl, substituted or unsubstituted N-indolocarbazolyl, substituted or unsubstituted N-benzofurocarbazolyl, substituted or unsubstituted N-benzothienocarbazolyl, or substituted or unsubstituted N-indenocarbazolyl.

3. A 1 and A 2 The compound according to claim 1 or 2, wherein each of the following is a group having N as the bonding position:

4. Z 1 , Z 2 and Z 3 and each of them is N.

5. A 1 and A 2 are both unsubstituted N-carbazolyl, and A 3 and A 4 The compound according to any one of claims 1 to 4, wherein each of

6. The compound according to claim 1, represented by any one of the following formulas: 【Transformation 3】

7. A material for an organic device, comprising the compound according to any one of claims 1 to 6.

8. An organic electroluminescent device comprising a pair of electrodes consisting of an anode and a cathode, and an organic layer disposed between the pair of electrodes, wherein the organic layer contains the compound according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8 , wherein the organic layer is a light-emitting layer.

10. The organic electroluminescent device according to claim 9 , wherein the light-emitting layer contains the compound as a host material and further contains a dopant material.

11. The organic electroluminescent device according to claim 8 , wherein the organic layer is an electron transport layer.

12. A display device or lighting device comprising the organic electroluminescent element according to any one of claims 8 to 11.

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