Polycyclic aromatic compound, organic electroluminescent element, display device, and lighting device

Abstract

Provided are a novel polycyclic aromatic compound which is useful as a material for an organic EL element, an organic electroluminescent element, a display device, and an illumination device. The compound is represented by a formula (1) and comprises partial structures represented by a formula (X-a-1) and a formula (X-b-1), xa is C, Si or the like, Xb is N-AR5 or the like, A-E rings and AR1-AR5 rings are substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings, and one to two of AR1-AR4 rings are bonded to A-C rings via a single bond or a partial structure of formula (X-b-1), or share a ring with A-C rings, or share a ring with A-C rings, or share a ring with D ring, E ring or AR5 ring in formula (X-b-1), and one to two rings selected from the group consisting of a D ring, an E ring, and an AR5 ring are bonded to the A-C rings via a single bond or a partial structure of formula (X-a-1), or share a ring with the A-C rings, or share a ring with the A-C rings, or share a ring with the A-C rings. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a polycyclic aromatic compound, organic devices such as an organic electroluminescent element, an organic field effect transistor and an organic thin film solar cell using the same, as well as a display device and a lighting device. Background Art

[0002] In the past, display devices using light-emitting elements that perform electroluminescence have been studied in various ways because they can achieve power saving or thinning, and organic electroluminescent elements containing organic materials have been actively studied because they can be easily lightweight or large-scaled. In particular, the development of organic materials having light-emitting properties such as blue or green, which are one of the three primary colors of light, and the development of organic materials having charge transport capabilities including holes, electrons, etc. (having the possibility of becoming semiconductors or superconductors) have been actively studied so far, regardless of whether they are polymer compounds or low molecular weight compounds.

[0003] An organic electroluminescence (EL) element has a structure including a pair of electrodes including an anode and a cathode, and one or more layers disposed between the pair of electrodes and including an organic compound. The layers including the organic compound include a light-emitting layer, a charge transport / injection layer for transporting or injecting charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

[0004] As the luminescent material for the luminescent layer, three types of materials are currently used: fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. For example, among fluorescent materials, improved materials such as azaborine derivatives have been reported (Patent Documents 1 and 2), and among phosphorescent materials, noble metal complexes having multidentate ligands have been developed (Patent Document 3), and among thermally activated delayed fluorescence (TADF) materials, carbazonitrile compounds have been developed (Non-Patent Document 1).

[0005] In an element using any material, in order to prevent energy leakage from the light-emitting layer or peripheral layers that causes a decrease in efficiency, a material having high lowest excited singlet energy or lowest excited triplet energy is used in a layer adjacent to the light-emitting layer or in a host.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] [Patent Document 1] International Publication No. 2015 / 102118

[0009] [Patent Document 2] International Publication No. 2018 / 212169

[0010] [Patent Document 3] Japanese Patent Application Publication No. 2014-239225

[0011] [Non-patent literature]

[0012] [Non-patent document 1] Nature (Vol. 492, December 13, 2012) Summary of the invention

[0013] [Problems to be solved by the invention]

[0014] As described above, various materials have been developed as materials used in organic EL elements, but in order to increase the selection of materials for organic EL elements, it is desired to develop a material containing a compound different from the previous materials. In addition, in Patent Documents 1 and 2, a polycyclic aromatic compound containing boron and an organic EL element using the same are reported, but in order to further improve the device characteristics, a light-emitting layer material and a peripheral layer material that can improve the luminous efficiency and device life are required.

[0015] [Technical means to solve the problem]

[0016] The inventors and others have made great efforts to solve the above-mentioned problems, and as a result, they have successfully produced novel polycyclic aromatic compounds, and further found that the compounds are effective as materials with high singlet energy and triplet energy. It is also found that, for example, by using such polycyclic aromatic compounds as the main material or the material of the layer adjacent to the light-emitting layer, an excellent organic EL element can be obtained compared with the case where the light-emitting layer with a compound having a smaller triplet energy than the compound as the dopant material is arranged between a pair of electrodes to constitute an organic EL element, thereby completing the present invention. That is, the present invention provides the following polycyclic aromatic compounds, and further provides materials for organic devices containing the following polycyclic aromatic compounds, etc.

[0017] <1> A polycyclic aromatic compound represented by formula (1) and comprising at least one of the partial structures represented by formula (Xa-1) and at least one of the partial structures represented by formula (Xb-1);

[0018] [Chemistry 1]

[0019]

[0020] In formula (1),

[0021] Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

[0022] In formula (Xa-1),

[0023] X a is C, Si, Ge or Sn, AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and AR1 ring, AR2 ring, AR3 ring and AR4 ring may be linked to any other of AR1 ring, AR2 ring, AR3 ring and AR4 ring via a single bond or a linking group,

[0024] One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring

[0025] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0026] An aryl or heteroaryl ring of ring D, ring E or ring AR5 in formula (Xb-1) that is bonded to ring A, ring B or ring C or that shares any ring with ring A, ring B or ring C is bonded to the ring-constituting atom via a single bond; or

[0027] Shares a ring with Ring A, Ring B or Ring C; or

[0028] a ring shared by the ring D, the ring E or the ring AR5 in the formula (Xb-1) that is bonded to the ring A, the ring B or the ring C or that shares any ring with the ring A, the ring B or the ring C,

[0029] In formula (Xb-1),

[0030] The D ring and the E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

[0031] X b is a divalent group represented by the formula (Xb-R5), >O or >S,

[0032] [Chemistry 2]

[0033]

[0034] In the formula (Xb-R5),

[0035] The two #s are the bonding positions with the D ring and the E ring respectively.

[0036] AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and AR5 ring can be linked to D ring and / or E ring by a single bond or a linking group,

[0037] One or two selected from the group consisting of D ring, E ring and AR5 ring

[0038] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0039] An aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) is bonded to the A, B or C ring via a single bond or is bonded to the A, B or C ring in a ring-constituting atom; or

[0040] Shares a ring with Ring A, Ring B or Ring C; or

[0041] a ring shared by the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) that is bonded to the A ring, the B ring or the C ring or that shares any ring with the A ring, the B ring or the C ring,

[0042] In formula (1), at least one hydrogen may be substituted with deuterium, and at least one nitrogen may be substituted with nitrogen-15( 15 N) substituted, at least one sulfur may be replaced by sulfur-33( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36 S), at least one oxygen may be replaced by oxygen-17( 17 O) or oxygen-18 ( 18 O) substituted, at least one carbon may be substituted by carbon-13 ( 13 C) substituted, at least one boron may be substituted by boron-11( 11 B) Replacement.

[0043] <2> The polycyclic aromatic compound according to <1>, wherein at least one selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring shares a ring with A ring, B ring or C ring, or shares a ring with D ring, E ring or AR5 ring in formula (Xb-1) bonded to A ring, B ring or C ring.

[0044] <3> The polycyclic aromatic compound according to <1>, which is represented by formula (1a), formula (1b) or formula (1c) and contains at least one of the partial structures represented by formula (Xa-2) and at least one of the partial structures represented by formula (Xb-2);

[0045] [Chemistry 3]

[0046]

[0047] In formula (1a), formula (1b), formula (1c), formula (Xa-2) and formula (Xb-2),

[0048] Choose from Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 One or two of the rings

[0049] is bonded to Z in the a-ring, b-ring or c-ring via a single bond; or

[0050] Bonded to the d ring, e ring or AR5 ring in the partial structure represented by the formula (Xb-2) to which Z in the a ring, b ring or c ring is bonded; or

[0051] Shares a ring with ring a, ring b or ring c; or

[0052] a ring bonded to ring a, ring b or ring c or a ring shared by ring d, ring e or ring AR5 in formula (Xb-2),

[0053] One or two selected from the group consisting of d ring, e ring and AR5 ring

[0054] is bonded to Z in the a-ring, b-ring or c-ring via a single bond; or

[0055] Ar in the partial structure represented by formula (Xa-2) bonded to Z in ring a, ring b or ring c 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 Z bonding in a ring; or

[0056] Shares a ring with ring a, ring b or ring c; or

[0057] Ar in formula (Xa-2) that is bonded to ring a, ring b or ring c or shares any ring with ring a, ring b or ring c 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 The ring has a total ring,

[0058] Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 The ring can be connected to Ar by a single bond or a linking group. 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 Any other link in the ring,

[0059] Y 1 and Y 2 Each independently is >NRNY 、>C(-R CY )2、>O、>Si(-R IY )2.>S or>Se, R NY , R CY and R IY are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CY Can bond to each other to form a ring, two R IY Can bond to each other to form a ring,

[0060] Z is a carbon atom having a bond to another ring, or -C(-R Z )=or-N=,R Z is hydrogen or a substituent, wherein two adjacent Zs constituting the e ring in formula (Xb-2) may be carbon atoms respectively bonded to the two *s in formula (Xb-2-e). In formula (Xb-2-e), X b is a divalent group represented by the formula (Xb-R5), >O, >C(-R CX )2、>Si(-R IX )2.>S or>Se, R CX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CX Can bond with each other to form a ring, R IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IX Can bond to each other to form a ring,

[0061] X b When AR5 is a divalent group represented by the formula (Xb-R5), the ring is a 6-membered ring.

[0062] <4> The polycyclic aromatic compound according to <3>, which is represented by formula (1b) or formula (1c).

[0063] <5> The polycyclic aromatic compound according to <3>, wherein in formula (Xa-2), X a C, Ge or Sn, Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 No two rings are connected to each other.

[0064] <6> The polycyclic aromatic compound according to <3>, wherein in the formula (Xa-2), X a is Si, and at least one of Z is -N=.

[0065] <7> The polycyclic aromatic compound according to <3>, wherein in the formula (Xa-2), X a Si, Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 At least two of the rings are interconnected.

[0066] <8> The polycyclic aromatic compound according to <3>, wherein in formula (Xb-2), at least one of Z is -N=.

[0067] <9> The polycyclic aromatic compound according to <3>, which is represented by any of the following formulas.

[0068] [Chemistry 4]

[0069]

[0070] [Chemistry 5]

[0071]

[0072] <10> The polycyclic aromatic compound according to <3>, which is represented by any of the following formulas.

[0073] [Chemistry 6]

[0074]

[0075] [Chemistry 7]

[0076]

[0077] [Chemistry 8]

[0078]

[0079] [Chemistry 9]

[0080]

[0081] [Chemistry 10]

[0082]

[0083] [Chemistry 11]

[0084]

[0085] [Chemistry 12]

[0086]

[0087] [Chemistry 13]

[0088]

[0089] [Chemistry 14]

[0090]

[0091] [Chemistry 15]

[0092]

[0093] [Chemistry 16]

[0094]

[0095] [Chemistry 17]

[0096]

[0097] [Chemistry 18]

[0098]

[0099] <11> The polycyclic aromatic compound according to <3>, which is represented by any of the following formulas.

[0100] [Chemistry 19]

[0101]

[0102] <12> An organic electroluminescent element comprising: a pair of electrodes including an anode and a cathode; and an organic layer disposed between the pair of electrodes, the organic layer containing the polycyclic aromatic compound according to any one of <1> to <11>.

[0103] <13> The organic electroluminescent element according to <12>, wherein the organic layer is a light-emitting layer.

[0104] <14> The organic electroluminescent element according to <13>, wherein the polycyclic aromatic compound is an electron-transporting host material, and the light-emitting layer further includes a hole-transporting host material and a dopant material.

[0105] <15> The organic electroluminescent element according to <14>, wherein the light-emitting layer further includes at least one selected from the group consisting of a thermally activated delayed phosphor and a phosphorescent material.

[0106] <16> A display device or a lighting device, comprising the organic electroluminescent element according to any one of <11> to <15>.

[0107] [Effects of the Invention]

[0108] According to a preferred embodiment of the present invention, an organic EL element with excellent quantum efficiency or element life can be provided by producing an organic EL element using a novel polycyclic aromatic compound as, for example, a main material in a light-emitting layer, a component of a main material, or a component of a layer adjacent to the light-emitting layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Figure 1 It is a schematic cross-sectional view showing the organic EL element according to this embodiment.

[0110] [Explanation of Symbols]

[0111] 100: Organic electroluminescent element

[0112] 101: Substrate

[0113] 102: Anode

[0114] 103: Hole injection layer

[0115] 104: Hole transport layer

[0116] 105: Luminous layer

[0117] 106: Electron transport layer

[0118] 107: Electron injection layer

[0119] 108: Cathode DETAILED DESCRIPTION

[0120] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below is sometimes based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range represented by "to" refers to a range including the numerical values ​​recorded before and after "to" as the lower limit and the upper limit. In addition, in this specification, "hydrogen" in the description of the structural formula refers to "hydrogen atom (H)". Similarly, in the case of representing atoms such as "carbon atom (C)", "atom" is sometimes omitted (for example, referred to as "carbon").

[0121] In the present specification, "adjacent groups" refer to two groups respectively bonded to two adjacent atoms (two atoms directly bonded by a covalent bond) in a structural formula.

[0122] In the present specification, "Me" represents a methyl group, "Et" represents an ethyl group, "nBu" represents a normal butyl group, "tBu" represents a tertiary butyl group, "iBu" represents an isobutyl group, "secBu" represents a secondary butyl group, "nPr" represents a normal propyl group, "iPr" represents an isopropyl group, "tAm" represents a tert-amyl group, "2EH" represents a 2-ethylhexyl group, "tOct" represents a tert-octyl group, "Ph" represents a phenyl group, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Ad" represents a 1-adamantyl group, "Tf" represents a trifluoromethanesulfonyl group, "TMS" represents a trimethylsilyl group, and "D" represents a deuterium group.

[0123] In this specification, an organic electroluminescent element may be referred to as an organic EL element.

[0124] In this specification, the chemical structure or substituent is sometimes represented by the carbon number, but the carbon number when the chemical structure is substituted with a substituent, or when the substituent is further substituted with a substituent, etc., refers to the carbon number of the chemical structure or the substituent, and does not refer to the total carbon number of the chemical structure and the substituent, or the total carbon number of the substituent and the substituent. For example, the so-called "substituent B with carbon number Y substituted by substituent A with carbon number X" means that "substituent A with carbon number X" is substituted on "substituent B with carbon number Y", and the carbon number Y is not the total carbon number of substituent A and substituent B. In addition, for example, the so-called "substituent B with carbon number Y substituted by substituent A" means that "substituent A (without carbon number limitation)" is substituted on "substituent B with carbon number Y", and the carbon number Y is not the total carbon number of substituent A and substituent B.

[0125] <Description of Ring and Substituent>

[0126] First, the details of the rings and substituents used in the present specification are described below.

[0127] Examples of the “aryl ring” in the present specification include 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.

[0128] Specific examples of the "aryl ring" include a benzene ring that is a monocyclic ring system, a biphenyl ring that is a bicyclic ring system, a naphthalene ring and an indene ring that are a condensed bicyclic ring system, a terphenyl ring (meta-terphenyl, o-terphenyl, p-terphenyl) that is a tricyclic ring system, an acenaphthene ring, fluorene ring, phenanthren ring, anthracene ring that are a condensed tricyclic ring system, a triphenylene ring, a pyrene ring, a tetracene ring, The ring is a perylene ring, a pentacene ring, etc. of a condensed five-ring system. In addition, the fluorene ring, the benzofluorene ring, and the indene ring also include structures in which the fluorene ring, the benzofluorene ring, the cyclopentane ring, etc. are spiro-bonded. In addition, the fluorene ring, the benzofluorene ring, and the indene ring also include rings in which two of the two hydrogen atoms of the methylene group in the structure are replaced by alkyl groups such as methyl groups described later as the first substituent to form dimethylfluorene rings, dimethylbenzofluorene rings, dimethylindene rings, etc.

[0129] As the "heteroaryl ring" in the present specification, for example, a heteroaryl ring having 2 to 30 carbon atoms can be mentioned, preferably a heteroaryl ring having 2 to 25 carbon atoms, more preferably a heteroaryl ring having 2 to 20 carbon atoms, further preferably a heteroaryl ring having 2 to 15 carbon atoms, and particularly preferably a heteroaryl ring having 2 to 10 carbon atoms can be mentioned. In addition, as the "heteroaryl ring", for example, a heterocyclic ring containing 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, boron, selenium, phosphorus, and tellurium as ring-constituting atoms other than carbon can be mentioned.

[0130] 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 (such as a furazan 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 phenoxathiol ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, a phenazasiline ring, an indolizine ring, a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, Thiophene ring, benzothiophene ring, dibenzothiophene ring, thianthrene ring, indolecarbazole ring, benzindolecarbazole ring, dibenzoindolecarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, dibenzodioxin ring, dioxaborinaphthoanthracene ring (5,9-dioxa-13b-bora-13bH-naphtho[3,2,1-de]anthracene ring, etc.), benzoselenophene ring, dibenzoselenophene ring, azacarbazole ring, azadibenzothiophene ring, azadibenzofuran ring, azadibenzoselenophene ring, azatriphenylene ring, imidazoimidazole ring, indoloindole ring, benzofuranocarbazole ring, benzothiophenocarbazole ring, indenocarbazole ring and selenophenecarbazole ring, spiro[fluorene-9,9'-xanthene] ring, spirobis[siliconfluorene] ring, etc. In addition, among the dihydroacridine ring, xanthene ring and thioxanthene ring, two of the two hydrogen atoms of the methylene group in the structure are preferably substituted with an alkyl group such as a methyl group as described later as the first substituent to form a dimethyldihydroacridine ring, a dimethylxanthene ring, a dimethylthioxanthene ring, etc. In addition, bipyridine ring, phenylpyridine ring, pyridylphenyl ring as a bicyclic ring system, terpyridine ring, bipyridylphenyl ring, pyridylbiphenyl ring as a tricyclic ring system can also be listed as a "heteroaryl ring". In addition, the "heteroaryl ring" also includes a pyran ring.

[0131] In this specification, a substituent may be substituted with a further 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 further substituent or is unsubstituted. In the same sense, it is sometimes referred to as "substitutable". In this specification, the specific substituent at this time may be referred to as a "first substituent" and the further substituent may be referred to as a "second substituent".

[0132] In the present specification, the substituent group Zα includes the substituents of the substituent group Z and the substituents represented by the formula (A30) described later.

[0133] In the present specification, the substituent group Z includes:

[0134] The aryl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group,

[0135] The heteroaryl group may be substituted by at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen.

[0136] The diarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two aryl groups in the diarylamino group may be bonded to each other via a linking group.

[0137] The diheteroarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two heteroaryl groups in the diheteroarylamino group may be bonded to each other via a linking group.

[0138] The arylheteroarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the aryl group and the heteroaryl group in the arylheteroarylamino group may be bonded to each other via a linking group.

[0139] The diarylboryl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two aryl groups in the diarylboryl group may be bonded via a single bond or a linking group.

[0140] The alkyl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, a cycloalkyl group, a cyano group and a halogen group,

[0141] The cycloalkyl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group,

[0142] The alkoxy group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, a cycloalkyl group, a cyano group and a halogen group,

[0143] The aryloxy group may be substituted by at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen.

[0144] Substituted silyl, cyano and halogen.

[0145] The aryl group as the second substituent in each group of the substituent group Z may be further substituted by an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group or a halogen. Similarly, the heteroaryl group as the second substituent may be substituted by an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group or a halogen.

[0146] In the present specification, when referred to as a "substituent", the type of the substituent is not particularly limited, and unless otherwise specified, any substituent selected from the substituent group Z may be used. For example, when a "substituted or unsubstituted" group is substituted, the group may be substituted with at least one group selected from the substituent group Z.

[0147] In the present specification, the "aryl group" is, for example, an aryl group having 6 to 30 carbon atoms, and preferably an aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms.

[0148] Specific examples of the "aryl group" include a monovalent group obtained by removing one hydrogen atom from the above-mentioned "aryl ring". For example, it is a phenyl group which is a monocyclic ring, a biphenyl group (2-biphenyl, 3-biphenyl, or 4-biphenyl) which is a bicyclic ring, a naphthyl group (1-naphthyl or 2-naphthyl) which is a condensed bicyclic ring, a terphenyl group (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) which is a tricyclic ring, a condensed tricyclic acenaphthene group (1-, 3-, 4-, or 5- The invention also includes the following: a 1-, 2-, 3-, 4-, or 9-) group, a phenanthren-(1-, 2-, 3-, 4-, or 9-) group, a tetraphenyl group (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, or m-quaterphenyl group) having a tetracyclic ring system, a triphenylene-(1-, 2-, or 4-) group, a pyrene-(1-, 2-, or 4-) group, or a tetracene-(1-, 2-, or 5-) group having a condensed tetracyclic ring system, or a perylene-(1-, 2-, or 3-) group, or a pentacene-(1-, 2-, 5-, or 6-) group having a condensed pentacyclic ring system. In addition, a monovalent group of spirofluorene and the like can be mentioned.

[0149] In addition, the aryl group serving as the second substituent also includes a structure in which the aryl group is substituted by at least one group selected from the group consisting of aryl groups such as phenyl (specific examples are the groups described above), alkyl groups such as methyl (specific examples are the groups described later), and cycloalkyl groups such as cyclohexyl or adamantyl (specific examples are the groups described later).

[0150] As an example thereof, there can be mentioned a group in which the 9-position of the fluorenyl group as the second substituent is substituted with an aryl group such as a phenyl group, an alkyl group such as a methyl group, or a cycloalkyl group such as a cyclohexyl group or an adamantyl group.

[0151] The “arylene group” is, for example, an arylene group having 6 to 30 carbon atoms, and preferably an arylene group having 6 to 20 carbon atoms, an arylene group having 6 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, or an arylene group having 6 to 10 carbon atoms.

[0152] Specific examples of the "arylene group" include a divalent group obtained by removing one hydrogen atom from the above-mentioned "aryl group" (monovalent group).

[0153] The “heteroaryl group” is, for example, a heteroaryl group having 2 to 30 carbon atoms, preferably a heteroaryl group having 2 to 25 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, a heteroaryl group having 2 to 15 carbon atoms, or a heteroaryl group having 2 to 10 carbon atoms. The “heteroaryl group” contains, in addition to carbon atoms, one or more, preferably one to five heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

[0154] Specific examples of "heteroaryl" include monovalent groups formed by removing one hydrogen from the "heteroaryl ring". Examples include 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, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiol, phenoxazinyl, phenanthrolinyl, phenanthroline ... Thiazinyl, phenazinyl, phenazasilinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, a monovalent group of a benzophospholine oxide ring, a monovalent group of a dibenzophospholine oxide ring, furazanyl, thianthrenyl, indolecarbazolyl, benzindolecarbazolyl, dibenzoindolecarbazolyl, imidazolinyl, or oxazolinyl, etc. In addition, a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirobis[silafluorene], and a monovalent group of benzoselenophene can be mentioned.

[0155] In addition, the heteroaryl group as the second substituent also includes a structure in which the heteroaryl group is substituted by at least one group selected from the group consisting of aryl groups such as phenyl (specific examples are the groups described above), alkyl groups such as methyl (specific examples are the groups described later), and cycloalkyl groups such as cyclohexyl or adamantyl (specific examples are the groups described later).

[0156] As an example, the 9-position of the carbazolyl group as the second substituent is substituted by an aryl group such as a phenyl group, an alkyl group such as a methyl group, or a cycloalkyl group such as a cyclohexyl group or an adamantyl group. In addition, a nitrogen-containing heteroaryl group such as a pyridyl group, a pyrimidyl group, a triazine group, a carbazolyl group, etc., which is further substituted by a phenyl group or a biphenyl group, is also included in the heteroaryl group as the second substituent.

[0157] The “heteroarylene group” is, for example, a heteroarylene group having 2 to 30 carbon atoms, preferably a heteroarylene group having 2 to 25 carbon atoms, a heteroarylene group having 2 to 20 carbon atoms, a heteroarylene group having 2 to 15 carbon atoms, or a heteroarylene group having 2 to 10 carbon atoms. In addition, the “heteroarylene group” is, for example, a divalent group such as a heterocycle containing 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms in addition to carbon.

[0158] Specific examples of the "heteroarylene group" include a divalent group obtained by removing one hydrogen atom from the above-mentioned "heteroaryl group" (monovalent group).

[0159] The "diarylamino group" is an amino group substituted with two aryl groups, and the description of the above-mentioned "aryl group" can be referred to for details of the aryl group.

[0160] The "diheteroarylamino group" is an amino group substituted with two heteroaryl groups, and the description of the "heteroaryl group" can be referred to for details of the heteroaryl group.

[0161] The "arylheteroarylamino group" is an amino group substituted with an aryl group or a heteroaryl group, and the description of the above-mentioned "aryl group" and "heteroaryl group" can be cited for the details of the above-mentioned aryl group and heteroaryl group.

[0162] The two aryl groups in the diarylamino group as the first substituent may be bonded to each other via a linking group, the two heteroaryl groups in the diheteroarylamino group as the first substituent may be bonded to each other via a linking group, and the aryl and heteroaryl groups in the arylheteroarylamino group as the first substituent may be bonded to each other via a linking group. Here, the description of "bonding via a linking group" is as shown below, for example, it means that the two phenyl groups of the diphenylamino group form a bond through a linking group. In addition, the description is also applicable to the diheteroarylamino group and the arylheteroarylamino group formed by aryl or heteroaryl groups.

[0163] [Chemistry 20]

[0164]

[0165] (* indicates the bond position)

[0166] Specific examples of the linking group include: >O, >NR X 、>C(-R X )2. -C(-R X )=C(-R X)-、>Si(-R X )2,>S,>CO,>CS,>SO,>SO2,>SeO,>SeO2,>PO,>B(-R X ) and >Se. R X are independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted by alkyl, cycloalkyl, aryl, or heteroaryl. X )2. -C(-R X )=C(-R X )-、>Si(-R X )2 Each of the two R X Can be linked to the group X via a single bond or Y bond to each other to form a ring. Y , can be listed as >O, >NR Y 、>C(-R Y )2、>Si(-R Y )2, >S, >CO, >CS, >SO, >SO2, and >Se, R Y are independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted by alkyl, cycloalkyl, aryl or heteroaryl. Y is>C(-R Y )2 and>Si(-R Y )2, the two R Y The alkylene group may be substituted with an alkylene group. 2X Replacement, R 2X are independently alkyl, cycloalkyl, substituted silyl, aryl and heteroaryl, which may be substituted by alkyl, cycloalkyl, substituted silyl or aryl. X )=C(-R X )-The two Rs in X They may be bonded to each other and form an aryl ring (such as a benzene ring) or a heteroaryl ring together with these bonded C=C. X )=C(-R X )- can be an arylene group (such as 1,2-phenylene) or a heteroarylene group.

[0167] In addition, when simply describing “diarylamino”, “diheteroarylamino” or “arylheteroarylamino” in the present specification, unless otherwise specified, descriptions such as “two aryl groups in the diarylamino group may be bonded to each other via a linking group”, “two heteroaryl groups in the diheteroarylamino group may be bonded to each other via a linking group” and “the aryl and heteroaryl groups in the arylheteroarylamino group may be bonded to each other via a linking group” are respectively added.

[0168] "Diarylboryl" is a boron group substituted with two aryl groups, and the details of the aryl group can be referred to the description of the "aryl group". In addition, the two aryl groups may be bonded via a single bond or a linking group (for example, -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >CO, >C=S, >S=O, >S(=O)2, >Se(=O), >Se(=O)2, >P(=O), >B(-R), >C(-R)2, >Si(-R)2, or >Se). Here, R of -CR=CR-, R of >NR, R of >B(-R), R of >C(-R)2, and R of >Si(-R) are aryl, heteroaryl, diarylamino, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen in the R may be further substituted by an aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. In addition, two adjacent Rs may be bonded to each other to form a ring, thereby forming a cycloalkylene, arylene, and heteroarylene. For details of the substituents listed here, the descriptions of "aryl", "arylene", "heteroaryl", "heteroarylene", and "diarylamino" described above, as well as the descriptions of "alkyl", "alkenyl", "alkynyl", "cycloalkyl", "cycloalkylene", "alkoxy", and "aryloxy" described later may be cited. In the present specification, when simply describing a "diarylboryl group", unless otherwise specified, it is assumed that "two aryl groups in the diarylboryl group may be bonded to each other via a single bond or a linking group" is included.

[0169] "Alkyl" can be any of straight chain and branched chain, for example, a straight chain alkyl group with 1 to 24 carbon atoms or a branched chain alkyl group with 3 to 24 carbon atoms, preferably an alkyl group with 1 to 18 carbon atoms (branched chain alkyl group with 3 to 18 carbon atoms), an alkyl group with 1 to 12 carbon atoms (branched chain alkyl group with 3 to 12 carbon atoms), an alkyl group with 1 to 6 carbon atoms (branched chain alkyl group with 3 to 6 carbon atoms), an alkyl group with 1 to 5 carbon atoms (branched chain alkyl group with 3 to 5 carbon atoms), an alkyl group with 1 to 4 carbon atoms (branched chain alkyl group with 3 to 4 carbon atoms), etc.

[0170] 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, sec-butyl, tert-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-dimethylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, tert-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, or n-icosyl.

[0171] The "alkylene group" is a divalent group obtained by removing any hydrogen atom from an "alkyl group", and examples thereof include a methylene group, an ethylene group, and a propylene group.

[0172] Regarding the "alkenyl group", please refer to the description of the "alkyl group". It is a group in which the CC single bond in the structure of the "alkyl group" is replaced by a C=C double bond, and also includes a group in which not only one but more than two single bonds are replaced by double bonds (also called a diene group or a triene group).

[0173] The "alkenylene group" is a divalent group obtained by removing any hydrogen atom of an "alkenyl group", and examples thereof include a vinylene group.

[0174] Regarding the “alkynyl group”, reference may be made to the description of the “alkyl group”, which is a group in which the C-C single bond in the structure of the “alkyl group” is replaced by a C≡C triple bond, and also includes a group in which not only one but two or more single bonds are replaced by triple bonds (also called a di-alkynyl group or a tri-alkynyl group).

[0175] The “cycloalkyl group” is, for example, a cycloalkyl group having 3 to 24 carbon atoms, preferably a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 16 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, a cycloalkyl group having 5 to 6 carbon atoms, or a cycloalkyl group having 5 carbon atoms.

[0176] Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyl (especially methyl) substituents having 1 to 5 carbon atoms or 1 to 4 carbon atoms, 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 (norbornyl), bicyclo[2.2.2]octyl, adamantyl, diadamantyl, decahydronaphthyl, or decahydroazulyl.

[0177] The “cycloalkylene group” is, for example, a cycloalkylene group having 3 to 24 carbon atoms, preferably a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkylene group having 3 to 16 carbon atoms, a cycloalkylene group having 3 to 14 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene group having 5 to 10 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a cycloalkylene group having 5 to 6 carbon atoms, or a cycloalkylene group having 5 carbon atoms.

[0178] Specific examples of the "cycloalkylene group" include a structure in which one hydrogen atom is removed from the above-mentioned "cycloalkyl group" (monovalent group) to give a divalent group.

[0179] The "cycloalkenyl group" includes a group having a structure in which at least one set of single bonds between two carbon atoms in the "cycloalkyl group" becomes a double bond (for example, a group in which -CH2-CH2- is substituted with -CH=CH-), and a group that is not equivalent to an aryl group. Specifically, 1-cyclohexenyl, 1-cyclopentenyl, etc. can be mentioned.

[0180] The "alkoxy group" is a group represented by "Alk-O-(Alk is an alkyl group)", and the description of the "alkyl group" can be cited for details of the alkyl group.

[0181] The "aryloxy group" is a group represented by "Ar-O-(Ar is an aryl group)", and the description of the "aryl group" can be cited for details of the aryl group.

[0182] The “substituted silyl group” is, for example, a silyl group substituted with at least one of an aryl group, an alkyl group, and a cycloalkyl group, and is preferably a triarylsilyl group, a trialkylsilyl group, a tricycloalkylsilyl group, a dialkylcycloalkylsilyl group, or an alkyldicycloalkylsilyl group.

[0183] The "triarylsilyl group" is a silyl group substituted with three aryl groups, and the description of the "aryl group" can be cited for details of the aryl groups.

[0184] Specific examples of the “triarylsilyl group” include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl groups.

[0185] The “trialkylsilyl group” is a silyl group substituted with three alkyl groups, and the description of the “alkyl group” mentioned above can be referred to for details of the alkyl groups.

[0186] Specific examples of “trialkylsilyl” include trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-sec-butylsilyl, tri-tert-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, sec-butyldimethylsilyl, tert-butyldimethylsilyl, methyldiethylsilyl, n-propyldimethylsilyl, tert-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, sec-butyldi-n-propylsilyl, tert-butyldi-n-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, sec-butyldiisopropylsilyl, or tert-butyldiisopropylsilyl.

[0187] The "tricycloalkylsilyl group" is a silyl group substituted with three cycloalkyl groups, and the description of the "cycloalkyl group" mentioned above can be cited for the details of the cycloalkyl group.

[0188] Specific examples of the “tricycloalkylsilyl group” include tricyclopentylsilyl and tricyclohexylsilyl groups.

[0189] The "dialkylcycloalkylsilyl group" is a silyl group substituted with two alkyl groups and one cycloalkyl group, and the description of the "alkyl group" and the "cycloalkyl group" can be cited for details of the alkyl group and the cycloalkyl group.

[0190] The "alkyldicycloalkylsilyl group" is a silyl group substituted with one alkyl group and two cycloalkyl groups, and the description of the "alkyl group" and the "cycloalkyl group" can be cited for details of the alkyl group and the cycloalkyl group.

[0191] The "halogen" is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, further preferably fluorine.

[0192] When the group is substituted with a cyano group or a halogen, it is also preferred that all or part of the hydrogen atoms in the aryl ring or the heteroaryl ring in the structure are substituted with a cyano group or a halogen.

[0193] The substituent represented by formula (A30) has the following structure.

[0194] [Chemistry 21]

[0195]

[0196] In formula (A30),

[0197] Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl or substituted or unsubstituted cycloalkenyl, at least one -CH2- in the alkyl, cycloalkyl and cycloalkenyl may be substituted by -O- or -S-,

[0198] R Ak is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, R Ak It can be bonded to Ak through a linking group or a single bond, and * is the bonding position.

[0199] In formula (A30), Ak is the substituent, and is not conjugated with the non-covalent electron pair on N, so that the non-covalent electron pair can be conjugated with the π electron of the bonding target, and a larger wavelength change can be achieved compared to the case where an aromatic group or the like exists at the same position. In addition, the same is true for the influence on the multiple resonance effect, and a greater improvement in the thermally activated delayed fluorescence (TADF) property can be achieved.

[0200] R Ak Preferred is an aryl group which may be substituted by an alkyl group or a cycloalkyl group, a heteroaryl group which may be substituted by an alkyl group or a cycloalkyl group, an alkyl group or a cycloalkyl group, more preferably an aryl group which may be substituted by an alkyl group, a heteroaryl group which may be substituted by an alkyl group, an alkyl group or a cycloalkyl group, further preferably an aryl group which may be substituted by an alkyl group, and particularly preferably a phenyl group which may be substituted by a methyl group.

[0201] In formula (A30), Ak is preferably an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 14 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, further preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group.

[0202] R Ak It may be the same as or different from Ak, but is preferably different.

[0203] R Ak It can be bonded to Ak via a linking group or a single bond. Examples of the linking group include >O, >S, or >Si(-R)2. R of >Si(-R)2 is hydrogen, an aryl group having 6 to 12 carbon atoms, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 14 carbon atoms. AkExamples of the structure bonded to Ak via a linking group or a single bond include the following structures.

[0204] [Chemistry 22]

[0205]

[0206] In the above formulas, * represents the bonding position.

[0207] <When two groups bonded to the same atom are bonded to each other>

[0208] In the present specification, when it is mentioned that two groups bonded to the same atom can be bonded to each other to form a ring, they can be bonded via a single bond or a linking group (these are also collectively referred to as a bonding group). 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-, -C(=O)-, -C(=S)-, -S(=O)-, -S(=O)2-, -Se(=O)-, -Se(=O)2-, -P(=O)-, -B(-R)-, -Si(-R)2- or -Se-. For example, the following structures can be mentioned. In addition, the R of -CHR-CHR-, the R of -CR2-CR2-, the R of -CR=CR-, the R of -N(-R)-, the R of -C(-R)2-, the R of -B(-R)-, and the R of -Si(-R)2- are independently hydrogen, aryl which may be substituted by alkyl or cycloalkyl, heteroaryl which may be substituted by alkyl or cycloalkyl, alkyl which may be substituted by cycloalkyl, alkenyl which may be substituted by alkyl or cycloalkyl, alkynyl which may be substituted by alkyl or cycloalkyl, or cycloalkyl which may be substituted by alkyl or cycloalkyl. In addition, two adjacent Rs may be bonded to each other to form a ring, and may form a cycloalkylene group, an arylene group, or a heteroarylene group.

[0209] [Chemistry 23]

[0210]

[0211] As the bonding group, a single bond, -CR=CR-, -N(-R)-, -O-, -S-, -C(-R)2-, -Si(-R)2-, and -Se- are preferred as the linking group; a single bond, -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R)2- are more preferred as the linking group; a single bond, -CR=CR-, -N(-R)-, -O-, and -S- are further preferred as the linking group; and a single bond is most preferred.

[0212] The position at which the two Rs are bonded via a bonding group is not particularly limited as long as it is a position at which bonding is possible, but it is preferred that the two Rs are bonded at the most adjacent position. For example, when the two groups are phenyl groups, it is preferred that the two Rs are bonded to each other at the ortho position (position 2) based on the bonding position (position 1) of "C" or "Si" in the phenyl group (refer to the structural formula).

[0213] <Stereoisomers, etc.>

[0214] The polycyclic aromatic compound of the present invention may exist as enantiomers or diastereomers depending on the type of substituents, but any stereoisomer in any pure form, any mixture of stereoisomers, racemates, etc. are all included in the scope of the present invention regardless of the structural formula described.

[0215] 1. Polycyclic aromatic compounds of the present invention

[0216] The polycyclic aromatic compound of the present invention is represented by formula (1), and contains at least one of the partial structures represented by formula (Xa-1) and at least one of the partial structures represented by formula (Xb-1).

[0217] [Chemistry 24]

[0218]

[0219] In formula (1),

[0220] Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

[0221] In formula (Xa-1),

[0222] X a is C, Si, Ge or Sn, AR1 ring, AR2 ring, AR3 ring and AR4 ring are independently substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings, and any two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring can be linked to each other by a single bond or a linking group,

[0223] One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring

[0224] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0225] An aryl or heteroaryl ring of ring D, ring E or ring AR5 in formula (Xb-1) that is bonded to ring A, ring B or ring C or that shares any ring with ring A, ring B or ring C is bonded to the ring-constituting atom via a single bond; or

[0226] Shares a ring with Ring A, Ring B or Ring C; or

[0227] a ring shared by the ring D, the ring E or the ring AR5 in the formula (Xb-1) that is bonded to the ring A, the ring B or the ring C or that shares any ring with the ring A, the ring B or the ring C,

[0228] In formula (Xb-1),

[0229] The D ring and the E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

[0230] X b is a divalent group having an AR5 ring described below, >O or >S,

[0231] AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and AR5 ring can be linked to D ring and / or E ring by a single bond or a linking group,

[0232] One or two selected from the group consisting of D ring, E ring and AR5 ring

[0233] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0234] An aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) is bonded to the A, B or C ring via a single bond or is bonded to the A, B or C ring in a ring-constituting atom; or

[0235] Shares a ring with Ring A, Ring B or Ring C; or

[0236] a ring shared by the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) that is bonded to the A ring, the B ring or the C ring or that shares any ring with the A ring, the B ring or the C ring,

[0237] At least one hydrogen in the structure may be substituted with deuterium.

[0238] The present inventors have found that the polycyclic aromatic compound of the present invention, which is formed by linking aromatic rings with oxygen, has a large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap (band gap Eg in a thin film) and high triplet energy. The reason for this is believed to be that the aromaticity of the ring containing the heteroelement is low, so the reduction of the HOMO-LUMO gap accompanying the expansion of the conjugated system is suppressed; and a large HOMO-LUMO gap can be obtained by suppressing the expansion of the conjugated system by utilizing deformation within the molecule.

[0239] In addition, the polycyclic aromatic compounds containing heteroelements of the present invention are also effectively used as a host compound of a phosphorescent organic EL element or an organic EL element using thermally activated delayed fluorescence, an electron blocking layer (electron blocking layer) or a hole blocking layer (hole blocking layer) adjacent to a light-emitting layer, an electron transport layer or a hole transport layer as a material having high triplet energy. Furthermore, these polycyclic aromatic compounds can arbitrarily change the energy of HOMO and LUMO by introducing substituents, so that the ionization potential or electron affinity can be optimized according to the surrounding materials.

[0240] <Description of Ring Structure in Compound>

[0241] In formula (1), "A", "B" and "C" in the circle are symbols representing the ring structure represented by the circle, in formula (Xa-1), "AR1", "AR2", "AR3" and "AR4" are symbols representing the ring structure represented by the circle, and in formula (Xb-1), "D" and "E" are symbols representing the ring structure represented by the circle. b The "AR5" in is a symbol indicating a ring structure represented by a circle.

[0242] Ring A, Ring B, Ring C, Ring D, Ring E, Ring AR1, Ring AR2, Ring AR3, Ring AR4 and Ring AR5 are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring.

[0243] Ring A forms a trivalent group having a bond on three consecutive atoms (preferably carbon) on the ring of the aryl ring or heteroaryl ring in its structure. Ring A is bonded to two O (oxygen) and B (boron) through the three bonds. When Ring A is further bonded to Ring AR1, Ring AR2, Ring AR3, Ring AR4, Ring AR5, Ring D or Ring E at another site as described later, or shares an aryl ring or heteroaryl ring with Ring AR1, Ring AR2, Ring AR3, Ring AR4, Ring AR5, Ring D or Ring E, Ring A may also become a tetravalent group or a pentavalent group. The ring in which the atom having the bond is set as a ring-constituting atom in Ring A is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. The ring may further be condensed with other rings. Examples of 6-membered rings include: a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and the like. Examples of 6-membered rings condensed with other rings include: naphthalene ring, quinoline ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, etc. Examples of 5-membered rings include: furan ring, thiophene ring, pyrrole ring, thiazole ring, etc. Examples of 5-membered rings condensed with other rings include: benzofuran ring, benzothiophene ring, indole ring, etc. In addition, as condensed rings, indene rings can also be listed.

[0244] The aryl ring or heteroaryl ring in the A ring is preferably a benzene ring.

[0245] Both the B ring and the C ring form a divalent group with a bond on two atoms (preferably carbon) adjacent to each other on the ring of the aryl ring or heteroaryl ring in its structure. The B ring is bonded to O (oxygen) and B (boron) through the two bonds, and the C ring is bonded to O (oxygen) and B (boron) through the two bonds. In the case where the B ring and the C ring are respectively bonded to the AR1 ring, AR2 ring, AR3 ring, AR4 ring, AR5 ring, D ring or E ring at another position as described later, or share an aryl ring or heteroaryl ring with the AR1 ring, AR2 ring, AR3 ring, AR4 ring, AR5 ring, D ring or E ring, the B ring and the C ring may also be a trivalent group or a tetravalent group, respectively. The ring in which the atoms having the two bonds are set as ring-constituting atoms in each of the B ring and the C ring is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. The ring may be further condensed with other rings. Examples of 6-membered rings include benzene rings, pyridine rings, pyrazine rings, pyrimidine rings, etc. Examples of 6-membered rings that are condensed with other rings include naphthalene rings, quinoline rings, benzofuran rings, benzothiophene rings, indole rings, benzoselenophene rings, dibenzofuran rings, dibenzothiophene rings, carbazole rings, dibenzoselenophene rings, etc. Examples of 5-membered rings include furan rings, thiophene rings, pyrrole rings, thiazole rings, selenophene rings, etc. Examples of 5-membered rings that are condensed with other rings include benzofuran rings, benzothiophene rings, indole rings, benzoselenophene rings, etc. In addition, indene rings may also be included as condensed rings.

[0246] The aryl ring or heteroaryl ring in the ring B or the ring C is preferably a benzene ring, a benzofuran ring, a benzothiophene ring or a benzoselenophene ring, and more preferably a benzene ring, a benzofuran ring or a benzothiophene ring, respectively and independently.

[0247] Both the D ring and the E ring form a divalent group having bonding bonds on two atoms (preferably carbon atoms) adjacent to each other on the aryl ring or heteroaryl ring in the structure. The D ring is bonded to X through the two bonding bonds. b and E ring, and E ring is connected to X through the two bonding bonds b And D ring bond. When D ring and E ring are further bonded to AR5 ring at another site, D ring and E ring can also be trivalent groups respectively. In addition, when D ring and E ring are further bonded to AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring at another site as described later, or share an aryl ring or heteroaryl ring with AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring, D ring and E ring can also be trivalent groups or tetravalent groups respectively. The ring in which the atoms having the two bonding bonds are set as ring-constituting atoms in each of D ring and E ring is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. The ring can be further condensed with other rings. Examples of 6-membered rings include: benzene ring, pyridine ring, pyrazine ring, pyrimidine ring, etc. Examples of 6-membered rings that are condensed with other rings include: naphthalene ring, quinoline ring, benzofuran ring, benzothiophene ring, indole ring, benzoselenophene ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, dibenzoselenophene ring, etc. Examples of 5-membered rings include: furan ring, thiophene ring, pyrrole ring, thiazole ring, selenophene ring, etc. Examples of 5-membered rings that are condensed with other rings include: benzofuran ring, benzothiophene ring, indole ring, benzoselenophene ring, etc.

[0248] The aryl ring or heteroaryl ring in the D ring or the E ring is preferably a benzene ring or a pyridine ring, and more preferably a benzene ring.

[0249] The AR1 ring, AR2 ring, AR3 ring, AR4 ring and AR5 ring each form a monovalent group having a bond to one atom (preferably carbon) on the aryl ring or heteroaryl ring in the structure. The AR1 ring, AR2 ring, AR3 ring and AR4 ring are each connected to X by one bond. a The AR5 ring is bonded to nitrogen through a single bond. When the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring are respectively connected to any other of the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring through a single bond or a linking group as described later, the ring may also be a divalent group. Furthermore, as described later, any of the following (1) or (2) among the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring becomes a divalent group, a trivalent group, or a tetravalent group.

[0250] (1) is bonded to an atom constituting an aryl ring or a heteroaryl ring in Ring A, Ring B, Ring C, Ring D, Ring E or Ring AR5 via a single bond or a linking group;

[0251] (2) It shares a ring with the A ring, the B ring, the C ring, the D ring, the E ring or the AR5 ring.

[0252] When the AR5 ring is further bonded to the D ring or the E ring at another position, the AR5 ring may be a divalent group or a trivalent group. In addition, when the AR5 ring is bonded to the AR1 ring, the AR2 ring, the AR3 ring, the AR4 ring, the A ring, the B ring or the C ring as described later, or when the AR5 ring shares an aryl ring or a heteroaryl ring with the AR1 ring, the AR2 ring, the AR3 ring, the AR4 ring, the A ring, the B ring or the C ring, the AR5 ring may be a divalent group, a trivalent group or a tetravalent group.

[0253] The ring in which the atom having the bonding bond is set as the ring-constituting atom in each of the AR1 ring, the AR2 ring, the AR3 ring, the AR4 ring, and the AR5 ring is preferably a 5-membered ring or a 6-membered ring, and more preferably a 6-membered ring. The ring may be further condensed with other rings. Examples of 6-membered rings include: benzene rings, pyridine rings, pyrazine rings, pyrimidine rings, etc. Examples of 6-membered rings further condensed with other rings include: naphthalene rings, quinoline rings, benzofuran rings, benzothiophene rings, indole rings, benzoselenophene rings, dibenzofuran rings, dibenzothiophene rings, carbazole rings, dibenzoselenophene rings, etc. Examples of 5-membered rings include: furan rings, thiophene rings, pyrrole rings, thiazole rings, selenophene rings, etc. Examples of 5-membered rings further condensed with other rings include: benzofuran rings, benzothiophene rings, indole rings, benzoselenophene rings, etc.

[0254] As the aryl ring or heteroaryl ring in each ring of AR1 ring, AR2 ring, AR3 ring, and AR4 ring, a benzene ring, a benzofuran ring, a benzothiophene ring, or a benzoselenophene ring is independently preferred, and a benzene ring is more preferred. As the aryl ring or heteroaryl ring in AR5 ring, a benzene ring, a benzofuran ring, a benzothiophene ring, or a benzoselenophene ring is independently preferred, and a benzene ring is more preferred.

[0255] <Description of partial structure and overall structure>

[0256] The polycyclic aromatic compound of the present invention contains at least one partial structure represented by formula (Xa-1), and preferably contains one partial structure.

[0257] In formula (Xa-1), X a is C, Si, Ge or Sn, X a Preferred is C or Si, more preferred is Si.

[0258] In formula (Xa-1), the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring are independently substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings, and the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring can be linked to any other of the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring through a single bond or a linking group. Here, when the link is mentioned, it means that the ring is not linked to the ring through X. a In addition to the connection of , there is also a connection through an additional single bond or a linking group. In the case of such a connection, it is preferred that AR1 ring and AR2 ring among AR1 ring, AR2 ring, AR3 ring or AR4 ring are connected, or AR1 ring and AR2 ring and AR3 ring and AR4 ring are connected respectively. In this case, it is preferably connected through a single bond, >O or >S, and more preferably connected through a single bond.

[0259] From the perspective of manufacturing devices with higher quantum efficiency and longer lifetime, when X a When X is Si, it is more preferred that at least two of the AR1 ring, AR2 ring, AR3 ring and AR4 ring are linked to each other. It is particularly preferred that they are linked by a single bond. a In the case of C, it is more preferred that any two of the AR1 ring, the AR2 ring, the AR3 ring, and the AR4 ring are not linked to each other.

[0260] The polycyclic aromatic compound of the present invention contains at least one partial structure represented by formula (Xb-1), and preferably contains one partial structure.

[0261] In formula (Xb-1), X b It is a divalent group represented by the formula (Xb-R5), >O or >S.

[0262] [Chemistry 25]

[0263]

[0264] In the formula (Xb-R5), the two #s represent the bonding positions to the D ring and the E ring, respectively.

[0265] From the perspective of high carrier transport and good carrier balance, X b It is preferably a divalent group represented by the formula (Xb-R5). That is, the formula (Xb-1) is preferably the following formula (Xb-1-R5).

[0266] [Chemistry 26]

[0267]

[0268] The AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR5 ring may be linked to the D ring and / or the E ring by a single bond or a linking group. Specific examples of the linking group include: >O, >NR de 、>C(-R de )2、>Si(-R de )2, >S, >CO, >CS, >SO, >SO2 and >Se. R de are independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted by alkyl, cycloalkyl, aryl or heteroaryl. de )2 and>Si(-R de )2 Each of the two R de They may be bonded to each other to form a ring. When the AR5 ring is linked to the D ring or / and the E ring by a single bond or a linking group, it is preferably linked by a single bond, >O, >C(-Me)2, >C(-Ph)2, >S or >Se. In addition, the two Ph in >C(-Ph)2 may be bonded to each other by a single bond to form a ring.

[0269] The partial structure represented by formula (Xa-1) and the partial structure represented by formula (Xb-1) are respectively linked by sharing a bond or ring with the A ring, B ring or C ring and another partial structure in formula (1), thereby constituting a partial structure of a polycyclic aromatic compound represented by formula (1).

[0270] Specifically, in formula (Xa-1), one or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring:

[0271] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0272] An aryl or heteroaryl ring of ring D, ring E or ring AR5 in formula (Xb-1) that is bonded to ring A, ring B or ring C or that shares any ring with ring A, ring B or ring C is bonded to the ring-constituting atom via a single bond; or

[0273] Shares a ring with Ring A, Ring B or Ring C; or

[0274] The ring D, ring E or ring AR5 in the formula (Xb-1) that is bonded to the ring A, ring B or ring C or that shares any one of the rings with the ring A, ring B or ring C is a shared ring.

[0275] In addition, one or two selected from the group consisting of ring D, ring E and ring AR5 in formula (Xb-1):

[0276] is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or

[0277] An aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) is bonded to the A, B or C ring via a single bond or is bonded to the A, B or C ring in a ring-constituting atom; or

[0278] Shares a ring with Ring A, Ring B or Ring C; or

[0279] The AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) that is bonded to the A ring, the B ring or the C ring or that shares any one of the rings with the A ring, the B ring or the C ring is a common ring.

[0280] When the AR1 ring, AR2 ring, AR3 ring or AR4 ring is bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the A ring, B ring or C ring via a single bond or a partial structure represented by the formula (Xb-1), it is preferably bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the ring (AR1 ring, AR2 ring, AR3 ring or AR4 ring).

[0281] When the D ring, E ring or AR5 ring is bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the A ring, B ring or C ring via a single bond or a partial structure represented by formula (Xa-1), it is preferably bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the ring (D ring, E ring or AR5 ring).

[0282] The following are examples of structures in which, as a polycyclic aromatic compound represented by formula (1) and comprising a partial structure represented by formula (Xa-1) and a partial structure represented by formula (Xb-1), any one of the rings in formula (Xa-1) and any one of the rings in formula (Xb-1) are bonded to the ring-constituting atoms of an aryl ring or a heteroaryl ring in another ring via a single bond.

[0283] [Chemistry 27]

[0284]

[0285] As described above, for example, a structure in which rings B and AR1 are bonded by a single bond and rings C and D are bonded by a single bond is represented as B-AR1C-D, and a structure in which rings B and D are bonded by a single bond and rings AR5 and AR1 are bonded by a single bond is represented as B-DAR5-AR1.

[0286] If shown in this representation, the following structures can be listed as other examples of structures in which each partial structure is bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the A ring, the B ring or the C ring or the aryl ring or heteroaryl ring in the ring of another partial structure through a single bond.

[0287] A-AR1B-D

[0288] A-AR1B-AR5

[0289] A-DB-AR1

[0290] A-AR5B-AR1

[0291] B-AR1C-AR5

[0292] A-AR1AR2-D

[0293] A-AR1AR3-D

[0294] A-AR1AR2-AR5

[0295] A-AR1AR3-AR5

[0296] A-DE-AR1

[0297] A-DAR5-AR1

[0298] A-AR5D-AR1

[0299] B-AR1AR2-D

[0300] B-AR1AR3-D

[0301] B-AR1AR2-AR5

[0302] B-AR1AR3-AR5

[0303] B-DE-AR1

[0304] B-AR5D-AR1

[0305] When each partial structure represented by Formula (Xa-1) or Formula (Xb-1) is bonded to a ring-constituting atom of an aryl ring or a heteroaryl ring in another ring via a single bond, it is preferably a substitution position that allows the conjugated system to be cross-conjugated.

[0306] In the present specification, when a common ring is mentioned for Ring A, Ring B, Ring C, Ring AR1, Ring AR2, Ring AR3, Ring AR4, Ring AR5, Ring D, and Ring E, it means that the target rings are integrated.

[0307] As examples of such a structure, examples of the structure of a polycyclic aromatic compound represented by formula (1) including one partial structure represented by formula (Xa-1) and one partial structure represented by formula (Xb-1) are shown below.

[0308] For example, the structure represented by the following formula (AAR5DAR1) is a structure in which the A ring and the AR5 ring share a ring, and the AR1 ring and the D ring share a ring.

[0309] [Chemistry 28]

[0310]

[0311] Similarly, for example, the structure represented by the following formula (AAR1CAR5) represents a structure in which the A ring and the AR1 ring share a ring, and the AR5 ring and the C ring share a ring.

[0312] [Chemistry 29]

[0313]

[0314] Similarly, for example, the structure represented by the following formula (AAR1AR3AR5) represents a structure in which the A ring and the AR1 ring share a ring, and the AR5 ring and the AR3 ring share a ring.

[0315] [Chemistry 30]

[0316]

[0317] As described above, for example, the structure represented by (AAR5DAR1) means a structure in which the A ring shares a ring with the AR5 ring, and the D ring shares a ring with the AR1 ring.

[0318] According to this notation, as examples of a structure in which each partial structure is bonded via a common ring, in addition to the above three examples, the following structures can be listed.

[0319] AAR1BD

[0320] AAR1BAR5

[0321] ADBAR1

[0322] AAR5BAR1

[0323] BAR1CD

[0324] AAR1AR2D

[0325] AAR1AR3D

[0326] AAR1AR2AR5

[0327] ADEAR1

[0328] ADAR5AR1

[0329] BAR1AR2D

[0330] BAR1AR3D

[0331] BAR1AR2AR5

[0332] BAR1AR3AR5

[0333] BDEAR1

[0334] BDAR5AR1

[0335] BAR5DAR1

[0336] The polycyclic aromatic compound of the present invention may include partial structures bonded via single bonds, etc. and partial structures of shared rings. As examples of such structures, examples of the structure of a polycyclic aromatic compound represented by formula (1) including a partial structure represented by formula (Xa-1) and a partial structure represented by formula (Xb-1) are shown below.

[0337] For example, in the structure represented by the following formula (B-AR1CD), the aryl ring or heteroaryl ring in the D ring in (Xb-1) is bonded to the ring-constituting atom of the aryl ring or heteroaryl ring in the C ring via a single bond, and the B ring shares a ring with AR1.

[0338] [Chemistry 31]

[0339]

[0340] According to the above-mentioned representation, the following structures can be listed as examples of other structures.

[0341] A-AR1BD

[0342] A-AR1BAR5

[0343] A-DBAR1

[0344] A-AR5BAR1

[0345] B-AR1CAR5

[0346] A-AR1AR2D

[0347] A-AR1AR3D

[0348] A-AR1AR2AR5

[0349] A-AR1AR3AR5

[0350] A-DEAR1

[0351] A-DAR5AR1

[0352] A-AR5DAR1

[0353] B-AR1AR2D

[0354] B-AR1AR3D

[0355] B-AR1AR2AR5

[0356] B-AR1AR3AR5

[0357] B-DEAR1

[0358] B-DAR5AR1

[0359] B-AR5DAR1

[0360] AAR1B-D

[0361] AAR1B-AR5

[0362] ADB-AR1

[0363] AAR5B-AR1

[0364] BAR1C-D

[0365] BAR1C-AR5

[0366] AAR1AR2-D

[0367] AAR1AR3-D

[0368] AAR1AR2-AR5

[0369] AAR1AR3-AR5

[0370] ADE-AR1

[0371] ADAR5-AR1

[0372] AAR5D-AR1

[0373] BAR1AR2-D

[0374] BAR1AR3-D

[0375] BAR1AR2-AR5

[0376] BAR1AR3-AR5

[0377] BDE-AR1

[0378] BDAR5-AR1

[0379] BAR5D-AR1

[0380] From the viewpoint of high T1 energy, compounds having a structure in which the D ring, E ring or AR5 ring in the structure (Xb-1) is bonded to or shares any ring with the formula (Xa-1) (the formula (Xa-1) to which the A ring, B ring or C ring is bonded or any ring is shared with the A ring, B ring or C ring). In addition, compounds in which two sp2 carbon-sp2 carbon bonds connecting the aryl or heteroaryl groups are ortho (o position) or meta (m position) are preferred because they have high T1, long life and high efficiency.

[0381] In addition, from the viewpoint of high TADF property and high efficiency, X in (Xb-1) is preferably b It is a divalent group represented by the formula (Xb-R5), and the AR5 ring shares a ring with the A ring, the B ring, or the C ring, and more preferably the AR5 ring shares a ring with the B ring or the C ring.

[0382] <Description of Substituents in Each Ring>

[0383] Regarding the A ring, the B ring and the C ring, as the substituent when referring to "substituted or unsubstituted (substituted or unsubstituted)" in the substituted or unsubstituted aryl ring or the substituted or unsubstituted heteroaryl ring, examples include substituents formed by formula (Xa-1), formula (Xb-1) or formula (Xa-1) and formula (Xb-1). As other substituents, examples include at least one substituent selected from the substituent group Zα (excluding the substituent formed by formula (Xa-1), formula (Xb-1) or formula (Xa-1) and formula (Xb-1)). As other substituents, phenyl, methyl, tert-butyl or cyano is preferred. From the viewpoint of improving the charge transport function, in addition to the aryl ring or heteroaryl ring having a substituent formed by formula (Xa-1), formula (Xb-1) or formula (Xa-1) and formula (Xb-1), the A ring, the B ring and the C ring preferably have one other substituent or are unsubstituted, and more preferably are unsubstituted. From the viewpoint of improving the charge transport function, the ring having a substituent formed by formula (Xa-1), formula (Xb-1), or formula (Xa-1) and formula (Xb-1) preferably has no other substituent.

[0384] Regarding the D ring, E ring, AR1 ring, AR2 ring, AR3 ring, AR4 ring and AR5 ring, the substituent when referring to "substituted or unsubstituted (substituted or unsubstituted)" as a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring can be at least one substituent selected from the substituent group Zα. As the substituent, phenyl, methyl, tert-butyl or cyano is preferred. From the viewpoint of improving the charge transport function, each aromatic ring in the A ring, B ring, C ring, D ring, E ring, AR1 ring, AR2 ring, AR3 ring, AR4 ring or AR5 ring is preferably unsubstituted or has one substituent, and more preferably unsubstituted.

[0385] <Preferred partial structure>

[0386] From the viewpoint of high carrier transport and good carrier balance, the polycyclic aromatic compound of the present invention preferably has a carbazole structure, and the compound having a carbazole structure can be preferably used as a hole transport layer, an electron blocking layer, and a main body material. In addition to the carbazole structure, the compound having a pyridine structure or a triazine structure is preferably used as a main body material.

[0387] The compound of the present invention having pyridine or triazine can be preferably used as an electron transporting host, a hole blocking layer, or an electron transporting layer.

[0388] <Polycyclic aromatic compound represented by formula (1a), formula (1b) or formula (1c)>

[0389] The polycyclic aromatic compound represented by formula (1) is preferably a polycyclic aromatic compound represented by formula (1a), formula (1b) or formula (1c). In this case, formula (Xa-1) is preferably represented by formula (Xa-2), and formula (Xb-1) is preferably represented by formula (Xb-2).

[0390] [Chemistry 32]

[0391]

[0392] The partial structure represented by formula (Xa-2) and the partial structure represented by formula (Xb-2) constitute the partial structure of the polycyclic aromatic compound represented by formula (1a), formula (1b) or formula (1c) respectively in the following manner: bonded to Z (ring-constituting atom in Z, such as carbon atom) in ring a, ring b or ring c in formula (1a), formula (1b) or formula (1c) via a single bond; or bonded to Z (ring-constituting atom in Z, such as carbon atom) in another partial structure to which Z in ring a, ring b or ring c is bonded; or share a ring with ring a, ring b or ring c; or share a ring with another partial structure that is bonded to ring a, ring b or ring c or shares any ring with ring a, ring b or ring c.

[0393] Specifically, in formula (Xa-2), Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 One or two of the group consisting of the rings d, e and AR5 are bonded to Z in the a, b or c ring via a single bond; or are bonded to the d, e or AR5 ring in the partial structure represented by formula (Xb-2) bonded to Z in the a, b or c ring; or share a ring with the a, b or c ring; or share a ring with the d, e or AR5 ring in the formula (Xb-2) bonded to the a, b or c ring or sharing any ring with the a, b or c ring. In addition, in formula (Xb-2), one or two of the group consisting of the rings d, e and AR5 are bonded to Z in the a, b or c ring via a single bond; or are bonded to the d, e or AR5 ring in the partial structure represented by formula (Xa-2) bonded to Z in the a, b or c ring 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 Z in the ring; or a ring shared with the a, b or c ring; or Ar in the formula (Xa-2) bonded to the a, b or c ring or sharing any ring with the a, b or c ring 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 Regarding this structure, reference can be made to the above description of how the partial structure represented by formula (Xa-1) and the partial structure represented by formula (Xb-1) become the partial structure of the polycyclic aromatic compound represented by formula (1).

[0394] In each of formula (1b) and formula (1c), Y 1 and Y 2 Each independently is >NR NY 、>C(-R CY )2、>O、>Si(-R IY )2、>S or >Se. R NY , R CY and R IY are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CY Can bond to each other to form a ring, two R IY They may bond to each other to form a ring. L is >NR NY R NY , preferably a substituted or unsubstituted aryl group, more preferably a phenyl group which may be substituted by an alkyl group. CY)2 CY , preferably methyl or phenyl. IY )2 IY , preferably methyl or phenyl. 1 and Y 2 Each independently preferably is >NR NY 、>C(-R CY )2, >O or >S, more preferably >O or >S. Y 1 , Y 2 They may be the same or different, but are preferably the same.

[0395] In each of Formula (1a), Formula (1b), Formula (1c), Formula (Xa-2) and Formula (Xb-2), Z is a carbon atom having a bond to another ring, or -C(-R Z )=or-N=,R Z is hydrogen or a substituent. Among them, two adjacent Zs constituting the e ring in formula (Xb-2) may be carbon atoms respectively bonded to two *s in formula (Xb-2-e). Any of the two adjacent Zs may be bonded to any *. In formula (Xb-2-e), X b is a divalent group represented by the formula (Xb-R5), >O, >C(-R CX )2、>Si(-R IX )2.>S or>Se, R CX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CX They can bond with each other to form a ring. CX Preferably it is methyl or phenyl. IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IX They can bond with each other to form a ring. IX Preferably, it is methyl or phenyl. Z in formula (Xb-2-e) has the same meaning as Z constituting ring d in formula (Xb-2), and is a carbon atom having a bond to another ring, or -C(-R Z )=or -N=.

[0396] As Z in each of the formulas (1a), (1b), (1c), (Xa-2) and (Xb-2), it is preferred that all other Z except the Z that is a carbon atom having a bond to another ring are -C (-R Z )=, or one or two are -N= and the others are -C(-R Z)=, more preferably all are -C(-R Z )=, or one is -N= and the other is -C(-R Z )=. In each of the formulas (1a), (1b), and (1c), other Zs except for the Zs that are carbon atoms are most preferably all -C(-R Z )=, and in each of the formulas (Xa-2) and (Xb-2), it is most preferred that one Z is -N= and the other is -C(-R Z )=. In each of Formula (1a), Formula (1b) and Formula (1c), R Z When it is a substituent, the substituent may be a substituent formed by formula (Xa-2), formula (Xb-2) or formula (Xa-2) and formula (Xb-2). As other substituents, at least one substituent selected from the substituent group Zα (excluding the substituent formed by formula (Xa-2), formula (Xb-2) or formula (Xa-2) and formula (Xb-2)) may be mentioned. As other substituents, phenyl, methyl or cyano is preferred. In each of formulas (1a), (1b) and (1c), R Z In each of Formula (Xa-2) and Formula (Xb-2), R Z When the substituent is a substituent, at least one substituent selected from the substituent group Zα can be cited. As the substituent, phenyl, methyl, tert-butyl or cyano is preferred. In each of formula (Xa-2) and formula (Xb-2), R Z Preferred is hydrogen.

[0397] In formula (Xa-2), X a and X in formula (Xa-1) a The meanings are the same, and the preferred ranges are also the same.

[0398] Regarding Ar in formula (Xa-2) 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 The rings may refer to the description of the AR1 ring, AR2 ring, AR3 ring and AR4 ring in formula (Xa-1). 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 Any two of the rings may be linked to each other via a single bond or a linking group.

[0399] In formula (Xb-2), X b and X in formula (Xb-1) b X bWhen the AR5 ring is a divalent group represented by the formula (XB-R5), it is preferably a 6-membered ring, such as a benzene ring or a pyridine ring.

[0400] Preferred structural examples of Formula (1a), Formula (1b), Formula (1c), Formula (Xa-2), and Formula (Xa-1) are shown below. In addition, Formula (1a), Formula (1b), and Formula (1c) represent structures other than the partial structures represented by Formula (Xa-2) and Formula (Xa-1).

[0401] [Chemistry 33]

[0402] (1a)

[0403]

[0404] [Chemistry 34]

[0405] (1b)

[0406]

[0407] [Chemistry 35]

[0408] (1c)

[0409]

[0410] [Chemistry 36]

[0411] (Xa-2)

[0412]

[0413] [Chemistry 37](Xb-2)

[0414]

[0415] <Substitution with heavy stable isotopes>

[0416] Each element in the polycyclic aromatic compound represented by formula (1) contains multiple isotopes in the natural occurrence ratio unless otherwise specified. All or part of the elements in each structural formula may contain more than the natural occurrence ratio (for example, in the case of boron-11 ( 11 In the present specification, it is referred to as "replaced with" "heavy stable isotopes". More specifically, at least one hydrogen can be replaced with deuterium, and at least one nitrogen can be replaced with nitrogen-15 ( 15 N), at least one sulfur may be substituted with sulfur-33 ( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36S), at least one oxygen may be substituted with oxygen-17 ( 17 O) or oxygen-18 ( 18 O), at least one carbon may be substituted with carbon-13 ( 13 C), at least one boron may be substituted with boron-11 ( 11 B). The same is true for the structure represented by formula (1a), formula (1b) or formula (1c), and this description is also applicable to the structure represented by formula (1a), formula (1b) or formula (1c). By replacing at least a part of the element with a heavy stable isotope, in particular by replacing the element with boron-11 ( 11 B) Substituting at least one boron can extend the life of an organic electroluminescent device using the polycyclic aromatic compound represented by formula (1).

[0417] <Substitution using deuterium>

[0418] All or part of the hydrogen atoms in the polycyclic aromatic compound represented by formula (1) may be deuterium. The same is true for the structures represented by formula (1a), formula (1b) or formula (1c), and the following description is also applicable to the polycyclic aromatic compounds represented by formula (1a), formula (1b) or formula (1c).

[0419] For example, hydrogen in the aryl ring or heteroaryl ring in the A ring, the B ring and the C ring, or in a substituent thereof may be substituted with deuterium, and among these, the form in which all or part of the hydrogen in the aryl ring or heteroaryl ring is substituted with deuterium can be cited. All or part of the hydrogen in the aryl ring and heteroaryl ring in the D ring and the E ring, or the AR1 ring, the AR2 ring, the AR3 ring, the AR4 ring or the AR5 ring in the formula (Xb-1) may be substituted with deuterium. In addition, from the viewpoint of durability, it is also preferred that all or part of the hydrogen in the polycyclic aromatic compound represented by the formula (1) is deuterated.

[0420] <Specific examples of the polycyclic aromatic compound of the present invention>

[0421] Specific examples of the polycyclic aromatic compound of the present invention include compounds represented by any of the following structural formulae, but the present invention is not limited to these compounds.

[0422] [Chemistry 38]

[0423]

[0424] [Chemistry 39]

[0425]

[0426] [Chemistry 40]

[0427]

[0428] [Chemistry 41]

[0429]

[0430] [Chemistry 42]

[0431]

[0432] [Chemistry 43]

[0433]

[0434] [Chemistry 44]

[0435]

[0436] [Chemistry 45]

[0437]

[0438] [Chemistry 46]

[0439]

[0440] [Chemistry 47]

[0441]

[0442] [Chemistry 48]

[0443]

[0444] [Chemistry 49]

[0445]

[0446] [Chemistry 50]

[0447]

[0448] [Chemistry 51]

[0449]

[0450] [Chemistry 52]

[0451]

[0452] [Chemistry 53]

[0453]

[0454] [Chemistry 54]

[0455]

[0456] [Chemistry 55]

[0457]

[0458] [Chemistry 56]

[0459]

[0460] [Chemistry 57]

[0461]

[0462] [Chemistry 58]

[0463]

[0464] [Chemistry 59]

[0465]

[0466] [Chemistry 60]

[0467]

[0468] [Chemistry 61]

[0469]

[0470] [Chemistry 62]

[0471]

[0472] [Chemistry 63]

[0473]

[0474] [Chemistry 64]

[0475]

[0476] [Chemistry 65]

[0477]

[0478] [Chemistry 66]

[0479]

[0480] [Chemistry 67]

[0481]

[0482] [Chemistry 68]

[0483]

[0484] [Chemistry 69]

[0485]

[0486] 2. Method for producing polycyclic aromatic compounds

[0487] The polycyclic aromatic compound represented by formula (1) can be basically produced by firstly bonding the A ring (a ring), the B ring (b ring) and the C ring (c ring) having a halogen at any position with O to produce an intermediate (first reaction), then bonding a condensed ring including the A ring (a ring), the B ring (b ring) and the C ring with boron to produce a partial structure (1) having a halogen (second reaction), and then linking the partial structure (Xa-1) and the partial structure (Xb-1) by a cross coupling reaction (third reaction). In the first reaction, a general reaction such as a nucleophilic substitution reaction and an Ullmann reaction can be used, and in the second reaction, a tandem hetero-Friedel-Crafts reaction (continuous aromatic electrophilic substitution reaction, the same below) can be used. In the third reaction, general reactions such as Suzuki-Miyaura reaction, Buchwald reaction, and Goldberg reaction can be used. In addition, the final product can also be obtained by introducing B into a precursor in which partial structure (Xa-1) and partial structure (Xb-1) are previously linked by means of a Bora-Friedel-Crafts reaction.

[0488] As shown in the following process (1), the second reaction is a reaction of introducing boron that bonds the condensed ring containing ring A (ring a), ring B (ring b) and ring C (ring c). First, the halogen atoms between nitrogen atoms are exchanged with halogen-metal using n-butyl lithium, sec-butyl lithium or tert-butyl lithium. Then, boron trichloride or boron tribromide is added to exchange lithium-boron metals, and then a Brünster base such as N,N-diisopropylethylamine is added to perform a tandem boro-Friedel-Crafts reaction, thereby obtaining the target product. In the second reaction, a Lewis acid such as aluminum chloride may also be added to promote the reaction. In addition, the halogen atom of Cl in the formula may be any one of Cl, Br, and I, and may be appropriately selected in consideration of the reactivity of the substrate.

[0489] [Chemistry 70]

[0490]

[0491] By appropriately selecting the raw materials to be used, a polycyclic aromatic compound having a substituent at a desired position can be synthesized.

[0492] Alternatively, the synthesis may be performed using a general coupling reaction, such as the method described in Nature Photonics (13, 540-546 (2019)) and Advanced Functional Materials (2021, 31, 2105805).

[0493] Specific examples of the solvent used in the above reaction include tert-butylbenzene and xylene.

[0494] In addition, in the synthesis method of the process (1), an example is shown in which halogen-metal exchange is performed on the halogen atoms between nitrogen atoms using butyl lithium or the like before adding boron trichloride or boron tribromide, thereby causing a tandem hetero Friedel-Crafts reaction to occur. However, the reaction can also be carried out by adding boron trichloride or boron tribromide or the like to a precursor in which the halogen is converted into hydrogen.

[0495] In addition, examples of the ortho-metallating agent used in the process (1) include alkyl lithiums such as methyl lithium, n-butyl lithium, sec-butyl lithium, and tert-butyl lithium, and organic alkali metal compounds such as lithium diisopropylamide, lithium tetramethylpiperidinide, lithium hexamethyldisilazide, and potassium hexamethyldisilazide.

[0496] Examples of the metal-boron metal exchange reagent used in the above process (1) include boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide, boron alkoxides, and boron aryloxides.

[0497] In addition, examples of the Brünster base used in the process (1) include: N,N-diisopropylethylamine, triethylamine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2,6-dimethylpyridine, sodium tetraphenylborate, potassium tetraphenylborate, triphenylborane, tetraphenylsilane, Ar4BNa, Ar4BK, Ar3B, Ar4Si (in addition, Ar is an aromatic group such as phenyl), etc.

[0498] Examples of the Lewis acid used in the process (1) include AlCl3, AlBr3, AlF3, BF3·OEt2, BCl3, BBr3, BI3, GaCl3, GaBr3, InCl3, InBr3, In(OTf)3, SnCl4, SnBr4, AgOTf, ScCl3, Sc(OTf)3, ZnCl2, ZnBr2, Zn(OTf)2, MgCl2, MgBr2, Mg(OTf)2, LiOTf, NaOTf, KOTf, Me3SiOTf, Cu(OTf)2, CuCl2, YCl3, Y(OTf)3, TiCl4, TiBr4, ZrCl4, ZrBr4, FeCl3, FeBr3, CoCl3, CoBr3, and the like.

[0499] In the process (1), in order to promote the tandem hetero Friedel-Crafts reaction, a Brünster base or a Lewis acid may also be used. Among them, when using boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide, as the aromatic electrophilic substitution reaction proceeds, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide are generated, so it is effective to use a Brünster base that captures the acid. On the other hand, when using boron amide halides and boron alkoxylates, as the aromatic electrophilic substitution reaction proceeds, amines and alcohols are generated, so in most cases, there is no need to use a Brünster base, but because the ability of amino or alkoxy groups to leave is low, it is effective to use a Lewis acid that promotes their departure.

[0500] The polycyclic aromatic compounds of the present invention also include compounds in which at least a portion of hydrogen atoms are substituted with deuterium or compounds in which a halogen such as fluorine or chlorine is substituted. Such compounds can be synthesized in the same manner as described above by using raw materials in which the desired positions are deuterated, fluorinated or chlorinated.

[0501] 3. Organic electroluminescent elements

[0502] The polycyclic aromatic compound of the present invention can be used as a material for organic devices. Examples of organic devices include organic electroluminescent devices, organic field effect transistors, and organic thin-film solar cells. The polycyclic aromatic compound of the present invention can be used particularly as an organic electroluminescent device.

[0503] 3-1. Structure of organic electroluminescent element

[0504] Hereinafter, the organic EL element of this embodiment will be described in detail with reference to the drawings. Figure 1 It is a schematic cross-sectional view showing the organic EL element according to this embodiment.

[0505] <Structure of organic electroluminescent element>

[0506] Figure 1 The organic EL element 100 shown includes: a substrate 101, an anode 102 arranged on the substrate 101, a hole injection layer 103 arranged on the anode 102, a hole transport layer 104 arranged on the hole injection layer 103, a light-emitting layer 105 arranged on the hole transport layer 104, an electron transport layer 106 arranged on the light-emitting layer 105, an electron injection layer 107 arranged on the electron transport layer 106, and a cathode 108 arranged on the electron injection layer 107.

[0507] In addition, the organic EL element 100 can also reverse the production order to form a structure such as the following, which includes: a substrate 101, a cathode 108 disposed on the substrate 101, an electron injection layer 107 disposed on the cathode 108, an electron transport layer 106 disposed on the electron injection layer 107, a light-emitting layer 105 disposed on the electron transport layer 106, a hole transport layer 104 disposed on the light-emitting layer 105, a hole injection layer 103 disposed on the hole transport layer 104, and an anode 102 disposed on the hole injection layer 103.

[0508] The above-mentioned layers are not all indispensable layers, and the minimum structural unit is set to a structure including an anode 102, a light-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 can be set arbitrarily. In addition, the above-mentioned layers may each include a single layer or a plurality of layers.

[0509] The morphology of the layers constituting the organic EL element may be, in addition to the structural morphology of “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”. The structural morphology of the 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 injection 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", and "substrate / anode / light-emitting layer / electron injection layer / cathode".

[0510] The organic EL element may further have any one or both selected from an electron blocking layer (electron blocking layer) and a hole blocking layer (hole blocking layer). The electron blocking layer has a LUMO that is shallower than the light-emitting layer and a HOMO that is close to the light-emitting layer or the hole transport layer, and is arranged between the light-emitting layer and the hole transport layer. Since the electrons are retained in the light-emitting layer and do not leak out to the hole transport layer, the shortening of the life caused by the degradation of the hole transport layer and the reduction in efficiency caused by the reduction in recombination efficiency can be prevented. The hole blocking layer has a HOMO that is deeper than the light-emitting layer and a LUMO that is close to the light-emitting layer or the hole transport layer, and is arranged between the light-emitting layer and the electron transport layer. Since the holes are retained in the light-emitting layer and do not leak out to the electron transport layer, the shortening of the life caused by the degradation of the electron transport layer and the reduction in efficiency caused by the reduction in recombination efficiency can be prevented. The hole injection / transport layer may also serve as an electron blocking layer. The electron injection / transport layer may also serve as a hole blocking layer.

[0511] The organic EL element may further have a high T1 layer. The high T1 layer has a higher T1 than the main compound, auxiliary dopant compound or emission dopant compound used in the light-emitting layer, and is arranged between the light-emitting layer and the hole transport layer and / or between the light-emitting layer and the electron blocking layer. The value of T1 energy varies depending on the light-emitting mechanism of the element, but has a higher T1 than the compound used in the main body. By having a high T1 layer around the light-emitting layer, triplet energy can be enclosed, and the triplet energy that is usually unrelated to light emission in the fluorescent molecules can be converted into singlet energy, thereby obtaining high efficiency. The hole injection / transport layer or the electron blocking layer can also serve as the high T1 layer. The electron injection / transport layer or the hole blocking layer can also serve as the high T1 layer.

[0512] The polycyclic aromatic compounds of the present invention are preferably used as materials for organic electroluminescent elements. Generally speaking, compounds with donor structures can be used in hole transport host materials and hole transport layers in the light-emitting layer, compounds with acceptor structures can be used in electron transport host materials and electron transport layers, and compounds with donor structures and acceptor structures can be used in hole transport layers, hosts in light-emitting layers, and any one of electron transport layers. The donor structure and the acceptor structure can be referred to, for example, in Advanced Functional Materials (2020, 2008332) and the like. More specifically, the donor structure can include triarylamine structures and carbazole structures, and the acceptor structure can include triazine structures, pyrimidine structures, and pyridine structures. The polycyclic aromatic compounds of the present invention can be used as host materials, hole transport layer materials, electron transport layer materials, etc. in the light-emitting layer according to the partial structures they have.

[0513] 3-2. Substrate in organic electroluminescent element

[0514] The substrate 101 is a support of the organic EL element 100, and quartz, glass, metal, plastic, etc. can be generally used. The substrate 101 is formed into a plate, film or sheet according to the purpose, for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, etc. can be used. Among them, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, polysulfone, etc. are preferably used. If it is a glass substrate, soda-lime glass or alkali-free glass, etc. can be used. In addition, the thickness can be sufficient to maintain the mechanical strength. In addition, in order to improve the gas barrier property, a gas barrier film such as a fine silicon oxide film can also be provided on at least one side of the substrate 101. When a plate, film or sheet made of a synthetic resin with low gas barrier property is used as the substrate 101, it is particularly preferred to provide a gas barrier film.

[0515] 3-3. Anode in organic electroluminescent element

[0516] The anode 102 plays a role of injecting 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 through these layers.

[0517] As materials for forming the anode 102, inorganic compounds and organic compounds can be cited. As inorganic compounds, for example, metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (Indium Tin Oxide, ITO), indium-zinc oxide (Indium Zinc Oxide, IZO), etc.), metal halides (copper iodide, etc.), copper sulfide, carbon black, ITO glass or Nesa glass, etc. As organic compounds, for example, polythiophenes such as poly(3-methylthiophene), conductive polymers such as polypyrrole and polyaniline, etc. can be cited. In addition, it can be appropriately selected from the substances used as the anode of the organic EL element for use.

[0518] 3-4. Hole injection layer and hole transport layer in organic electroluminescent element

[0519] The hole injection layer 103 plays a role of efficiently injecting holes migrated from the anode 102 into the light-emitting layer 105 or the hole transport layer 104. The hole transport layer 104 plays a role of efficiently transporting 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 formed by stacking or mixing one or more hole injection / transport materials. In addition, an inorganic salt such as iron (III) chloride can be added to the hole injection / transport material to form a layer.

[0520] As a hole injection / transport material, it is necessary to efficiently inject / transmit holes from the positive electrode between electrodes to which an electric field is applied, and it is ideal that the hole injection efficiency is high and the injected holes are efficiently transmitted. Therefore, it is preferred that the ionization potential is small, the hole mobility is large, and the stability is excellent, and it is not easy to produce impurities that become traps during manufacture and use. As a material for the hole transport layer, it is also preferred to use the polycyclic aromatic compounds of the present invention.

[0521] 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, and known compounds used in hole injection layers and hole transport layers of p-type semiconductors and organic EL elements. 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-carbazole-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N 4 ,N 4 ,N 4 ',N 4 '-tetrakis[1,1'-biphenyl]-4-yl-[1,1'-biphenyl]-4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine and other triphenylamine derivatives, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives or thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (for example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilane, etc. Among polymer systems, polycarbonate or styrene derivatives, polyvinylcarbazole and polysilane having the above-mentioned monomers on the side chain are preferred, but there is no particular limitation as long as it is a compound that can form a thin film required for the production of a light-emitting element, can inject holes from the anode, and can further transport holes.

[0522] In addition, it is also known that the conductivity of organic semiconductors is strongly affected by their doping. Such organic semiconductor matrix materials contain compounds with good electron donating properties or compounds with good electron accepting properties. In order to dope electron donating materials, strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are known (for example, refer to the literature "M. Pfeiffer, A. Bayer, T. Fritz, K. Leo (M. Pfeiffer , A. Beyer, T. Fritz, K. Leo), "Applied Physics Letters (Appl. Phys. Lett.)", 73(22), 3202-3204 (1998)" and the reference "J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo (J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo), "Applied Physics Letters (Appl. Phys. Lett.)", 73(6), 729-731 (1998)"). These so-called holes are generated through the electron migration process of the electron-donating basic material (hole transport material). The conductivity of the basic material varies greatly depending on the number and mobility of the holes. As a host material having hole transport properties, for example, benzidine derivatives (N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine, TPD), starburst amine derivatives (4,4',4"-tris(N,N-diphenylamino)triphenylamine (4,4',4"-tris(N,N-diphenylamino)triphenylamine, TDATA), or specific metal phthalocyanines (especially zinc phthalocyanine (ZnPc), etc.) are known (Japanese Patent Publication No. 2005-167175).

[0523] The hole injection layer material and the hole transport layer material can also be used in the hole layer material as the following polymer compound or its polymer cross-linked product, or the following pendant polymer compound or its pendant polymer cross-linked product, wherein the polymer compound is obtained by polymerizing a reactive compound substituted with a reactive substituent in the hole injection layer material and the hole transport layer material as a monomer, and the pendant polymer compound is obtained by reacting a main chain polymer with the reactive compound.

[0524] 3-5. Light-emitting layer in organic electroluminescent element

[0525] The light-emitting layer 105 is a layer that emits light by allowing holes injected from the anode 102 to recombine with electrons injected from the cathode 108 between electrodes to which an electric field is applied. As a material for forming the light-emitting layer 105, any compound (luminescent compound) that is excited to emit light by recombination of holes and electrons can be used, and preferably a compound that can form a stable thin film shape and shows strong luminescence (fluorescence) efficiency in a solid state. The polycyclic aromatic compound of the present invention is also preferably used as a material for the light-emitting layer.

[0526] The light-emitting layer may be a single layer or may include multiple layers, either of which is acceptable, and is formed by light-emitting layer materials (host material, dopant material). The host material and the dopant material may be one type or a combination of multiple types, either of which is acceptable. The dopant material may be contained in the host material as a whole or in part of the host material, either of which is acceptable. As a doping method, it can be formed by co-evaporation with the host material, or it can be pre-mixed with the host material and then evaporated simultaneously, or it can be pre-mixed with the host material together with an organic solvent and then prepared by a wet film-forming method.

[0527] The amount of the host material used varies depending on the type of the host material and can be determined by matching the characteristics of the host material. The base amount of the host material used is preferably 50% to 99.999% by mass, more preferably 80% to 99.95% by mass, and further preferably 90% to 99.9% by mass relative to the total mass of the material for the light-emitting layer.

[0528] The amount of the dopant material used varies depending on the type of the dopant material, and can be determined by matching the characteristics of the dopant material. The basis for the amount of the dopant material used is preferably 0.001% to 50% by mass relative to the total mass of the material for the light-emitting layer, more preferably 0.05% to 20% by mass, and further preferably 0.1% to 10% by mass. If it is within the above range, it is preferred, for example, in terms of preventing concentration quenching. In addition, from the perspective of durability, it is also preferred that part or all of the hydrogen in the dopant material is deuterated.

[0529] As the dopant material, an emitting dopant material and an acylated dopant material can be used. As the acylated dopant material, it is preferred to use a thermally active delayed fluorescence material. In an organic electroluminescent element using an acylated dopant material, it is preferred that the amount of the emitting dopant material used is low in terms of preventing the concentration quenching phenomenon. In terms of the efficiency of the thermally active delayed fluorescence mechanism, it is preferred that the amount of the auxiliary dopant material used is high in terms of concentration. Furthermore, in an organic electroluminescent element using a thermally active delayed fluorescence auxiliary dopant material, it is preferred that the amount of the emitting dopant material used is low in terms of the efficiency of the thermally active delayed fluorescence mechanism of the auxiliary dopant material compared to the amount of the auxiliary dopant material used.

[0530] 1. When using an auxiliary dopant material, the base usage of the main material, the auxiliary dopant material and the emission dopant material is 40% to 99% by mass, 59% to 1% by mass and 20% to 0.001% by mass, respectively, relative to the total mass of the material for the light-emitting layer, preferably 60% to 95% by mass, 39% to 5% by mass and 10% to 0.01% by mass, respectively, and more preferably 70% to 90% by mass, 29% to 10% by mass and 5% to 0.05% by mass, respectively.

[0531] <Main material>

[0532] Examples of the host material include condensed ring derivatives of anthracene, pyrene and the like which have been known as light emitters in the past, bistyryl derivatives such as bistyrylanthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, fluorene derivatives, benzofluorene derivatives, N-phenylcarbazole derivatives, and carbazolenitrile derivatives.

[0533] From the viewpoint of promoting rather than hindering the generation of TADF in the light-emitting layer, it is preferred that the triplet energy of the host material is higher than the triplet energy of the dopant or auxiliary 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 further preferably 0.1 eV or more. In addition, TADF-active compounds may also be used in the host material.

[0534] 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.

[0535] The polycyclic aromatic compound of the present invention can be preferably used as a host material. The polycyclic aromatic compound of the present invention can be used alone, as a hole transport host material, or as an electron transport host material. The polycyclic aromatic compound of the present invention is particularly preferably used as an electron transport host material.

[0536] [Hole-transporting host material (HH) and electron-transporting host material (EH)]

[0537] The hole transporting host material (HH) and the electron transporting host material (EH) satisfy the following relationship with respect to the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).

[0538] The HOMO of the hole-transporting host material (HH) is shallower than the HOMO of the electron-transporting host material (EH), and the LUMO of the electron-transporting host material (EH) is deeper than the LUMO of the hole-transporting host material (HH).

[0539] In addition, it is preferred that the HOMO of the emissive dopant is shallower than the HOMO of the hole-transporting host material (HH), or the LUMO of the emissive dopant is deeper than the LUMO of the electron-transporting host material (EH).

[0540] In addition, from the viewpoint of promoting rather than inhibiting the generation of TADF in the light-emitting layer, the lowest excited triplet level (E T1 ) is higher than the highest E T1 The E of the emitting dopant or auxiliary dopant T1 Specifically, the E of the main material T1 Preferably, the E of the emitting dopant or the auxiliary dopant is T1 It is higher by 0.01 eV or more, more preferably higher by 0.03 eV or more, and even more preferably higher by 0.1 eV or more. T1 It is preferably 2.47 eV or more, more preferably 2.49 eV or more, and further preferably 2.56 eV or more.

[0541] In addition, it is also preferred to use a hole transporting host material in the hole transport layer adjacent to the light-emitting layer, and to use an electron transporting host material in the electron transport layer adjacent to the light-emitting layer. This is because it is not easy to cause carrier leakage and energy leakage from the light-emitting layer to the adjacent layer, and a highly efficient organic EL element can be obtained. The host material (hole transporting host material) in the light-emitting layer may be the same as or different from the hole transport layer material. In addition, the host material (electron transporting host material) in the light-emitting layer may be the same as or different from the material of the electron transport layer.

[0542] The hole-transporting host material and the electron-transporting host material that can be used together with the polycyclic aromatic compound of the present invention are exemplified below.

[0543] [Hole transport host material (HH)]

[0544] Examples of preferred hole transport host materials (HH) include compounds represented by formula (HH-1), or compounds having a partial structure represented by formula (HH-1) and having a structure containing at least three rings selected from the group consisting of an aryl ring and a heteroaryl ring. The compounds preferably do not contain an imine structure (-N=C-; partial structure containing a heteroaryl ring), boron (>B-), and a cyano group (CN).

[0545] [Chemistry 71]

[0546]

[0547] In formula (HH-1),

[0548] Q is >O, >S or >NA H ,

[0549] One carbon atom adjacent to the carbon atom bonded to Q in each of the two phenyl groups in formula (HH-1) may be bonded to each other via L.

[0550] L is a single bond, >O, >S or >C(-A H )2,

[0551] A H is hydrogen, aryl or heteroaryl, and >C(-A H ) The two A's in 2 H Can bond to each other.

[0552] When the hole transport host material includes the structure represented by formula (HH-1) as a partial structure, it may include one of the partial structures, but it is also preferred to include two or more. In the case of including two or more, the two or more partial structures may be the same as or different from each other. The two or more partial structures may be bonded to each other through a single bond, or they may be bonded in a manner that any ring contained in the partial structure is shared, or they may be bonded in a manner that any ring contained in the partial structure is condensed with each other. The partial structure may further have a substituent selected from an aryl group, a heteroaryl group, a diarylamino group, or an aryloxy group.

[0553] The compound represented by the formula (HH-1) or the compound having the partial structure represented by the formula (HH-1) has a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings. The number of rings contained is preferably 6 or more, more preferably 8 or more. In addition, it is preferably 20 or less, more preferably 15 or less, and further preferably 10 or less. The number of rings refers to the number of single rings, and with respect to condensed rings, it is the number obtained by counting the single rings constituting the condensed rings.

[0554] The hole transport host material is preferably a compound comprising 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 condensed polycyclic ring containing phenoxazine or phenothiazine. The hole transport host material may contain one such partial structure, but preferably contains two or more. In the case of containing two or more, the two or more partial structures may be the same or different from each other.

[0555] Specific examples of the hole-transporting host material include the following compounds.

[0556] [Chemistry 72]

[0557]

[0558] [Chemistry 73]

[0559]

[0560] [Chemistry 74]

[0561]

[0562] [Chemistry 75]

[0563]

[0564] [Chemistry 76]

[0565]

[0566] [Chemistry 77]

[0567]

[0568] [Chemistry 78]

[0569]

[0570] [Chemistry 79]

[0571]

[0572] [Chemistry 80]

[0573]

[0574] [Chemistry 81]

[0575]

[0576] [Chemistry 82]

[0577]

[0578] [Chemistry 83]

[0579]

[0580] [Chemistry 84]

[0581]

[0582] Among the above, preferred are 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, and HH-1 -82, HH-1-84~HH-1-89, HH-1-91, HH-1-92, HH-1-106~HH-1-108, and HH-1-109~HH-1-115.

[0583] [Electron transport host material (EH)]

[0584] Examples of electron transport host materials (EH) include compounds represented by formula (EH-1A) to (EH-1D), or compounds having partial structures represented by formula (EH-1A) to (EH-1D) and having a structure comprising at least three rings selected from the group consisting of aryl rings and heteroaryl rings.

[0585] [Chemistry 85]

[0586]

[0587] In Formula (EH-1A) to Formula (EH-1D),

[0588] Ar is a heteroaryl ring containing N═C as a partial structure constituting the ring,

[0589] Z is a single bond, -O-, -S-, or -N(-A E )-,

[0590] The carbon atoms adjacent to the carbon atom bonded to Z and the A atom bonded to Z E Can bond to each other through L,

[0591] L is a single bond, >O, >S or >C(-A E )2,

[0592] A E is an aryl group, a heteroaryl group or a triarylsilyl group. In formula (EH-1C), any one of A E It may be a diarylamino group,

[0593] Two A's bonded to the same atom E can be bonded to each other via L,

[0594] X is C, P or S,

[0595] When X is C, n=2, m=1,

[0596] When X is P, n=3, m=1,

[0597] When X is S, n=2, m=1-2.

[0598] The compounds represented by the formula (EH-1A) to the formula (EH-1D), or the compounds having the partial structures represented by the formula (EH-1A) to the formula (EH-1D), have a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings. The number of rings contained is preferably 4 or more, more preferably 6 or more, and further preferably 8 or more. In addition, it is preferably 20 or less, more preferably 15 or less, and further preferably 10 or less. The number of rings refers to the number as a single ring, and with respect to a condensed ring, it is set to the number obtained by counting the single rings constituting the condensed ring.

[0599] When the electron transport host material includes the structure represented by formula (EH-1A) to formula (EH-1D) as a partial structure, it may include one of the partial structures, but it is also preferred to include two or more. In the case of including two or more, the two or more partial structures may be the same as or different from each other. The two or more partial structures may be bonded to each other by a single bond, or they may be bonded in a manner that any ring contained in the partial structure is shared, or they may be bonded in a manner that any ring contained in the partial structure is condensed with each other. The partial structure may further have a substituent selected from an aryl group, a heteroaryl group, a diarylamino group, or an aryloxy group.

[0600] Specific examples of the electron transporting host material include the following compounds.

[0601] [Chemistry 86]

[0602]

[0603] [Chemistry 87]

[0604]

[0605] [Chemistry 88]

[0606]

[0607] [Chemistry 89]

[0608]

[0609] [Chemistry 90]

[0610]

[0611] [Chemistry 91]

[0612]

[0613] [Chemistry 92]

[0614]

[0615] [Chemistry 93]

[0616]

[0617] [Chemistry 94]

[0618]

[0619] Other preferred examples of electron transport host materials (compounds having a partial structure represented by formula (EH-1)) include polycyclic aromatic compounds represented by the following formula (EH-1b) or polymers of polycyclic aromatic compounds having multiple structures represented by the following formula (EH-1b).

[0620] [Chemistry 95]

[0621]

[0622] In formula (EH-1b),

[0623] R 1 , R 2 , R 3 , R 4 and R 5(hereinafter also referred to as “R 1 ", etc.) are each independently hydrogen or a substituent. The substituent only needs to be a substituent selected from the substituent group Z.

[0624] In formula (EH-1b), X 1 and X 2 Each of the following is independently >NR (amine nitrogen), >O, >C(-R)2, >S or >Se, X 1 and X 2 Different from >C(-R)2,

[0625] The R in the >NR and >C(-R)2 is independently hydrogen or a substituent selected from the substituent group Z, and may be further substituted by an aryl group, a heteroaryl group, an alkyl group or a cycloalkyl group (the above is the second substituent). The R in the >NR and >C(-R)2 may be independently bonded to at least one of the a ring, the b ring and the c ring through a linking group or a single bond.

[0626] Y 1 , Y 2 , Y 3 , Y 4 , Y 5 and Y 6 (hereinafter also referred to as "Y 1 ", etc.) are independently =C(-R)- or =N-(pyridinic nitrogen), at least one of which is =N-(pyridinic nitrogen),

[0627] The R in the ═C(—R)— is independently hydrogen or a substituent selected from the substituent group Z.

[0628] The R 1 , R 2 , R 3 , R 4 and R 5 , and as the Y 1 ~Y 6 Adjacent groups in R of =C(-R)- may bond to each other and form an aryl ring or a heteroaryl ring together with at least one of the a ring, b ring and c ring, and at least one hydrogen in the formed ring may be substituted by an aryl group, a heteroaryl group, a diarylamino group, a diheteroarylamino group, an arylheteroarylamino group, a diarylboryl group (two aryl groups may be bonded via a single bond or a linking group), an alkyl group, a cycloalkyl group, an alkoxy group or an aryloxy group (the above are the first substituents), and at least one hydrogen in these groups may be further substituted by an aryl group, a heteroaryl group, an alkyl group or a cycloalkyl group (the above are the second substituents).

[0629] At least one hydrogen in the compound and structure represented by formula (EH-1b) may be substituted by cyano, halogen or deuterium.

[0630] In formula (EH-1b), R 1 , R 2 , R 3 , R 4 and R 5 are hydrogen, or R 3 and R 4 are hydrogen and are selected from R 1 , R 2 and R 5 Any one or more of the group is a substituent other than hydrogen, and the others are hydrogen. As a substituent, an alkyl group, an aryl group that may be substituted by an alkyl group or a heteroaryl group, a heteroaryl group that may be substituted by an alkyl group or an aryl group, or a diarylamino group that may be substituted by an alkyl group or an aryl group is preferred. At this time, as an alkyl group, an alkyl group having 1 to 6 carbon atoms (methyl, tert-butyl, etc.) is preferred, as an aryl group, a phenyl group or a biphenyl group is preferred, and as a heteroaryl group, a triazine group, a carbazolyl group (2-carbazolyl, 3-carbazolyl, 9-carbazolyl, etc.), a pyrimidinyl group, a pyridyl group, a dibenzofuranyl group or a dibenzothienyl group is preferred. As specific examples, phenyl, biphenyl, diphenyltriazine group, carbazolyltriazine group, monophenylpyrimidinyl group, diphenylpyrimidinyl group, carbazolyltriazine group, pyridyl group, dibenzofuranyl group and dibenzothienyl group can be cited.

[0631] Y 1 etc. are independently =C(-R)- or =N-, and at least one is =N-. 1 ~Y 6 Any of may be =N-. Preferably Y 1 and Y 6 =N-(ring a is a pyrimidine ring), Y 1 or Y 6 =N-(ring a 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 5 =N- (ring b and ring c are pyrimidine rings), Y 1 , Y 3 , Y 4 and Y 6 =N- (ring a is a pyrimidine ring, ring b and ring c are pyridine rings), Y 1 , Y 2 , Y 5 and Y 6 =N- (ring a is a pyrimidine ring, ring b and ring c are pyridine rings), Y 1 ~Y 6 =N- (ring a, ring b and ring c are pyrimidine rings), Y2 or Y 5 =N- (the b ring or the c ring is a pyridine ring).

[0632] In addition to the above arrangement relationship of =N-, it is preferred that X 1 and X 2 is >0, and is preferably a polycyclic aromatic compound including a partial structure represented by any of the following formulae.

[0633] [Chemistry 96]

[0634]

[0635] 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 .

[0636] Specific examples of the polycyclic aromatic compound represented by formula (EH-1b) are shown below.

[0637] [Chemistry 97]

[0638]

[0639] [Chemistry 98]

[0640]

[0641] [Chemistry 99]

[0642]

[0643] [Chemical 100]

[0644]

[0645] [Chemistry 101]

[0646]

[0647] [Chemistry 102]

[0648]

[0649] Among the above, preferred are 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, and EH-1-7. 2. EH-1-90, EH-1-94~EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1- 115. EH-1-117, EH-1-120, EH-1-122, EH-1-123, EH-1-127~EH-1-130.

[0650] [Combination of hole-transporting host material and electron-transporting host material]

[0651] The combination of the hole transporting host material and the electron transporting host material is determined by the HOMO, LUMO and the lowest excited triplet energy level (E T1 ) to select.

[0652] Regarding 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 HOMO (HH) is at least 0.10 eV shallower than HOMO (EH), and LUMO (HH) is at least 0.10 eV deeper than HOMO (EH) is preferably selected, a combination in which HOMO (HH) is at least 0.20 eV shallower than HOMO (EH), and LUMO (HH) is at least 0.20 eV deeper than HOMO (EH) is more preferably selected, and a combination in which HOMO (HH) is at least 0.25 eV shallower than HOMO (EH), and LUMO (HH) is at least 0.25 eV deeper than HOMO (EH) is further preferably selected.

[0653] The hole transporting host material and the electron transporting host material may be a combination of an association body called an exciplex. It is generally known that an exciplex is easily formed between a material having a relatively deep LUMO level and a material having a shallow HOMO level. Regarding the interaction between the hole transporting host material and the electron transporting host material, specifically whether an exciplex is formed, it can be judged in the following manner: a monolayer film containing only the hole transporting host material and the electron transporting host material is formed in the same manner as the formation conditions of the light-emitting layer, and the luminescence spectrum (fluorescence, phosphorescence spectrum) is measured. For the obtained luminescence spectrum, it is compared with the luminescence spectrum displayed by each of the hole transporting host material and the electron transporting host material separately. It can be judged in the following manner: the spectrum of the mixed film containing the hole transporting host material and the electron transporting host material shows a different luminescence wavelength from the spectrum of the film of the hole transporting host material and the spectrum of the film of the electron transporting host material. Specifically, as long as the peak wavelength of the spectrum differs by more than 10nm, it can be used as an indicator.

[0654] As specific examples of the combination of a hole transporting host material and an electron transporting host material that do not form an exciplex, the following combinations can be cited. T1 The physical property values ​​of, in the hole transport host material, preferably a compound having carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolecarbazole and benzoxazinephenoxazine as a partial structure, more preferably a compound having carbazole, dibenzofuran and dibenzothiophene as a partial structure, and further preferably a compound having carbazole as a partial structure. Similarly, in the electron transport host material, preferably a compound having pyridine, triazine, phosphine oxide, benzofuranopyridine and dibenzooxasiloline as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuranopyridine and dibenzooxasiloline as a partial structure, and further preferably a compound having triazine.

[0655] More specifically, the hole transport 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 transport host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-10, EH-1-21~EH-1-25, EH-1-32, EH-1-33, EH-1-51~EH-1-59, EH-1-61, EH-1-71, EH-1-72, EH-1-90, In the group consisting of 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~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.

[0656] As specific examples of the combination of a hole transporting host material and an electron transporting host material that form an exciplex, the following combinations can be cited. T1 The physical property values ​​of, in the hole transport host material, preferably a compound having carbazole, triarylamine, indolecarbazole and benzoxazine-phenoxazine as a partial structure, more preferably a compound having triarylamine, indolecarbazole and benzoxazine-phenoxazine as a partial structure, and further preferably a compound having triarylamine as a partial structure. Similarly, in the electron transport host material, preferably a compound having pyridine, triazine, phosphine oxide and benzofuranopyridine as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuranopyridine and dibenzooxasiloline as a partial structure, and further preferably a compound having phosphine oxide and triazine.

[0657] More specifically, the hole transport 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, HH-1-24 and HH-1-115, and the electron transport 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-1 -51~EH-1-57, EH-1-59, EH-1-66, EH-1-68, EH-1-90, EH-1-94, EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and the group consisting of EH-1-127~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-1-94, 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, compound HH-1-49 and compound EH-1-117, and compound HH-1-115 and compound EH-1-99.

[0658] In addition, for specific combinations of hole-transporting host materials and electron-transporting host materials, please refer to: Organic Electronics (66 (2019) 227-24), Advanced Functional Materials (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 (Journal of Materials Chemistry) Materials Chemistry" (C, 2018, 6, 8784-8792), "Angewandte Chemie International Edition." (2018, 57, 12380-12384), "Advanced Functional Materials" (24, 2014, 3970), "Advanced Materials" (26, 2014, 5684), "Synthetic Metals" (201, 2015, 49), and "Nature Photonics" (16, 212-218 (2022)).

[0659] <Dopant material (Emitting dopant material)>

[0660] As the dopant material, known compounds can be used, and it can be selected from various materials according to the desired luminescent color. Specifically, for example, phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and Condensed ring derivatives such as benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives or stilbenebenzene derivatives such as bisstyrylanthracene derivatives (Japanese Patent Laid-Open No. 1-245087), bisstyrylarylene derivatives (Japanese Patent Laid-Open No. 2-247278), diazabenzodiindene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, isobenzofuran derivatives such as phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7- Coumarin derivatives such as piperidinyl coumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolyl coumarin derivatives, 3-benzimidazolyl coumarin derivatives, 3-benzoxazolyl coumarin derivatives, dicyanomethylene pyran derivatives, dicyanomethylene thiopyran derivatives, polymethine derivatives, cyanine derivatives, oxybenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein Derivatives, pyrylium derivatives, quinolone derivatives, acridine derivatives, oxazine derivatives, phenyl ether derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furanopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, purple ring ketone derivatives, pyrrolopyrrole derivatives, squarylium salt derivatives, purple anthrone derivatives, phenazine derivatives, acridone derivatives, deazotflavin derivatives, fluorene derivatives and benzofluorene derivatives, etc.

[0661] As an emitting dopant material, it is also preferred to use a polycyclic aromatic compound containing boron as described in paragraphs 0097 to 0269 of International Publication No. 2015 / 102118, International Publication No. 2020 / 162600, and Japanese Patent Publication No. 2021-077890. The polycyclic aromatic compound having a boron atom may be a phosphor or a TADF material (thermally active delayed phosphor). The polycyclic aromatic compound having a boron atom is preferably a blue light-emitting compound.

[0662] Preferred examples of the polycyclic aromatic compound containing boron include compounds represented by the following formula (12), formula (13) or formula (14).

[0663] [Chemistry 103]

[0664]

[0665] 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,

[0666] Y is B (boron),

[0667] X 1 , X 2 , X 3 and X 4 are independently >O, >NR, >S or >Se, wherein R of the >NR is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl or a substituted or unsubstituted alkyl, and further, 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,

[0668] R 1 and R 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, a heteroaryl group having 2 to 15 carbon atoms, or a diarylamino group (wherein the aryl group is an aryl group having 6 to 12 carbon atoms),

[0669] Z 1 and Z 2 are independently any substituent selected from the substituent group Z, 1 It can be bonded to the A ring via a linking group or a single bond, 2 It may be bonded to the C ring via a linking group or a single bond, and,

[0670] At least one hydrogen in the compound represented by formula (12) may be substituted by a cyano group, a halogen or a deuterium group.

[0671] When the aryl ring or heteroaryl ring in the ring A, ring B, ring C and ring D of formula (12) is substituted, and Z 1 , Z 2 , substituents selected from the substituent group Z can be listed.

[0672] X in formula (12) 1 , X 2 , X 3 and X 4 Each of them is independently >O, >NR, >S or >Se, and R of the >NR is independently aryl having 6 to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, cycloalkyl having 3 to 12 carbon atoms or alkyl having 1 to 6 carbon atoms.

[0673] In the compound represented by formula (12), from the viewpoint of high TADF property, Z 1 and Z 2Preferably, it is a diphenylamino group which may have a substituent or an N-carbazolyl group which may have a substituent, and more preferably, it is a diphenylamino group which may have a substituent. As the diphenylamino group which may have a substituent, it is preferably an unsubstituted diphenylamino group or a diphenylamino group having at least one alkyl group having 1 to 4 carbon atoms, and more preferably, it is an unsubstituted diphenylamino group or a diphenylamino group having at least one methyl group 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 the A ring, the B ring, the C ring and the D ring is preferably an aryl ring except Z. 1 and Z 2 It has no substituent other than Z, or has only an alkyl group having 1 to 6 carbon atoms as other substituents, and more preferably 1 and Z 2 It has no substituent other than this.

[0674] Examples of the compound represented by formula (12) are shown below.

[0675] [Chemistry 104]

[0676]

[0677] [Chemistry 105]

[0678]

[0679] [Chemistry 106]

[0680]

[0681] [Chemistry 107]

[0682]

[0683] In formula (13) and formula (14),

[0684] A 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B 21 Ring, C 11 Ring and C 31 The rings are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

[0685] Y 11 , Y 21 , Y 31 is B (boron),

[0686] X 11 , X 12 , X 21 , X 22 , X 31 and X32 are independently >O, >NR, >S or >Se, wherein 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 can be connected to A by a linking group or a single bond. 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B 21 Ring, C 11 Ring and / or C 31 Ring bond,

[0687] At least one hydrogen in the compounds represented by formula (13) and formula (14) may be substituted by a cyano group, a halogen or a deuterium group.

[0688] As A in formula (13) and formula (14) 11 Ring, A 21 Ring, A 31 Ring, B 11 Ring, B 21 Ring, C 11 Ring and C 31 When the aryl ring or heteroaryl ring in the ring is substituted, the substituent and Z 1 , Z 2 , substituents selected from the substituent group Z can be listed.

[0689] X in formula (13) and formula (14) 11 , X 12 , X 21 , X 22 , X 31 and X 32 Each of them is independently >O, >NR, >S or >Se, and R of the >NR is independently aryl having 6 to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, cycloalkyl having 3 to 12 carbon atoms or alkyl having 1 to 6 carbon atoms.

[0690] Examples of the compound represented by formula (13) or formula (14) are shown below.

[0691] [Chemistry 108]

[0692]

[0693] [Chemistry 109]

[0694]

[0695] <Assisted dopant (thermally activated delayed phosphor or phosphorescent material)>

[0696] The light-emitting layer also preferably contains an emitting dopant, a host material, and an auxiliary dopant. The auxiliary dopant is preferably a thermally activated delayed fluorescent substance or a phosphorescent material.

[0697] In this embodiment, it is also preferable to use a combination of a hole-transporting host material and an electron-transporting host material as a host, and the polycyclic aromatic compound of the present invention can be preferably used as the electron-transporting host material.

[0698] From the viewpoint of promoting rather than hindering the generation of TADF in the light-emitting layer, the lowest excited triplet energy level E(1, T, Sh) of the main compound obtained from the shoulder peak on the short-wavelength side of the peak of the phosphorescence spectrum is preferably higher than the lowest excited triplet energy levels E(2, T, Sh) and E(3, T, Sh) of the emitting dopant or auxiliary dopant having the highest lowest excited triplet energy level in the light-emitting layer. Specifically, compared with E(2, T, Sh) and E(3, T, Sh), the lowest excited triplet energy level E(1, T, Sh) of the main compound is preferably 0.01 eV or more higher, more preferably 0.03 eV or more higher, and further preferably 0.1 eV or more higher.

[0699] [Thermally activated delayed phosphor]

[0700] The so-called "thermally activated delayed fluorescence" refers to a compound that absorbs thermal energy and undergoes reverse intersystem crossing from the lowest excited triplet state to the lowest excited singlet state, and is radiatively deactivated from the lowest excited singlet state, thereby emitting delayed fluorescence. The so-called "thermally activated delayed fluorescence" also includes the case where a higher-order triplet state is passed during the excitation process from the lowest excited triplet state to the lowest excited singlet state. For example, there are the papers published by Monkman et al. of Durham University (Nature Communications (7: 13680, digital object identifier (DOI) : 10.1038 / ncomms13680)), the papers published by Hosokai et al. of the National Institute of Advanced Industrial Science and Technology (Hosokai et al., Science Advances (Sci. Adv.) (2017; 3: e1603282)), and the papers published by Sato et al. of Kyoto University (Scientific Reports (2017)). 4820, DOI: 10.1038 / s41598-017-05007-7)), and a society paper by Sato et al. of Kyoto University (98th Spring Annual Meeting of the Chemical Society of Japan, publication number: 2I4-15, "Mechanism of high-efficiency luminescence in organic electroluminescence using diazaboranaphthoanthracene (DABNA) as a luminescent molecule," Journal of the Graduate School of Engineering, Kyoto University The present invention relates to a sample containing a target compound, and the target compound is determined to be a "thermally activated delayed fluorescent substance" by observing a slow fluorescent component when the fluorescence lifetime is measured at 300K. Here, the so-called slow fluorescent component refers to a component with a fluorescence lifetime of 0.1 μsec or more. The fluorescence lifetime can be measured, for example, using a fluorescence lifetime measuring apparatus (manufactured by Hamamatsu Photonics Co., Ltd., C11367-01).

[0701] In the light-emitting layer further comprising a "thermally active delayed phosphor" as an auxiliary dopant, the polycyclic aromatic compound containing boron is preferably used as an emitting dopant. That is, the "thermally active delayed phosphor" can function as an auxiliary dopant that assists the light emission of the polycyclic aromatic compound containing boron.

[0702] In this specification, an organic electroluminescent element using a thermally activated delayed phosphor as an assisting dopant may be referred to as a "TAF element" (TADF Assisting Fluorescence element).

[0703] The so-called "host compound" in the TAF element refers to a compound whose lowest excited singlet energy level obtained from the shoulder peak on the short-wavelength side of the peak of the fluorescence spectrum is higher than the lowest excited singlet energy level of the thermally active delayed phosphor as an auxiliary dopant and the emitting dopant.

[0704] The thermally active delayed phosphor (TADF compound) used in the TAF element is preferably the following donor-acceptor type thermally active delayed phosphor (DA-type TADF compound): it is designed to use an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to localize the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the molecule to produce efficient reverse intersystem crossing.

[0705] Here, in this specification, the so-called "electron donating substituent" (donor) refers to the substituent and partial structure locally present at HOMO in the thermally active delayed phosphor molecule, and the so-called "electron accepting substituent" (acceptor) refers to the substituent and partial structure locally present at LUMO in the thermally active delayed phosphor molecule.

[0706] Generally speaking, due to the structure of the thermally activated delayed fluorescent material using donors or acceptors, the spin orbit coupling (SOC) is large, and the exchange interaction between HOMO and LUMO is small, so ΔE S1T1Small, so a very fast reverse intersystem crossing speed can be obtained. By using the polycyclic aromatic compound containing boron as an emitting dopant and using a thermally active delayed phosphor (TADF material) as an auxiliary dopant, an element that satisfies any one or all of high efficiency, high color purity and long life can be provided. The thermally active delayed phosphor can be a compound whose luminescence spectrum overlaps at least part of the absorption spectrum of the emitting dopant. The emitting dopant and the thermally active delayed phosphor can be both contained in the same layer, or in adjacent layers or other adjacent layers.

[0707] As the thermally active 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 the electron-accepting group (acceptor structure) used in the thermally active delayed phosphor of the present invention, for example, the structure described in "Chemistry of Materials" (2017, 29, 1946-1963) can be used. Examples of the donor structure include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothiophenocarbazole, phenyldihydroindolecarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazole-based amine, tetraphenylcarbazole-based diamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridine diamine, tetramethyl-dihydro-indenoacridine and diphenyl-dihydrodibenzazasilin, etc. Examples of the acceptor structure include sulfonyldiphenyl, benzophenone, phenylenebis(phenyl ketone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, terephthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthrone, anthracene dione, 5H-cycloheptyl[1,2-b:5,4-b′]bipyridine, fluorene dicarbonitrile, triphenyltriazine, pyrazine dicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridine dicarbonitrile, dibenzoquinoxaline dicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thianthracene tetraoxide, and tri(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence in the TAF element is preferably a compound having at least one selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenyl sulfone, triazole, oxadiazole, thiadiazole and benzophenone as a partial structure.

[0708] The compound used as an auxiliary dopant of the light-emitting layer in the TAF element is a thermally active delayed phosphor, and preferably a compound whose emission spectrum overlaps at least partially with the absorption peak of the emitting dopant. The following is an example of a compound that can be used as the second component (thermally active delayed phosphor) of the light-emitting layer in the TAF element. However, the compound that can be used as a thermally active delayed phosphor in the TAF element is not to be interpreted in a limiting sense by the following example compounds.

[0709] [Chemistry 110]

[0710]

[0711] [Chemistry 111]

[0712]

[0713] [Chemistry 112]

[0714]

[0715] [Chemistry 113]

[0716]

[0717] [Chemistry 114]

[0718]

[0719]

[0720] Furthermore, as the thermally activated delayed phosphor, a compound represented by any one of the following formula (AD1), formula (AD2), and formula (AD3) may be used.

[0721] [Chemistry 115]

[0722]

[0723] In the formula (AD1), formula (AD2) and formula (AD3), M is independently a single bond, -O-, >N-Ar or >CAr2, and is preferably a single bond, -O- or >N-Ar from the viewpoint of the depth of the HOMO of the partial structure formed and the height of the lowest excited singlet energy level and the lowest excited triplet energy level. J is a spacer structure that separates the donor partial structure from the acceptor partial structure, and is independently an arylene group having 6 to 18 carbon atoms, and is preferably an arylene group having 6 to 12 carbon atoms from the viewpoint of the size of the conjugation that oozes out from the donor partial structure and the acceptor partial structure. More specifically, phenylene, methylphenylene and dimethylphenylene can be listed. Q is independently =C(-H)- or =N-, and is preferably =N- from the viewpoint of the shallowness of the LUMO of the partial structure formed and the height of the lowest excited singlet energy level and the lowest excited triplet energy level. Ar is independently hydrogen, an aryl group having 6 to 24 carbon atoms, a heteroaryl group having 2 to 24 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 3 to 18 carbon atoms. From the viewpoint of the depth of the HOMO of the partial structure formed and the height of the lowest excited singlet energy level and the lowest excited triplet energy level, preferably hydrogen, an aryl group having 6 to 12 carbon atoms, a heteroaryl group having 2 to 14 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms, more preferably hydrogen, phenyl, tolyl, xylyl, mesityl, biphenyl, pyridyl, bipyridyl, triazine, carbazolyl, dimethylcarbazolyl, di-tert-butylcarbazolyl, benzimidazolyl, or phenylbenzimidazolyl, and further preferably hydrogen, phenyl, or carbazolyl. m is 1 or 2. n is an integer of (6-m) or less, and from the viewpoint of steric hindrance, preferably an integer of 4 to (6-m). Furthermore, at least one hydrogen atom in the compounds represented by the above formulae may be substituted by a halogen or deuterium.

[0724] More specifically, the compound used as the second component of this embodiment is preferably 4CzBN, 4CzBN-Ph, 5CzBN, 3Cz2DPhCzBN, 4CzIPN, 2PXZ-TAZ, Cz-TRZ3, BDPCC-TPTA, MA-TA, PA-TA, FA-TA, PXZ-TRZ, DMAC-TRZ, BCzT, DCzTrz, DDCzTRz, spiroAC-TRZ, Ac-HPM, Ac-PPM, Ac-MPM, TCzTrz, TmCzTrz and DCzmCzTrz.

[0725] The compound used as the second component of this embodiment can be a donor-acceptor type TADF compound represented by DA in which a donor D is directly bonded to an acceptor A or is bonded via a linking group. The compound having a structure represented by the following formula (DAD1) in which multiple donors D are directly bonded to an acceptor A or are bonded via a linking group is a compound with better characteristics of the organic electroluminescent element and is therefore preferred.

[0726] (D 1 -L 1 )n 1 (DAD1)

[0727] Formula (DAD1) includes a compound represented by the following formula (DAD2).

[0728] D 2 -L 2 -A 2 -L 3 -D 3 (DAD2)

[0729] In formula (DAD1) and formula (DAD2), D 1 , D 2 and D 3 Each independently represents a donor group. As the donor group, the above-mentioned donor structure can be adopted. 1 and A 2 Each independently represents an acceptor group. As the acceptor group, the above-mentioned acceptor structure can be adopted. 1 , L 2 and L 3 Each independently represents a single bond or a conjugated linking group. The conjugated linking group is a spacer structure that separates the donor group and the acceptor group, and is preferably an arylene group having 6 to 18 carbon atoms, and more preferably an arylene group having 6 to 12 carbon atoms. 1 , L 2 and L 3 Furthermore, it is preferred that each is independently phenylene, methylphenylene or dimethylphenylene. In formula (DAD1), n ​​is 2 or more and represents an integer less than the maximum number of substitutions that can be made by A1. n can be selected, for example, in the range of 2 to 10, or in the range of 2 to 6. When n is 2, it is a compound represented by formula (DAD2). n D 1 Can be the same or different, n L 1 Preferred specific examples of the compounds represented by formula (DAD1) and formula (DAD2) include 2PXZ-TAZ and the following compounds, but the second component that can be used in the present invention is not limited to these compounds.

[0730] [Chemistry 116]

[0731]

[0732] [Phosphorescent materials (auxiliary dopants)]

[0733] In the light-emitting layer, a phosphorescent material can be used as an auxiliary dopant. In this specification, an organic electroluminescent element using a phosphorescent material as an auxiliary dopant is sometimes referred to as a phosphorescent auxiliary element: a phosphor-sensitized fluorescent element, a PSF element. Phosphorescent materials utilize the intramolecular spin-orbit interaction (heavy atom effect) caused by metal atoms to obtain light emission from an excited triplet state. As such a phosphorescent material, for example, a luminescent metal complex can be used. As the luminescent metal complex, for example, compounds represented by the following formula (B-1) and the following formula (B-2) can be listed.

[0734] [Chemistry 117]

[0735]

[0736] 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 "XY" are each independently a bidentate ligand.

[0737] 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.

[0738] In formula (B-1), M is preferably Ir and n is preferably 3 from the viewpoint of efficiency and life.

[0739] In formula (B-2), M is preferably Pt from the viewpoint of efficiency and life.

[0740] 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: as a part thereof.

[0741] [Chemistry 118]

[0742]

[0743] In the formula,

[0744] It is bonded to the central metal M at ---,

[0745] Y is independently BR e NR e , PR e,O,S,Se,C=O,S=O,SO2,CR e R f 、SiR e R f , or GeR e R f ,

[0746] The aromatic carbon CH in the ring can be substituted with N independently.

[0747] R e and R f Can be condensed or bonded to form a ring,

[0748] R a , R b , R c and R d Each independently is unsubstituted or substituted to a range from 1 to the maximum number of substitutions possible,

[0749] R a , R b , R c , R d , R e , and R f are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, thiol or a combination thereof,

[0750] Among them, R a , R b , R c , and R d Any two adjacent substituents in the group may be condensed or bonded to form a ring, or may form a multidentate ligand.

[0751] 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)(fac-tris(2-(3-p-xylyl)phenyl)pyridinium(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.

[0752] Examples of the compound represented by formula (B-1) include the following compounds in addition to the above.

[0753] [Chemistry 119]

[0754]

[0755] [Chemistry 120]

[0756]

[0757] [Chemistry 121]

[0758]

[0759] In addition, iridium complexes described in Japanese Patent Laid-Open No. 2006-089398, Japanese Patent Laid-Open No. 2006-080419, Japanese Patent Laid-Open No. 2005-298483, Japanese Patent Laid-Open No. 2005-097263, and Japanese Patent Laid-Open No. 2004-111379, U.S. Patent Application Publication No. 2019 / 0051845, or Advanced Materials (26: 7116-7121), Nature Asia Materials (NPG Asia Materials) (13, 53 (2021)), Applied Physics Letters (Applied Physics Letters) (117, 253301 (2020)), Light-Emitting Diode-An Outlook On the Empirical Features and Its Recent Technological Progress Outlook (Light-Emitting Diode-An Outlook On the Empirical Features and Its Recent Technological Progress Outlook) can also be used. The platinum complex described in "Technological Advances" (Chapter 5).

[0760] 3-6. Electron injection layer and electron transport layer in organic electroluminescent elements

[0761] The electron injection layer 107 plays a role of efficiently injecting electrons migrated 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 respectively formed by stacking or mixing one or more electron transport / injection materials, or are formed by a mixture of an electron transport / injection material and a polymer binder.

[0762] The so-called electron injection / transport layer is a layer responsible for injecting electrons from the cathode and then transmitting electrons, and it is desirable that the electron injection efficiency is high and the injected electrons are transmitted efficiently. Therefore, it is preferably a material with large electron affinity, large electron mobility, excellent stability, and impurities that are not easy to produce when manufacturing and using it. However, considering the transmission balance of holes and electrons, in the case of mainly playing the role of efficiently preventing the holes from the anode from being recombined and flowing to the cathode side, even if the electron transmission ability is not so high, it has the effect of improving luminous efficiency equally with the material with high electron transmission ability. Therefore, the electron injection / transport layer in the present embodiment may also include the function of the layer that can efficiently prevent the migration of holes.

[0763] As the material (electron transport material) forming the electron transport layer 106 or the electron injection layer 107, any compound conventionally used as an electron transfer compound in a photoconductive material, or a known compound used in an electron injection layer and an electron transport layer of an organic EL element can be selected and used. It is also preferred to use the polycyclic aromatic compound of the present invention as a material for the electron transport layer.

[0764] As the material used in the electron transport layer or the electron injection layer, it is preferably containing at least one selected from the following compounds: a compound containing an aromatic ring or heteroaromatic ring containing one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus; a pyrrole derivative and its condensed ring derivative; and a metal complex with electron-accepting nitrogen. Specifically, it can be listed: condensed ring aromatic ring derivatives such as naphthalene and anthracene, styrene aromatic ring derivatives represented by 4,4'-bis(diphenylvinyl)biphenyl, purple ring ketone derivatives, coumarin derivatives, naphthalene dicarboximide derivatives, quinone derivatives such as anthraquinone or diphenylquinone, phosphorus oxide derivatives, aromatic nitrile derivatives and indole derivatives. As a metal complex with electron-accepting nitrogen, for example, hydroxyl azole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes and benzoquinoline metal complexes can be listed. These materials can be used alone or mixed with different materials.

[0765] In addition, specific examples of other electron transfer compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perirone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (1,3-bis[(4-tert-butylphenyl)1,3,4-oxadiazolyl]phenylene, etc.), thiophene derivatives, triazole derivatives (N-naphthyl-2,5-diphenyl-1,3,4-triazole, etc.), thiadiazole derivatives, metal complexes of 8-hydroxyquinoline derivatives, hydroxyquinoline metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzoazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, Biologicals, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spirobifluorene, etc.), imidazopyridine derivatives, borane derivatives, benzimidazole derivatives (tris(N-phenylbenzimidazol-2-yl)benzene, etc.), benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(2,2':6',2"-terpyridine-4'-yl)benzene, etc.), naphthyridine derivatives (bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphorus oxide derivatives, bisphenylvinyl derivatives, etc.

[0766] In addition, metal complexes having electron-accepting nitrogen can also be used, examples of which include hydroxyquinoline metal complexes, hydroxyoxazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

[0767] The materials can be used alone or in combination with different materials.

[0768] Among the above materials, preferred are borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, aromatic nitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and hydroxyquinoline metal complexes.

[0769] The electron transport layer or the electron injection layer may further contain a substance that can reduce the material forming the electron transport layer or the electron injection layer. The reducing substance may be a variety of substances as long as it has a certain reducing property, 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 preferably used.

[0770] As preferred reducing substances, alkali metals such as Na (work function 2.36eV), K (work function 2.28eV), Rb (work function 2.16eV) or Cs (work function 1.95eV) or alkaline earth metals such as Ca (work function 2.9eV), Sr (work function 2.0eV~2.5eV) or Ba (work function 2.52eV) can be listed, and substances with a work function of 2.9eV or less are particularly preferred. Among these, the more preferred reducing substances are alkali metals of K, Rb or Cs, and more preferably Rb or Cs, and most preferably Cs. The reducing ability of these alkali metals is particularly high. By adding a relatively small amount of the alkali metal to the material forming the electron transport layer or the electron injection layer, the luminous brightness in the organic EL element can be improved or the life can be prolonged. In addition, as the 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 a combination containing Cs is particularly preferred, such as a combination of Cs and Na, Cs and K, Cs and Rb, or Cs and Na and K. By including Cs, the reducing ability can be efficiently exerted, and by adding it to the material forming the electron transport layer or the electron injection layer, the luminance of the light emission in the organic EL element can be improved or the life can be prolonged.

[0771] 3-7. Cathode in organic electroluminescent element

[0772] The cathode 108 plays a role of injecting electrons into the light-emitting layer 105 via the electron injection layer 107 and the electron transport layer 106 .

[0773] As the material forming the cathode 108, if it is a substance that can inject electrons into the organic layer with good efficiency, it is not particularly limited, and the same material as the material forming the anode 102 can be used. Among them, preferably metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium and magnesium or their alloys (magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy such as lithium fluoride / aluminum, etc.) and the like. In order to improve the electron injection efficiency to improve the device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium or alloys containing these low work function metals are effective. However, generally speaking, these low work function metals are unstable in the atmosphere in most cases. In order to improve this point, it is known that there is a method of doping a trace amount of lithium, cesium or magnesium into the organic layer and using an electrode with high stability. As other dopants, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. Among them, it is not limited to these.

[0774] Furthermore, the following are preferred examples: in order to protect the electrode, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys of these metals, inorganic substances such as silicon dioxide, titanium dioxide and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon polymer compounds, etc. are stacked. The method for making these electrodes is not particularly limited as long as it is a method that can achieve conduction such as resistance heating, electron beam evaporation, sputtering, ion plating and coating.

[0775] 3-8. Method for producing an organic electroluminescent element

[0776] Each layer constituting the organic EL element can be formed by making the material to constitute each layer into a thin film using a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular stacking, printing, spin coating, casting, coating, etc. The film thickness of each layer formed in the above manner is not particularly limited and can be appropriately set according to the properties of the material, but is generally in the range of 2nm to 5000nm. The film thickness can generally be measured using a quartz oscillation film thickness measuring device or the like. When using the vapor deposition method for thin film formation, the vapor deposition conditions vary depending on the type of material, the target crystal structure and association structure of the film, etc. The vapor deposition conditions are generally preferably a boat heating temperature of +50°C to +400°C and a vacuum degree of 10 -6 Pa~10 -3 Pa, the vapor deposition rate is 0.01 nm / sec to 50 nm / sec, the substrate temperature is -150°C to +300°C, and the film thickness is appropriately set within the range of 2 nm to 5 μm.

[0777] When a direct current voltage is applied to the organic EL element obtained in the above manner, it can be applied with the anode as + polarity and the cathode as - polarity. If a voltage of about 2V to 40V is applied, light emission can be observed from the transparent or translucent electrode side (anode or cathode, or both). In addition, the organic EL element also emits light when a pulse current or an alternating current is applied. In addition, the waveform of the applied alternating current can be arbitrary.

[0778] Next, as an example of a method for producing an organic EL element, a method for producing an organic EL element including anode / hole injection layer / hole transport layer / light-emitting layer including a host material and a dopant material / electron transport layer / electron injection layer / cathode is described.

[0779] <Evaporation method>

[0780] On a suitable substrate, a thin film of an anode material is formed by a vapor deposition method to make an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. The main material and the dopant material are co-evaporated on the thin film to form a thin film as a light-emitting layer, and an electron transport layer and an electron injection layer are formed on the light-emitting layer, and then a thin film containing a cathode material is formed by a vapor deposition method as a cathode, thereby obtaining a target organic EL element. In addition, in the production of the organic EL element, the production order can also be reversed, and the cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, anode are produced in the order of cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, anode.

[0781] <Wet film forming method>

[0782] A low molecular weight compound capable of forming each organic layer of an organic EL element is prepared as a liquid organic layer-forming composition, and the composition is used to perform a wet film-forming method. In the absence of an appropriate organic solvent for dissolving the low molecular weight compound, the organic layer-forming composition may be prepared from a high molecular weight compound or the like, wherein the high molecular weight compound is polymerized together with other monomers or main chain polymers having a solubility function as a reactive compound substituted with a reactive substituent in the low molecular weight compound.

[0783] The wet film forming method generally forms a coating film by passing through the following process, wherein the process is a coating process of applying an organic layer forming composition on a substrate and a drying process of removing a solvent from the coated organic layer forming composition. In the case where the polymer compound has a cross-linking substituent (also referred to as a cross-linking polymer compound), the drying process is further cross-linked to form a polymer cross-linked body. Depending on the coating process, the method using a spin coater is called a spin coating method, the method using a slit coater is called a slit coating method, the method using a plate is called a gravure, lithography, reverse lithography, flexographic printing method, the method using an inkjet printer is called an inkjet method, and the method of blowing with a mist is called a spray method. There are methods such as air drying, heating, and reduced pressure drying in the drying process. The drying process can be performed only once, or it can be performed multiple times using different methods or conditions. In addition, for example, different methods can also be used, such as calcination under reduced pressure.

[0784] The wet film forming method refers to a film forming method using a solution, such as a partial printing method (inkjet method), a spin coating method or a casting method, a coating method, etc. The wet film forming method is different from the vacuum evaporation method in that it does not require the use of an expensive vacuum evaporation device and can be formed under atmospheric pressure. In addition, the wet film forming method can be large-scale or continuously produced, thereby reducing manufacturing costs.

[0785] On the other hand, compared with the vacuum evaporation method, the wet film forming method is sometimes difficult to laminate. When using the wet film forming method to make a laminated film, it is necessary to prevent the dissolution of the lower layer caused by the composition of the upper layer, and use a composition with controlled solubility, crosslinking of the lower layer, and an orthogonal solvent (orthogonal solvent, mutually insoluble solvent) etc. However, there are cases where it is difficult to use the wet film forming method for coating all films even if these technologies are used.

[0786] Therefore, a method is generally adopted in which only some layers are formed by a wet film-forming method and the remaining layers are formed by a vacuum deposition method to produce an organic EL element.

[0787] For example, the following shows a part of the procedure for manufacturing an organic EL element by applying the wet film formation method.

[0788] (Procedure 1) Anode film formation by vacuum deposition method

[0789] (Procedure 2) Film formation of a hole injection layer-forming composition containing a hole injection layer material by a wet film formation method

[0790] (Procedure 3) Film formation of a hole transport layer-forming composition containing a hole transport layer material by a wet film formation method

[0791] (Procedure 4) Film formation of a composition for forming a light-emitting layer containing a host material and a dopant material by a wet film formation method

[0792] (Procedure 5) Film formation of electron transport layer by vacuum deposition method

[0793] (Procedure 6) Film formation of electron injection layer by vacuum deposition method

[0794] (Procedure 7) Cathode film formation by vacuum deposition method

[0795] By going through the above process, an organic EL element including anode / hole injection layer / hole transport layer / light-emitting layer including a host material and a dopant material / electron transport layer / electron injection layer / cathode can be obtained.

[0796] Of course, for the electron transport layer and the electron injection layer, a layer-forming composition containing an electron transport layer material and an electron injection layer material can also be used to form a film by a wet film-forming method. In this case, it is preferred to use a method that prevents the lower light-emitting layer from dissolving, or a method of forming a film from the cathode side in the opposite manner to the above procedure.

[0797] <Other film forming methods>

[0798] Laser heating drawing method (Laser Induced Thermal Imaging (LITI)) can be used for film formation of the organic layer-forming composition. LITI refers to a method of heating and evaporating a compound attached to a substrate using a laser, and the organic layer-forming composition can be used in the material coated on the substrate.

[0799] <Optional process>

[0800] Before and after each film forming step, appropriate treatment steps, cleaning steps and drying steps may be appropriately added. Examples of treatment steps include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent and heating treatment. Furthermore, a series of steps for making a bank may be mentioned.

[0801] Photolithography can be used in the production of the bank. As the bank material that can be photolithographically processed, positive resist materials and negative resist materials can be used. In addition, printing methods that can be patterned, such as inkjet printing, gravure lithography, reverse lithography, and screen printing, can also be used. At this time, a permanent resist material can also be used.

[0802] <Organic layer forming composition used in wet film forming method>

[0803] The composition for forming an organic layer is obtained by dissolving a low molecular compound that can form each organic layer of an organic EL element, or a high molecular compound obtained by polymerizing the low molecular compound, in an organic solvent. For example, the composition for forming a luminescent layer contains at least one dopant material, i.e., a polycyclic aromatic compound (or its high molecular compound) as a first component, at least one main material as a second component, and at least one organic solvent as a third component. The first component functions as a dopant component of the luminescent layer obtained from the composition, and the second component functions as a main component of the luminescent layer. The third component functions as a solvent that dissolves the first component and the second component in the composition, and provides a smooth and uniform surface shape by using the controlled evaporation rate of the third component itself during coating.

[0804] <Organic solvent>

[0805] The organic layer forming composition comprises at least one organic solvent. By controlling the evaporation rate of the organic solvent during film formation, the film forming property and the presence or absence of defects, surface roughness, and smoothness of the coating film can be controlled and improved. In addition, when using the inkjet method for film formation, the stability of the meniscus at the pinhole of the inkjet head can be controlled, and the ejection property can be controlled / improved. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, the electrical properties, luminescent properties, efficiency, and life of the organic EL element having the organic layer obtained by the organic layer forming composition can be improved.

[0806] The organic solvent is removed from the coating by drying processes such as vacuum, decompression, heating, etc. after film formation. When heating, from the perspective of improving the coating film-forming property, it is preferably carried out below the glass transition temperature (Tg) of at least one of the solutes + 30 ° C. In addition, from the perspective of reducing the residual solvent, it is preferably heated above the glass transition temperature (Tg) of at least one of the solutes -30 ° C. Even if the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is also fully removed because the film is thin. In addition, it can be dried multiple times at different temperatures, and a variety of drying methods can also be used in combination.

[0807] (2) Specific examples of organic solvents

[0808] As the organic solvent used in the composition for forming the organic layer, 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 can be cited, but are not limited thereto. In addition, the solvents can be used alone or in combination.

[0809] <Optional ingredients>

[0810] The composition for forming an organic layer may contain an optional component within a range that does not impair its properties. Examples of the optional component include a binder and a surfactant.

[0811] <Composition and physical properties of the organic layer-forming composition>

[0812] The content of each component in the organic layer forming composition is determined from the viewpoints of good solubility, storage stability and film-forming properties of each component in the organic layer forming composition, high-quality film quality of the coating obtained from the organic layer forming composition, good ejection properties when using an inkjet method, and good electrical properties, luminescent properties, efficiency and life of an organic EL element having an organic layer made using the composition.

[0813] The composition for forming an organic layer can be prepared by appropriately selecting the components and stirring, mixing, heating, cooling, dissolving, dispersing, etc. by known methods. In addition, filtering, degassing (also called degassing), ion exchange treatment, and inert gas replacement / sealing treatment can also be appropriately selected after preparation.

[0814] <Application examples of organic electroluminescent elements>

[0815] Furthermore, the present invention can also be applied to a display device including an organic EL element, a lighting device including an organic EL element, or the like.

[0816] A display device or lighting device including an organic EL element can be manufactured by a known method such as connecting the organic EL element of this embodiment to a known driving device, and can be driven using a known driving method such as DC driving, pulse driving, AC driving, etc. as appropriate.

[0817] As display devices, for example, panel displays such as color flat panel displays, flexible displays such as flexible color organic electroluminescent (EL) displays, etc. (for example, refer to Japanese Patent Laid-Open No. 10-335066, Japanese Patent Laid-Open No. 2003-321546, Japanese Patent Laid-Open No. 2004-281086, etc.). In addition, as display modes of displays, for example, matrix modes and segment modes can be listed. In addition, matrix display and segment display can coexist in the same panel.

[0818] In a matrix, pixels for display are arranged two-dimensionally in a grid or mosaic shape, etc., so that text or images are displayed by a collection of pixels. The shape or size of a pixel is determined according to the purpose. For example, in the image and text display of personal computers, monitors, and televisions, quadrilateral pixels with a side of less than 300 μm are usually used. In addition, in the case of large displays such as display screens, pixels with a side of mm are used. In the case of monochrome display, it is sufficient to arrange pixels of the same color. In the case of color display, red, green, and blue pixels are displayed in parallel. In the case, typical ones are triangular and stripe types. Moreover, as a driving method of the matrix, it can be either a line-sequential driving method or an active matrix. Line-sequential driving has the advantage of simple structure, but in the case of considering the operating characteristics, active matrix is ​​sometimes more excellent, so the driving method also needs to be used according to the purpose.

[0819] In the segmented method (type), a pattern is formed in a manner to display predetermined information, and the determined area is illuminated. Examples include: time or temperature display in a digital clock or thermometer, operating status display of audio equipment or induction cookers, and panel display of a car.

[0820] As lighting devices, for example, lighting devices such as indoor lighting, backlight sources of liquid crystal display devices, etc. can be listed (for example, refer to Japanese Patent Publication No. 2003-257621, Japanese Patent Publication No. 2003-277741, Japanese Patent Publication No. 2004-119211, etc.). Backlight sources are mainly used to improve the visibility of display devices that do not emit light by themselves, and are used for liquid crystal display devices, clocks, audio devices, automobile panels, display boards, and logos. In particular, as a backlight source for personal computers where thinning is becoming a problem in liquid crystal display devices, if it is considered that the existing methods are difficult to be thinned due to the inclusion of fluorescent lamps or light guide plates, the backlight source using the light-emitting element of this embodiment has the characteristics of being thin and lightweight.

[0821] 4. Other organic devices

[0822] The polycyclic aromatic compound of the present invention can be used not only in the organic electroluminescent element, but also in the preparation of organic field effect transistors or organic thin film solar cells.

[0823] [Example]

[0824] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0825] <<Synthesis example>>

[0826] Synthesis example (1):

[0827] Synthesis of compound (1-1)

[0828] [Chemistry 122]

[0829]

[0830] Under nitrogen atmosphere, 1.6M tert-butyl lithium pentane solution (1.6 ml) was added to a flask containing compound (S-1-1) (0.72 g) and tert-butylbenzene (7.0 ml) at -30°C. After the addition was completed, the temperature was raised to 60°C and stirred for 2 hours, and the components with a boiling point lower than that of tert-butylbenzene were distilled off under reduced pressure. The mixture was cooled to -30°C and added with boron tribromide (0.63 g), and the temperature was raised to room temperature and stirred for 0.5 hours. Thereafter, the mixture was cooled to 0°C again and N,N-diisopropylethylamine (0.43 ml) was added, and the mixture was stirred at room temperature until the heat subsided, and then the temperature was raised to 120°C and heated and stirred for 3 hours. The reaction solution was cooled to room temperature, and an aqueous sodium acetate solution cooled in an ice bath was added, followed by heptane for separation. After purification using a silica gel short-path column (eluent: toluene), the solvent was distilled off under reduced pressure, and the obtained solid was dissolved in toluene, and heptane was added to cause reprecipitation, thereby obtaining compound (1-1) (0.37 g).

[0831] The following compounds were synthesized by the method according to Synthesis Example (1).

[0832] [Chemistry 123]

[0833]

[0834] [Chemistry 124]

[0835]

[0836] The compounds (1-286) to (1-494) were further synthesized by the method according to Synthesis Example (1).

[0837] The formation of the target product was confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

[0838] [Table 1]

[0839]

[0840]

[0841]

[0842] <<Manufacturing and evaluation of organic EL elements>>

[0843] Using the synthesized compounds of the present invention and comparative compounds, organic EL devices of TAF and PSF were produced.

[0844] <TADF structure: Examples 1-1 to 1-19 and Comparative Example 1-1>

[0845] ITO (50nm) / HAT-CN (10nm) / HT-1 (60nm) / SiCzCz (5nm) / SiCzCz: Compounds listed in Table 2: new-DABNA (60:39:1) (35nm) / mSiTrz (5nm) / mSiTrz: Liq (1:1) (30nm) / LiF (1nm) / Al (100nm)

[0846] A glass substrate of 26 mm × 28 mm × 0.7 mm (manufactured by Opto Science Co., Ltd.) was used as a transparent support substrate. The transparent support substrate was fixed on a substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Vacuum Co., Ltd.), and a molybdenum vapor deposition boat containing HAT-CN, HT-1, SiCzCz, each compound listed in Table 2, new-DABNA, mSiTrz and Liq, and a tungsten vapor deposition boat containing LiF and aluminum, respectively, were installed.

[0847] The following layers were formed in sequence on the ITO film of the transparent supporting substrate. The vacuum chamber was depressurized to 5×10 -4Pa, first, HAT-CN is heated and evaporated in a manner that the film thickness becomes 10nm to form a hole injection layer. Then, HT-1 is heated and evaporated in a manner that the film thickness becomes 60nm to form a hole transport layer 1, and then SiCzCz is heated and evaporated in a manner that the film thickness becomes 5nm to form a hole transport layer 2. Next, SiCzCz, each compound described in Table 2 and new-DABNA are heated simultaneously, and evaporated in a manner that the film thickness becomes 35nm to form a light-emitting layer. The evaporation speed is adjusted in a manner that the mass ratio of SiCzCz, each compound described in Table 2 and new-DABNA becomes approximately 60 to 39 to 1. Next, mSiTrz is heated and evaporated in a manner that the film thickness becomes 5nm to form an electron transport layer 1, and then mSiTrz and Liq are heated and evaporated in a manner that the film thickness becomes 30nm to form an electron transport layer 2. The evaporation rate is adjusted so that the mass ratio of SiTrz to Liq is approximately 1 to 1. The evaporation rate of each layer is 0.01 nm / second to 1 nm / second. Thereafter, LiF is heated and evaporated at a evaporation rate of 0.01 nm / second to 0.1 nm / second so that the film thickness becomes 1 nm, and then aluminum is heated and evaporated in a manner so that the film thickness becomes 100 nm to form a cathode, thereby obtaining an organic EL element. At this time, the evaporation rate of aluminum is adjusted to 1 nm / second to 10 nm / second. In addition, the SiCzCz of the light-emitting layer is equivalent to a hole-transporting main material, and each compound described in Table 2 is equivalent to an electron-transporting main material.

[0848] <TAF structure: Example 2-1 to Example 2-19 and Comparative Example 2-1>

[0849] ITO (50nm) / HAT-CN (10nm) / HT-1 (60nm) / SiCzCz (5nm) / SiCzCz: Compounds listed in Table 2: TADF-1: new-DABNA (60: 26: 13: 1) (35nm) / mSiTrz (5nm) / mSiTrz: Liq (1: 1) (30nm) / LiF (1nm) / Al (100nm)

[0850] Except for the light-emitting layer, the structure was prepared in the same manner as the TADF structure. For the light-emitting layer, SiCzCz, the compounds listed in Table 2, (TADF-1) and new-DABNA were heated simultaneously and evaporated to a film thickness of 35 nm. The evaporation rate was adjusted so that the mass ratio of SiCzCz, the compounds listed in Table 2, (TADF-1) and new-DABNA was approximately 60:26:13:1.

[0851] <PSF structure: Example 3-1 to Example 3-228 and Comparative Example 3-1>

[0852] ITO (50nm) / HAT-CN (10nm) / HT-1 (60nm) / SiCzCz (5nm) / SiCzCz: The compounds listed in Table 2: PtON7: new-DABNA (60: 26: 13: 1) (35nm) / mSiTrz (5nm) / mSiTrz: Liq (1: 1) (30nm) / LiF (1nm) / Al (100nm)

[0853] The TAF structure (TADF-1) was replaced with PtON7, and an element was produced in the same manner.

[0854] The chemical structures of the compounds used in the production of the above-mentioned elements are shown below.

[0855] [Chemistry 125]

[0856]

[0857] [evaluate]

[0858] Evaluation items include driving voltage (V), emission wavelength (nm), Commission Internationale de L'Eclairage (CIE) chromaticity (x, y), external quantum efficiency (%), maximum wavelength (nm) and half-value width (nm) of emission spectrum. These evaluation items can be measured using, for example, 1000 cd / m 2 The value when emitting light.

[0859] The quantum efficiency of a light-emitting element includes internal quantum efficiency and external quantum efficiency. The internal quantum efficiency indicates the proportion of external energy injected into the light-emitting layer of the light-emitting element as electrons (or holes) that is purely converted into photons. On the other hand, the external quantum efficiency is calculated based on the amount of photons released to the outside of the light-emitting element. A portion of the photons generated in the light-emitting layer are absorbed by the inside of the light-emitting element or continuously reflected without being released to the outside of the light-emitting element, so the external quantum efficiency is lower than the internal quantum efficiency.

[0860] The spectral radiance (luminescence spectrum) and external quantum efficiency were measured as follows. A voltage / current generator R6144 manufactured by Advantest was used to apply a voltage so that the device brightness reached 1000 cd / m 2The element emits light by applying a voltage of . Using a spectroradiometer SR-3AR manufactured by TOPCON, the spectral radiance brightness in the visible light region is measured from a direction perpendicular to the light-emitting surface. Assuming that the light-emitting surface is a completely diffuse surface, the value of the spectral radiance brightness of each wavelength component measured is divided by the wavelength energy and multiplied by π to obtain the number of photons at each wavelength. Then, the number of photons is accumulated in the observed full wavelength region and set as the total number of photons released from the element. The value obtained by dividing the applied current value by the elementary charge is set as the number of carriers injected into the element, and the value obtained by dividing the total number of photons released from the element by the number of carriers injected into the element is the external quantum efficiency. In addition, the half-value width of the luminescence spectrum is calculated as the width between the upper and lower wavelengths where the maximum luminescence wavelength is set as the center and its intensity becomes 50%.

[0861] The ITO electrode was used as the anode and the LiF / aluminum electrode was used as the cathode. A DC voltage was applied and the 1000 cd / m 2 Characteristics during light emission. In addition, the time (lifetime) during which the luminance was maintained at 50% or more of the initial luminance was measured. In addition, the light emission peak of each element was in the range of 469 nm to 475 nm.

[0862] Table 2 shows the results.

[0863] [Table 2]

[0864]

[0865]

[0866]

[0867]

[0868]

[0869]

[0870] The obtained results show that the element of the embodiment has higher efficiency and longer life than the element of the comparative example having a corresponding skeleton.

Claims

1. A polycyclic aromatic compound represented by formula (1) and comprising at least one of the partial structures represented by formula (Xa-1) and at least one of the partial structures represented by formula (Xb-1); [Chemistry 1] In formula (1), Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, In formula (Xa-1), X a is C, Si, Ge or Sn, The AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring may be linked to any other of the AR1 ring, AR2 ring, AR3 ring and AR4 ring via a single bond or a linking group. One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or An aryl or heteroaryl ring of ring D, ring E or ring AR5 in formula (Xb-1) that is bonded to ring A, ring B or ring C or that shares any ring with ring A, ring B or ring C is bonded to the ring-constituting atom via a single bond; or Shares a ring with Ring A, Ring B or Ring C; or a ring shared by the ring D, the ring E or the ring AR5 in the formula (Xb-1) that is bonded to the ring A, the ring B or the ring C or that shares any ring with the ring A, the ring B or the ring C, In formula (Xb-1), The D ring and the E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, X b is a divalent group represented by the formula (Xb-R5), >O or >S, [Chemistry 2] In the formula (Xb-R5), The two #s are the bonding positions with the D ring and the E ring respectively. AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and AR5 ring can be linked to D ring and / or E ring by a single bond or a linking group, One or two selected from the group consisting of D ring, E ring and AR5 ring is bonded to an atom of an aryl or heteroaryl ring in Ring A, Ring B or Ring C via a single bond; or An aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) is bonded to the A, B or C ring via a single bond or is bonded to the A, B or C ring in a ring-constituting atom; or Shares a ring with Ring A, Ring B or Ring C; or a ring shared by the AR1 ring, AR2 ring, AR3 ring or AR4 ring in the formula (Xa-1) that is bonded to the A ring, the B ring or the C ring or that shares any ring with the A ring, the B ring or the C ring, In formula (1), at least one hydrogen may be substituted with deuterium, and at least one nitrogen may be substituted with nitrogen-15( 15 N) substituted, at least one sulfur may be replaced by sulfur-33( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36 S), at least one oxygen may be replaced by oxygen-17( 17 O) or oxygen-18 ( 18 O) substituted, at least one carbon may be substituted by carbon-13 ( 13 C) substituted, at least one boron may be substituted by boron-11 ( 11 B) Replacement.

2. The polycyclic aromatic compound according to claim 1, wherein At least one selected from the group consisting of ring AR1, ring AR2, ring AR3 and ring AR4 shares a ring with ring A, ring B or ring C, or shares a ring with ring D, ring E or ring AR5 in formula (Xb-1) to which ring A, ring B or ring C is bonded.

3. The polycyclic aromatic compound according to claim 1, which is represented by formula (1a), formula (1b) or formula (1c), and contains at least one of the partial structures represented by formula (Xa-2) and at least one of the partial structures represented by formula (Xb-2); [Chemistry 3] In formula (1a), formula (1b), formula (1c), formula (Xa-2) and formula (Xb-2), Choose from Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 One or two of the rings is bonded to Z in the a-ring, b-ring or c-ring via a single bond; or Bonded to the d ring, e ring or AR5 ring in the partial structure represented by the formula (Xb-2) to which Z in the a ring, b ring or c ring is bonded; or Shares a ring with ring a, ring b or ring c; or a ring bonded to ring a, ring b or ring c or a ring shared by ring d, ring e or ring AR5 in formula (Xb-2), One or two selected from the group consisting of d ring, e ring and AR5 ring is bonded to Z in the a-ring, b-ring or c-ring via a single bond; or Ar in the partial structure represented by formula (Xa-2) bonded to Z in ring a, ring b or ring c 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 Z bonding in a ring; or Shares a ring with ring a, ring b or ring c; or Ar in formula (Xa-2) that is bonded to ring a, ring b or ring c or shares any ring with ring a, ring b or ring c 1 Ring, Ar 2 Ring, Ar 3 Ring or Ar 4 The ring has a total ring, Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 The ring can be connected to Ar by a single bond or a linking group. 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 Any other link in the ring, Y 1 and Y 2 Each independently is >NR NY 、>C(-R CY )2、>O、>Si(-R IY )2、>S or >Se, R NY , R CY and R IY are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CY Can bond to each other to form a ring, two R IY Can bond to each other to form a ring, Z is a carbon atom having a bond to another ring, or -C(-R Z )=or-N=,R Z is hydrogen or a substituent, wherein, Two adjacent Zs constituting the e ring in formula (Xb-2) may be carbon atoms respectively bonded to the two *s in formula (Xb-2-e). In formula (Xb-2-e), X b is a divalent group represented by the formula (Xb-R5), >O, >C(-R CX )2、>Si(-R IX )2、>S or >Se, R CX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R CX Can bond with each other to form a ring, R IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IX Can bond to each other to form a ring, X b When AR5 is a divalent group represented by the formula (Xb-R5), the ring is a 6-membered ring. The polycyclic aromatic compound according to claim 3, which is represented by formula (1b) or formula (1c).

5. The polycyclic aromatic compound according to claim 3, wherein In formula (Xa-2), X a C, Ge or Sn, Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 No two rings are connected to each other.

6. The polycyclic aromatic compound according to claim 3, wherein In formula (Xa-2), X a is Si, and at least one of Z is -N=.

7. The polycyclic aromatic compound according to claim 3, wherein In formula (Xa-2), X a Si, Ar 1 Ring, Ar 2 Ring, Ar 3 Ring and Ar 4 At least two of the rings are interconnected.

8. The polycyclic aromatic compound according to claim 3, wherein In formula (Xb-2), at least one of Z is -N=.

9. The polycyclic aromatic compound according to claim 3, which is represented by any of the following formulas: [Chemistry 4] [Chemistry 5] 10. The polycyclic aromatic compound according to claim 3, which is represented by any of the following formulas: [Chemistry 7] [Chemistry 8] [Chemistry 9] [Chemistry 10] [Chemistry 11] [Chemistry 12] [Chemistry 13] [Chemistry 14] [Chemistry 15] [Chemistry 16] [Chemistry 17] [Chemistry 18] 11. The polycyclic aromatic compound according to claim 3, which is represented by any of the following formulas: [Chemistry 19] 12 . An organic electroluminescent element comprising: a pair of electrodes including an anode and a cathode; and an organic layer disposed between the pair of electrodes, wherein the organic layer contains the polycyclic aromatic compound according to claim 1 .

13. The organic electroluminescent element according to claim 12, wherein: The organic layer is a light-emitting layer.

14. The organic electroluminescent element according to claim 13, wherein The polycyclic aromatic compound is an electron transport host material, and the light emitting layer further includes a hole transport host material and a dopant material.

15. The organic electroluminescent element according to claim 14, wherein The light-emitting layer further includes at least one selected from the group consisting of a thermally active delayed fluorescent body and a phosphorescent material.

16. A display device or a lighting device, comprising the organic electroluminescent element according to claim 12.

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