JP2023059129A - Polycyclic aromatic compound - Google Patents

Abstract

To provide a novel compound useful as a material for organic devices such as an organic electroluminescent device.SOLUTION: A polycyclic aromatic compound has a structure comprising a structural unit represented by the formula (1A) or the formula (1B) (Z is N or C-RZ, and RZ is H or a substituent; X is >O, >N-RXN, >S or the like; RXN is an aryl or the like; Y bound to adjacent Y via a single bond is >C(-RY1)2; RY1 is an alkyl or the like; adjacent two RY1 may be bound to each other, forming a ring, and Y bound to adjacent Y via a double bond is N or C-RY2; RY2 is H or a substituent; adjacent two RY2 may be bound to each other, forming a ring).SELECTED DRAWING: None

Description

The present invention relates to polycyclic aromatic compounds. The invention particularly relates to polycyclic aromatic compounds containing nitrogen and boron. The present invention also relates to an organic device material, an organic electroluminescence device, a display device and a lighting device containing the polycyclic aromatic compound.

Conventionally, display devices using light-emitting elements that emit electroluminescence have been studied in various ways because they can be reduced in power consumption and thickness. Further, organic electroluminescence elements made of organic materials can be easily reduced in weight and increased in size. has been actively investigated. In particular, the development of organic materials that emit light such as blue, one of the three primary colors of light, and the development of organic materials that have the ability to transport electrons and holes (potentially become semiconductors and superconductors). As for the development, active research has been conducted so far, regardless of whether it is a polymer compound or a low-molecular-weight compound.

An organic electroluminescence device has a structure comprising a pair of electrodes consisting of an anode and a cathode, and one or more layers interposed between the pair of electrodes and containing an organic compound. Layers containing organic compounds include light-emitting layers and charge transport/injection layers that transport or inject charges such as holes and electrons. Various organic materials suitable for these layers have been developed.

Among them, Patent Document 1 discloses that a polycyclic aromatic compound containing boron is useful as a material for an organic electroluminescence device or the like. An organic electroluminescent device containing this polycyclic aromatic compound is reported to have good external quantum efficiency.

WO2015/102118

As described above, various materials have been developed as materials for use in organic EL devices. However, in order to increase options for materials for organic EL devices, development of materials composed of compounds different from conventional ones is desired. there is
An object of the present invention is to provide a novel compound useful as an organic device material such as an organic EL element.

The present inventors have made intensive studies to solve the above problems, and have found that, like the compound described in Patent Document 1, a novel polycyclic aromatic compound containing boron in its structure has more excellent light-emitting properties. succeeded in producing a group compound. Further, the present inventors have found that an excellent organic EL device can be obtained by arranging a layer containing this polycyclic aromatic compound between a pair of electrodes to form an organic EL device, and completed the present invention. That is, the present invention provides the following polycyclic aromatic compounds, organic device materials, etc. containing the following polycyclic aromatic compounds.

<1> A polycyclic aromatic compound having a structure containing a structural unit represented by the following formula (1A) or formula (1B);

In formula (1A) and formula (1B),
each Z is independently N or C—R ^Z and each R ^Z is independently hydrogen or a substituent;
Two adjacent R ^Z may be bonded to each other to form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring together with the a-ring, b-ring or c-ring,
X is >O, >N—R ^xN , >C(—R ^xC ) ₂ , >Si(—R ^XI ) ₂ , >S, or >Se, and R ^xN is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^XC and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, two R ^XC optionally bonded together to form a ring, and two R ^XI bonded together to form a ring; R ^XN , R ^XC , and R ^XI are each bound to at least one of Z adjacent to the carbon to which X is bound by a linking group or single bond,
two adjacent Y bonds are each independently a single bond or a double bond,
Each Y bonded to an adjacent Y by a single bond is independently >C(-R ^Y1 ) ₂ , and each R ^Y1 is independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted Two R ^Y1 which are heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl and are bonded to the same carbon may be combined to form a ring, and two adjacent R ^Y1 may combine with each other to form a ring,
Y bonded to adjacent Y by a double bond is N or C—R ^Y2 , R ^Y2 is hydrogen or a substituent, and two adjacent R ^Y2 are bonded to each other to form a ring; may be used, provided that two adjacent R ^Y2 do not bond to each other to form a benzene ring,
Y and Z may be bonded to each other to further form a ring consisting of Y—N—C—Z or a ring consisting of Y—C—Z,
At least one of the aryl or heteroaryl rings in the structure may be fused with at least one cycloalkane, the cycloalkane may have at least one substituent, and at least one —CH ₂ — may be replaced with —O—,
At least one hydrogen in the structure may be replaced with cyano, halogen, or deuterium.

<2> Z is all CR ^Z ,
each R ^Z is independently hydrogen, any substituent selected from substituent group Z, or a substituent represented by formula (A30);
The polycyclic aromatic compound according to <1>, wherein each R ^Y2 is independently hydrogen, any substituent selected from substituent group Z, or a substituent represented by formula (A30);

In formula (A30),
Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted cycloalkenyl, and at least one —CH ₂ — may be replaced with —O— or —S—;
R ^Ak is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^Ak is bonded to Ak through a single bond or a linking group. * is the binding position,
Substituent group Z is
aryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
heteroaryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
diarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (the two aryls may be bonded to each other via a linking group);
diheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two heteroaryls may be bonded to each other via a linking group) ,
arylheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (aryl and heteroaryl may be ),
diarylboryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (the two aryls may be bonded via a single bond or a linking group);
alkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;
cycloalkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
alkoxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;
It consists of aryloxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl, and substituted silyl.

<3> R ^Z at the para position of B in each of the a ring, the b ring, and the c ring is hydrogen, a substituent selected from the substituent group Z or a substituent represented by the formula (A30); Other polycyclic aromatic compounds according to <2>, wherein R ^Z is hydrogen.
<4> X is >O, >N-R ^xN , >C(-R ^xC ) ₂ , or >S;
The polycyclic aromatic compound according to any one of <1> to <3>, wherein R ^XN is substituted or unsubstituted phenyl and R ^XC is methyl.

<5> The polycyclic aromatic compound according to any one of <1> to <4>, wherein two adjacent Y bonds are both single bonds.

式中、Ｍｅはメチルであり、アリール環は炭素数１～４のアルキルまたは炭素数１～４のアルキルで置換されていてもよいフェニルを置換基として有していてもよく、各式で表される構造中の少なくとも１つの水素は重水素で置き換えられていてもよい。
＜７＞ 隣接する２つのＹの結合がいずれも二重結合である＜１＞～＜４＞のいずれかに記載の多環芳香族化合物。 <6> The polycyclic aromatic compound according to <5>, represented by any one of the following formulas;

In the formula, Me is methyl, and the aryl ring may have alkyl having 1 to 4 carbon atoms or phenyl optionally substituted with alkyl having 1 to 4 carbon atoms as a substituent, and At least one hydrogen in the structure may be replaced with deuterium.
<7> The polycyclic aromatic compound according to any one of <1> to <4>, wherein two adjacent Y bonds are both double bonds.

式中、Ｍｅはメチルであり、アリール環は炭素数１～４のアルキルまたは炭素数１～４のアルキルで置換されていてもよいフェニルを置換基として有していてもよく、各式で表される構造中の少なくとも１つの水素は重水素で置き換えられていてもよい。 <8> The polycyclic aromatic compound according to <7>, represented by any one of the following formulas;

In the formula, Me is methyl, and the aryl ring may have alkyl having 1 to 4 carbon atoms or phenyl optionally substituted with alkyl having 1 to 4 carbon atoms as a substituent, and At least one hydrogen in the structure may be replaced with deuterium.

<9> An organic device material containing the polycyclic aromatic compound according to any one of <1> to <8>.
<10> The polycyclic aromatic compound according to any one of <1> to <8>, which has a pair of electrodes consisting of an anode and a cathode and an organic layer disposed between the pair of electrodes, wherein the organic layer is <1> to <8>. An organic electroluminescence device containing
<11> The organic electroluminescence device according to <10>, wherein the organic layer is a light-emitting layer.
<12> A display device or lighting device comprising the organic electroluminescence device according to <10> or <11>.

INDUSTRIAL APPLICABILITY The present invention provides a novel polycyclic aromatic compound useful as a material for organic devices such as organic electroluminescence elements. The polycyclic aromatic compound of the present invention can be used for producing organic devices such as organic electroluminescence devices.

It is a schematic sectional drawing which shows an example of an organic electroluminescent element. FIG. 3 is an energy level diagram showing the energy relationship between a host, an assisting dopant and an emitting dopant in a TAF device using a general fluorescent dopant. FIG. 2 is an energy level diagram showing an example of the energy relationship among a host, an assisting dopant, and an emitting dopant in an organic electroluminescence device of one embodiment of the present invention.

The present invention will be described in detail below. Although the constituent elements described below may be described based on representative embodiments and specific examples, the present invention is not limited to such embodiments. In the present specification, a numerical range represented by "-" means a range including the numerical values described before and after "-" as lower and upper limits. Further, "hydrogen" in the description of structural formulas in this specification means "hydrogen atom (H)". Similarly, "carbon atom (C)" may be referred to as "carbon".
As used herein, the term "adjacent groups" means two groups respectively bonded to two adjacent atoms (two atoms directly bonded by covalent bonds) in the structural formula.

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

In this specification, chemical structures and substituents are sometimes represented by the number of carbon atoms. It refers to the number of carbon atoms in each group and does not refer to the total number of carbon atoms in the chemical structure and substituents, or the total number of carbon atoms in the substituent and substituents. For example, “substituent B having Y carbon atoms and substituted with substituent A having X carbon atoms” means that “substituent B having Y carbon atoms” is substituted with “substituent A having X carbon atoms”. However, the carbon number Y is not the total carbon number of the substituents A and B. Further, for example, “substituent B having Y carbon atoms and substituted with substituent A” means that “substituent B having Y carbon atoms” is substituted with “substituent A (with no carbon number limitation)”. However, the carbon number Y is not the total carbon number of the substituents A and B.

<Description of Ring and Substituent>
First, the details of the rings and substituents used herein are described below.

As used herein, the "hydrocarbon ring" includes an "aryl ring" described later, as well as a cycloalkane ring and a cycloalkene ring. Specific examples of the cycloalkane ring include a cyclopentane ring and a cyclohexane ring. Specific examples of the cycloalkene ring include cyclopentene ring, cyclohexene ring, 1,3-cyclohexadiene ring and 1,4-cyclohexadiene ring.

The "heterocyclic ring" used herein includes the below-described "heteroaryl ring" as well as non-aromatic heterocyclic rings. Examples of non-aromatic heterocycles include piperidine ring, piperazine ring, morpholine ring and the like.

The "aryl ring" in the present specification includes, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 16 carbon atoms, more preferably an aryl ring having 6 to 12 carbon atoms. Particularly preferred are 6-10 aryl rings.

Specific “aryl rings” include monocyclic benzene ring, bicyclic biphenyl ring, condensed bicyclic naphthalene ring and indene ring, tricyclic terphenyl ring (m-ter phenyl, o-terphenyl, p-terphenyl), condensed tricyclic acenaphthylene ring, fluorene ring, phenalene ring, phenanthrene ring, anthracene ring, condensed tetracyclic triphenylene ring, pyrene ring, naphthacene ring, Examples include a chrysene ring, a condensed pentacyclic perylene ring, and a pentacene ring. The fluorene ring, benzofluorene ring, and indene ring also include structures in which fluorene rings, benzofluorene rings, cyclopentane rings, and the like are spiro-bonded, respectively. In the fluorene ring, benzofluorene ring and indene ring, two of the two hydrogens of methylene in the structure are respectively replaced with alkyl such as methyl as a first substituent described later, resulting in a dimethylfluorene ring, Those having a dimethylbenzofluorene ring, a dimethylindene ring, and the like are also included.

As used herein, the "heteroaryl ring" includes, for example, a heteroaryl ring having 2 to 30 carbon atoms, preferably a heteroaryl ring having 2 to 25 carbon atoms, more preferably a heteroaryl ring having 2 to 20 carbon atoms. A heteroaryl ring having 2 to 15 carbon atoms is more preferable, and a heteroaryl ring having 2 to 10 carbon atoms is particularly preferable. Examples of the "heteroaryl ring" include heterocyclic rings containing 1 to 5 heteroatoms selected from oxygen, sulfur and nitrogen in addition to carbon as ring-constituting atoms.

Specific "heteroaryl rings" include, for example, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, oxadiazole ring, thiadiazole ring, triazole ring, tetrazole ring, pyrazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring, indole ring, isoindole ring, 1H-indazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, 1H-benzotriazole ring, quinoline ring, isoquinoline ring , cinnoline ring, quinazoline ring, quinoxaline ring, phthalazine ring, naphthyridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenoxathiine ring, phenoxazine ring, phenothiazine ring, phenazine ring, phenazacilline ring, indolizine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, furazan ring, thianthrene ring, indolocarbazole ring, benzoindolocarbazole ring, dibenzoindolocarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, dibenzodioxin ring and the like. In the dihydroacridine ring, xanthene ring, and thioxanthene ring, two of the two hydrogens of methylene in the structure are replaced by alkyl such as methyl as the first substituent described below, respectively, to form a dimethyldihydroacridine ring. , dimethylxanthene ring, dimethylthioxanthene ring, etc. are also preferred. Bipyridine ring, phenylpyridine ring and pyridylphenyl ring which are bicyclic ring systems, and terpyridyl ring, bispyridylphenyl ring and pyridylbiphenyl ring which are tricyclic systems are also mentioned as "heteroaryl ring". Moreover, a pyran ring shall also be contained in a "heteroaryl ring."

Substituents herein may be substituted with additional substituents. For example, a particular substituent may be described as "substituted or unsubstituted." This means that the particular substituent may or may not be substituted with at least one further substituent. In the same sense, it may be said to be "optionally substituted". In the present specification, the specific substituent at this time may be referred to as the "first substituent", and the additional substituent may be referred to as the "second substituent".

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

In the present specification, the term "substituent" may be any group selected from the substituent group Z, unless otherwise specified. 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.

As used herein, "aryl" is, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 20 carbon atoms, aryl having 6 to 16 carbon atoms, aryl having 6 to 12 carbon atoms, or Aryl of numbers 6 to 10 and the like.

A specific “aryl” is, for example, a monocyclic phenyl, a bicyclic biphenylyl (2-biphenylyl, 3-biphenylyl, or 4-biphenylyl), a condensed bicyclic naphthyl (1-naphthyl or 2-naphthyl), tricyclic terphenylyl (m-terphenyl-2′-yl, m-terphenyl-4′-yl, m-terphenyl-5′-yl, o-terphenyl-3′- yl, o-terphenyl-4′-yl, p-terphenyl-2′-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o -terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, or p-terphenyl- 4-yl), acenaphthylene-(1-, 3-, 4-, or 5-)yl, fluorene-(1-, 2-, 3-, 4-, or 9-)yl, which is a fused tricyclic system , phenalen-(1- or 2-)yl, phenanthrene-(1-, 2-, 3-, 4-, or 9-)yl, or anthracen-(1-, 2-, or 9-)yl, tetra The ring system quaterphenylyl (5′-phenyl-m-terphenyl-2-yl, 5′-phenyl-m-terphenyl-3-yl, 5′-phenyl-m-terphenyl-4-yl , or m-quaterphenyl), a fused tetracyclic ring system, triphenylene-(1- or 2-)yl, pyren-(1-, 2-, or 4-)yl, or naphthacene-(1-, 2 -, or 5-)yl, or perylene-(1-, 2-, or 3-)yl, or pentacene-(1-, 2-, 5-, or 6-)yl, which is a fused five-ring system and so on. Other examples include a monovalent group of spirofluorene.

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

"Arylene" is, for example, arylene having 6 to 30 carbon atoms, preferably arylene having 6 to 20 carbon atoms, arylene having 6 to 16 carbon atoms, arylene having 6 to 12 carbon atoms, or arylene having 6 to 10 carbon atoms. Arylene and others.
A specific “arylene” is, for example, a divalent group obtained by removing one hydrogen from the above-mentioned “aryl” (monovalent group).

“Heteroaryl” is, for example, heteroaryl having 2 to 30 carbon atoms, preferably heteroaryl having 2 to 25 carbon atoms, heteroaryl having 2 to 20 carbon atoms, heteroaryl having 2 to 15 carbon atoms, or carbon Heteroaryl of numbers 2 to 10 and the like. “Heteroaryl” contains 1 or more, preferably 1 to 5, heteroatoms selected from oxygen, sulfur, nitrogen and the like as ring-constituting atoms in addition to carbon atoms.

Specific examples of "heteroaryl" 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, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, napthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenazacilinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, benzophosphoryl, dibenzophosphoryl , a monovalent group of a benzophosphole oxide ring, a monovalent group of a dibenzophosphole oxide ring, furazanyl, thianthrenyl, indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl, or oxazolinyl and so on. Other examples include a spiro[fluorene-9,9'-xanthene] monovalent group, a spirobi[silafluorene] monovalent group, and a benzoselephene monovalent group.

The heteroaryl as the second substituent includes aryl such as phenyl (specific examples are the groups described above), alkyl such as methyl (specific examples are groups described later), and cyclohexyl or adamantyl. Structures substituted with at least one group selected from the group consisting of alkyl (specific examples are groups described later) are also included.
Examples thereof include groups in which the 9-position of carbazolyl as the second substituent is substituted with aryl such as phenyl, alkyl such as methyl, or cycloalkyl such as cyclohexyl or adamantyl. In addition, groups in which nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl and carbazolyl are further substituted with phenyl or biphenylyl are also included in heteroaryl as the second substituent.

"Heteroarylene" is, for example, heteroarylene having 2 to 30 carbon atoms, preferably heteroarylene having 2 to 25 carbon atoms, heteroarylene having 2 to 20 carbon atoms, heteroarylene having 2 to 15 carbon atoms, or carbon Heteroarylene of numbers 2 to 10 and the like. Further, "heteroarylene" is a divalent group such as a heterocyclic ring containing, for example, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen in addition to carbon as ring-constituting atoms.
A specific “heteroarylene” is, for example, a divalent group obtained by removing one hydrogen from the above-mentioned “heteroaryl” (monovalent group).

"Diarylamino" is amino substituted with two aryls, and the above description of "aryl" can be referred to for details of this aryl.
"Diheteroarylamino" is an amino group substituted with two heteroaryls, and the above description of "heteroaryl" can be referred to for details of this heteroaryl.
"Arylheteroarylamino" is an amino group substituted with aryl and heteroaryl, and for details of this aryl and heteroaryl, the above descriptions of "aryl" and "heteroaryl" can be referred to.

Two aryls in the diarylamino as the first substituent may be bonded to each other via a linking group, and two heteroaryls in the diheteroarylamino as the first substituent may be bonded to each other via a linking group. The aryl and heteroaryl of the arylheteroarylamino as the first substituent may be bonded to each other via a linking group. Here, the description "bonded via a linking group" means that two phenyls such as diphenylamino form a bond via the linking group as shown below. This explanation also applies to diheteroarylamino and arylheteroarylamino formed by aryl and heteroaryl.

Specific examples of the linking groups include >O, >N—R ^x , >C(—R ^x ) ₂ , >Si(—R ^x ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se. Each R ^X is independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. In addition, R ^X in >C(-R ^X ) ₂ and >Si(-R ^X ) ₂ may be bonded via a single bond or a linking group X ^Y to form a ring. X ^Y is >O, >N-R ^Y , >C(-R ^Y ) ₂ , >Si(-R ^Y ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se and each R ^Y is independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. However, when X ^Y is >C(-R ^Y ) ₂ and >Si(-R ^Y ) ₂ , the two R ^Y do not combine to form a further ring. Further examples of linking groups include alkenylene. Any hydrogen of said alkenylene may each independently be substituted with R ^X , each R ^X being independently alkyl, cycloalkyl, substituted silyl, aryl and heteroaryl, which are alkyl, cycloalkyl, It may be substituted with substituted silyl or aryl.

In the present specification, when simply described as "diarylamino", "diheteroarylamino" or "arylheteroarylamino", unless otherwise specified, "the two aryls of diarylamino are may be bonded via a linking group", "two heteroaryls of the diheteroarylamino may be bonded to each other via a linking group", and "the aryl and heteroaryl of the arylheteroarylamino may be bonded to each other via a linking group".

"Diarylboryl" is boryl substituted with two aryls, and the above description of "aryl" can be referred to for details of this aryl. The two aryls may also be a single bond or a linking group (e.g., -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >C(-R ) ₂ , >Si(-R) ₂ , or >Se). Here, R of -CR=CR-, R of >NR, 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 said R may be further substituted with aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. Also, two adjacent R's may form a ring to form cycloalkylene, arylene, and heteroarylene. For details of the substituents listed here, see the description of "aryl", "arylene", "heteroaryl", "heteroarylene" and "diarylamino" above, and "alkyl" and "alkenyl" below. , “alkynyl”, “cycloalkyl”, “cycloalkylene”, “alkoxy” and “aryloxy” descriptions can be cited. In addition, when simply described as "diarylboryl" in this specification, unless otherwise specified, "two aryls of diarylboryl may be bonded to each other via a single bond or a linking group." It is assumed that the explanation is added.

"Alkyl" may be either straight-chain or branched-chain, for example straight-chain alkyl having 1 to 24 carbon atoms or branched-chain alkyl having 3 to 24 carbon atoms, preferably alkyl having 1 to 18 carbon atoms ( 3 to 18 branched chain alkyl), C 1 to 12 alkyl (C 3 to 12 branched chain alkyl), C 1 to 6 alkyl (C 3 to 6 branched chain alkyl), carbon number Examples include alkyl of 1 to 5 (branched alkyl of 3 to 5 carbon atoms), alkyl of 1 to 4 carbon atoms (branched alkyl of 3 to 4 carbon atoms), and the like.

Specific "alkyl" include, for example, methyl, ethyl, n-propyl, isopropyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1,1,2 , 2-tetramethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-ethylbutyl, 1,1-dimethylbutyl, 3,3-dimethyl Butyl, 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, t-octyl (1,1,3,3-tetramethylbutyl), 1,1-dimethyloctyl, n-nonyl, n-decyl, 1-methyldecyl, n-undecyl, n-dodecyl, n- tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-eicosyl, and the like.

"Alkylene" is a divalent group derived by removing any hydrogen from "alkyl", eg, methylene, ethylene, propylene.

For "alkenyl", the above description of "alkyl" can be referred to. Also includes groups in which two or more single bonds are substituted with double bonds (also called alkadien-yl or alkanetrien-yl).

"Alkenylene" is a divalent group obtained by removing any hydrogen from "alkenyl", such as vinylene.

For "alkynyl", the above description of "alkyl" can be referred to. Also included are groups in which two or more single bonds are replaced by triple bonds (also called alkadiyn-yl or alkanetriin-yl).

"Cycloalkyl" is, for example, cycloalkyl having 3 to 24 carbon atoms, preferably cycloalkyl having 3 to 20 carbon atoms, cycloalkyl having 3 to 16 carbon atoms, cycloalkyl having 3 to 14 carbon atoms, and cycloalkyl having 3 to 14 carbon atoms. cycloalkyl having 3 to 12 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, cycloalkyl having 5 to 8 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, cycloalkyl having 5 carbon atoms, and the like.

Specific "cycloalkyl" includes, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyls having 1 to 5 carbon atoms or 1 to 4 carbon atoms (especially methyl). substituted, norbornenyl, bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1 .0]hexyl, bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, or decahydroazulenyl.

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

“Cycloalkenyl” is a group having a structure in which at least one pair of single bonds between two carbon atoms in the above “cycloalkyl” is a double bond (for example, —CH ₂ —CH ₂ — is —CH= (groups substituted for CH--) which are not aryl groups. Specific examples include 1-cyclohexenyl, 1-cyclopentenyl and the like.

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

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

"Substituted silyl" is, for example, silyl substituted with at least one of aryl, alkyl, and cycloalkyl, preferably triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, or alkyl It is a dicycloalkylsilyl.

"Triarylsilyl" is a silyl group substituted with three aryls, and the above description of "aryl" can be referred to for details of this aryl.
A specific "triarylsilyl" is, for example, triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, or trinaphthylsilyl.

"Trialkylsilyl" is a silyl group substituted with three alkyls, and for details of this alkyl, the above description of "alkyl" can be cited.
Specific "trialkylsilyl" includes, for example, trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-s-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldiethylsilyl, isopropyldiethylsilyl, n-butyldiethyl silyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, s-butyldi-n-propylsilyl, t-butyldi-n-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, t-butyldiisopropylsilyl, and the like.

"Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyls, and for details of this cycloalkyl, the above description of "cycloalkyl" can be cited.
A specific "tricycloalkylsilyl" is, for example, tricyclopentylsilyl or tricyclohexylsilyl.

A "dialkylcycloalkylsilyl" is a silyl group substituted with two alkyls and one cycloalkyl, and the details of the alkyl and cycloalkyl can be referred to the above explanations of "alkyl" and "cycloalkyl".

"Alkyldicycloalkylsilyl" is a silyl group substituted with one alkyl and two cycloalkyls, and the details of this alkyl and cycloalkyl can be referred to the above explanations of "alkyl" and "cycloalkyl" .

<When two groups bonded to the same atom are bonded to each other>
In the present specification, when two groups bonded to the same atom may be bonded to each other to form a ring, if they are bonded by a single bond or a linking group (collectively referred to as a bonding group) Commonly, the linking groups include -CH ₂ -CH ₂ -, -CHR-CHR-, -CR ₂ -CR ₂ -, -CH=CH-, -CR=CR-, -C≡C-, -N( -R)-, -O-, -S-, -C(-R) ₂ -, -Si(-R) ₂ -, or -Se-, for example the following structures. In addition, R of -CHR-CHR-, R of -CR ₂ -CR ₂ -, R of -CR=CR-, R of -N(-R)-, R of -C(-R) ₂ -, and -Si(-R) ₂ - are each independently hydrogen, aryl optionally substituted with alkyl or cycloalkyl, heteroaryl optionally substituted with alkyl or cycloalkyl, or cycloalkyl optionally substituted alkyl, alkenyl optionally substituted with alkyl or cycloalkyl, alkynyl optionally substituted with alkyl or cycloalkyl, or cycloalkyl optionally substituted with alkyl or cycloalkyl . Also, two adjacent R's may form a ring to form cycloalkylene, arylene, and heteroarylene.

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

The position where the two R are bonded by the bonding group is not particularly limited as long as it is a bondable position, but it is preferable to bond at the most adjacent position. For example, when the two groups are phenyl, "C" in phenyl It is preferable to bond at the ortho (2-position) positions with respect to the bonding position (1-position) of or "Si" (see the structural formula above).

1. Polycyclic Aromatic Compound The polycyclic aromatic compound of the present invention is a polycyclic aromatic compound having a structure containing structural units represented by formula (1A) or formula (1B).

The polycyclic aromatic compound of the present invention has a structure in which the B (boron)-containing skeleton of the polycyclic aromatic compound described in International Publication No. 2015/102118 is entirely condensed around B. Such a structure increases the stability of the molecule and extends the life of the device. In addition, such a structure enhances the multiple resonance effect of boron (electron-withdrawing) and nitrogen (electron-donating), narrowing the half width. Furthermore, the addition of a nitrogen-containing 5-membered ring prevents the condensed ring structure around boron from collapsing, increases the stability of the molecule, adjusts the emission wavelength, and produces a deep blue color.

<Ring Structure etc. of Polycyclic Aromatic Compound>
The polycyclic aromatic compound of the present invention is a polycyclic aromatic compound having a structure containing structural units represented by formula (1A) or (1B). A polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or (1B) includes one or more structural units represented by formula (1A) or (1B) Polycyclic aromatic compounds having a structure consisting of are included. Examples of polycyclic aromatic compounds having a structure consisting of one of the above structural units include polycyclic aromatic compounds represented by formula (1A) or formula (1B). As the polycyclic aromatic compound having a structure consisting of two or more structural units represented by formula (1A) or (1B), a multimer of the compound represented by formula (1A) or (1B) Corresponding compounds are mentioned. The multimer is preferably a 2- to 6-mer, more preferably a 2- to 3-mer, and particularly preferably a dimer. The multimer may be in a form having a plurality of the above unit structures in one compound, and any ring (a ring, b ring, c ring or ring containing Y) contained in the above structural unit may be a plurality of units It may be in the form of bonding so as to share the structure, and any rings included in the unit structure (a ring, b ring, c ring, or ring containing Y) are condensed and bonded It can be in any form. In addition, the above unit structure may be in a form in which a plurality of units are bonded by a single bond, a linking group such as alkylene having 1 to 3 carbon atoms, phenylene, naphthylene, or the like. Among these, preferred is a form in which the ring is shared.

The polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) includes a polycyclic aromatic compound having a structure represented by formula (1A) or formula (1B) ( monomer) are preferred.

In Formula (1A) and Formula (1B), each Z is independently N or C—R ^Z and each R ^Z is independently hydrogen or a substituent. Therefore, the a-ring, b-ring, or c-ring (monocyclic) sites can each constitute a benzene ring, a pyridine ring, a pyrimidine ring, or a pyridazine ring. Also, two adjacent R ^Z may be bonded to form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring together with the a-ring, b-ring or c-ring. At this time, a condensed ring containing a benzene ring, a pyridine ring, a pyrimidine ring, or a pyridazine ring can be formed.

In formulas (1A) and (1B), two adjacent Y bonds are each independently a single bond or a double bond.

Each Y bonded to an adjacent Y by a single bond is independently >C(-R ^Y1 ) ₂ , and each R ^Y1 is independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl. R ^Y1 is preferably unsubstituted alkyl or unsubstituted cycloalkyl. Two R ^Y1s attached to the same carbon may be attached to each other to form a ring. Also, two adjacent R ^Y1 may be bonded to each other to form a ring. Specifically, two adjacent R ^Y1 are bonded to each other and together with the carbon to which they are bonded are substituted or unsubstituted hydrocarbon rings (excluding aryl rings) or substituted or unsubstituted heterocyclic rings (excluding heteroaryl rings) ) may be formed. For example, the following structures are preferred examples.

式中、＊は窒素とａ環、ｂ環またはｃ環上の炭素との結合位置である。

In the formula, * is the bonding position between nitrogen and carbon on the a-ring, b-ring or c-ring.

Y bonded to adjacent Y by a double bond is N or C—R ^Y2 , and R ^Y2 is hydrogen or a substituent.

Two adjacent R ^Y2 may be bonded to each other to form a ring. Specifically, two adjacent R ^Y2 may be bonded together to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring together with the carbon to which they are bonded. However, two adjacent R ^Y2 do not combine with each other to form a benzene ring. A pentene ring or a cyclohexene ring is preferable as the ring formed by bonding two adjacent R ^Y2 to each other. These rings may have a substituent. In particular, it is preferable to have a substituent at the carbon α-position to the double bond (the carbon at the position adjacent to the carbon bonded with the double bond). As the substituent, alkyl is preferable, and methyl is more preferable. It is preferred that no hydrogen is bonded to the α-position carbon.

In formulas (1A) and (1B), Y may be combined with Z to further form a ring consisting of Y—N—C—Z or a ring consisting of Y—C—Z. That is, each Y may be bonded to the nearest Z, indicated by an arrow below.

Specifically, R ^Y1 in Y that is >C ⁽ -R ^Y1 ) ₂ may be mutually bonded to R ^Z in Z that is C—R ^Z , and R ^Y2 may be bonded to R ^Z in Z that is CR ^Z . Both R ^Y1 and R ^Y2 may be bonded to R ^Z via a single bond or a linking group, and at this time either one of the bonds may be a bond. (That is, the hydrogen or the hydrogen in the substituent group serves as a bond and bonds.)
Examples of such structures include compounds represented by formula (1-123) or formula (1-124) described below.

In formulas (1A) and (1B), X is >O, >NR ^XN , >C(-R ^XC ) ₂ , >Si(-R ^XI ) ₂ , >S, or >Se. X is preferably >O, >N-R ^xN , >C(-R ^xC ) ₂ or >S, more preferably >O, >N-R ^xN or >S, >N -R ^XN is more preferred.

R ^XN is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, preferably substituted or unsubstituted aryl, substituted Alternatively, it is preferably unsubstituted phenyl, more preferably unsubstituted phenyl. R ^XC and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; Aryl, substituted or unsubstituted heteroaryl, or unsubstituted alkyl are preferred. Preferably, both R ^XC are methyl. It is also preferred that both R ^XI are methyl. Two R ^XC may be bonded together to form a ring, and two R ^XI may be bonded together to form a ring.

R ^XN , R ^XC and R ^XI may each be attached to at least one Z adjacent to the carbon to which X is attached through a linking group or single bond. Z at this time may be C—R ^Z and R ^Z may be a bond. It is sufficient that this bond replaces any hydrogen in R ^XN , R ^XC and R ^XI . As the linking group, the same examples as the linking group in which two groups bonded to the same atom are bonded to each other can be given. Of these, --O--, --S--, --C(--Me) ₂ --, --Si(--Me) ₂ -- and 1,2-phenylene are preferred.

Preferred examples of structural units represented by formula (1A) or formula (1B) include formula (1A-a), formula (1A-b), formula (1A-c), formula (1B-a), formula Structural units represented by (1B-b) or formula (1B-c) can be mentioned.

In formula (1A-a), formula (1A-b), formula (1A-c), formula (1B-a), formula (1B-b) and formula (1B-c), Z, X, R ^Y1 , R ^Y2 has the same meaning as Z, X, R ^Y1 and R ^Y2 in Formula (1A) and Formula (1B).

Further preferred examples of structural units represented by formula (1A) or (1B) include structural units represented by any of the following formulas. However, the following formulas all show skeletons excluding substituents, and the skeletons represented by the following formulas may further have substituents.

<Substituent of Polycyclic Aromatic Compound>
In Formula (1A) and Formula (1B), each Z is independently N or C—R ^Z and each R ^Z is independently hydrogen or a substituent. A ring formed by bonding two adjacent R ^Z to each other to form together with the a-ring, the b-ring or the c-ring may have a substituent. Also, Ys bonded to adjacent Ys by double bonds are N or C—R ^Y2 , and each R ^Y2 is independently hydrogen or a substituent. Examples of these substituents and the substituents of the aryl or heteroaryl rings in formulas (1A) and (1B) are described below.

Steric hindrance of the structure of the substituent of a compound used as a dopant (assisting dopant or emitting dopant) such as a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) Emission wavelengths can be tuned by their electron-donating and electron-withdrawing properties. Groups represented by the following structural formulas are preferable, and more preferably methyl, t-butyl, t-amyl, t-octyl, neopentyl, adamantyl, phenyl, o-tolyl, p-tolyl, 2,4- xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6- dimethylcarbazolyl, 3,6-di-t-butylcarbazolyl and phenoxy, more preferably methyl, t-butyl, t-amyl, t-octyl, neopentyl, adamantyl, phenyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6-dimethylcarbazolyl and 3,6 -di-t-butylcarbazolyl. From the viewpoint of ease of synthesis, larger steric hindrance is preferred for selective synthesis, specifically t-butyl, t-amyl, t-octyl, adamantyl, o-tolyl, p-tolyl , 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, 3,6- Dimethylcarbazolyl and 3,6-di-t-butylcarbazolyl are preferred.

In the following structural formulas, * represents a bonding position.

When a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) is used as a dopant (assisting dopant or emitting dopant), other compounds used as dopants are As a substituent containing "alkyl", a tertiary-alkyl represented by the following formula (tR) is particularly preferred as a substituent for the aryl ring or heteroaryl ring in the a ring, b ring, c ring or ring containing Y. It is one of the things. This is because such a bulky substituent increases the intermolecular distance, thereby improving the light emission quantum yield (PLQY). Further, a substituent in which a tertiary-alkyl represented by formula (tR) substitutes another substituent as a second substituent is also preferable. Specifically, tertiary-alkyl-substituted diarylamino represented by (tR), tertiary-alkyl-substituted carbazolyl (preferably N-carbazolyl) represented by (tR) or (tR) and benzocarbazolyl (preferably N-benzocarbazolyl) substituted with tertiary-alkyl represented. Substitution forms of the group of formula (tR) on diarylamino, carbazolyl and benzocarbazolyl include substitution of a group of formula (tR) for some or all hydrogens of the aryl ring or benzene ring in these groups. Here are some examples.

In formula (tR), R ^a , R ^b , and R ^c are each independently alkyl having 1 to 24 carbon atoms, and any —CH ₂ — in the alkyl may be substituted with —O—. , the group represented by the formula (tR) is attached to the substitution site at *.

The "alkyl having 1 to 24 carbon atoms" of R ^a , R ^b and R ^c may be either linear or branched chain, for example, linear alkyl having 1 to 24 carbon atoms or branched Chain Alkyl, C1-C18 Alkyl (C3-C18 Branched Alkyl), C1-C12 Alkyl (C3-C12 Branched Alkyl), C1-C6 Alkyl (Cb branched chain alkyl having 3 to 6 carbon atoms) and alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms).

The total number of carbon atoms of R ^a , R ^b and R ^c in formula (tR) is preferably from 3 to 20 carbon atoms, particularly preferably from 3 to 10 carbon atoms.

Specific alkyls for R ^a , R ^b , and R ^c include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t -pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1- methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-eicosyl and the like.

Examples of groups represented by formula (tR) include t-butyl, t-amyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-ethyl-1- methylbutyl, 1,1,3,3-tetramethylbutyl, 1,1,4-trimethylpentyl, 1,1,2-trimethylpropyl, 1,1-dimethyloctyl, 1,1-dimethylpentyl, 1,1- dimethylheptyl, 1,1,5-trimethylhexyl, 1-ethyl-1-methylhexyl, 1-ethyl-1,3-dimethylbutyl, 1,1,2,2-tetramethylpropyl, 1-butyl-1- methylpentyl, 1,1-diethylbutyl, 1-ethyl-1-methylpentyl, 1,1,3-trimethylbutyl, 1-propyl-1-methylpentyl, 1,1,2-trimethylpropyl, 1-ethyl- 1,2,2-trimethylpropyl, 1-propyl-1-methylbutyl, 1,1-dimethylhexyl and the like. Of these, t-butyl and t-amyl are preferred.

A polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) is a tertiary-alkyl represented by the above formula (tR) (such as t-butyl or t-amyl) , neopentyl or adamantyl, and preferably includes a tertiary-alkyl (t-butyl, t-amyl, etc.) represented by the formula (tR). This is because such a bulky substituent increases the intermolecular distance, thereby improving the light emission quantum yield (PLQY). Moreover, as a substituent, diarylamino is also preferable. Furthermore, diarylamino substituted with a group of formula (tR), carbazolyl (preferably N-carbazolyl) substituted with a group of formula (tR) or benzocarbazolyl substituted with a group of formula (tR) ( N-benzocarbazolyl) is also preferred. Substitution forms of the group of formula (tR) on diarylamino, carbazolyl and benzocarbazolyl include substitution of a group of formula (tR) for some or all hydrogens of the aryl ring or benzene ring in these groups. Here are some examples.

A substituent represented by formula (A30) is also preferred as a substituent in a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or (1B).

In formula (A30),
Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl or substituted or unsubstituted cycloalkenyl, and at least one —CH ₂ — may be replaced with —O— or —S—,
R ^Ak is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and R ^Ak is attached to Ak through a linking group or a single bond. * is the binding position.

In formula (A30), since Ak is the above substituent, it is not conjugated with the lone pair on N, so the lone pair can be conjugated with the π electron of the binding destination, and aryl etc. Larger wavelength changes are possible than with In addition, the effect on the multiple resonance effect is the same, and a greater improvement in thermally activated delayed fluorescence (TADF) properties is possible.

R ^Ak is preferably aryl optionally substituted by alkyl or cycloalkyl, heteroaryl optionally substituted by alkyl or cycloalkyl, alkyl or cycloalkyl, aryl optionally substituted by alkyl, It is more preferably heteroaryl optionally substituted with alkyl, alkyl or cycloalkyl, further preferably aryl optionally substituted with alkyl, and phenyl optionally substituted with methyl is particularly preferred.

In formula (A30), Ak is preferably alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 14 carbon atoms, and is preferably alkyl having 1 to 4 carbon atoms or cycloalkyl having 3 to 8 carbon atoms. It is preferably alkyl having 1 to 4 carbon atoms, more preferably methyl.

^RAk may be attached to Ak through a linking group or a single bond. Examples of the linking group at this time include >O, >S, and >Si(--R) ₂ . >Si(-R) ₂ , R is hydrogen, aryl having 6 to 12 carbon atoms, alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 14 carbon atoms. Examples of structures in which ^RAk is bound to Ak via a linking group or a single bond are shown below.

上記各式中、＊は結合位置である。

In each of the above formulas, * is a bonding position.

In formula (1A) or formula (1B), the substituent of the aryl ring or heteroaryl ring in the a ring, b ring, c ring or ring containing Y is a substituent represented by the following formula (A20) good too.

the substituent represented by formula (A20) is bound by two * to two adjacent atoms on the ring of the aryl or heteroaryl ring,
In formula (A20), L is >N—R, >O, >Si(—R) ₂ or >S, and R in >N—R is substituted or unsubstituted aryl, substituted or unsubstituted is heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and R in >Si(—R) ₂ is hydrogen, optionally substituted aryl, optionally substituted alkyl or optionally substituted cycloalkyl, which may be linked to each other by a linking group, and at least one of the >N—R and >Si(—R) ₂ R is a linking group or a single may be bonded to at least one aryl or heteroaryl ring in the a ring, b ring, c ring or ring containing Y by a bond;
r is an integer from 1 to 4,
Each R ^A is independently hydrogen, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and any R ^A may be bonded to any other R ^A via a linking group or a single bond. good.

Examples of the above substituent include substituents represented by any of the following.

In each formula, * binds to two or three consecutive (adjacent) atoms on any aryl or heteroaryl ring in the a ring, b ring, c ring, or ring containing Y, respectively. It is good if there is

The substituent represented by R ^Z is preferably any substituent selected from the substituent group Z or a substituent represented by formula (A30), such as alkyl, substituted or unsubstituted aryl, substituted or unsubstituted hetero Aryl, substituted or unsubstituted diarylamino, or a substituent represented by formula (A30) is more preferable, and alkyl, phenyl optionally substituted with alkyl, diphenylamino optionally substituted with alkyl, or substituted with alkyl Further preferred is carbazolyl which may be substituted.

When R ^Z is a substituent, it is preferably in the para position ^of B (boron). More preferably, R ^Z at the para-position of B (boron) is hydrogen or a substituent, and other R ^Z are hydrogen.

The substituent represented by R ^Y2 is preferably any substituent selected from the substituent group Z or a substituent represented by formula (A30), such as alkyl, substituted or unsubstituted aryl, substituted or unsubstituted hetero Aryl, substituted or unsubstituted diarylamino, or a substituent represented by formula (A30) is more preferable, and alkyl, phenyl optionally substituted with alkyl, diphenylamino optionally substituted with alkyl, or substituted with alkyl Further preferred is carbazolyl which may be substituted.

<Cycloalkane condensation>
At least one selected from the group consisting of an aryl ring and a heteroaryl ring in a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) is at least one cycloalkane It may be condensed. Any selected from the group consisting of formula (1A-a), formula (1A-b), formula (1A-c), formula (1B-a), formula (1B-b) and formula (1B-c) The same applies to a polycyclic aromatic compound having a structure containing a structural unit represented by the following formula, and the following description similarly applies to the polycyclic aromatic compound represented by any of these formulas.

A cycloalkane having 3 to 24 carbon atoms may be used as the cycloalkane. At least one hydrogen in the cycloalkane at this time is substituted with aryl having 6 to 30 carbon atoms, heteroaryl having 2 to 30 carbon atoms, alkyl having 1 to 24 carbon atoms or cycloalkyl having 3 to 24 carbon atoms. and at least one —CH ₂ — in the cycloalkane may be replaced with —O—.

The cycloalkane is a cycloalkane having 3 to 20 carbon atoms, and at least one hydrogen in the cycloalkane is aryl having 6 to 16 carbon atoms, heteroaryl having 2 to 22 carbon atoms, or alkyl having 1 to 12 carbon atoms. Alternatively, it is preferably a cycloalkane optionally substituted with cycloalkyl having 3 to 16 carbon atoms.

"Cycloalkane" includes cycloalkanes having 3 to 24 carbon atoms, cycloalkanes having 3 to 20 carbon atoms, cycloalkanes having 3 to 16 carbon atoms, cycloalkanes having 3 to 14 carbon atoms, cycloalkanes having 5 to 10 carbon atoms, Examples include alkanes, cycloalkanes having 5 to 8 carbon atoms, cycloalkanes having 5 to 6 carbon atoms, cycloalkanes having 5 carbon atoms, and the like.

Specific cycloalkanes include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, norbornane (bicyclo[2.2.1]heptane), bicyclo[1.1.0]butane , bicyclo[1.1.1]pentane, bicyclo[2.1.0]pentane, bicyclo[2.1.1]hexane, bicyclo[3.1.0]hexane, bicyclo[2.2.2]octane , adamantane, diamantane, decahydronaphthalene and decahydroazulene, and alkyl (especially methyl)-substituted, halogen (especially fluorine)-substituted and deuterium-substituted products thereof having 1 to 5 carbon atoms.

Among these, for example, at least one hydrogen at the α-position carbon of a cycloalkane (the carbon at the position adjacent to the carbon of the condensation site in the cycloalkyl fused to an aryl ring or heteroaryl ring) as shown in the following structural formula A structure in which is substituted is preferred, a structure in which two hydrogens at the α-position carbons are substituted is more preferred, and a structure in which a total of four hydrogens at two α-position carbons are substituted is even more preferred. Examples of this substituent include alkyl having 1 to 5 carbon atoms (especially methyl), halogen (especially fluorine) and deuterium. In particular, it is preferable to have a structure in which a partial structure represented by the following formula (B) is bonded to adjacent carbon atoms in the aryl ring or heteroaryl ring.

式（Ｂ）中、＊は結合位置を示す。

In formula (B), * indicates a binding position.

The number of cycloalkanes condensed on one aryl ring or heteroaryl ring is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. For example, examples in which one benzene ring (phenyl) is condensed with one or more cycloalkanes are shown below. * indicates a bonding position, which may be any carbon that constitutes a benzene ring and does not constitute a cycloalkane. The condensed cycloalkanes of formula (Cy-1-4) and formula (Cy-2-4) may be condensed. Even if the ring (group) to be condensed is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), or if the cycloalkane to be condensed is a cycloalkane other than cyclopentane or cyclohexane, is also the same.

At least one —CH ₂ — in the cycloalkane may be replaced with —O—. For example, examples in which one or more —CH ₂ — in a cycloalkane condensed to one benzene ring (phenyl) are replaced with —O— are shown below. Even if the ring (group) to be condensed is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), or if the cycloalkane to be condensed is a cycloalkane other than cyclopentane or cyclohexane, is also the same.

At least one hydrogen in the cycloalkane may be substituted, and examples of this substituent include aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (two aryls are a single bond or may be linked via a linking group), alkyl, cycloalkyl, alkoxy, aryloxy, substituted silyl, deuterium, cyano or halogen, the details of which are described above for the first substituent You can cite the description. Among these substituents, alkyl (eg, alkyl having 1 to 6 carbon atoms), cycloalkyl (eg, cycloalkyl having 3 to 14 carbon atoms), halogen (eg, fluorine) and deuterium are preferred. In addition, when cycloalkyl is substituted, it may be in a form of substitution forming a spiro structure, an example of which is shown below.

As a form of cycloalkane condensation, first, in a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B), each ring containing ring a, ring b, ring c or Y A form in which the aryl ring and heteroaryl ring in is condensed with cycloalkane can be mentioned.

Another form of cycloalkane condensation is a polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B), for example, R is aryl fused with cycloalkane >NR, cycloalkane-fused diarylamino (fused to the aryl moiety), cycloalkane-fused carbazolyl (fused to the benzene ring moiety) or cycloalkane-fused benzocarbazolyl (fused to the benzene fused to a ring portion).

By introducing a cycloalkane structure into the polycyclic aromatic compound of the present invention, a decrease in melting point and sublimation temperature can be expected. This is because sublimation refining, which is almost indispensable as a refining method for materials for organic devices such as organic EL elements that require high purity, can be refined at relatively low temperatures, so thermal decomposition of materials can be avoided. means The same is true for the vacuum deposition process, which is a powerful means for producing organic devices such as organic EL elements. As a result, a high-performance organic device can be obtained. In addition, since the introduction of the cycloalkane structure improves the solubility in organic solvents, it can be applied to device fabrication using a coating process. However, the present invention is not specifically limited to these principles.

<Substitution with Deuterium, Cyano, or Halogen>
All or part of the hydrogen in the structure containing structural units represented by formula (1A) or formula (1B) may be deuterium, cyano, or halogen. Any selected from the group consisting of formula (1A-a), formula (1A-b), formula (1A-c), formula (1B-a), formula (1B-b) and formula (1B-c) The same applies to a polycyclic aromatic compound having a structure containing a structural unit represented by the following formula (1A-a), (1A-b), (1A-c), The same applies to polycyclic aromatic compounds represented by any formula selected from the group consisting of formula (1B-a), formula (1B-b) and formula (1B-c).

For example, in a structure containing a structural unit represented by formula (1A) or formula (1B), a ring containing a ring, b ring, c ring or Y, a ring containing a ring, b ring, c ring or Y and at R (=alkyl, cycloalkyl, aryl, or heteroaryl) when X ¹ is >N—R, >C(—R) ₂ , or >Si(—R) ₂ Hydrogen can be replaced with deuterium, cyano, or halogen, and among these, there is an embodiment in which all or part of the hydrogen in aryl or heteroaryl is replaced with deuterium, cyano, or halogen. Halogen is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, even more preferably fluorine. From the viewpoint of durability, it is also preferable that all or part of hydrogen in the structure containing the structural unit represented by formula (1A) or (1B) is deuterated.

Specific examples of polycyclic aromatic compounds having a structure containing a structural unit represented by formula (1A) or (1B) include compounds represented by any of the following formulas. In addition, the aryl aromatic ring in the following formula may have alkyl having 1 to 4 carbon atoms or phenyl optionally substituted with alkyl having 1 to 4 carbon atoms as a substituent, and is represented by each formula At least one hydrogen in the structure may be replaced with deuterium.

Further specific examples of the polycyclic aromatic compound having a structure containing a structural unit represented by formula (1A) or formula (1B) include the following compounds. The polycyclic aromatic compound having a structure containing the structural unit represented by formula (1A) or formula (1B) is not limited to the following specific examples.

<Method for producing polycyclic aromatic compound>
The polycyclic aromatic compound represented by formula (1A) or formula (1B) is basically prepared by first bonding the a-ring to the b-ring and c-ring with a bonding group (a group containing N). (first reaction), followed by bonding of the a, b and c rings with boron to prepare an intermediate (second reaction), and finally the b and c rings with a linking group. It can be synthesized by binding (third reaction). A general reaction such as the Buchwald-Hartwig reaction can be used for the first reaction. Moreover, in the second reaction, a tandem hetero Friedel-Crafts reaction (continuous aromatic electrophilic substitution reaction, hereinafter the same) can be used. General reactions such as nucleophilic aromatic substitution, Ullmann reaction, and Buchwald-Hartwig reaction can be used for the third reaction.

The second reaction, as shown in schemes (1) and (2) below, is a reaction for introducing boron that bonds rings a, b and c. First, halogen atoms between nitrogen atoms are halogen-metal exchanged with n-butyllithium, sec-butyllithium, t-butyllithium or the like. Next, boron trichloride, boron tribromide, or the like is added to carry out metal exchange of lithium-boron, and then a Bronsted base such as N,N-diisopropylethylamine is added to cause a tandem bolus Friedel-Crafts reaction to achieve the desired can get things. In the second reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction.

By appropriately selecting raw materials to be used, a polycyclic aromatic compound having a substituent at a desired position and a polymer thereof can be synthesized.

Specific examples of the solvent used in the above reaction are t-butylbenzene, xylene, and the like.

The ortho-metalating reagents used in the above schemes (1) and (2) include alkyllithium such as methyllithium, n-butyllithium, sec-butyllithium and t-butyllithium, lithium diisopropylamide, lithium tetramethyl Examples include organic alkaline compounds such as piperidide, lithium hexamethyldisilazide, potassium hexamethyldisilazide.

The metal-boron metal exchange reagents used in schemes (1) and (2) above include boron trifluoride, boron trichloride, boron tribromide, boron triiodide and other boron halides; alkoxylated products of boron, aryloxylated products of boron, and the like.

The Bronsted bases used in schemes (1) and (2) above include N,N-diisopropylethylamine, triethylamine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6 - pentamethylpiperidine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2,6-lutidine, sodium tetraphenylborate, potassium tetraphenylborate, triphenylborane, tetraphenylsilane, Ar ₄ BNa, Ar ₄ BK, Ar ₃ B, Ar ₄ Si (Ar is aryl such as phenyl) and the like.

Examples of Lewis acids used in schemes (1) and (2) include _AlCl3 , _AlBr3 , _AlF3 , _BF3.OEt2 , _BCl3 , _BBr3 , _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 _, etc. mentioned.

In schemes (1) and (2) above, Bronsted bases or Lewis acids may be used to facilitate the tandem hetero Friedel-Crafts reaction. However, when boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide are used, hydrogen fluoride, hydrogen chloride, bromine Since acids such as hydrogen chloride and hydrogen iodide are generated, it is effective to use Bronsted bases that scavenge acids. On the other hand, when aminated halides of boron and alkoxylated boron compounds are used, amines and alcohols are generated as the aromatic electrophilic substitution reaction progresses, so in many cases it is not necessary to use a Bronsted base. However, since the leaving ability of amino and alkoxy is low, it is effective to use a Lewis acid to promote their leaving.

In addition, the polycyclic aromatic compounds and polymers thereof of the present invention include those in which at least some of the hydrogen atoms are replaced with deuterium and those in which halogens such as fluorine and chlorine are substituted, Such compounds and the like can be synthesized in the same manner as described above by using raw materials in which desired sites are deuterated, fluorinated or chlorinated.

2. Organic Device The polycyclic aromatic compound of the present invention can be used as a material for organic devices. Organic devices include, for example, organic electroluminescence devices, organic field effect transistors, organic thin film solar cells, and the like.

2-1. organic electroluminescent device
2-1-1. Structure of Organic Electroluminescence Device FIG. 1 is a schematic sectional view showing an example of an organic EL device.
The organic EL device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, and a The hole-transport layer 104 provided, the light-emitting layer 105 provided over the hole-transport layer 104, the electron-transport layer 106 provided over the light-emitting layer 105, and the electron-transport layer 106 provided and a cathode 108 provided on the electron injection layer 107 .

Note that the organic EL element 100 is fabricated in reverse order, for example, the substrate 101, the cathode 108 provided on the substrate 101, the electron injection layer 107 provided on the cathode 108, and the electron injection layer 107 an electron transport layer 106 provided on the electron transport layer 106; a light emitting layer 105 provided on the electron transport layer 106; a hole transport layer 104 provided on the light emitting layer 105; A structure having a hole-injection layer 103 provided at the bottom and an anode 102 provided on the hole-injection layer 103 may be employed.

All of the above layers are not indispensable, and the minimum structural unit is composed of the anode 102, the light emitting layer 105, and the cathode 108, and the hole injection layer 103, the hole transport layer 104, the electron transport layer 106, and the electron injection Layer 107 is an optional layer. Moreover, each of the above layers may be composed of a single layer, or may be composed of a plurality of layers.

In addition to the configuration of the above-described "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport layer/electron injection layer/cathode", the layers constituting the organic EL element may include " substrate/anode/hole-transporting layer/luminescent layer/electron-transporting layer/electron-injecting layer/cathode”, “substrate/anode/hole-injecting layer/luminescent layer/electron-transporting layer/electron-injecting layer/cathode”, “substrate/ Anode/Hole Injection Layer/Hole Transport Layer/Light Emitting Layer/Electron Injection Layer/Cathode", "Substrate/Anode/Hole Injection Layer/Hole Transport Layer/Light Emitting Layer/Electron Transport Layer/Cathode", "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 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 /Emitting layer/Electron transporting layer/Cathode" or "Substrate/Anode/Emitting layer/Electron injection layer/Cathode".

2-1-2. The substrate substrate 101 in the organic electroluminescence element is a support for the organic EL element 100, and is usually made of quartz, glass, metal, plastic, or the like. The substrate 101 is formed in a plate shape, a film shape, or a sheet shape depending on the purpose, and for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like is used. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate and polysulfone are preferred. If it is a glass substrate, soda-lime glass, alkali-free glass, or the like is used, and the thickness should be sufficient to maintain mechanical strength. In addition, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one side thereof in order to enhance gas barrier properties. When used, it is preferable to provide a gas barrier film.

2-1-3. The anode 102 in the organic electroluminescent device 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. It will be.

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

2-1-4. Hole Injection Layer and Hole Transport Layer in the Organic Electroluminescent Device The hole injection layer 103 plays a role of efficiently injecting holes moving from the anode 102 into the light emitting layer 105 or the hole transport layer 104. Fulfill. The hole transport layer 104 plays a role of efficiently transporting holes injected from the anode 102 or holes injected from the anode 102 through the hole injection layer 103 to the light emitting layer 105 . The hole injection layer 103 and the hole transport layer 104 are each formed by stacking or mixing one or more kinds of hole injection/transport materials. Also, an inorganic salt such as iron (III) chloride may be added to the hole injection/transport material to form the layer.

As a hole-injecting/transporting substance, it is necessary to efficiently inject and transport holes from the positive electrode between electrodes to which an electric field is applied. It is desirable to For this purpose, it is preferable that the ionization potential is low, the hole mobility is high, the stability is excellent, and impurities that become traps are less likely to occur during manufacture and use.

Materials for forming the hole injection layer 103 and the hole transport layer 104 include compounds conventionally used as charge transport materials for holes in photoconductive materials, p-type semiconductors, and hole injection layers of organic EL devices. Any compound can be selected and used from known compounds used for the hole transport layer. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (aromatic tertiary Polymers with amino in the main or side chain, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4 ,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4 ,4′-diphenyl-1,1′-diamine, N,N′-dinaphthyl-N,N′-diphenyl-4,4′-diphenyl-1,1′-diamine, N ⁴ ,N ⁴ ′ -diphenyl- N ⁴ ,N ^4′ -bis(9-phenyl-9H-carbazol-3-yl)-[1,1′-biphenyl]-4,4′-diamine, N ⁴ ,N ⁴ ,N ^4′ ,N ^{4 '} -tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl) triphenylamine derivatives such as amino)triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives , quinoxaline derivatives (e.g., 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. Polycarbonate, styrene derivatives, polyvinylcarbazole, polysilane and the like having the above-mentioned monomers in the side chains are preferable for polymer systems, but a thin film necessary for manufacturing a light-emitting device can be formed and holes can be injected from the anode. Further, the compound is not particularly limited as long as it is a compound capable of transporting holes.

It is also known that the conductivity of organic semiconductors is strongly influenced by their doping. Such an organic semiconductor matrix material is composed of a compound with good electron-donating property or a compound with good electron-accepting property. Strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are known for doping electron donors. (For example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998)” and the literature “J. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)"). They generate so-called holes by an electron transfer process in an electron donating base material (hole transport material). The conductivity of the base material varies considerably depending on the number and mobility of holes. As matrix materials with hole-transport properties, for example, benzidine derivatives (such as TPD) or starburst amine derivatives (such as TDATA), or certain metal phthalocyanines (especially zinc phthalocyanine (ZnPc), etc.) are known ( Japanese Patent Application Laid-Open No. 2005-167175).

The hole injection layer material and the hole transport layer material described above are polymer compounds obtained by polymerizing a reactive compound having a reactive substituent substituted thereon as a monomer, or a polymer crosslinked product thereof, or A pendant-type polymer compound obtained by reacting a main chain-type polymer with the reactive compound or a pendant-type polymer crosslinked product thereof can also be used as a hole layer material.

2-1-5. Light-Emitting Layer in Organic Electroluminescent Device The polycyclic aromatic compound of the present invention is preferably used as a material for forming one or more organic layers in an organic electroluminescent device, and is used as a material for forming a light-emitting layer. more preferably. In the light-emitting layer, the compound of the present invention having a structure containing a structural unit represented by formula (1A) or formula (1B) is an emitting dopant of a TTF (Triplet-Triplet Fusion) device, TAF It can be used as an emitting dopant for devices and an emitting dopant for phosphorescent assist devices. The TTF emitting dopant is preferable from the viewpoint of long life, and the emitting dopant of the TAF element and the phosphorescent assist element are preferable from the viewpoint of high efficiency. The emitting dopant of the TTF element is preferable from the viewpoint that the smaller the material used in the element, the easier it is to manufacture, and the emitting dopant of the phosphorescent assist element is preferable for high efficiency and long life.

The light-emitting layer 105 is a layer that emits light by recombining holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. As a material for forming the light-emitting layer 105, any compound (light-emitting compound) that emits light when excited by recombination of holes and electrons can be used. It is preferably a compound that exhibits a strong luminescence (fluorescence) efficiency at .
The polycyclic aromatic compound of the present invention can be used as a material for a light-emitting layer, can be used as a dopant material, or can be used as a host material, but is preferably used as a dopant material.

The light-emitting layer may be a single layer or a plurality of layers, each of which is formed of a light-emitting layer material (host material, dopant material). The host material and the dopant material may be of one kind, or may be a combination of a plurality of them. The dopant material may be included entirely or partially in the host material. As a doping method, it can be formed by a co-evaporation method with a host material, but it may be mixed with the host material in advance and then vapor-deposited simultaneously.

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

The amount of dopant material used varies depending on the type of dopant material, and may be determined according to the properties of the dopant material. A guideline for the amount of dopant used is preferably 0.001 to 50% by mass, more preferably 0.05 to 20% by mass, and still more preferably 0.1 to 10% by mass of the total mass of the light-emitting layer material. is. The above range is preferable in that, for example, the phenomenon of concentration quenching can be prevented.

As the dopant material, an emitting dopant and an assisting dopant material may be used. A thermally activated delayed fluorescence material is preferably used as the assisting dopant material. In an organic electroluminescence device using an assisting dopant material, it is preferable to use a low concentration of the emitting dopant material in order to prevent the concentration quenching phenomenon. A higher concentration of the assisting dopant material is preferable from the viewpoint of the efficiency of the thermally activated delayed fluorescence mechanism. Furthermore, in an organic electroluminescence device using a thermally activated delayed fluorescence assisting dopant material, the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant material is lower than the amount of the assisting dopant material used. It is preferred that the amount of emitting dopant material used is low.

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

<Host material>
Host materials include condensed ring derivatives such as anthracene and pyrene, bisstyryl anthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, fluorene derivatives, benzo Examples include fluorene derivatives, N-phenylcarbazole derivatives, carbazonitrile derivatives and the like.

The lowest excited triplet energy level (E _T1 ) of the host material is the dopant having the highest E _T1 in the light-emitting layer or the assisting dopant E It is preferably higher than _T1 , specifically, the host material _ET1 is preferably 0.01 eV or more higher than the above-described dopant or assisting dopant _ET1 , preferably 0.03 eV or more. More preferably, it is still more preferably higher than 0.1 eV. The _ET1 of the host material is preferably 2.70 eV or more, more preferably 2.73 eV or more, and still more preferably 2.80 eV or more.
A TADF active compound may be used as the host material.

The host material may be of one type or a combination of multiple types. In the case of a combination of a plurality of materials, it is preferably a combination of a hole-transporting host material and an electron-transporting host material.

[Anthracene derivative]
As for the anthracene derivative, the descriptions of paragraphs 0124 to 0192 of JP-A-2020-136284 and the descriptions of paragraphs 0072-0257 of JP-A-2021-118354 can be referred to.
Specifically, the anthracene derivative includes a compound represented by formula (3-H) or a compound represented by formula (3-H2).

In formula (3-H),
X and Ar ⁴ are each independently hydrogen or any group selected from Substituent Group Z, and all X and Ar ⁴ are not hydrogen at the same time.
At least one hydrogen in the compound represented by formula (3-H) may be replaced with halogen, cyano or deuterium.

In formula (3-H2), Ar ^c is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl, R ^c is hydrogen, alkyl, or cycloalkyl, Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ¹⁵ , Ar ¹⁶ , Ar ¹⁷ and Ar ¹⁸ are each independently hydrogen or any group selected from Substituent Group Z and represented by formula (3-H2) At least one hydrogen in the compound may be replaced with halogen, cyano, or deuterium.

In the compound represented by formula (3-H), X is each independently a group represented by formula (3-X1), formula (3-X2) or formula (3-X3), preferably The group represented by formula (3-X1), formula (3-X2) or formula (3-X3) is bonded to the anthracene ring of formula (3-H) at *. Preferably, two Xs are not simultaneously a group represented by formula (3-X3). More preferably, two X's are not simultaneously a group represented by formula (3-X2).

Alternatively, a multimer (preferably a dimer) may be formed using the structure represented by formula (3-H) as a unit structure. In this case, for example, the unit structures represented by the formula (3-H) may be bonded through X, where X is a single bond, arylene (phenylene, biphenylene, naphthylene, etc.) and heteroarylene (pyridine a group having a divalent bond such as a ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a benzocarbazole ring, and a phenyl-substituted carbazole ring).

The naphthylene moiety in formulas (3-X1) and (3-X2) may be fused with one benzene ring. The structure fused in this way is as follows.

Ar ¹ and Ar ² are each independently hydrogen, phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or represented by formula (A) (including carbazolyl, benzocarbazolyl and phenyl-substituted carbazolyl). When Ar ¹ or Ar ² is a group represented by formula (A), the group represented by formula (A) is represented by * in formula (3-X1) or formula (3-X2). Bonds with the naphthalene ring.

Ar ³ is phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or a group represented by formula (A) (carbazolyl, benzocarbazolyl and phenyl-substituted carbazolyls). When Ar ³ is a group represented by formula (A), the group represented by formula (A) is bonded to the single bond represented by the straight line in formula (3-X3) at *. . That is, the anthracene ring of formula (3-H) and the group represented by formula (A) are directly bonded.

Ar ³ may have a substituent, and at least one hydrogen in Ar ³ is further alkyl having 1 to 4 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, phenyl, biphenylyl, terphenylyl, naphthyl and phenanthryl. , fluorenyl, chrysenyl, triphenylenyl, pyrenylyl, or a group represented by formula (A) (including carbazolyl and phenyl-substituted carbazolyl). When the substituent of Ar ³ is a group represented by formula (A), the group represented by formula (A) is bonded to Ar ³ in formula (3-X3) at *.

Each Ar ⁴ is independently substituted with hydrogen, phenyl, biphenylyl, terphenylyl, naphthyl, or alkyl having 1 to 4 carbon atoms (methyl, ethyl, t-butyl, etc.) and/or cycloalkyl having 5 to 10 carbon atoms. preferably silyl.

Further, hydrogen in the chemical structure of the anthracene compound represented by formula (3-H) may be replaced with a group represented by formula (A). When substituted with a group of formula (A), the group of formula (A) replaces at least one hydrogen in the compound of formula (3-H) at *.

The group represented by formula (A) is one of the substituents that the anthracene compound represented by formula (3-H) may have.

In formula (A), Y is —O—, —S— or >N—R ²⁹ , and each of R ²¹ to R ²⁸ is independently hydrogen or any group selected from substituent group Z , R ²¹ to R ²⁸ may combine with each other to form a hydrocarbon ring, an aryl ring or a heteroaryl ring, and R ²⁹ is hydrogen or substituted or unsubstituted aryl. At least one hydrogen in formula (A) may be replaced with halogen, cyano or deuterium.
Y in formula (A) is preferably -O-.

[Hole-transporting host material (HH)]
Examples of preferred hole-transporting host materials (HH) include compounds represented by formula (HH-1) and compounds having a partial structure represented by formula (HH-1).

In formula (HH-1),
Q is >O, >S, or >NA;
one carbon atom next to the carbon atom to which Q is bonded in each of the two phenyls in formula (HH-1) may be bonded to each other with L;
L is a single bond, >O, >S or >C(-A) ₂ ;
A is a hydrogen atom, aryl, heteroaryl, _diarylamino , alkyl, cycloalkyl, alkoxy or aryloxy; may be formed.

When the hole-transporting host material contains a structure represented by formula (HH-1) as a partial structure, it may contain one partial structure 1, but preferably contains two or more. When two or more are included, the two or more partial structures may be the same or different. Two or more partial structures may be bonded to each other with a single bond, or may be bonded so as to share any rings contained in the partial structures, and any rings contained in the partial structures may be fused to each other. may be combined in such a way that The substructure may further have substituents selected from aryl, heteroaryl, diarylamino, or aryloxy.

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

Specific examples of hole-transporting host materials include the following compounds.

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

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

In formula (EH-1),
each J is independently =C(-A)- or =N-, and at least three Js are =C(-A)-;
Z is -O-, -S-, -C(=O)-, -P(=O)(-A)-, -P(=S)(-A)-, -N(-A)- , -B(-A)- or -S(=O) ₂ -,
J next to the carbon atom to which Z is bonded and A to which Z is bonded may be bonded to each other with L,
L is a single bond, >O, >S or >C(-A) ₂ ;
A is hydrogen, aryl, heteroaryl, diarylamino _, alkyl, cycloalkyl, triarylsilyl, alkoxy or aryloxy; , may form a cycloalkyl,
When all J are =C(-A)-, either one of A or Z has a heteroatom.

For aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, triarylsilyl, alkoxy or aryloxy represented by A in formula (EH-1), refer to the description of A in formula (HH-1). can. For aryl, heteroaryl, and cycloalkyl when two A's in formula (EH-1) are bonded together to form aryl, heteroaryl, and cycloalkyl, refer to the description in formula (HH-1). can.

When the electron-transporting host material contains the structure represented by Formula (EH-1) as a partial structure, it may contain one partial structure, but preferably contains two or more partial structures. When two or more are included, the two or more partial structures may be the same or different. Two or more partial structures may be bonded to each other with a single bond, or may be bonded so as to share any rings contained in the partial structures, and any rings contained in the partial structures may be fused to each other. may be combined in such a way that The substructure may further have substituents selected from aryl, heteroaryl, diarylamino, or aryloxy.

Specific examples of electron-transporting host materials include the following compounds.

Another preferred example of the electron-transporting host material (compound having a partial structure represented by formula (EH-1)) is a polycyclic aromatic compound represented by the following formula (EH-1b), or the following formula ( Multimers of polycyclic aromatic compounds having a plurality of structures represented by EH-1b) can be mentioned.

In formula (EH-1b),
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 selected from Substituent Group Z;
In formula (EH-1b), X ¹ and X ² are each independently >NR (amine nitrogen), >O, >C(-R) ₂ , >S or >Se; ¹ and X ² cannot both be >C(-R) ₂ ,
Each R in >N--R and >C(--R) ₂ is independently hydrogen or a substituent selected from substituent group Z, and furthermore, aryl, heteroaryl, alkyl or cycloalkyl ( , a second substituent), and the Rs of the above-mentioned >NR and >C(-R) ₂ are each independently connected to the above-mentioned a-ring, b-ring and c-ring by a linking group or a single bond. It may be attached to at least one ring.
Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ (hereinafter also referred to as “Y ¹ etc.”) are each independently =C(-R)- or =N- (pyridinic nitrogen ) and at least one is =N- (pyridinic nitrogen);
Each R in the =C(-R)- is independently hydrogen or a substituent selected from the group Z of substituents.
Adjacent groups among R ¹ , R ² , R ³ , R ⁴ and R ⁵ , and R of ═C(—R)— as Y ¹ to Y ⁶ are bonded to form a ring, b An aryl ring or a heteroaryl ring may be formed together with at least one ring of the ring and the c ring, and at least one hydrogen in the formed ring is aryl, heteroaryl, diarylamino, diheteroarylamino, arylhetero optionally substituted with arylamino, diarylboryl (two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy or aryloxy (these are first substituents) , at least one hydrogen in these may be further substituted with aryl, heteroaryl, alkyl or cycloalkyl (these are the second substituents).
At least one hydrogen in the compound and structure represented by formula (EH-1b) may be replaced with cyano, halogen or deuterium.

In formula (EH-1b), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are all hydrogen, or both R ³ and R ⁴ are hydrogen and R ¹ , R ² and R ⁵ are substituents other than hydrogen, and the others are preferably hydrogen. Preferred substituents are alkyl, aryl optionally substituted with alkyl or heteroaryl, heteroaryl optionally substituted with alkyl or aryl, or diarylamino optionally substituted with alkyl or aryl. At this time, alkyl is preferably alkyl having 1 to 6 carbon atoms (methyl, t-butyl, etc.), aryl is preferably phenyl or biphenyl, and heteroaryl is triazinyl, carbazolyl (2-carbazolyl, 3-carbazolyl , 9-carbazolyl, etc.), pyrimidinyl, pyridinyl, dibenzofuranyl or dibenzothienyl are preferred. Specific examples include phenyl, biphenyl, diphenyltriazinyl, carbazolyltriazinyl, monophenylpyrimidinyl, diphenylpyrimidinyl, carbazolyltriazinyl, pyridinyl, dibenzofuranyl and dibenzothienyl.

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

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

In particular, the polycyclic aromatic compound containing the partial structure represented by formula (EH-1b-N1) has a higher E _S1 , a higher E _T1 and a smaller ΔE _S1T1 than the structure without N.
Specific examples of the polycyclic aromatic compound represented by formula (EH-1b) are shown below.

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

[Combination of hole-transporting host material and electron-transporting host material]
The combination of hole-transporting host material and electron-transporting host material is selected according to the HOMO, LUMO and lowest excited triplet energy levels (E _T1 ) of the hole-transporting host material, the electron-transporting host material and the dopant material. be.
Regarding HOMO and LUMO, 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 shallower than the LUMO of the hole-transporting host material. A combination deeper than (HH) is selected, more specifically, a combination in which HOMO (HH) is shallower than HOMO (EH) by 0.10 eV or more and LUMO (HH) is deeper than HOMO (EH) by 0.10 eV or more is preferable, A combination in which HOMO (HH) is 0.20 eV or more shallower than HOMO (EH) and LUMO (HH) is 0.20 eV or more deeper than HOMO (EH) is more preferable, and HOMO (HH) is 0.25 eV or more than HOMO (EH). A shallow combination in which LUMO (HH) is deeper than HOMO (EH) by 0.25 eV or more is more preferable.

The hole-transporting host material and the electron-transporting host material may be a combination that forms an aggregate called an exciplex. It is generally known that an exciplex is likely to form between a material with a relatively deep LUMO level and a material with a shallow HOMO level. Interaction between a hole-transporting host material and an electron-transporting host material, specifically whether or not an exciplex is formed, can be determined by using a single-layer film consisting of only a hole-transporting host material and an electron-transporting host material. Emission spectra (fluorescence and phosphorescence spectra) are measured by forming under the same conditions as those for forming the light-emitting layer, and the obtained emission spectra are the light emitted by the hole-transporting host material and the electron-transporting host material independently. It can be judged by comparing with the spectrum. The spectrum of the mixed film containing the hole-transporting host material and the electron-transporting host material exhibits an emission wavelength different from the spectrum of the film of the hole-transporting host material and the spectrum of the film of the electron-transporting host material. can be determined by Specifically, a difference of 10 nm or more in the peak wavelengths of the spectra may be used as an index.

Specific examples of combinations of hole-transporting host materials and electron-transporting host materials that do not form exciplexes include the following combinations. In order to satisfy the physical property values of HOMO, LUMO and E _T1 , the hole-transporting host material has carbazole, dibenzofuran, dibenzothiophene, triarylamine, inderocarbazole and benzoxazinophenoxazine as partial structures. Compounds are preferred, compounds having carbazole, dibenzofuran and dibenzothiophene as partial structures are more preferred, and compounds having carbazole as a partial structure are even more preferred. Similarly, in the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide, benzofuropyridine and dibenzooxacillin as partial structures are preferred, and compounds having triazine, phosphine oxide, benzofuropyridine and dibenzooxacillin as partial structures. is more preferred, and triazine-bearing compounds are even more preferred.

More specifically, the hole-transporting host material is HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92 and HH-1-106 to HH- 1-108, and the electron-transporting host material is 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-1-71, EH-1-72, EH-1-90, EH -1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH- It is preferably selected from the group consisting of 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 and EH-1-128.

Specific examples of combinations of hole-transporting host materials and electron-transporting host materials that form an exciplex include the following combinations. In order to satisfy the physical property values of HOMO, LUMO, and E _T1 , compounds having carbazole, triarylamine, inderocarbazole, and benzoxazinophenoxazine as partial structures are preferred as hole-transporting host materials. Compounds having arylamine, inderocarbazole and benzoxazinophenoxazine as partial structures are more preferred, and compounds having triarylamine as a partial structure are even more preferred. Similarly, in the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide and benzofuropyridine as partial structures are preferred, and compounds having triazine, phosphine oxide, benzofuropyridine and dibenzoxacillin as partial structures are more preferred. , phosphine oxides and triazines are more preferred.

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

For other specific combinations of hole-transporting host materials and electron-transporting host materials, see 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 C, 2018, 6, 879284 China mie International Edition. 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684, and Synthetic Metals, 201, 2015, 49.

<Dopant material>
The polycyclic aromatic compound of the present invention having a structure containing structural units represented by Formula (1A) or Formula (1B) is preferably used as a dopant material. In addition, known compounds can be used as dopant materials that can be used, and can be selected from various materials depending on the desired emission color. Specifically, for example, phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene and chrysene condensed ring derivatives, 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, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives (JP-A-1-245087), bisstyrylarylene derivatives (JP-A-2-247278), diazaindacene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl) isobenzofuran derivatives such as isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7- Coumarin derivatives such as methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives, 3-benzoxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyryl derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1 , 2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives and benzofluorene derivatives.

As the emitting dopant material, use a polycyclic aromatic compound containing boron described in WO 2015/102118, WO 2020/162600, paragraphs 0097 to 0269 of JP 2021-077890, etc. is also preferred. Using these polycyclic aromatic compounds containing boron as an emitting dopant material, and assisting the polycyclic aromatic compound of the present invention having a structure containing a structural unit represented by formula (1A) or formula (1B) It may also be used as a dopant material. A polycyclic aromatic compound having boron atoms may be a phosphor or a TADF material (thermally activated delayed phosphor). The polycyclic aromatic compound having boron atoms is preferably a blue light-emitting compound.

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

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

The substituents and Z ¹ and Z ² when the aryl ring or heteroaryl ring in the A ring, B ring, C ring and D ring of formula (12) are substituted are selected from the substituent group Z Substituents can be mentioned.

X ¹ , X ² , X ³ and X ⁴ in formula (12) are each independently >O, >NR, >S or >Se, and R in >NR is each 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.
In the compound represented by formula (12), from the viewpoint of high TADF properties, Z ¹ and Z ² are optionally substituted diphenylamino or optionally substituted N-carbazolyl. is preferred, and diphenylamino, which may have a substituent, is more preferred. The diphenylamino which may have a substituent is preferably unsubstituted diphenylamino or diphenylamino having at least one alkyl of 1 to 4 carbon atoms, and is preferably unsubstituted diphenylamino or m Diphenylamino with at least one methyl in the or o-position is more preferred. From the viewpoint of ease of synthesis and emission wavelength, the aryl or heteroaryl rings other than Z ¹ and Z ² in the A, B, C and D rings are unsubstituted or have 1 to 6 carbon atoms. as other substituents, and it is more preferable that Z ¹ and Z ² are not substituted.
Examples of compounds represented by formula (12) are shown below.

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

the aryl or heteroaryl ring in A ¹¹ ring, A ²¹ ring, A ³¹ ring, B ¹¹ ring, B ²¹ ring, C ¹¹ ring, and C ³¹ of formula (13) and formula (14) is substituted Substituents selected from the substituent group Z can be mentioned as the substituents when and Z ¹ and Z ² .

X ¹¹ , X ¹² , X ²¹ , X ²² , X ³¹ , and X ³² in formulas (13) and (14) are each independently >O, >NR, >S, or >Se; , the Rs in the above >NR are each 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. .

Examples of compounds represented by Formula (13) or Formula (14) are shown below.

<Thermal activated delayed phosphor (assisting dopant)>
"Thermal activated delayed fluorescent material" absorbs thermal energy to cause reverse intersystem crossing from the excited triplet state to the excited singlet state, and radiates from the excited singlet state to emit delayed fluorescence. It means a compound that can However, the term “thermally activated delayed fluorescence” also includes those that pass through a higher triplet in the excitation process from the excited triplet state to the excited singlet state. For example, a paper by Monkman et al., University of Durham (NATURE COMMUNICATIONS, 7:13680, DOI: 10.1038/ncomms13680), a paper by Hosokai et al., National Institute of Advanced Industrial Science and Technology (Hosokai et al., Sci. Adv. 2017;3: e1603282), Kyoto University Sato et al.'s paper (Scientific Reports, 7:4820, DOI: 10.1038/s41598-017-05007-7) and Kyoto University Sato et al. 15, Mechanism of high-efficiency luminescence in organic electroluminescence using DABNA as a luminescent molecule, Graduate School of Engineering, Kyoto University). In the present invention, when the fluorescence lifetime is measured at 300 K for a sample containing the target compound, the target compound is determined to be a "thermally activated delayed phosphor" based on the fact that a slow fluorescent component is observed. Here, the term "slow fluorescence component" refers to a component having a fluorescence lifetime of 0.1 μsec or longer. The fluorescence lifetime can be measured using, for example, a fluorescence lifetime measurement device (C11367-01, manufactured by Hamamatsu Photonics K.K.).

The polycyclic aromatic compound of the present invention having a structure containing a structural unit represented by formula (1A) or formula (1B) can function as an emitting dopant, and the "thermally activated delayed phosphor" is It can function as an assisting dopant that assists the emission of the polycyclic aromatic compound of the present invention.
In the following description, an organic electroluminescence device using a thermally activated delayed phosphor as an assisting dopant may be referred to as a "TAF device" (TADF Assisting Fluorescence device).
The "host compound" in the TAF element means that the excited singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum is higher than the thermally activated delayed phosphor as an assisting dopant and the emitting dopant. It means compound.

FIG. 2 shows an energy level diagram of a light-emitting layer of a TAF device using a general fluorescent dopant as an emitting dopant (ED). In the figure, E (1, G) is the ground state energy level of the host, E (1, S, Sh) is the excited singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the host, and E (1, S, Sh) is the energy level of the host. E (1, T, Sh) is the excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescent spectrum, E (2, G) is the ground state energy level of the assisting dopant, E (2, S, Sh) is the excited singlet energy level obtained from the short-wavelength shoulder of the fluorescence spectrum, and the excited triplet energy level obtained from the short-wavelength shoulder of the phosphorescence spectrum of the assisting dopant is E (2, T, Sh), E (3, G) the energy level of the ground state of the emitting dopant, and E the excited singlet energy level obtained from the short-wavelength shoulder of the fluorescence spectrum of the emitting dopant. (3, S, Sh), E (3, T, Sh) the excited triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the emitting dopant, h + the hole, e - the electron, Fluorescence resonance energy transfer is referred to as FRET (Fluorescence Resonance Energy Transfer). In the TAF element, when a general fluorescent dopant is used as the emitting dopant (ED), the energy upconverted by the assisting dopant is converted to the excited singlet energy level E (3, S, Sh) of the emitting dopant. It moves and emits light. However, some excited triplet energy E(2, T, Sh) on the assisting dopant is transferred to the excited triplet energy level E(3, T, Sh) of the emitting dopant, or At , an intersystem crossing from the excited singlet energy level E(3,S,Sh) to the excited triplet energy level E(3,T,Sh) occurs, followed by a thermal transition to the ground state E(3,G). effectively inactivated. Some of the energy is not available for light emission due to this pathway, resulting in wasted energy.

On the other hand, in the organic electroluminescence device of this aspect, the energy transferred from the assisting dopant to the emitting dopant can be efficiently used for light emission, thereby realizing high light emission efficiency. This is presumed to be due to the following light emission mechanism.
FIG. 3 shows a preferable energy relationship in the organic electroluminescence device of this embodiment. In the organic electroluminescence device of this embodiment, the compound having a boron atom as the emitting dopant has a high excited triplet energy level E(3, T, Sh). Therefore, even if the excited singlet energy upconverted at the assisting dopant intersystem-crosses to the excited triplet energy level E(3,T,Sh) at the emitting dopant, It is either upconverted or recovered to the excited triplet energy level E(2,T,Sh) on the assisting dopant (thermally activated delayed phosphor). Therefore, the generated excitation energy can be used for light emission without waste. It is also expected that the separation of the upconversion and luminescence functions into two separate molecules will reduce the high energy residence time and reduce the burden on the compound.
In this embodiment, known host compounds can be used, for example, compounds having at least one of a carbazole ring and a furan ring. It is preferable to use a compound in which at least one of is bound. Specific examples include mCP and mCBP.

The excited triplet energy level E(1, T, Sh) obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the host compound promotes the generation of TADF in the light-emitting layer without hindering it. E (2, T, Sh) of the emitting dopant or assisting dopant having the highest triplet energy level in the excited triplet energy level E (2, T, Sh), preferably higher than E (3, T, Sh) Specifically, the excited triplet energy level E (1, T, Sh) of the host compound is higher than E (2, T, Sh) and E (3, T, Sh) by 0.01 eV or more. It is preferably 0.03 eV or more, more preferably 0.1 eV or more. A TADF-active compound may also be used as the host compound.

The thermally activated delayed fluorescent substance (TADF compound) used in the TAF element uses an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to perform intramolecular HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital), designed to cause efficient reverse intersystem crossing, donor-acceptor thermally activated delayed phosphor (DA type TADF compound ) is preferred.

Here, the term "electron-donating substituent" (donor) as used herein means a substituent and a partial structure in which a HOMO orbital is localized in a thermally activated delayed phosphor molecule. The term “acceptable substituent” (acceptor) means a substituent and a partial structure in which a LUMO orbital is localized in a thermally activated delayed phosphor molecule.

In general, a thermally activated delayed phosphor using a donor or acceptor has a large spin orbit coupling (SOC) due to its structure, and a small exchange interaction between HOMO and LUMO, resulting in ΔE _S1T1 . Its small size results in very fast reverse intersystem crossing velocities. On the other hand, thermally activated delayed fluorophores using donors and acceptors exhibit greater structural relaxation in the excited state (for some molecules, the stable structure differs between the ground state and the excited state, so external stimuli can cause excitation from the ground state). When the conversion occurs, the structure then changes to the stable structure in the excited state), giving a broad emission spectrum, which can reduce color purity when used as a light-emitting material.

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

The compound used as the assisting dopant in the light-emitting layer of the TAF device is preferably a thermally activated delayed phosphor whose emission spectrum at least partially overlaps with the absorption peak of the emitting dopant.

<Phosphorescent material (assisting dopant)>
A phosphorescent material may be used as an assisting dopant in the light-emitting layer. Phosphorescent materials utilize intramolecular spin-orbital interactions (heavy atom effect) by metal atoms to obtain emission from triplets. As such a phosphorescent material, for example, a luminescent metal complex can be used. Examples of the luminescent metal complex include compounds represented by the following formulas (B-1) and (B-2).

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; XY" is each independently a bidentate ligand.
In formula (B-2), M is at least one selected from the group consisting of Pt, Re and Cu, and "WXYZ" is a tetradentate ligand.
In formula (B-1), M is preferably Ir and n is preferably 3 from the viewpoint of efficiency and life.
In formula (B-2), M is preferably Pt from the viewpoint of efficiency and life.
The ligand (XY) in formula (B-1) has at least one ligand selected from the group consisting of: The ligand (WXYZ) in formula (B-2) has as a part thereof at least one ligand selected from the group consisting of the following.

During the ceremony,
--- is bound to the central metal M,
Y is each independently BR _e , NR _e , PR _e , O, S, Se, C=O, S=O, SO2, CR _e R _f , SiRe _{R f} , or GeRe _{R f} each aromatic carbon C-H in the ring may be independently substituted with N,
R _e and R _f may optionally be fused or joined to form a ring;
R _a , R _b , R _c , and R _d are each independently unsubstituted or optionally substituted from 1 to the maximum possible number of substitutions;
R _a , R _b , R _c , R _d , R _e , and R _f are each independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, or combinations thereof;
However, any two adjacent substituents in R _a , R _b , R _c , and R _d may be fused or joined to form a ring or to form a multidentate ligand.

Examples of compounds 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), fac-Tris(2-(3-p-xylyl) phenyl)pyridine iridium (III), Eu(dbm) ₃ (Phen), Ir(piq) ₃ , Ir(piq) ₂ (acac), Ir(Fliq) ₂ (acac), Ir(FIq) ₂ (acac), Ru(dtb-bpy) ₃ 2(PF ₆ ), Ir(2-phq) ₃ , Ir(BT) ₂ (acac), Ir(DMP) ₃ , Ir(Mphq) ₃ IR(phq) ₂ tpy, 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, and the like.

Other examples of the compound represented by formula (B-1) include the following compounds.

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

2-1-6. Electron Injection Layer and Electron Transport Layer in Organic Electroluminescence Device The electron injection layer 107 plays a role of efficiently injecting electrons moving from the cathode 108 into the light emitting layer 105 or the electron transport layer 106 . The electron transport layer 106 plays a role of efficiently transporting electrons injected from the cathode 108 or electrons injected from the cathode 108 through the electron injection layer 107 to the light emitting layer 105 . The electron transport layer 106 and the electron injection layer 107 are formed by stacking and mixing one or more electron transport/injection materials, or by a mixture of an electron transport/injection material and a polymer binder.

The electron injection/transport layer is a layer in which electrons are injected from the cathode and is responsible for transporting the electrons. It is desirable that the electron injection efficiency is high and the injected electrons are efficiently transported. For this purpose, it is preferable to use a substance that has high electron affinity, high electron mobility, excellent stability, and does not easily generate trapping impurities during production and use. However, when considering the transport balance of holes and electrons, if the function mainly plays the role of efficiently preventing holes from the anode from flowing to the cathode side without recombination, the electron transport capacity is not so high. Even if it is not high, the effect of improving the luminous efficiency is equivalent to that of a material with a high electron transport ability. Therefore, the electron injection/transport layer in this embodiment may also have the function of a layer capable of efficiently blocking the movement of holes.

Materials (electron transport materials) forming the electron transport layer 106 or the electron injection layer 107 include compounds conventionally used as electron transport compounds in photoconductive materials, and those used in the electron injection layer and electron transport layer of organic EL elements. It can be used by arbitrarily selecting from among the known compounds that are known.

Materials used for the electron transport layer or electron injection layer include compounds composed of aromatic rings or heteroaromatic rings composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus, It preferably contains at least one selected from pyrrole derivatives, condensed ring derivatives thereof, and metal complexes having electron-accepting nitrogen. Specifically, condensed ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives typified by 4,4'-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, and naphthalimide derivatives. , quinone derivatives such as anthraquinone and diphenoquinone, phosphorus oxide derivatives, arylnitrile derivatives and indole derivatives. Examples of metal complexes having electron-accepting nitrogen include hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes and benzoquinoline metal complexes. These materials may be used alone, but may be used in combination with different materials.

Specific examples of other electron transfer compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, and oxadiazole. derivatives (1,3-bis[(4-t-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 oxine derivatives, quinolinol metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, 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-phenylbenzimidazole- 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, phosphine oxides derivatives, bis-styryl derivatives and the like.

Metal complexes having electron-accepting nitrogen can also be used, for example, quinolinol-based metal complexes, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, benzoquinoline metal complexes, and the like. can give.

Although the above materials can be used alone, they may be used in combination with different materials.

Borane derivatives, pyridine derivatives, fluoranthene derivatives, BO-based derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol derivatives, among the materials mentioned above. Metal complexes are preferred.

The electron-transporting layer or electron-injecting layer may further contain a substance capable of reducing the material forming the electron-transporting layer or electron-injecting layer. Various substances are used as the reducing substance as long as they have a certain reducing property. from the group consisting of 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 At least one selected can be preferably used.

Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (2.28 eV), Rb (2.16 eV) or Cs (1.95 eV), and Ca (2.95 eV). 9 eV), Sr (2.0 to 2.5 eV) or Ba (2.52 eV), and materials with a work function of 2.9 eV or less are particularly preferred. Among these, more preferred reducing substances are alkali metals of K, Rb or Cs, more preferably Rb or Cs, and most preferably Cs. These alkali metals have a particularly high reducing ability, and by adding a relatively small amount to the material forming the electron transport layer or the electron injection layer, it is possible to improve the emission luminance and extend the life of the organic EL device. As a reducing substance having a work function of 2.9 eV or less, a combination of two or more of these alkali metals is also preferable, particularly a combination containing Cs, such as Cs and Na, Cs and K, Cs and Rb, or A combination of Cs, Na and K is preferred. By containing Cs, the reduction ability can be efficiently exhibited, and by addition to the material forming the electron transport layer or the electron injection layer, the luminance of the organic EL device can be improved and the life of the device can be extended.

2-1-7. The cathode cathode 108 in the organic electroluminescent device plays a role of injecting electrons into the light emitting layer 105 via the electron injection layer 107 and the electron transport layer 106 .

The material for forming the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but the same material as the material for forming the anode 102 can be used. 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 alloys, magnesium - indium alloys, aluminum-lithium alloys such as lithium fluoride/aluminum, etc.). Lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low work function metals are effective in increasing the electron injection efficiency and improving the device characteristics. However, these low work function metals are generally unstable in the atmosphere. In order to improve this point, for example, a method of doping an organic layer with a small amount of lithium, cesium, or magnesium to use a highly stable electrode is known. Other dopants can also be inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide. However, it is not limited to these.

Furthermore, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals, inorganic substances such as silica, titania and silicon nitride, polyvinyl alcohol, vinyl chloride A preferable example is lamination of a hydrocarbon-based polymer compound or the like. The method of manufacturing these electrodes is not particularly limited, either by resistance heating, electron beam deposition, sputtering, ion plating, coating, or the like, as long as it can provide electrical continuity.

2-1-8. A method for producing an organic electroluminescence device Each layer constituting an organic EL device is formed by applying a material to each layer by vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method, printing method, spin coating method or casting method. It can be formed by forming a thin film by a method such as a coating method. The thickness of each layer thus formed is not particularly limited and can be appropriately set according to the properties of the material, but is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a crystal oscillation film thickness measuring device or the like. When thin film formation is performed using a vapor deposition method, the vapor deposition conditions vary depending on the type of material, the desired crystal structure and association structure of the film, and the like. Deposition conditions are generally boat heating temperature +50 to +400°C, degree of vacuum 10 ^-6 to 10 ^-3 Pa, deposition rate 0.01 to 50 nm/sec, substrate temperature -150 to +300°C, film thickness 2 nm to 5 μm. It is preferable to set appropriately within the range.

When a DC voltage is applied to the organic EL device thus obtained, it is sufficient to apply the positive polarity to the positive electrode and the negative polarity to the negative electrode. Light emission can be observed from the side (anode or cathode, and both). Further, this organic EL element emits light even when a pulse current or an alternating current is applied. Note that the AC waveform to be applied may be arbitrary.

Next, as an example of a method for producing an organic EL device, an organic EL device comprising an anode/hole injection layer/hole transport layer/light-emitting layer comprising a host material and a dopant material/electron transport layer/electron injection layer/cathode. The manufacturing method of is explained.

<Deposition method>
A thin film of an anode material is formed on a suitable substrate by a vapor deposition method or the like to prepare an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. A host material and a dopant material are co-deposited thereon to form a thin film to form a light-emitting layer, an electron-transporting layer and an electron-injecting layer are formed on the light-emitting layer, and a thin film of a cathode material is formed by vapor deposition or the like. A target organic EL element is obtained by forming the material and using it as a cathode. In the production of the organic EL element described above, the order of production can be reversed to produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. is.

<Wet film formation method>
The wet film-forming method is carried out by preparing a low-molecular-weight compound capable of forming each organic layer of an organic EL element as a liquid composition for forming an organic layer, and using this. In the absence of a suitable organic solvent for dissolving this low-molecular-weight compound, a reactive compound obtained by substituting a reactive substituent on the low-molecular-weight compound can be used together with other monomers or main-chain polymers that have a solubility function. A composition for forming an organic layer may be prepared from a molecularized polymer compound or the like.

In the wet film-forming method, a coating film is generally formed through a coating step of applying an organic layer-forming composition to a substrate and a drying step of removing a solvent from the applied organic layer-forming composition. In the case where the polymer compound has a crosslinkable substituent (also referred to as a crosslinkable polymer compound), the drying step further crosslinks the polymer to form a crosslinked polymer. Depending on the difference in the coating process, the method using a spin coater is called the spin coating method, the method using a slit coater is the slit coating method, the method using a plate is gravure, offset, reverse offset, flexographic printing, and the method using an inkjet printer is the inkjet method. , the method of spraying in the form of a mist is called the spray method. The drying process includes methods such as air drying, heating, and drying under reduced pressure. The drying step may be performed only once, or may be performed multiple times using different methods and conditions. Also, different methods may be used in combination, such as firing under reduced pressure.

A wet film-forming method is a film-forming method using a solution, and includes, for example, some printing methods (inkjet methods), spin coating methods or casting methods, and coating methods. Unlike the vacuum evaporation method, the wet film formation method does not require the use of an expensive vacuum evaporation apparatus and can form a film under atmospheric pressure. In addition, the wet film formation method enables large-area production and continuous production, leading to a reduction in manufacturing costs.

On the other hand, lamination may be difficult with the wet film-forming method when compared with the vacuum deposition method. When preparing a laminated film using a wet film formation method, it is necessary to prevent the dissolution of the lower layer by the composition of the upper layer. solvent) is used. However, even with those techniques, it can be difficult to use wet deposition methods for all film applications.

Therefore, in general, a method is adopted in which only some layers are formed by a wet film formation method, and the remaining layers are formed by a vacuum vapor deposition method.

For example, the procedure for partially applying the wet film formation method to fabricate an organic EL element is shown below.
(Procedure 1) Film formation of anode by vacuum deposition method (Procedure 2) Film formation of hole injection layer forming composition containing hole injection layer material by wet film formation method (Procedure 3) Hole transport layer material Film formation by a wet film formation method of a composition for forming a hole transport layer containing a host material and a dopant material by a wet film formation method (Procedure 5) Electron transport layer (Procedure 6) Electron injection layer film formation by vacuum vapor deposition method (Procedure 7) Cathode film formation by vacuum vapor deposition method Through this procedure, anode/hole injection layer/hole transport An organic EL device comprising a layer/host material and dopant material comprising a luminescent layer/electron-transporting layer/electron-injecting layer/cathode is obtained.
Of course, the electron-transporting layer and the electron-injecting layer may also be formed by a wet film-forming method using a layer-forming composition containing an electron-transporting layer material and an electron-injecting layer material, respectively. In this case, it is preferable to use a means for preventing dissolution of the lower light-emitting layer or a means for forming a film from the cathode side in reverse to the above procedure.

<Other film forming methods>
A laser thermal lithography method (LITI) can be used to form a film from the composition for forming an organic layer. LITI is a method in which a compound adhered to a base material is thermally vapor-deposited with a laser, and an organic layer-forming composition can be used as the material applied to the base material.

<Optional step>
Appropriate treatment steps, washing steps, and drying steps may be appropriately added before and after each step of film formation. Examples of treatment steps include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent, and heat treatment. Furthermore, a series of steps for fabricating a bank can also be mentioned.

A photolithography technique can be used to fabricate the bank. Positive resist materials and negative resist materials can be used as bank materials that can be used in photolithography. In addition, patternable printing methods such as ink jet method, gravure offset printing, reverse offset printing, and screen printing can also be used. In that case, a permanent resist material can also be used.

<Organic Layer Forming Composition Used in Wet Film Forming Method>
The composition for forming an organic layer is obtained by dissolving a low-molecular-weight compound capable of forming each organic layer of an organic EL element or a high-molecular-weight compound obtained by polymerizing the low-molecular-weight compound in an organic solvent. For example, the composition for forming a light-emitting layer includes at least one dopant material polycyclic aromatic compound (or polymer compound thereof) as a first component, at least one host material as a second component, and a third It contains at least one organic solvent as a component. The first component functions as a dopant component for the light-emitting layer obtained from the composition, and the second component functions as a host component for the light-emitting layer. The third component functions as a solvent that dissolves the first and second components in the composition, and provides a smooth and uniform surface profile during application due to the controlled evaporation rate of the third component itself.

<Organic solvent>
The composition for forming an organic layer contains at least one kind of organic solvent. By controlling the evaporation rate of the organic solvent during film formation, it is possible to control and improve the film formability, the presence or absence of defects in the coating film, the surface roughness, and the smoothness. In addition, when forming a film using an inkjet method, the stability of the meniscus at the pinhole of the inkjet head can be controlled, and the ejection property can be controlled and improved. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, the electrical properties, luminescence properties, efficiency and life of the organic EL device having an organic layer obtained from the composition for forming an organic layer are improved. can be done.

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

(2) Specific Examples of Organic Solvents Examples of organic solvents used in the composition for forming an organic layer include alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, and monocyclic solvents. Examples include, but are not limited to, ketone solvents, solvents having a diester skeleton, fluorine-containing solvents, and the like. Also, the solvents may be used singly or in combination.

<Optional component>
The composition for forming an organic layer may contain optional components as long as the properties thereof are not impaired. Optional components include binders and surfactants.

<Composition and physical properties of composition for forming organic layer>
The content of each component in the organic layer-forming composition is obtained from the good solubility, storage stability, and film-forming properties of each component in the organic layer-forming composition, and the organic layer-forming composition. Good film quality of the coating film, good dischargeability when using the inkjet method, good electrical properties, luminescence properties, efficiency and life of the organic EL element having an organic layer produced using the composition It is determined in consideration of the viewpoint of

The composition for forming an organic layer can be produced by appropriately selecting the above-described components by stirring, mixing, heating, cooling, dissolving, dispersing, and the like by a known method. After preparation, filtration, degassing (also referred to as degassing), ion exchange treatment, inert gas replacement/encapsulation treatment, and the like may be appropriately selected and performed.

2-1-9. APPLICATION EXAMPLES OF THE ORGANIC ELECTROLUMINUM DEVICE The present invention can also be applied to a display device provided with an organic EL device, a lighting device provided with an organic EL device, or the like.
A display device or a lighting device including an organic EL element can be manufactured by a known method such as connecting the organic EL element according to the present embodiment and a known driving device, and can be manufactured by direct current driving, pulse driving, alternating current driving, or the like. It can be driven by appropriately using a known driving method.

Examples of display devices include panel displays such as color flat panel displays, and flexible displays such as flexible color organic electroluminescence (EL) displays (for example, JP-A-10-335066 and JP-A-2003-321546). (See Japanese Patent Laid-Open No. 2004-281086, etc.). Moreover, the display method of the display includes, for example, a matrix method and a segment method. Note that matrix display and segment display may coexist in the same panel.

In the matrix, pixels for display are arranged in a two-dimensional pattern such as a grid pattern or a mosaic pattern, and a set of pixels displays characters and images. The shape and size of the pixels are determined by the application. For example, in the image and character display of personal computers, monitors, and televisions, square pixels with a side of 300 μm or less are usually used, and in the case of a large display such as a display panel, a pixel with a side of mm order is used. become. In the case of monochrome display, pixels of the same color may be arranged, but in the case of color display, pixels of red, green, and blue are displayed side by side. In this case, there are typically delta type and stripe type. As a method for driving this matrix, either a line-sequential driving method or an active matrix method may be used. The line-sequential drive has the advantage of being simpler in structure, but considering the operating characteristics, the active matrix may be superior.

In the segment method (type), a pattern is formed so as to display predetermined information, and a predetermined area is illuminated. Examples include time and temperature displays in digital clocks and thermometers, operating state displays in audio equipment and electromagnetic cookers, and panel displays in automobiles.

Examples of lighting devices include lighting devices such as indoor lighting, backlights for liquid crystal display devices, and the like (for example, JP-A-2003-257621, JP-A-2003-277741, JP-A-2004-119211, and the like). etc.). Backlights are mainly used for the purpose of improving the visibility of display devices that do not emit light by themselves, and are used in liquid crystal display devices, clocks, audio devices, automobile panels, display boards, signs, and the like. In particular, as a liquid crystal display device, especially a backlight for a personal computer, for which thinning is a problem, it is difficult to reduce the thickness of the conventional method because it is made of a fluorescent lamp or a light guide plate. The backlight using the light-emitting element according to 1 is characterized by its thinness and light weight.

2-2. Other Organic Devices The polycyclic aromatic compound according to the present invention can be used for the production of organic field effect transistors, organic thin film solar cells, etc., in addition to the organic electroluminescence devices described above.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

Synthesis example (1):
Synthesis of compound (1-1)

Compound (I-1) was synthesized with reference to Organic Letters (2011), 13(24), 6516-6519.

Step 1 In a flask containing compound (I-1) (0.62 g) and tert-butylbenzene (7.0 ml), a 1.6 M tert-butyllithium pentane solution ( 1.6 ml) was added. After completion of the dropwise addition, the temperature was raised to 60° C. and the mixture was stirred for 2 hours. After cooling to −30° C., boron tribromide (0.63 g) was added, the temperature was raised to room temperature, and the mixture was stirred for 0.5 hour. Then, the mixture was cooled to 0° C. again, N,N-diisopropylethylamine (0.43 ml) was added, and the mixture was stirred at room temperature until heat generation subsided, then heated to 120° C. and heated with stirring for 3 hours. The reaction solution was cooled to room temperature, an aqueous sodium acetate solution cooled in an ice bath, and then heptane were added to separate the layers. Then, after purification with a silica gel short pass column (eluent: toluene), the solid obtained by distilling off the solvent under reduced pressure was dissolved in toluene, heptane was added to reprecipitate, and compound (I-2) (0. 15 g).

Synthesis of compound (1-1) A flask containing compound (I-2) (0.15 g), aniline (0.026 g), potassium carbonate (0.138 g) and acetonitrile (5.0 ml) was heated under reflux for 5 hours. After that, the low boiling point component was distilled off under reduced pressure at 40°C. Water and toluene are added to separate the layers, and the mixture is purified with a silica gel short-path column (eluent: toluene). The solvent is distilled off under reduced pressure, and the obtained solid is dissolved in toluene, and heptane is added to reprecipitate. Purification by sublimation gave 0.06 g of compound (1-1).
LC-MS: [M+H] ⁺ =672.33.

Synthesis example (2):
Synthesis of compound (1-2)

It was synthesized in the same manner as in Synthesis Example (1). Compound (I-3) was synthesized with reference to JP-A-2013-187419.
LC-MS: [M+H] ⁺ =822.40

Synthesis example (3):
Synthesis of compound (1-3)

It was synthesized in the same manner as in Synthesis Example (1). Compound (I-5) was synthesized with reference to JP-A-2013-187419.
LC-MS: [M+H] ⁺ =738.50

Synthesis example (4):
Synthesis of compound (1-4)

It was synthesized in the same manner as in Synthesis Example (1). Compound (I-7) was synthesized with reference to Korean Patent Publication No. 10-2014-0074858.
LC-MS: [M+H] ⁺ =686.46

Synthesis example (5):
Synthesis of compound (1-5)

Compound (I-9) was synthesized in the same manner as in Synthesis Example (1).
A flask containing compound (I-9) (0.13 g) and tert-butylbenzene (2.0 ml) was cooled to 0° C. under a nitrogen atmosphere and boron tribromide (0.30 g) was added. After heating to 80° C. and stirring for 1 hour, the mixture was cooled to 0° C. again, N,N-diisopropylethylamine (0.20 ml) was added, and the mixture was stirred at room temperature until heat generation subsided. Heated and stirred for hours. The reaction solution was cooled to room temperature, an aqueous sodium acetate solution cooled in an ice bath, and then heptane were added to separate the layers. Then, after purification with a silica gel short pass column (eluent: toluene), the solid obtained by distilling off the solvent under reduced pressure is dissolved in toluene, heptane is added to reprecipitate, and sublimation purification is performed to compound (1-5). ) (0.03 g).
LC-MS: [M+H] ⁺ =597.28.

Synthesis example (6):
Synthesis of compound (1-6)

A flask containing compound (I-2) (0.15 g), sodium methanethiol (0.037 g) and dimethylformamide (5.0 ml) was heated under reflux at 80° C. for 3 hours, and then water and toluene were added. After liquid separation and purification with a silica gel short pass column (eluent: toluene), the solvent was distilled off under reduced pressure, and the obtained solid was dissolved in toluene, heptane was added to reprecipitate, and then sublimation purification was performed. 0.07 g of compound (1-6) was obtained.
LC-MS: [M+H] ⁺ =613.26.

Synthesis example (7):
Synthesis of compound (1-7)

It was synthesized in the same manner as in Synthesis Example (1). Compound (I-10) was synthesized with reference to Organic Letters (2011), 13(24), 6516-6519.
LC-MS: [M+H] ⁺ =712.27.

Synthesis example (8):
Synthesis of compound (1-8)

It was synthesized in the same manner as in Synthesis Example (1). Compound (I-12) was synthesized with reference to JP-A-2013-187419.
LC-MS: [M+H] ⁺ =862.34.

Other compounds of the present invention can be synthesized by methods according to the synthesis examples described above by appropriately changing the starting compounds.

<Evaluation of organic EL element>
Evaluation items and evaluation method Evaluation items include driving voltage (V), emission wavelength (nm), CIE chromaticity (x, y), external quantum efficiency (%), maximum wavelength (nm) and half width of emission spectrum ( nm). For these evaluation items, values at the time of appropriate emission luminance can be used.

The quantum efficiency of a light-emitting device includes internal quantum efficiency and external quantum efficiency. The internal quantum efficiency is purely converted from external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting device into photons. indicates the percentage of On the other hand, the external quantum efficiency is calculated based on the amount of photons emitted to the outside of the light-emitting device, and some of the photons generated in the light-emitting layer continue to be absorbed or reflected inside the light-emitting device. Therefore, the external quantum efficiency is lower than the internal quantum efficiency because the light is not emitted to the outside of the light emitting device.

The methods for measuring spectral radiance (luminescence spectrum) and external quantum efficiency are as follows. Using a voltage/current generator R6144 manufactured by Advantest, the device was caused to emit light by applying a voltage. Using a spectral radiance meter SR-3AR manufactured by TOPCON, the spectral radiance in the visible light region was measured from the direction perpendicular to the light emitting surface. Assuming that the light-emitting surface is a perfect diffusion surface, the number of photons at each wavelength is obtained by dividing the measured spectral radiance of each wavelength component by the wavelength energy and multiplying by π. Then, the number of photons in the entire observed wavelength region was integrated to obtain the total number of photons emitted from the device. The external quantum efficiency is obtained by dividing the total number of photons emitted from the device by the number of carriers injected into the device, with the value obtained by dividing the applied current value by the elementary charge as the number of carriers injected into the device. Also, the half width of the emission spectrum is obtained as the width between the upper and lower wavelengths at which the intensity becomes 50% with respect to the maximum emission wavelength.

Next, preparation and evaluation of an organic EL device using the polycyclic aromatic compound of the present invention will be described.

<Examples 1-1 to 1-8, and Comparative Example 1>
Table 1 below shows the material structure of each layer in each organic EL device.

In Table 1, "HI" is ^N4 , ^N4' -diphenyl- ^N4 , ^N4' -bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4, 4′-diamine, “HAT-CN” is 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile, “HT-1” is N-([1,1′-biphenyl ]-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine, and “HT-2” is N,N-bis(4-(dibenzo[b,d]furan-4-yl)phenyl)-[1,1′:4′,1″-terphenyl]-4-amine and “BH” is , 2-(10-phenylanthracen-9-yl)dibenzo[b,d]furan, and “ET-1” is 9,9′-[(5-(6-(1,1′-biphenyl) -4-yl)-2-phenylpyrimidin-4-yl)-1,3-phenylene]bis(9H-carbazole) and "ET-2" is 2-ethyl-1-(4-(10-phenyl Anthracen-9-yl)phenyl)-1H-benzo[d]imidazole. The chemical structure is shown below together with "Liq" and comparative compound (1) (compound described in International Publication No. 2015/102118).

(Example 1-1)
A 26 mm×28 mm×0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) obtained by polishing an ITO film having a thickness of 180 nm by sputtering to a thickness of 150 nm is used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Shinku Co., Ltd.), and HI, HAT-CN, HT-1, HT-2, BH, compound (1-1), and ET-1 were obtained. A molybdenum deposition boat containing ET-2 and ET-2, and an aluminum nitride deposition boat containing Liq, LiF and aluminum were mounted.

The following layers are sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was evacuated to 5×10 ⁻⁴ Pa, first HI was heated to vapor-deposit to a film thickness of 40 nm, then HAT-CN was heated to vapor-deposit to a film thickness of 5 nm, Next, HT-1 was heated and vapor-deposited to a thickness of 45 nm, and then HT-2 was heated and vapor-deposited to a thickness of 10 nm. , 2 and hole transport layers 1, 2 were formed. Next, BH and the compound (1-1) were simultaneously heated and evaporated to a thickness of 25 nm to form a light-emitting layer. The deposition rate was adjusted so that the mass ratio of BH to compound (1-1) was approximately 97:3. Further, ET-1 was heated and vapor-deposited to a thickness of 5 nm, and then ET-2 and Liq were simultaneously heated and vapor-deposited to a thickness of 25 nm to form an electron transport layer consisting of two layers. formed. The deposition rate was adjusted so that the weight ratio of ET-2 to Liq was approximately 50:50. The deposition rate of each layer was 0.01-1 nm/sec. After that, LiF is heated and vapor-deposited at a deposition rate of 0.01 to 0.1 nm/sec so that the film thickness becomes 1 nm, and then aluminum is heated and vapor-deposited so that the film thickness becomes 100 nm to form a cathode. Then, an organic EL device was obtained.

(Examples 1-2 to 1-8, Comparative Example 1)
An organic EL device was obtained in the same manner as in Example 1-1, except that the compound shown in Table 1 was used instead of compound (1-1).

(evaluation)
The organic EL devices of Examples 1-1 to 1-6 and Comparative Example 1 were continuously driven at a luminance of 1000 cd/m ² at an external quantum efficiency (EQE) and LT95 (current density at an initial luminance of 1000 cd/m ² ). time to reach 950 cd/m ² ) was measured. Table 2 shows the results.

Examples 1-1 to 1-8 showed higher efficiency and longer life than Comparative Example 1. The examples using compounds (1-1) to (1-4) having multiple alkyl groups in the structure and X>N-Ph as the dopant were highly efficient. On the other hand, the examples using compounds (1-5) to (1-8) having no alkyl in the structure or having X>O or >S as dopants exhibited a long life.

<Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2>
Table 3 below shows the material structure of each layer in each organic EL element.

(Comparative Example 2-1)
A 26 mm×28 mm×0.7 mm glass substrate (manufactured by OptoScience Co., Ltd.) was used as a transparent support substrate, on which an ITO film having a thickness of 200 nm was formed by sputtering and polished to 50 nm. This transparent support substrate was fixed to a substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Shinku Co., Ltd.), and a molybdenum vapor deposition boat containing HAT-CN, HTL-1, TcTa, ETL-1, and ET7, respectively, Tungsten evaporation boats containing LiF and aluminum, respectively, were installed.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was evacuated to 5×10 ⁻⁴ Pa, and HAT-CN was first heated and evaporated to a thickness of 5 nm to form a hole injection layer. Next, HTL-1 is heated and vapor-deposited to a thickness of 90 nm to form a hole-transport layer 1, and TcTa is heated and vapor-deposited to a thickness of 10 nm to form a hole-transport layer 2. formed. Next, TcTa, ETL-1, BCC-TPTA and comparative compound (1) were simultaneously heated and evaporated to a thickness of 20 nm to form a light-emitting layer. The deposition rate was adjusted so that the mass ratio of TcTa, ETL-1, BCC-TPTA and comparative compound (1) was approximately 44.5:44.5:10:1. Next, ETL-1 is heated and evaporated to a thickness of 20 nm to form an electron transport layer 1, and ET7 is heated and evaporated to a thickness of 10 nm to form an electron transport layer 2. bottom. The deposition rate of each layer was 0.01-1 nm/sec. After that, LiF is heated and vapor-deposited at a deposition rate of 0.01 to 0.1 nm/sec so that the film thickness becomes 1 nm, and then aluminum is heated and vapor-deposited so that the film thickness becomes 100 nm to form a cathode. Then, an organic EL device of Comparative Example 2-1 was obtained. At this time, the deposition rate of aluminum was adjusted to 1 to 10 nm/sec.

The chemical structures in Table 3 and Comparative Example 2-1 are shown below.

(Examples 2-1 to 2-4 and Comparative Example 2-2)
Each device was fabricated by changing the emitting dopant of Comparative Example 2-1 to each material and concentration shown in Table 3.

(evaluation)
Regarding the organic EL devices according to Examples 2-1 to 2-4 and Comparative Examples 2-1 to ^2-2 , the external quantum efficiency and LT50 (at the initial luminance of 1000 cd/m ² The time to reach 500 cd/m ² when continuously driven at a current density) was measured. Table 4 shows the results.

From the comparison with the comparative example, it can be seen that high efficiency and long life can be obtained by using the compound of the present invention. Further, from a comparison between Examples, the use of compound (1-7) provides high efficiency, and the use of compound (1-8) provides long life.

REFERENCE SIGNS LIST 100 organic electroluminescent element 101 substrate 102 anode 103 hole injection layer 104 hole transport layer 105 light emitting layer 106 electron transport layer 107 electron injection layer 108 cathode

Claims (12)

A polycyclic aromatic compound having a structure containing a structural unit represented by the following formula (1A) or formula (1B);

In formula (1A) and formula (1B),
each Z is independently N or C—R ^Z and each R ^Z is independently hydrogen or a substituent;
Two adjacent R ^Z may be bonded to each other to form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring together with the a-ring, b-ring or c-ring,
X is >O, >N—R ^xN , >C(—R ^xC ) ₂ , >Si(—R ^XI ) ₂ , >S, or >Se, and R ^xN is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^XC and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, two R ^XC optionally bonded together to form a ring, and two R ^XI bonded together to form a ring; R ^XN , R ^XC , and R ^XI are each bound to at least one of Z adjacent to the carbon to which X is bound by a linking group or single bond,
two adjacent Y bonds are each independently a single bond or a double bond,
Each Y bonded to an adjacent Y by a single bond is independently >C(-R ^Y1 ) ₂ , and each R ^Y1 is independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted Two R ^Y1 which are heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl and are bonded to the same carbon may be combined to form a ring, and two adjacent R ^Y1 may combine with each other to form a ring,
Y bonded to adjacent Y by a double bond is N or C—R ^Y2 , R ^Y2 is hydrogen or a substituent, and two adjacent R ^Y2 are bonded to each other to form a ring; may be used, provided that two adjacent R ^Y2 do not bond to each other to form a benzene ring,
Y and Z may be bonded to each other to further form a ring consisting of Y—N—C—Z or a ring consisting of Y—C—Z,
At least one of the aryl or heteroaryl rings in the structure may be fused with at least one cycloalkane, the cycloalkane may have at least one substituent, and at least one —CH ₂ — may be replaced with —O—,
At least one hydrogen in the structure may be replaced with cyano, halogen, or deuterium. both Z are C—R ^Z ;
each R ^Z is independently hydrogen, any substituent selected from substituent group Z, or a substituent represented by formula (A30);
The polycyclic aromatic compound according to claim 1, wherein R ^Y2 is each independently hydrogen, any substituent selected from substituent group Z, or a substituent represented by formula (A30);

In formula (A30),
Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted cycloalkenyl, and at least one —CH ₂ — may be replaced with —O— or —S—;
R ^Ak is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^Ak is bonded to Ak through a single bond or a linking group. * is the binding position,
Substituent group Z is
aryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
heteroaryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
diarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (the two aryls may be bonded to each other via a linking group);
diheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two heteroaryls may be bonded to each other via a linking group) ,
arylheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (aryl and heteroaryl may be ),
diarylboryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (the two aryls may be bonded via a single bond or a linking group);
alkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;
cycloalkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;
alkoxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;
It consists of aryloxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl, and substituted silyl. In each of the a ring, b ring, and c ring, R at the para position of ^B is hydrogen, any substituent selected from substituent group Z or a substituent represented by formula (A30), and other R 3. The polycyclic aromatic compound of claim 2, wherein ^Z is hydrogen. X is >O, >N—R ^xN , >C(—R ^xC ) ₂ , or >S;
4. The polycyclic aromatic compound according to any one of claims 1 to 3, wherein R ^XN is substituted or unsubstituted phenyl and both R ^XC are methyl. 5. The polycyclic aromatic compound according to any one of claims 1 to 4, wherein each of two adjacent Y bonds is a single bond. The polycyclic aromatic compound according to claim 5, represented by any one of the following formulas;

In the formula, Me is methyl, and the aryl ring may have alkyl having 1 to 4 carbon atoms or phenyl optionally substituted with alkyl having 1 to 4 carbon atoms as a substituent, and At least one hydrogen in the structure may be replaced with deuterium. 5. The polycyclic aromatic compound according to any one of claims 1 to 4, wherein both bonds of two adjacent Y's are double bonds. The polycyclic aromatic compound according to claim 7, represented by any one of the following formulas;

In the formula, Me is methyl, and the aryl ring may have alkyl having 1 to 4 carbon atoms or phenyl optionally substituted with alkyl having 1 to 4 carbon atoms as a substituent, and At least one hydrogen in the structure may be replaced with deuterium. An organic device material containing the polycyclic aromatic compound according to any one of claims 1 to 8. It has a pair of electrodes consisting of an anode and a cathode and an organic layer disposed between the pair of electrodes, wherein the organic layer contains the polycyclic aromatic compound according to any one of claims 1 to 8. , an organic electroluminescent device. 11. The organic electroluminescent device according to claim 10, wherein said organic layer is a light-emitting layer. A display device or lighting device comprising the organic electroluminescence device according to claim 10 or 11.

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