KR20230046226A - Polycyclic aromatic compound - Google Patents

Abstract

The present invention relates to a polycyclic aromatic compound which has a structure consisting of one or two or more structural units represented by formula (1), wherein an A ring, a B ring, a C ring, and a D ring are substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings, and X^1, X^2, and X^3 are >N-R^XN, >O, >S, or a single bond, etc., and R^XN represents substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl, etc. The polycyclic aromatic compound is useful as a material for organic devices such as organic electroluminescent elements.

Description

Polycyclic aromatic compound {POLYCYCLIC AROMATIC COMPOUND}

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

Conventionally, display devices using electroluminescent light-emitting elements can be reduced in power and reduced in thickness, so various researches have been conducted, and organic electroluminescent elements made of organic materials have been actively studied because they are easy to reduce in weight and increase in size. In particular, for the development of organic materials having luminescent properties such as blue or green, which are one of the three primary colors of light, and the development of organic materials having charge transport capabilities (possibly becoming semiconductors or superconductors) such as holes and electrons, Both high-molecular compounds and low-molecular compounds have been actively studied.

An organic EL element has a structure composed of a pair of electrodes composed of an anode and a cathode, and one layer or a plurality of layers disposed between the pair of electrodes and containing an organic compound. Layers containing organic compounds include a light emitting layer and a charge transport/injection layer that transports or injects charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

As light-emitting materials for the light-emitting layer, three types of fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials are currently used. For example, materials improved from azaborine derivatives have been reported as fluorescent materials (Patent Document 1), noble metal complexes having multidentate ligands, etc. have been developed as phosphorescent materials (Patent Document 2), and thermally activated type A carbazonitrile compound or the like has been developed as a delayed fluorescence (TADF) material (Non-Patent Document 1).

In any device using either material, a material having a high minimum singlet excitation energy or minimum triplet excitation energy is used as an adjacent layer or host of the light emitting layer in order to prevent energy leakage from the light emitting layer or neighboring layers leading to a decrease in efficiency.

Patent Document 1: International Publication No. 2015/102118 Patent Document 2: Japanese Unexamined Patent Publication No. 2014-239225

Non-Patent Document 1: Nature Vol.49213 December 2012

As described above, various materials have been developed as materials used for organic EL devices, but development of materials composed of compounds different from conventional ones is expected in order to increase the choice of materials for organic EL devices. In addition, in Patent Document 1, a polycyclic aromatic compound containing boron and an organic EL device using the same are reported, but in order to further improve device characteristics, materials for light emitting layers and materials for peripheral layers capable of improving luminous efficiency and lifetime of devices is being requested.

As a result of intensive studies to solve the above problems, the inventors of the present invention succeeded in producing a novel polycyclic aromatic compound and found that this compound is effective as a material having high singlet energy and triplet energy. Then, for example, an organic EL element by disposing a light emitting layer using such a polycyclic aromatic compound as a host material or a material of a layer adjacent to the light emitting layer and using a compound having a lower triplet energy as a dopant material between a pair of electrodes. By constituting, it was found that an excellent organic EL element can be obtained, and the present invention was completed. That is, the present invention provides a polycyclic aromatic compound as described below, a material for an organic device containing the polycyclic aromatic compound as described below, and the like.

<1> A polycyclic aromatic compound having a structure composed of one or two or more structural units represented by the following formula (1);

In formula (1),

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;

Ring B and C may further bond through a single bond or linking group, when X ² is a single bond, ring C and ring D may further bond through a linking group, and when X ³ is a single bond, ring D and ring A further bond through a linking group you can do,

X ¹ , X ² and X ³ are each independently >C(-R ^XC ) ₂ , >NR ^XN , >O, >Si(-R ^XI ) ₂ , >S or a single bond, provided that X ¹ and X ² do not form a single bond at the same time,

R ^XC , R ^XN and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, or the same element One or two rings selected from rings A to D bonded to and together with the above elements form a ring, provided that two R ^XC may be bonded to each other, and two R ^XI are bonded to each other, may be,

At least one hydrogen in the compound or structure represented by formula (1) may be substituted with heavy hydrogen, cyano or halogen.

<2> The polycyclic aromatic compound according to <1>, which has a structure composed of one structural unit represented by Formula (1).

<3> The polycyclic aromatic compound according to <1> or <2>, wherein all of ring A, ring B, ring C, and ring D are substituted or unsubstituted benzene rings.

<4> X ¹ , X ² and X ³ are each independently >NR ^XN , >O, >S or a single bond, and R ^XN is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl , The polycyclic aromatic compound according to any one of <1> to <3>.

<5> The polycyclic aromatic compound according to <1>, represented by any of the following formulas.

<6> A material for organic devices containing the polycyclic aromatic compound according to any one of <1> to <5>.

<7> An organic electric field comprising a pair of electrodes composed 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 <1> to <5>. light emitting element.

<8> The organic electroluminescent element according to <7>, wherein the organic layer is a light emitting layer.

<9> The organic electroluminescent element according to <8>, wherein the light emitting layer contains the polycyclic aromatic compound as a host material and a dopant material.

<10> The organic electroluminescent device according to <7>, wherein the organic layer is an electron transport layer.

<11> The organic electroluminescent device according to <7>, wherein the organic layer is a hole transport layer.

<12> A display device or lighting device provided with the organic electroluminescent element according to any one of <7> to <11>.

According to a preferred embodiment of the present invention, by producing an organic EL device using a novel polycyclic aromatic compound as, for example, a host material in the light emitting layer, one component of the host material, or a component of a layer adjacent to the light emitting layer, quantum efficiency and device An organic EL element with excellent lifetime can be provided.

1 is a schematic cross-sectional view showing an organic EL element according to this embodiment.
2 is an energy level diagram showing energy relationships among a host, an assisting dopant, and an emitting dopant of a TAF device using a typical fluorescent dopant.
3 is an energy level diagram showing an example of an energy relationship among a host, an assisting dopant, and an emitting dopant in an organic electroluminescent device according to one embodiment of the present invention.

In the following, the present invention will be described in detail. The description of the constitutional requirements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range expressed using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

In this specification, "hydrogen atom (H)" may be referred to as "hydrogen" in the description of the structural formula. Similarly, "carbon atom (C)" may be referred to as "carbon".

In this specification, "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, "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, “ Ph" represents phenyl, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Tf" represents trifluoromethanesulfonyl, "TMS" represents trimethylsilyl, and "D" represents deuterium.

In this specification, an organic electroluminescent element is sometimes referred to as an organic EL element.

In the present specification, chemical structures and substituents are expressed in terms of carbon number, but the number of carbon atoms in the case where a substituent is substituted in a chemical structure or a substituent is further substituted in a substituent means the number of carbon atoms in each chemical structure or substituent, It does not mean the total carbon number of a chemical structure and a substituent, or the total number of carbon atoms of a substituent and a substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent A of carbon number X" is substituted for "substituent B of carbon number Y", and carbon number Y is substituent A and substituent It is not the carbon number of the sum of B. Further, for example, "substituent B of carbon number Y substituted with substituent A" means that "substituent A (with no carbon number limitation)" is substituted for "substituent B of carbon number Y", and carbon number Y is substituent A and It is not the carbon number of the sum of the substituents B.

In this specification, a substituent may be substituted with another substituent. For example, a specific substituent may be described as "substituted or unsubstituted". This means that the specific substituent is substituted with at least one other substituent or is not substituted. In some cases, "may be substituted" with the same meaning. In this specification, the specific substituent at this time may be referred to as a "first substituent" and the other substituent described above as a "second substituent".

1. of the present invention dahwan aromatic compounds

The polycyclic aromatic compound of the present invention is a polycyclic aromatic compound having a structure composed of one or two or more structural units represented by formula (1).

The inventors of the present invention found that the polycyclic aromatic compound of the present invention in which aromatic rings are linked by hetero elements such as oxygen, nitrogen, and sulfur has a large HOMO-LUMO gap (band gap Eg in thin films) and high triplet energy. Found it. This is because the ring containing a hetero element has low aromaticity, so the reduction of the HOMO-LUMO gap due to the expansion of the conjugated system is suppressed, and a large HOMO-LUMO gap is obtained by suppressing the expansion of the conjugated system using intramolecular strain. It is thought that what could be the cause.

In addition, the polycyclic aromatic compound containing a hetero element according to the present invention is a material having high triplet energy, and is a host compound of a phosphorescent organic EL device or an organic EL device using thermally activated delayed fluorescence, and electron blocking adjacent to a light emitting layer. It is useful also as a layer (electron blocking layer), a hole blocking layer (hole blocking layer), an electron transport layer, or a hole transport layer. Furthermore, since these polycyclic aromatic compounds can arbitrarily move the energies of HOMO and LUMO by introducing a substituent, it is possible to optimize the ionization potential and electron affinity according to the surrounding material.

<Ring structure of structural unit represented by formula (1)>

In Formula (1), "A", "B", "C", and "D" in a circle are symbols representing ring structures represented by circles.

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.

In the substituted or unsubstituted aryl ring or substituted or unsubstituted heteroaryl ring in the A ring, B ring, C ring and D ring of the structural unit represented by Formula (1), "substituted or unsubstituted ( As the substituent in the case of "substituted or unsubstituted)", at least one substituent selected from the substituent group Z described later is preferable.

The structural unit represented by formula (1) has a structure in which a ring structure is further formed by linking at least four aromatic rings, namely A ring, B ring, C ring and D ring, with hetero elements such as oxygen, nitrogen and sulfur. The formed ring structure is a condensed ring structure and is composed of at least two rings, including a 7- to 9-membered ring structure as one ring. The structural unit represented by Formula (1) has a structure in which ring A, ring B, ring C, and ring D are each further condensed with this condensed ring.

The A ring forms a trivalent group having bonds at three consecutive carbon atoms of the aryl ring or heteroaryl ring in the structure. Each of these three bonds binds to X ¹ , N, and X ³ . When ring A is further bonded to another ring, it may be a tetravalent group. Among the A rings, the ring containing carbon having the above three bonds as a ring constituent element is preferably a 5-membered ring or a 6-membered ring, and more preferably a 6-membered ring. This ring may further condense with another ring. A benzene ring is mentioned as an example of a 6-membered ring. Examples of further condensation of the benzene ring with other rings include a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring.

Ring B, C ring and D ring all form a divalent group having a bond at two carbon atoms adjacent to each other in the ring of the aryl ring or heteroaryl ring in the structure. Ring B binds to X ¹ and N in the above two bonds, Ring C bonds to N and X ² in the above two bonds, and Ring D bonds to X ² and X ³ in the above two bonds. are doing When ring B, ring C, and ring D are further bonded to other rings, they may be trivalent. Among the B rings, C rings and D rings, the ring containing carbon having the above two bonds as a ring constituent element is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. This ring may further condense with another ring. A benzene ring is mentioned as an example of a 6-membered ring. Examples of further condensation of the benzene ring with other rings include a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring.

In the structural unit represented by Formula (1), ring B and ring C may be further bonded through a single bond or a linking group, and when X ² is a single bond, ring C and ring D may be further bonded through a linking group, and when X ³ is a single bond, When it is a single bond, ring D and ring A may be further bonded via a linking group. Examples of the linking group include >NR, >C(-R) ₂ , >Si(-R) ₂ , >O or >S. R in this case is each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and >C(-R) ₂ The two Rs in may be bonded to each other to form a ring, and the two Rs in >Si(-R) ₂ may be bonded to each other to form a ring.

A structure in which all of the A rings, B rings, C rings and D rings in formula (1) are substituted or unsubstituted benzene rings can be represented by the following formula (2), and the structural unit represented by formula (2) is formula (1) It is a preferred example of the structural unit represented by

A ring, B ring, C ring and D ring in formula (1) are, respectively, a ring and its substituents, b ring and its substituents, c ring and its substituents, and d ring and its substituents in formula (2), respectively. corresponding to that substituent.

R ^a in Formula (2) is a substituent each independently. This substituent is at least one substituent selected from substituent group Z described later. "R ^a -" is an element constituting the ring at the end of the line and indicates that any one of the substitutable elements may be substituted by the substituent represented by R ^a , and n1 to n4 indicate the number of substitutions. . On the other hand, when the ring in which the end of the line of "R ^a -" is inside is a condensed ring together with a broken line, the substituent represented by R ^a may be substituted at any position in the condensed ring. Specifically, n1 is an integer of 0 to 3, n2 is an integer of 0 to 4, n3 is an integer of 0 to 4, and n4 is an integer of 0 to 4. X ¹ , X ² , X ³ have the same meaning as X ¹ , X ² , X ³ in Formula (1), respectively, and the preferred ranges are also the same.

The broken line in Formula (2) indicates that elements at both ends of the broken line may be connected. Specifically, it is as follows.

A condensed ring may be formed by a ring and a broken line bonded to two carbon atoms of the a ring. A condensed ring may be formed by either of the broken lines bonded to the b ring and the two carbon atoms of the b ring. A condensed ring may be formed by a c ring and a broken line bonded to two carbon atoms of the c ring. A condensed ring may be formed by a broken line bonded to the d ring and the two carbon atoms of the d ring. The formed ring may form a condensed ring together with other rings indicated by broken lines. As the condensed ring formed, any of them is preferably a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring or a carbazole ring.

In addition, the b ring and the c ring may be further bonded such that the broken line is a single bond, >NR ^XBC , >O or >S. When X ² is a single bond, rings c and d may be further bonded with a broken line indicating >NR ^XCD , >O or >S. When X ³ is a single bond, the d and a rings may be further bonded such that the broken line indicates >NR ^XDA , >O or >S. R ^XBC , R ^XCD , and R ^XDA are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl. Here, as a substituent in the case of "substituted or unsubstituted", at least one substituent selected from the substituent group Z described later can be mentioned.

A condensed ring in which at least three rings are condensed is formed by connecting the other cyclic elements at both ends of the broken line. In addition to the carbazole ring, the condensed ring at this time is a phenoxazine ring, a phenothiazine ring, etc. when ring b and c ring are connected. can be heard

In Formula (2), the broken line connecting the elements at both ends is preferably 0 to 3 of the structural units represented by Formula (2), more preferably 0 to 2, and still more preferably 0. .

In formula (2), R ^a is preferably a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl. It is preferable that all of n1-n4 are 0 or 1, and it is more preferable that they are 0.

<X ¹ , X ² , X ³ >

X ¹ , X ² and X ³ are each independently >C(-R ^XC ) ₂ , >NR ^XN , >O, >Si(-R ^XI ) ₂ , >S or a single bond. R ^XC , R ^XN , and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, or the same One or two rings selected from rings A to D bonded to an element and the element together form a ring, provided that two R ^XC may be bonded to each other, and two R ^XI are bonded to each other However, X ¹ and X ² do not form a single bond at the same time.

In R ^XC , R ^XN and R ^XI , the substituent in the case of "substituted or unsubstituted" etc. includes at least one substituent selected from substituent group Z, and includes substituted or unsubstituted aryl, substituted or unsubstituted A substituted heteroaryl, unsubstituted cycloalkyl or unsubstituted alkyl is preferred. As R ^XN , substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl is preferable, and for example, biphenylyl, diphenyltriazinyl, etc., and groups using these as substituents are preferable. As R ^XC and R ^XI , substituted or unsubstituted aryl or unsubstituted alkyl is preferable.

R ^XC , R ^XN , or R ^XI forms a ring with one or two rings selected from A to D rings bonded to the same element together with the above element, which means that the ring is formed by any of the following bonds. means to form

at least one R ^XC of X ¹ >C(-R ^XC ) ₂ bonded to ring A and/or ring B;

R ^XN of >NR ^XN where X ¹ is bonded to ring A and/or ring B;

X ¹ >Si(-R ^XI ) ₂ At least one R ^XI bonded to ring A and/or ring B

X ² >C(-R ^XC ) ₂ where at least one R ^XC is bonded to ring C and/or ring D;

R ^XN of >NR ^XN where X ² is bonded to ring C and/or ring D;

X ² >Si(-R ^XI ) ₂ where at least one R ^XI is bonded to the C ring and/or the D ring;

At least one R ^XC of >C(-R ^XC ) ₂ where X ³ is bonded to ring D and/or ring A:

R ^XN of >NR ^XN of X ³ is bonded to ring D and/or ring A;

At least one R ^XI of X ³ >Si(-R ^XI ) ₂ is bonded to the D ring and/or the A ring.

Among the above, any of the following is preferable.

R ^XN of >NR ^XN where X ² is bonded to ring C and/or ring D; or

R ^XN of >NR ^XN of X ³ is bonded to D ring and/or A ring.

As described above, it is preferable that R ^XC , R ^XN , and R ^XI bonded to one or two rings selected from rings A to D are one or two of the structural units represented by formula (1), , more preferably one.

An example of the ring structure formed is shown below. In the following, it is shown as an example in which R ^XN of X ² >NR ^XN is bonded to the C ring and/or the D ring to form a ring structure.

X ¹ , X ² , and X ³ are each independently >NR ^XN , >O, >S or preferably a single bond, more preferably >O, >S or a single bond, and more preferably a single bond. more preferable

X ¹ is more preferably >0 or a single bond. More preferably, both X ² and X ³ are >NR ^XN , or one of them is >NR ^XN and the other is a single bond. R ^XN is preferably a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl.

<When two groups bonded to the same atom bond to each other>

>C(-R ^XC ) ₂ , >Si(-R ^XI ) ₂ - Two groups (two R ^XC , two R ^XI , other two Rs) bonded to the same atom in the etc. are bonded to each other, respectively. Thus, a ring may be formed. What is necessary is just to couple by a single bond or a linking group (these are collectively referred to as a linking group), and as the linking group, -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- are mentioned, and the following structures are mentioned, for example. Meanwhile, the R of -CHR-CHR-, the R of -CR ₂ -CR ₂ -, the R of -CR=CR-, the R of -N(-R)-, the R of -C(-R) ₂ -, and R in -Si(-R) ₂ - are each independently hydrogen, aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, alkyl which may be substituted with cycloalkyl , alkenyl which may be substituted with alkyl or cycloalkyl, alkynyl which may be substituted with alkyl or cycloalkyl, or cycloalkyl which may be substituted with alkyl or cycloalkyl. Moreover, two adjacent Rs may form a ring, and may form cycloalkylene, arylene, and heteroarylene.

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

The position at which two R are bonded by a bonding group is not particularly limited as long as it can be bonded, but it is preferable to bond at the most adjacent position, for example, when the two groups are phenyl, "C" in phenyl or It is preferable to bond to each other at ortho (second position) positions based on the bonding position (first position) of "Si" (see the above structural formula).

<Specific description of rings and substituents>

The details of the rings and substituents described in this specification are described below.

"Aryl ring" is, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 20 carbon atoms, an aryl ring having 6 to 16 carbon atoms, an aryl ring having 6 to 12 carbon atoms, or a carbon number 6 to 12 ring. an aryl ring of 10; and the like.

Specific "aryl rings" include, for example, a monocyclic benzene ring, a condensed bicyclic naphthalene ring, a condensed tricyclic acenaphthylene ring, a fluorene ring, a phenalene ring, or a phenanthrene ring, an anthracene ring, or a condensed tricyclic ring. A ring system, such as a triphenylene ring, a pyrene ring, or a naphthacene ring, or a condensed five-ring system, such as a perylene ring or a pentacene ring.

The "heteroaryl ring" is, for example, a heteroaryl ring having 2 to 30 carbon atoms, and preferably a heteroaryl ring having 2 to 25 carbon atoms, a heteroaryl ring having 2 to 20 carbon atoms, and a heteroaryl ring having 2 to 15 carbon atoms. , or a heteroaryl ring having 2 to 10 carbon atoms. In addition, a "heteroaryl ring" is, for example, a heterocyclic ring 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, a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring (such as a furazane ring), a thiadiazole ring, a triazole ring, and a tetracyclic ring. sol ring, pyrazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring, indole ring, isoindole ring, 1H-indazole ring, benzoimidazole ring, benzooxazole ring, benzothiazole ring, 1H-benzo Triazole ring, quinoline ring, isoquinoline ring, cinnoline ring, quinazoline ring, quinoxaline ring, phenanthroline ring, phthalazine ring, naphthridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenol Noxathiin ring, phenoxazine ring, phenothiazine ring, phenazine ring, phenazacillin ring, indolizine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, naphthobenzofuran ring, thiophene ring , Benzothiophene ring, isobenzothiophene ring, dibenzothiophene ring, naphthobenzothiophene ring, benzophosphole ring, dibenzophosphole ring, benzophosphole oxide ring, dibenzophosphole oxide ring, thianthrene ring , an indolocarbazole ring, a benzoindolocarbazole ring, a dibenzoindolocarbazole ring, an imidazoline ring, or an oxazoline ring.

In the present specification, the substituent group Z is,

aryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

heteroaryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

diarylamino which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two aryls may be bonded to each other via a linking group);

diheteroarylamino which may be 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 which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (aryl and heteroaryl may be bonded to each other via a linking group);

diarylboryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two aryls may be bonded via a single bond or a linking group);

Alkyl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;

cycloalkyl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

alkoxy which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;

aryloxy which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl, and

It consists of substituted silyl.

The aryl as the second substituent in each group of the substituent group Z may be further substituted with aryl, heteroaryl, alkyl, or cycloalkyl, and similarly, the heteroaryl as the second substituent is aryl, heteroaryl, alkyl, or cycloalkyl. It may be substituted by alkyl.

In the present specification, “aryl” refers to, 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 having 6 to 12 carbon atoms. aryl of 10, etc.

Specific "aryl" includes, for example, monocyclic phenyl, bicyclic biphenylyl (2-biphenylyl, 3-biphenylyl, or 4-biphenylyl), 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), condensed tricyclic, acenaphthylene-(1-, 3-, 4-, or 5-)yl, fluorene-(1-, 2-, 3-, 4-, or 9-)yl, phenalen-(1- or 2-)yl, phenanthrene-(1-, 2-, 3-, 4-, or 9-)yl, or anthracene-(1-, 2-, Or 9-) day, tetracyclic quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl -4-yl, or m-quaterphenyl), condensed tetracyclic, triphenylene-(1- or 2-)yl, pyrene-(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-) days, etc. In addition, the monovalent group of spirofluorene, etc. are mentioned.

In the aryl as the second substituent, the aryl is aryl such as phenyl (specific examples are groups described above), alkyls such as methyl (specific examples are groups described later), and cycloalkyls such as cyclohexyl or adamantyl. (Specific examples are groups described later) and structures substituted with at least one group selected from the group consisting of are also included.

One example thereof is a group in which the ninth position of fluorenyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl.

"Arylene" is, for example, arylene having 6 to 30 carbon atoms, and preferably includes 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 12 carbon atoms. Arylene of 10, etc.

A specific "arylene" includes, for example, a divalent group obtained by removing one hydrogen from the aforementioned "aryl" (monovalent group).

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

Specific examples of "heteroaryl" include pyrroleyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyr Dill, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindoleyl, 1H-indazolyl, benzoimidazolyl, benzooxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl , isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathinyl, phenoxazinil, phenothiazinil, phenazinyl, phenazacillinyl, indolizinyl, furanil, benzofuranil, isobenzofuranil, dibenzofuranil, naphthobenzofuranil, thienyl, benzothienyl, Isobenzothienyl, dibenzothienyl, naphthobenzothienyl, benzophosphoryl, dibenzophosphoryl, monovalent group of benzophosphole oxide ring, monovalent group of dibenzophosphole oxide ring, furazanyl, thianthrenyl , indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl, or oxazolinyl, and the like. In addition, a monovalent group of spirofluorene, a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirovi[silafluorene], and a monovalent group of benzoselenophene are exemplified. .

In the heteroaryl as the second substituent, the heteroaryl is aryl such as phenyl (specific examples are groups described above), alkyls such as methyl (specific examples are groups described later), and cyclohexyl or adamantyl such as cyclohexyl. Structures substituted with at least one group selected from the group consisting of alkyl (specific examples of which will be described later) are also included.

One example thereof is a group in which the ninth position of carbazolyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl. In addition, groups in which nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl, and carbazolyl is 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, and heteroarylene having 2 to 15 carbon atoms. , or heteroarylene having 2 to 10 carbon atoms. In addition, "heteroarylene" is a divalent group such as a heterocycle containing, for example, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen in addition to carbon as ring-constituting atoms.

Specific examples of the "heteroarylene" include a divalent group obtained by removing one hydrogen from the aforementioned "heteroaryl" (monovalent group).

"Diarylamino" is amino in which two aryls are substituted, and the description of "aryl" described above can be cited for details of this aryl.

"Diheteroarylamino" is amino in which two heteroaryls are substituted, and the description of "heteroaryl" described above can be cited for details of this heteroaryl.

"Arylheteroarylamino" is amino in which aryl and heteroaryl are substituted, and the description of "aryl" and "heteroaryl" described above can be cited for details of the aryl and heteroaryl.

The two aryls in diarylamino as the first substituent may be bonded to each other via a linking group, and the two heteroaryls in diheteroarylamino as the first substituent may be bonded to each other via a linking group. The aryl and heteroaryl of arylheteroarylamino as a substituent may be bonded to each other through a linking group. Here, the description of "bonding via a linking group" indicates that, for example, two phenyls of diphenylamino form a bond with a linking group, as shown below. This statement also applies to diheteroarylamino and arylheteroarylamino, formed from aryls or heteroaryls.

Specifically as the linking group, >O, >NR ^X , >C(-R ^X ) ₂ , >Si(-R ^X ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se can be heard R ^X is each independently an 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 to each other via a single bond or a linking group ^XY to form a ring. Examples of X ^Y include >O, >NR ^Y , >C(-R ^Y ) ₂ , >Si(-R ^Y ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se. and R ^Y are each independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. However, when ^XY is >C(-R ^Y ) ₂ and >Si(-R ^Y ) ₂ , two R ^Y are bonded together to form no further ring. Furthermore, alkenylene is also mentioned as a linking group. Any hydrogen of the alkenylene may be each independently substituted with R ^X , and each R ^X is independently an alkyl, cycloalkyl, substituted silyl, aryl, and heteroaryl, which are alkyl, cycloalkyl, substituted silyl, or aryl. may be substituted.

In addition, in the present specification, when simply described as “diarylamino,” “diheteroarylamino,” or “arylheteroarylamino,” unless otherwise specified, each “two aryls of diarylamino are a linking group may be bonded through", "the two heteroaryls of the diheteroarylamino may be bonded to each other through a linking group", and "the aryl and heteroaryl of the arylheteroarylamino may be bonded to each other through a linking group" It is assumed that an explanation such as "is added.

"Diarylboryl" is a boryl in which two aryls are substituted, and the description of "aryl" described above can be cited for details of this aryl. In addition, these two aryls are single bonds or linking groups (for example, -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >C(-R) ₂ , >Si(-R) ₂ , or >Se). Here, the 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 these groups may be further substituted with aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. Moreover, two adjacent Rs may form a ring, and may form cycloalkylene, arylene, and heteroarylene. For the details of the substituents listed here, the description of "aryl", "arylene", "heteroaryl", "heteroarylene", and "diarylamino" described above, and "alkyl" and "alkyl" described later Descriptions of "kenyl", "alkynyl", "cycloalkyl", "cycloalkylene", "alkoxy", and "aryloxy" can be cited. In addition, when it is simply described as "diaryl boryl" in this specification, unless otherwise limited, "two aryls of diaryl boryl may be bonded to each other through a single bond or a linking group". do as there is

"Alkyl" may be either straight chain or branched chain, and is, 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 (C 3 to 24 carbon atoms). branched chain alkyl of 18), alkyl of 1 to 12 carbon atoms (branched chain alkyl of 3 to 12 carbon atoms), alkyl of 1 to 6 carbon atoms (branched chain alkyl of 3 to 6 carbon atoms), alkyl of 1 to 5 carbon atoms (3 carbon atoms) to 5 branched chain alkyl), C1-4 alkyl (C3-4 branched chain alkyl), and the like.

Specific "alkyl" includes, 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-dimethylbutyl, 1,1-diethylbutyl, 1-ethyl-1-methylbutyl, 1-propyl-1-methylbutyl, 1,1,3-trimethylbutyl, 1-ethyl-1,3-dimethyl Butyl, 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, or n-eicosyl.

Regarding "alkenyl", the description of "alkyl" described above can be referred to, and it is a group in which the C-C single bond in the structure of "alkyl" is substituted with a C=C double bond, and not only one but two or more groups Also includes groups in which a bond is substituted with a double bond (also called alkadien-yl or alkathien-yl).

Regarding "alkynyl", the description of "alkyl" described above can be referred to, and it is a group in which the C-C single bond in the structure of "alkyl" is substituted with a C≡C triple bond, and not only one but two or more groups Also includes groups in which a bond is substituted with a triple bond (also called alkadiyn-yl or alkathrin-yl).

"Cycloalkyl" is, for example, a cycloalkyl of 3 to 24 carbon atoms, preferably a cycloalkyl of 3 to 20 carbon atoms, a cycloalkyl of 3 to 16 carbon atoms, a cycloalkyl of 3 to 14 carbon atoms, or a cycloalkyl of 3 to 12 carbon atoms. cycloalkyl, cycloalkyl of 5 to 10 carbon atoms, cycloalkyl of 5 to 8 carbon atoms, cycloalkyl of 5 to 6 carbon atoms, or cycloalkyl of 5 carbon atoms.

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) substituents, 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, bi cyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, or decahydroazulenyl, and the like.

"Cycloalkylene" is, for example, a cycloalkylene having 3 to 24 carbon atoms, preferably a cycloalkylene having 3 to 20 carbon atoms, a cycloalkylene having 3 to 16 carbon atoms, or a cycloalkylene having 3 to 14 carbon atoms. , C3-C12 cycloalkylene, C5-C10 cycloalkylene, C5-C8 cycloalkylene, C5-C6 cycloalkylene, or C5 cycloalkylene.

Specific examples of "cycloalkylene" include divalent groups obtained by removing one hydrogen from the aforementioned "cycloalkyls" (monovalent groups).

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

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

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

"Triarylsilyl" is a silyl group substituted with three aryls, and the description of "aryl" described above can be cited for details of this aryl.

Specific examples of "triarylsilyl" include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl.

"Trialkylsilyl" is a silyl group substituted with three alkyls, and the description of "alkyl" described above can be cited for details of this alkyl.

Specific "trialkylsilyl" includes, for example, trimethylsilyl, triethylsilyl, trin-propylsilyl, triisopropylsilyl, trin-butylsilyl, triisobutylsilyl, tris-butylsilyl, trit- Butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldi Ethylsilyl, isopropyldiethylsilyl, n-butyldiethylsilyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldin- propylsilyl, s-butyldin-propylsilyl, t-butyldin-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, or t-butyldiisopropylsilyl and the like.

"Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyls, and the description of "cycloalkyl" described above can be cited for details of this cycloalkyl.

Specific "tricycloalkylsilyl" is, for example, tricyclopentylsilyl or tricyclohexylsilyl.

"Dialkylcycloalkylsilyl" is a silyl group substituted with two alkyls and one cycloalkyl, and the descriptions of "alkyl" and "cycloalkyl" described above can be cited for details of these alkyls and cycloalkyls. .

"Alkyldicycloalkylsilyl" is a silyl group substituted with one alkyl and two cycloalkyls, and for details of these alkyls and cycloalkyls, the descriptions of "alkyl" and "cycloalkyl" described above can be cited. .

What is necessary is just to select the substituent which the said structural unit has according to the use of the polycyclic aromatic compound which has the structure which consists of 1 or 2 or more structural units represented by Formula (1). Preferably, methyl, t-butyl, adamantyl, phenyl, o-tolyl, naphthyl, biphenylyl, terphenyl, diphenylamino, carbazolyl, dibenzofuranyl, dibenzothiophenyl, 3, 5-di-carbazolylphenyl, carbazolyl substituted phenyl, pyridyl, phenyl substituted pyridyl, bipyridyl, piperidinyl, phenyl substituted piperidinyl, pyrazinyl, phenyl substituted pyrazinyl, triazinyl, 3, 5-diphenyl-triazinyl, biphenyl substituted triazinyl, carbazolyl substituted triazinyl, cyano. When a polycyclic aromatic compound having a structure composed of one or two or more structural units represented by Formula (1) is used as a hole transport layer or a hole transport host, the substituent is diphenylamino, carbazolyl, dibenzofuranyl, Benzothiophenyl, 3,5-di-carbazolylphenyl, and carbazolyl-substituted phenyl are more preferable. When used as an electron transport layer or electron transport host, substituents include pyridyl, phenyl substituted pyridyl, bipyridyl, piperidinyl, phenyl substituted piperidinyl, pyrazinyl, phenyl substituted pyrazinyl, triazinyl, 3,5-di Phenyl-triazinyl, biphenyl-substituted triazinyl, carbazolyl-substituted triazinyl, and cyano are preferred. When used as a host material, substituents include phenyl, naphthyl, biphenylyl, terphenyl, diphenylamino, carbazolyl, dibenzofuranyl, dibenzothiophenyl, 3,5-di-carbazolylphenyl, carbazolyl Bazolyl substituted phenyl, pyridyl, phenyl substituted pyridyl, bipyridyl, piperidinyl, phenyl substituted piperidinyl, pyrazinyl, phenyl substituted pyrazinyl, triazinyl, 3,5-diphenyl-triazinyl, biphenyl Substituted triazinyl and carbazolyl substituted triazinyl are preferred.

In R ^XC , R ^XN , R ^XI , R ^XBC , R ^XCD , and R ^XDA , as a substituent for "substituted or unsubstituted", aryl (may be substituted with aryl or heteroaryl), substituted or unsubstituted heteroaryl (which may be substituted with aryl or heteroaryl), alkyl, cycloalkyl, or a substituent represented by any of the following formulas; and the like.

<Structure consisting of one or more structural units>

The polycyclic aromatic compound of the present invention is a polycyclic aromatic compound having a structure composed of one or two or more structural units represented by formula (1). The polycyclic aromatic compound having a structure composed of one structural unit is a polycyclic aromatic compound represented by the formula described above as a structural unit represented by formula (1). The polycyclic aromatic compound having a structure composed of two or more structural units represented by formula (1) is a compound corresponding to a multimer of the polycyclic aromatic compound represented by the formula described above as the structural unit represented by formula (1). . As for a multimer, a 2-hexamer is preferable, a 2-3mer is more preferable, and a dimer is especially preferable. The multimer may be in the form of having a plurality of the unit structures in one compound, and any rings (A rings, B rings, C rings or D rings) contained in the structural units are shared in a plurality of unit structures and bonded. It may be a form, and any ring (ring A, B, C, or D) contained in the unit structure may be condensed and bonded to each other. Moreover, the form in which the said unit structure couple|bonded with multiple coupling groups, such as a single bond and C1-C3 alkylene, phenylene, and naphthylene, may be sufficient. Among these, a form in which rings are shared and bonded is preferable.

<Description of Substitution with Deuterium, Cyano or Halogen>

At least one hydrogen in the polycyclic aromatic compound of the present invention may be substituted with heavy hydrogen, cyano or halogen. Halogen is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine.

<Specific examples of polycyclic aromatic compounds of the present invention>

Specific examples of the polycyclic aromatic compound of the present invention include compounds represented by any one of the following structural formulas.

2. dahwan Method for producing aromatic compounds

The polycyclic aromatic compound of the present invention basically prepares a condensed ring structure of ring A and ring B in which the position of X3 is halogenated, and a structure containing X2-D ring-X3, respectively (at this time, ring C belongs to which structure may be present), and finally prepared by cyclization.

The intermediate is synthesized by a conventional method, and in the cyclization reaction, for example, in the case of an etherification reaction, a general reaction such as a nucleophilic substitution reaction or a Ullmann reaction can be used, and in the case of an amination reaction, a nucleophilic substitution reaction or a Birchwald-Hartwick reaction can be used. A general reaction can be used.

The cyclization reaction has two cases of cyclization reactions as shown in the following schemes (1) to (2). However, in the following schemes (1) to (2), substituents such as ring A, ring B, ring C, ring D, and leaving groups bonded to X1, X2 and X3 used in the cyclization reaction are omitted.

In the case described above, a method for producing a cyclization reaction will be described below using compounds (a), (b) and (c) in which rings A, B, C and D are benzene rings as examples.

As an example of Case 1, there is the method described in Scheme (3).

In Scheme (3), a cross-coupling reaction can be carried out using a copper catalyst, a palladium catalyst, or the like, so that the desired product can be obtained.

In the scheme (3), when a copper catalyst is used, copper powder, copper oxide or copper halide is used. The base used is cesium carbonate, potassium carbonate, sodium carbonate, calcium carbonate, magnesium carbonate, sodium hydrogen carbonate, tripotassium phosphate, sodium hydride, etc., and the reaction accelerator is crown ether (e.g., 18-crown-6-ether), Polyethylene glycol (PEG), polyethylene glycol dialkyl ether (PEGDM), etc. are mentioned. In addition, N,N-dimethylformamide, nitrobenzene, dimethyl sulfoxide, dichlorobenzene, o-dichlorobenzene, quinoline, etc. are used as the reaction solvent. The reaction temperature is 160 to 250°C, but when the reactivity of the substrate is low, the reaction may be performed at a higher temperature using an autoclave or the like.

In the case of using a palladium catalyst, palladium acetate, palladium chloride, palladium bromide, tris(dibenzylideneacetone)2palladium(0), tris(dibenzylideneacetone)2palladiumchloroform complex(0), tetrakis(triphenyl Phosphine) palladium (0), [1,1'-bis (diphenylphosphino) ferrocene] palladium (II) dichloride dichloromethane complex (1: 1), etc. are used. The base used is lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, sodium hydrogen carbonate, sodium hydride, potassium alkoxy (e.g. potassium methoxy, potassium ethoxy, normal propoxy potassium, isopropoxy potassium, n-butoxypotassium and tert-butoxypotassium, etc.), alkoxysodium (e.g., methoxysodium, ethoxysodium, n-propoxysodium, isopropoxysodium, n-butoxysodium and tert-butoxysodium etc.) can be mentioned. The reaction promoter is 2,2'-(diphenylphosphino)-1,1'-binaphthyl, 1,1'-(diphenylphosphino)ferrocene, dicyclohexylphosphinobiphenyl, di-tert-butyl Phosphinobiphenyl, tri(tert-butyl)phosphine, 1-(N,N-dimethylaminomethyl)-2-(di-tert-butylphosphino)ferrocene, 1-(N,N-dibutylaminomethyl )-2-(di-tert-butylphosphino)ferrocene, 1-(methoxymethyl)-2-(di-tert-butylphosphino)ferrocene, 1,1'-bis(di-tert-butylphosphino ) Ferrocene, 2,2'-bis(di-tert-butylphosphino)-1,1'-binaphthyl, 2-methoxy-2'-(di-tert-butylphosphino)-1,1' -Binaphthyl, etc. are used. In addition, aromatic hydrocarbon solvents such as benzene, toluene, xylene, and mesitylene are used as the reaction solvent. The solvent may be used alone or as a mixed solvent. The reaction temperature is usually carried out in the range of 50 to 200°C, but is more preferably 80 to 140°C.

As examples of case 2, there are methods described in schemes (4) and (5).

In schemes (4) and (5), the target product can be obtained by carrying out intramolecular cross-coupling reaction using a copper catalyst or a palladium catalyst. The reaction conditions at this time are the same as in Scheme (3).

In Scheme (4), thereafter, the obtained intermediate having a ring is subjected to a cross-coupling reaction with an aryl halide compound using a copper catalyst or a palladium catalyst to obtain the target product.

Schemes (1) to (5) described above are methods for producing representative compounds of the polycyclic aromatic compounds of the present invention, and other compounds can also be synthesized by similar methods. The polycyclic aromatic compounds of the present invention also include compounds in which at least a portion of hydrogen is substituted with deuterium, cyano, or halogen. In such compounds, the desired position is deuterated, cyanated, fluorinated, or halogenated such as chlorinated. By using the prepared raw material, it can be manufactured in the same way as above.

3. organic device

The polycyclic aromatic compound according to the present invention can be used as a material for organic devices. As an organic device, an organic electroluminescent element, an organic field effect transistor, or an organic thin-film solar cell etc. are mentioned, for example.

3-1. abandonment electric field light emitting element

Hereinafter, the organic EL element according to the present embodiment will be described in detail based on the drawings. 1 is a schematic cross-sectional view showing an organic EL element according to this embodiment.

<Structure of organic electroluminescent device>

The organic EL device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, and a hole injection layer ( 103), the hole transport layer 104 provided on the hole transport layer 104, the light emitting layer 105 provided on the hole transport layer 104, the electron transport layer 106 provided on the light emitting layer 105, and the electron injection provided on the electron transport layer 106 It has a layer (107) and a cathode (108) provided on the electron injection layer (107).

In addition, the organic EL element 100 is manufactured by reversing the manufacturing order, for example, the substrate 101, the cathode 108 provided on the substrate 101, and the electron injection layer provided on the cathode 108 ( 107), an electron transport layer 106 provided on the electron injection layer 107, a light emitting layer 105 provided on the electron transport layer 106, a hole transport layer 104 provided on the light emitting layer 105, and a hole transport layer It is good also as a structure which has the hole injection layer 103 provided on 104, and the anode 102 provided on the hole injection layer 103.

It is not necessary to have all of the above layers, and the minimum structural unit is composed of an anode 102, a light emitting layer 105, and a cathode 108, and the hole injection layer 103, the hole transport layer 104, and the electron transport layer ( 106), the electron injection layer 107 is an arbitrarily provided layer. In addition, each said layer may consist of a single layer, respectively, and may consist of multiple layers.

As an aspect of the layer constituting the organic EL element, in addition to the constitutional aspect of the above-described "substrate/anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole transport layer/ Emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/emission layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/hole transport layer/emission layer/electron injection layer" / cathode", "substrate/anode/hole injection layer/hole transport layer/emission layer/electron transport layer/cathode", "substrate/anode/emission layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole transport layer/emission layer" /electron injection layer/cathode", "substrate/anode/hole transport layer/light emitting layer/electron transport layer/cathode", "substrate/anode/hole injection layer/light emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer" /Light emitting layer/electron transport layer/cathode”, “substrate/anode/light emitting layer/electron transport layer/cathode”, or “substrate/anode/light emitting layer/electron injection layer/cathode” may be used.

The organic EL element may further have any one or both selected from an electron blocking layer (electron blocking layer) and a hole blocking layer (hole blocking layer). The electron blocking layer has a LUMO shallower than that of the light emitting layer and a HOMO close to that of the light emitting layer or the hole transport layer, and is disposed between the light emitting layer and the hole transport layer. Since electrons stay in the light emitting layer and do not leak into the hole transport layer, shortening of life due to deterioration of the hole transport layer and decrease in efficiency due to reduction in recombination efficiency can be prevented. The hole blocking layer has a HOMO deeper than that of the light emitting layer and a LUMO close to that of the light emitting layer or the hole transporting layer, and is disposed between the light emitting layer and the electron transporting layer. Since the holes stay in the light emitting layer and do not leak into the electron transport layer, shortening of life due to deterioration of the electron transport layer and decrease in efficiency due to reduction in recombination efficiency can be prevented. The hole injection/transport layer may also serve as an electron blocking layer. The electron injection/transport layer may also serve as a hole blocking layer.

The organic EL element may further have a high T1 layer. The high T1 layer has a T1 higher than that of the host compound, assisting dopant compound or emitting dopant compound used in the light emitting layer, and is disposed between the light emitting layer and the hole transport layer and/or between the light emitting layer and the electron blocking layer. The value of T1 energy varies depending on the light emission mechanism of the device, but has a higher T1 than the compound used for the host. By having a high T1 layer around the light emitting layer, the triplet energy is confined and the triplet energy, which is not normally converted to light emission in fluorescent molecules, is converted into singlet energy, so that high efficiency can be obtained. The hole injection/transport layer or the electron blocking layer may serve as the high T1 layer. The electron injection/transport layer or the hole blocking layer may serve as the high T1 layer.

The polycyclic aromatic compound of the present invention is preferably used as a material for an organic electroluminescent device. In general, a compound having a donor structure can be used for a hole transporting host material and a hole transporting layer in a light emitting layer, and a compound having an acceptor structure can be used for an electron transporting host material and an electron transporting layer, and a donor structure and an acceptor structure A compound having both can be used for any of the host and electron transport layer in a hole transport layer and a light emitting layer. For the donor structure and the acceptor structure, reference may be made to, for example, Advanced Functional Materials 2020, 2008332, and the like. More specifically, the donor structure includes a triarylamine structure and a carbazole structure, and the acceptor structure includes a triazine structure, a pyrimidine structure, and a pyridine structure. The polycyclic aromatic compound according to the present invention can be used as a host material, a hole transport layer material, an electron transport layer material, or the like in a light emitting layer depending on the partial structure it has.

<Substrate in organic electroluminescence device>

The substrate 101 is a support for the organic EL element 100, and usually quartz, glass, metal, plastic or the like is used. The substrate 101 is formed in the shape of a plate, film, or sheet 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. Especially, a glass plate and a board made of transparent synthetic resins, such as polyester, polymethacrylate, polycarbonate, and polysulfone, are preferable. In the case of a glass substrate, soda-lime glass, non-alkali glass, etc. are used, and thickness should just have enough thickness to maintain mechanical strength. In addition, a gas barrier film such as a dense silicon oxide film may be formed on at least one side of the substrate 101 to improve gas barrier properties, and in particular, a plate, film or sheet made of synthetic resin having low gas barrier properties is used as the substrate. When used as (101), it is preferable to form a gas barrier film.

<Anode in Organic Electroluminescence Device>

The anode 102 serves to inject holes into the light emitting layer 105 . Meanwhile, 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 them. .

Materials forming the anode 102 include inorganic compounds and organic compounds. Examples of the inorganic compound include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO)) etc.), metal halides (such as copper iodide), copper sulfide, carbon black, ITO glass and Nessa glass. As an organic compound, conductive polymers, such as polythiophene, such as poly(3-methylthiophene), polypyrrole, and polyaniline, etc. are mentioned, for example. In addition, it can be used suitably selected from materials used as anodes of organic EL elements.

<Hole Injection Layer, Hole Transport Layer in Organic Electroluminescent Device>

The hole injection layer 103 serves to efficiently inject holes moving from the anode 102 into the light emitting layer 105 or into the hole transport layer 104 . The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 through the hole injection layer 103 to the light emitting layer 105 . The hole injection layer 103 and the hole transport layer 104 are formed by laminating or mixing one type or two or more types of hole injection/transport materials, respectively. Alternatively, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injection/transport material.

As the hole injection/transport material, it is necessary to efficiently inject/transport holes from the positive electrode between electrodes to which an electric field is applied, and it is preferable to have high hole injection efficiency and efficiently transport the injected holes. For this purpose, it is preferable that the material has a small ionization potential, a high hole mobility, and excellent stability, and is difficult to generate trap impurities during production and use. As a material for the hole transport layer, it is also preferable to use the polycyclic aromatic compound of the present invention.

As the material forming the hole injection layer 103 and the hole transport layer 104, in the photoconductive material, a compound conventionally used as a hole charge transport material, a p-type semiconductor, a hole injection layer of an organic EL device, and a hole Any compound may be selected and used from known compounds used in the 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 (polymers having aromatic tertiary aminos in the main or side chains, 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'-bi phenyl] -4,4'-diamine, N ⁴ ,N ⁴ ,N ^{4 '} ,N ^4' -tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]- Triphenylamine derivatives such as 4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburstamine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (no metals, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone-based compounds, benzofuran derivatives or thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (e.g., 1,4,5,8,9,12-hexaaza triphenylene-2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. In the polymer system, polycarbonates or styrene derivatives having the above monomers in their side chains , polyvinylcarbazole, polysilane, etc. are preferable, but it is not particularly limited as long as it is a compound capable of forming a thin film necessary for manufacturing a light emitting device, injecting holes from an anode, and transporting holes.

It is also known that the conductivity of an organic semiconductor is strongly influenced by its doping. Such an organic semiconductor matrix material is composed of a compound having good electron donating property or a compound having good electron accepting property. For doping of electron donor materials, strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are used. known (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz , M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes by an electron transfer process in an electron donating base material (hole transport material). Depending on the number and mobility of holes, the conductivity of the base material varies considerably. As matrix materials having hole transport properties, for example, benzidine derivatives (TPD, etc.) or starburstamine derivatives (TDATA, etc.), or specific metal phthalocyanines (particularly, zinc phthalocyanine (ZnPc), etc.) are known (Japanese Patent Publication) Publication No. 2005-167175).

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

<Light-emitting layer in organic electroluminescent device>

The light-emitting layer 105 is a layer that emits light by recombination of holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material for forming the light emitting layer 105 may be a compound (luminescent compound) that is excited by recombination of holes and electrons and emits light. It is preferable that it is a compound which shows. It is also preferable to use the polycyclic aromatic compound of the present invention as a material for a light emitting layer.

The light emitting layer may be either a single layer or a plurality of layers, and each is formed of a light emitting layer material (host material, dopant material). The host material and the dopant material may be of one type, a combination of a plurality of materials, or any of them. The dopant material may be included in the entire host material, or partially included, or any of them may be used. As the doping method, it can be formed by co-evaporation with the host material, but it may be deposited simultaneously after mixing with the host material in advance, or formed into a film by wet film forming after mixing with the host material in advance with an organic solvent.

The amount of host material used varies depending on the type of host material, and may be determined according to the characteristics of the host material. The standard for the amount of host material used is preferably 50 to 99.999% by mass, more preferably 80 to 99.95% by mass, still more preferably 90 to 99.9% by mass with respect to 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 characteristics of the dopant material. The reference amount of the dopant material used is preferably 0.001 to 50% by mass, more preferably 0.05 to 20% by mass, still more preferably 0.1 to 10% by mass with respect to the total mass of the material for the light emitting layer. The above range is preferable in that, for example, the concentration quenching phenomenon can be prevented. From the standpoint of durability, it is also preferable that part or all of the hydrogen in the dopant material is deuterated.

As the dopant material, you may use an emitting dopant and an assisting dopant material. As the assisting dopant material, it is preferable to use a thermally activated delayed fluorescent material. In an organic EL device using an assisting dopant material, it is preferable that the amount of the emitting dopant material used is low in concentration to prevent concentration quenching. A high concentration of the assisting dopant material is preferred from the viewpoint of the efficiency of the thermally activated delayed fluorescence device. In addition, in an organic electroluminescent device using a thermally activated delayed fluorescence assisting dopant material, in terms of the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant material, the amount of the assisting dopant material is compared to the amount of the assisting dopant material. It is preferable that the amount used is low concentration.

In the case where an assisting dopant material is used, the standards for the amounts of the host material, the assisting dopant material, and the emitting dopant material used are 40 to 99% by mass and 59 to 1% by mass, respectively, with respect to 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, 29 to 10% by mass and It is 5-0.05 mass %.

<Host Material>

As the host material, condensed ring derivatives such as anthracene and pyrene, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, fluorene derivatives, Benzofluorene derivatives, N-phenylcarbazole derivatives, carbazonitrile derivatives, etc. are mentioned.

The triplet energy of the host material is preferably higher than the triplet energy of the dopant or assisting dopant having the highest triplet energy in the light emitting layer from the viewpoint of promoting the generation of TADF in the light emitting layer without hindering it, Specifically, the triplet energy of the host material is preferably 0.01 eV or higher, more preferably 0.03 eV or higher, and still more preferably 0.1 eV or higher. Further, a compound having TADF activity may be used for the host material.

One type of host material may be sufficient as it, and a some combination may be sufficient as it. In the case of a plurality of combinations, a combination of a hole-transporting host material and an electron-transporting host material is preferable.

The polycyclic aromatic compound of the present invention can be preferably used as a host material. The polycyclic aromatic compound of the present invention may be used alone, may be used as a hole-transporting host material, or may be used as an electron-transporting host material.

[Hole-transporting host material (HH)]

Examples of preferable hole-transporting host materials (HH) include, in addition to the polycyclic aromatic compounds of the present invention, compounds represented by formula (HH-1) and compounds having partial structures represented by formula (HH-1).

In formula (HH-1),

Q is >O, >S, or >N-A;

The carbon atom to which Q is bonded in each of the two phenyls in the formula (HH-1) and the adjacent one carbon atom may be bonded to each other by L,

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

A is hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy or aryloxy, and the two A's in >C(-A) ₂ are bonded to each other to form aryl, heteroaryl, cycloalkyl may form

When the hole-transporting host material contains the structure represented by formula (HH-1) as a partial structure, it may contain one partial structure, but it is also preferable to include two or more of these partial structures. When two or more are included, the two or more partial structures may be the same as or different from each other. Two or more partial structures may be bonded to each other by a single bond, may be bonded by sharing an arbitrary ring included in the partial structure, or may be bonded by condensing arbitrary rings included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

The hole-transporting host material has at least one partial structure selected from the group consisting of a triarylamine structure, a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring, and a phenoxazine or phenothiazine-containing condensed polycyclic ring. It is preferable that it is a compound containing. The hole-transporting host material may contain one such partial structure, but it is also preferable to include two or more. When two or more are included, the two or more partial structures may be the same as or different from each other.

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

Among 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 transport host material (EH)]

Examples of the electron-transporting host material (EH) include, in addition to the polycyclic aromatic compound of the present invention, a compound represented by formula (EH-1) and a compound having a partial structure represented by formula (EH-1).

In formula (EH-1),

J is, each 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(=0) ₂ -,

The carbon atom to which Z is bonded and the A to which neighboring J and Z are bonded may be bonded to each other by L,

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

A is hydrogen, aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, triarylsilyl, alkoxy or aryloxy, and the two A's in >C(-A) ₂ are bonded to each other to form aryl, hetero may form aryl or cycloalkyl;

When all J's are =C(-A)-, either A or Z has a heteroatom.

Description of A in formula (HH-1) for aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, triarylsilyl, alkoxy or aryloxy represented by A in formula (EH-1) can refer to. For aryls, heteroaryls, and cycloalkyls when two A's in formula (EH-1) combine with each other to form an aryl, heteroaryl, or cycloalkyl, see the description in formula (HH-1). can do.

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 it is also preferable to include two or more of these partial structures. When two or more are included, the two or more partial structures may be the same as or different from each other. Two or more partial structures may be bonded to each other by a single bond, may be bonded by sharing an arbitrary ring included in the partial structure, or may be bonded by condensing arbitrary rings included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

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

As another preferable example of the electron-transporting host material (a compound having a partial structure represented by formula (EH-1)), a polycyclic aromatic compound represented by the following formula (EH-1b) or a compound represented by the following formula (EH-1b) Polymers of polycyclic aromatic compounds having a plurality of supporting structures are exemplified.

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, and X ¹ and X ² together does not result in >C(-R) ₂ ,

R in >NR and >C(-R) ₂ is each independently hydrogen or a substituent selected from substituent group Z, and R in >NR and >C(-R) ₂ is each independently a linking group. Alternatively, it may be bonded to at least one of the a-rings, b-rings and c-rings by a single bond.

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- (pyridinous nitrogen) , and at least one is =N-(pyridinic nitrogen),

R in =C(-R)- above is each independently hydrogen or a substituent selected from substituent group Z.

Adjacent groups among R ¹ , R ² , R ³ , R ⁴ and R ⁵ , and R in =C(-R)- as Y ¹ to ^{Y 6} are bonded to each other to form ring a, ring b and ring c An aryl ring or a heteroaryl ring may be formed together with at least one of the rings, and the formed ring may be substituted with at least one group selected from substituent group Z.

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

In the 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 also It is preferable that any one or more selected from the group which consists of is a substituent other than hydrogen, and others are hydrogen. As the substituent, aryl which may be substituted with alkyl, alkyl or heteroaryl, heteroaryl which may be substituted with alkyl or aryl, or diarylamino which may be substituted with alkyl or aryl is preferable. At this time, the alkyl is preferably an alkyl having 1 to 6 carbon atoms (methyl, t-butyl, etc.), the aryl is preferably phenyl or biphenyl, and the 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. can be heard

Y ¹ and the like are each independently =C(-R)- or =N-, and at least one of them 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 and Y ⁶ are =N- (a ring is a pyridine ring), Y ² and Y ⁵ are =N- (b ring and ring c is pyridine ring), Y ³ and Y ⁴ are =N- (ring b and c are pyridine rings), Y ² to ^{Y 5} are =N- (ring b and c are pyrimidine rings), Y ¹ , Y ³ , Y ⁴ and Y ⁶ are =N- (ring a is a pyrimidine ring, ring b and ring c are a pyridine ring), Y ¹ , Y ² , Y ⁵ and Y ⁶ are =N- (ring a is a pyrimidine ring, ring b and c ring is a pyridine ring), Y ¹ to ^{Y 6} is =N- (ring a, b and c are pyrimidine rings), and Y ² or Y ⁵ is =N- (ring b or c is a pyridine ring).

Further, in addition to the arrangement relationship of =N- above, it is preferable that X ¹ and X ² are >0, and a polycyclic aromatic compound containing a partial structure represented by any one of the following formulas is preferable.

In particular, a polycyclic aromatic compound having a partial structure represented by formula (EH-1b-N1) has higher E _S1 , higher E _T1 , and smaller ΔE _S1T1 than a 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 ∼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]

A combination of the hole-transporting host material and the electron-transporting host material is selected according to the HOMO, LUMO, and triplet excitation energy of the hole-transporting host material, the electron-transporting host material, and the dopant material.

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 deeper than the LUMO (HH) of the hole-transporting host material. Select a combination, more specifically, a combination in which HOMO(HH) is 0.10 eV or more shallower than HOMO(EH), LUMO(HH) is 0.10 eV or more deeper than HOMO(EH), and HOMO(HH) is HOMO A combination in which 0.20eV or more shallow than (EH), LUMO(HH) is 0.20eV or more deeper than HOMO(EH) is more preferable, HOMO(HH) is 0.25eV or more shallower than HOMO(EH), and LUMO(HH) is HOMO A combination at least 0.25 eV deeper than (EH) is more preferable.

The hole-transporting host material and the electron-transporting host material may be a combination that forms an association called an exciplex. It is generally known that exciplex is easy to form between a material having a relatively deep LUMO level and a material having a shallow HOMO level. The interaction of the hole-transporting host material and the electron-transporting host material, specifically, whether or not an exciplex is formed is determined by forming a monolayer film composed of the hole-transporting host material and the electron-transporting host material under the same conditions as the formation conditions of the light emitting layer, and emitting light. It can be judged by measuring the spectrum (fluorescence and phosphorescence spectrum) and comparing the obtained emission spectrum with the emission spectrum exhibited by each of the hole-transporting host material and the electron-transporting host material alone. The spectrum of the mixed film containing the hole-transporting host material and the electron-transporting host material can be determined by showing an emission wavelength different from both the spectrum of the film of the hole-transporting host material and the spectrum of the film of the electron-transporting host material. Specifically, what is necessary is just to use the indicator as the peak wavelengths of the spectra differing by 10 nm or more.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material that do not form an exciplex include the following combinations. In order to satisfy the above physical property values of HOMO, LUMO and excitation triplet energy, in the hole transporting host material, carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolocarbazole and benzoxazinophenoxazine A compound having as a partial structure is preferable, a compound having carbazole, dibenzofuran and dibenzothiophene as a partial structure is more preferable, and a compound having carbazole as a partial structure is even more preferable. Similarly, in the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide, benzofuropyridine and dibenzoxacillin as partial structures are preferred, and triazine, phosphine oxide, benzofuropyridine and dibenzooxa A compound having silin as a partial structure is more preferred, and a compound having triazine is 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 It is preferably selected from the group consisting of, 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-1-130 It is preferable to be selected from the group. Preferred examples of combinations include compound HH-1-1 and compound EH-1-22, compound HH-1-1 and compound EH-1-23, compound HH-1-1 and compound EH-1-24, compound HH- 1-2 and compound EH-1-22, compound HH-1-2 and compound EH-1-23, compound HH-1-2 and compound EH-1-24, or compound HH-1-1 and compound EH- 1-128 may be cited.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material forming an exciplex include the following combinations. In order to satisfy the above physical properties of HOMO, LUMO and excitation triplet energy, compounds having carbazole, triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are preferred for the hole-transporting host material, , compounds having triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are more preferred, and compounds having triarylamine as partial structures 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 triazine, phosphine oxide, benzofuropyridine, and dibenzoxacillin as partial structures. Compounds having phosphine oxide and triazine 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, HH-1 It is preferably selected from the group consisting of -23 and HH-1-24, and 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. Preferable 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 heard.

In addition, for a specific combination of a hole-transporting host material and an electron-transporting host material, Organic Electronics 66 (2019) 227-24, Advanced. Functional Materals 25 (2015) 361-366., Advanced Materials 26 (2014) 4730-4734., ACS Applied Materials and Interfaces 8 (2016) 32984-32991., ACS Applied Materals and Interfaces 2016, 8, 9806-9810, ACS Applied Materials and Interfaces 2016, 8, 32984-32991, Journal of Materials Chemisty C, 2018, 6, 8784-8792, Angewante Chemie International Edition. 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684, and Synthetic Metals, 201, 2015, 49 may be referred to.

<Dopant material>

As the dopant material, a known compound can be used, and it can be selected from various materials depending on the desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene and chrysene, benzoxazole derivatives, and benzothiazole derivatives, benzoimidazole 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 (Japanese Patent Laid-Open No. 1-245087), bisstyrylarylene derivatives (Japanese Patent Laid-Open No. 2 -247278), diazaindacene derivatives, furan derivatives, benzofuran derivatives, phenyl isobenzofuran, dimethyl isobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)iso Isobenzofuran derivatives such as benzofuran and phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7 -Coumarin derivatives such as acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzoimidazolylcoumarin derivatives, and 3-benzooxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, Quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrimethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, bioranthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives and benzofluorene derivatives, and the like.

As a dopant material, it is also preferable to use a polycyclic aromatic compound containing boron described in International Publication No. 2015/102118, International Publication No. 2018/212169, International Publication No. 2020/162600 and the like. The polycyclic aromatic compound having a boron atom may be a phosphor or a TADF material (heat activated delayed phosphor). The polycyclic aromatic compound having a boron atom is preferably a blue light emitting compound.

By reducing the energy difference between the singlet excited state and the triplet excited state, inverse intersystem crossing from the triplet excited state, which usually has a low transition probability, to the excited singlet state is generated with high efficiency, thereby emitting light from the singlet (thermal activity). delayed fluorescence, TADF) is expressed. In normal fluorescence emission, since 75% of triplet excitons generated by current excitation pass through the thermal deactivation pathway, they cannot be extracted as fluorescence. On the other hand, in TADF, all excitons can be used for fluorescence, and a highly efficient organic EL device can be realized.

As a preferable example of the polycyclic aromatic compound containing boron, the compound represented by following formula (12), formula (13), or formula (14) is mentioned.

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, wherein R of >NR is substituted or unsubstituted aryl, substituted or unsubstituted hetero aryl or substituted or unsubstituted alkyl, and R in >NR may be bonded to the A ring, B ring, C ring and/or D ring by a linking group or a single bond;

R ¹ and R ² are each independently hydrogen, alkyl having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, or diarylamino (wherein aryl is aryl having 6 to 12 carbon atoms); ,

Z ¹ and Z ² are each independently a substituent selected from substituent group Z, Z ¹ may bond to the A ring through a linking group or a single bond, and Z ² may bond to the C ring through a linking group or a single bond; and,

At least one hydrogen in the compound represented by formula (12) may be substituted with cyano, halogen or deuterium.

In the A ring, B ring, C ring and D ring of formula (12), as the substituent when the aryl ring or heteroaryl ring is substituted, and Z ¹ , Z ² , a substituent selected from substituent group Z is exemplified. there is.

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 6 carbon atoms It is aryl of -12, heteroaryl of 2-15 carbon atoms, cycloalkyl of 3-12 carbon atoms, or alkyl of 1-6 carbon atoms.

In the compound represented by formula (12), from the viewpoint of high TADF property, it is preferable that Z ¹ and Z ² are diphenylamino which may have a substituent or N-carbazolyl which may have a substituent, and has a substituent It is more preferable that it is also diphenylamino. As diphenylamino which may have a substituent, unsubstituted diphenylamino or diphenylamino having at least one alkyl of 1 to 4 carbon atoms is preferable, and unsubstituted diphenylamino or m-position or o relative to N Diphenylamino having at least one methyl at the position is more preferred. From the viewpoint of the ease of synthesis and emission wavelength, the aryl or heteroaryl ring in the A ring, B ring, C ring, and D ring has no substituents other than Z ¹ and Z 2 , or only alkyl having 1 to 6 carbon atoms other than Z 1 and Z ² . It is preferable to have as a substituent, and it is more preferable to have no substituent other than Z ¹ and Z ² .

The example of the compound represented by Formula (12) is 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 ring. ,

Y ¹¹ , Y ²¹ , 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, wherein R in >NR is substituted or unsubstituted aryl , substituted or unsubstituted heteroaryl or substituted or unsubstituted alkyl, and R in >NR is A ¹¹ ring, A ²¹ ring, A ³¹ ring, B ¹¹ ring, B ²¹ ring by a linking group or a single bond. , may be bonded to the C ¹¹ ring, and/or the C ³¹ ring;

At least one hydrogen in the compounds represented by formulas (13) and (14) may be substituted with cyano, halogen or deuterium.

The aryl ring or heteroaryl ring in the A ¹¹ ring, the A ²¹ ring, the A ³¹ ring, the B ¹¹ ring, the B ²¹ ring, the C ¹¹ ring, and the C ³¹ ring in Formulas (13) and (14) is substituted. As the substituent and Z ¹ , Z ² when present, a substituent selected from the substituent group Z is exemplified.

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, and the above R in >NR is each independently an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, or an alkyl having 1 to 6 carbon atoms.

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

In the light emitting layer, while using the polycyclic aromatic compound of the present invention as a host material, it is preferable to use a phosphorescent material or a TADF material (heat activated delayed phosphor) as a dopant material. The phosphorescent material or TADF material may be included in the light emitting layer as an emitting dopant or may be included as an assisting dopant.

[Phosphorescent material]

Phosphorescent materials utilize intramolecular spin-orbit interactions (heavy atom effect) by metal atoms to obtain light emission from triplets. As such a phosphorescent material, a luminescent metal complex can be used, for example. Examples of the luminescent metal complex include compounds represented by the following formula (B-1) and the following formula (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, and "X-Y" are 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 "W-X-Y-Z" is a tetradentate ligand.

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

In Formula (B-2), M is preferably Pt from the viewpoint of efficiency and lifetime.

The ligand (X-Y) in the formula (B-1) has at least one ligand selected from the group consisting of the following. The ligand (W-X-Y-Z) in the formula (B-2) has at least one ligand selected from the group consisting of the following as a part.

step,

--- in combination with 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 , SiR _e R _f , or GeR _e R _f ;

Aromatic carbons C-H in the ring may each independently be substituted with N,

R _e and R _f may be optionally condensed or bonded to form a ring,

R _a , R _b , R _c , and R _d may each independently be unsubstituted or substituted by 1 to the maximum number of substitutions;

R _a , R _b , R _c , R _d , R _e , and R _f are each, independently, hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl , cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, or a combination thereof,

However, arbitrary two adjacent substituents in R _a , R _b , R _c , and R _d may form a ring by condensation or bonding, or may form a multidentate ligand.

Examples of the compound represented by formula (B-1) include Ir(ppy) ₃ , Ir(ppy) ₂ (acac), Ir(mppy) ₃ , Ir(PPy) ₂ (m-bppy), BtpIr( acac), Ir(btp) ₂ (acac), Ir(2-phq) ₃ , Hex-Ir(phq) ₃ , Ir(fbi) ₂ (acac), fac-Tris(2-(3-p-xylyl) phenyl)pyridine iridium(III), Eu(dbm) ₃ (Phen), Ir(piq) ₃ , Ir(piq) ₂ (acac), Ir(Fliq) ₂ (acac), Ir(Flq) ₂ (acac), Ru(dtb-bpy) ₃ 2(PF ₆ ), Ir(2-phq) ₃ , Ir(BT) ₂ (acac), Ir(DMP) ₃ , Ir(Mphq) ₃ IR(phq) ₂ tpy, fac -Ir(ppy) ₂ Pc, Ir(dp)PQ ₂ , Ir(Dpm)(Piq) ₂ , Hex-Ir(piq) ₂ (acac), Hex-Ir(piq) ₃ , Ir(dmpq) ₃ , Ir (dmpq) ₂ (acac), FPQIrpic, and the like.

As a compound represented by Formula (B-1), the compound represented by a following formula is mentioned, for example in addition to this.

Further, Japanese Unexamined Patent Publication No. 2006-089398, Japanese Unexamined Patent Publication No. 2006-080419, Japanese Unexamined Patent Publication No. 2005-298483, Japanese Unexamined Patent Publication No. 2005-097263, and Japanese Unexamined Patent Publication No. 2004-111379, US Patent Iridium complexes described in the specification of 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- The platinum complex described in An Outlook On the Empirical Features and Its Recent Technological Advancements, Chapter 5 may be used.

[Heat activated delayed phosphor used as assisting dopant]

"Thermally activated delayed phosphor" is a phosphor capable of absorbing thermal energy to cause inverse intersystem crossing from the lowest triplet excited state to the lowest singlet excited state, and radiatively deactivated from the lowest singlet excited state to emit delayed fluorescence. means compound. However, "heat-activated delayed fluorescence" includes high-order triplet excitation in the excitation process from the lowest triplet excited state to the lowest singlet excited state. For example, a paper by Monkmans, Durham University (NATURE COMMUNICATIONS, 7:13680, DOI:10.1038/ncomms 13680), a paper by Hosokai et al. :e1603282), a paper by Kyoto University scholars (Scientific Reports, 7:4820, DOI:10.1038/s41598-017-05007-7), and a conference presentation by Kyoto University scholars (Japan Chemical Society 98th Spring Banquet) , Publication No.: 2I4-15, Mechanism of High Efficiency Luminescence in Organic Electroluminescence Using DABNA as a Light-Emitting Molecule, Graduate School of Engineering, Kyoto University), and the like. For example, when the fluorescence lifetime of a sample containing a target compound is measured at 300 K, a slow fluorescence component is observed, and the target compound can be determined to be a “heat-activated delayed phosphor”. Here, the slow fluorescence component refers to a fluorescence lifetime of 0.1 μsec or more. The fluorescence lifetime can be measured using, for example, a fluorescence lifetime measuring device (C11367-01 manufactured by Hamamatsu Photonics Co., Ltd.).

The "heat-activated delayed phosphor" can function as an assisting dopant that assists the light emission of the emitting dopant.

In the following description, an organic electroluminescent element using a thermally activated delayed phosphor as an assisting dopant is sometimes referred to as a "TAF element" (TADF Assisting Fluorescence element).

The "host compound" in the TAF element means a compound having a lower excitation singlet energy level determined from the shoulder of the short wavelength side of the peak of the fluorescence spectrum than the assisting dopant and the emitting dopant.

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, the energy level of the ground state of the host is E(1, G), the lowest excitation singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the host is E(1, S, Sh), and the phosphorescence spectrum of the host The lowest excitation triplet energy level obtained from the shoulder on the short wavelength side is E(1, T, Sh), the ground state energy level of the assisting dopant is E(2, G), and the fluorescence spectrum of the assisting dopant is from the shoulder on the short wavelength side. The lowest excitation singlet energy level obtained is E(2, S, Sh), the lowest excitation triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the assisting dopant is E(2, T, Sh), the emitting dopant The energy level of the ground state of E(3, G), the lowest excitation singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the emitting dopant is E(3, S, Sh), the short wavelength phosphorescence spectrum of the emitting dopant The lowest excitation triplet energy level obtained from the side shoulder is E(3, T, Sh), the hole is h+, the electron is e-, and the fluorescence resonance energy transfer is FRET (Fluorescence Resonance Energy Transfer). In the TAF device, when a general fluorescent dopant is used as the emitting dopant (ED), energy upconverted from the assisting dopant moves to the lowest excitation singlet energy level E(3, S, Sh) of the assisting dopant and emits light. do. However, some lowest excitation triplet energy level E(2, T, Sh) on the assisting dopant moves to the lowest excitation triplet energy level E(3, T, Sh) of the emitting dopant, or Intersystem crossing occurs from the excitation singlet energy level E(3, S, Sh) to the lowest excitation triplet energy level E(3, T, Sh), and continues to the ground state E(3, G) deactivate with A part of the energy is not used for light emission through this path, and energy is wasted.

In contrast, for example, in a TAF element using a compound represented by Formula (12), (13) or (14) as an emitting dopant, energy transferred from the assisting dopant to the emitting dopant is efficiently utilized for light emission. Therefore, high luminous efficiency can be realized. This is estimated to be based on the following light emission mechanism.

A preferable energy relationship in the organic electroluminescent device of the present embodiment is shown in FIG. 3 . In the organic electroluminescent device of this embodiment, a compound having a boron atom as an emitter dopant has a high lowest triplet excitation energy level E(3, T, Sh). Because of this, even when the lowest excitation singlet energy upconverted in the assisting dopant crosses intersystem to, for example, the lowest excitation triplet energy level E(3, T, Sh) in the emitting dopant, on the emitting dopant Upconverted or recovered to the lowest excitation 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. In addition, by dividing into two types of molecules capable of improving the function of upconversion and light emission, respectively, it is expected that the residence time of high energy is reduced and the burden on the compound is reduced.

In this aspect, it is preferable to use the polycyclic aromatic compound of this invention as a host compound.

The lowest excitation triplet energy level E (1, T, Sh) determined from the shoulder of the short wavelength side of the peak of the phosphorescence spectrum of the host compound is the highest in the light emitting layer from the viewpoint of promoting the generation of TADF in the light emitting layer without hindering it. It is preferably higher than the lowest triplet excitation energy levels E(2, T, Sh) and E(3, T, Sh) of the emitting dopant or assisting dopant having the highest lowest excitation triplet energy level, specifically, , The lowest excitation triplet energy level E(1, T, Sh) of the host compound is preferably 0.01 eV or more, and preferably 0.03 eV or more, compared to E(2, T, Sh), E(3, T, Sh). It is more preferable, and 0.1eV or more is even more preferable. Further, a compound having TADF activity may be used as the host compound.

The thermally activated delayed phosphor (TADF compound) used in the TAF element uses an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to achieve HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied It is preferable to be a donor-acceptor type thermally activated delayed phosphor (D-A type TADF compound) designed to localize molecular orbitals and cause efficient reverse intersystem crossing.

Here, "electron-donating substituent" (donor) means a substituent and partial structure in which HOMO is localized in a thermally activated delayed phosphor molecule, and "electron-accepting substituent" (acceptor) means a thermally activated delayed phosphor It shall mean the substituent and partial structure in which LUMO localizes in a 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 at the same time, the exchange interaction between HOMO and LUMO is small and ΔE _ST is small, so, Very fast inverse interphase crossing velocities are obtained. On the other hand, thermally activated delayed phosphors using a donor or acceptor have a large structural relaxation in the excited state (since the stable structure is different between the ground state and the excited state in some molecules, it is changed from the ground state to the excited state by external stimulation). When conversion occurs, the structure is then changed to a stable structure in an excited state), providing a wide luminescence spectrum, so there is a possibility of reducing color purity when used as a luminescent material. However, high color purity is provided by using a thermally activated delayed phosphor using a donor or acceptor as an assisting dopant together with an appropriate emitting dopant such as a compound represented by formula (12), (13) or (14). can do.

As the thermally activated delayed phosphor in the TAF element, for example, a compound in which a donor and an acceptor are bonded directly or through a spacer can be used. As the electron-donating group (donor structure) and electron-accepting group (acceptor structure) used in the thermally activated delayed phosphor of the present invention, for example, the structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used As the donor structure, 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-dihydrodibenzoazacillin; and the like. As the acceptor structure, sulfonyldibenzene, benzophenone, phenylenebis (phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole , oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzooxazole, benzobis(oxazole), quinoline, benzoimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide , dimethylanthracenone, anthracenedione, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorenedicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyridine midine, methylpyrimidine, pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthenedioxide, thianthrenetetraoxide 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, isop It is preferably a compound having at least one selected from talonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole and benzophenone.

The compound used as the assisting dopant of the light emitting layer in the TAF element is a thermally activated delayed phosphor, and it is preferable that the emission spectrum overlaps at least partially with the absorption peak of the emitting dopant.

<Electron Injection Layer and Electron Transport Layer in Organic Electroluminescent Device>

The electron injection layer 107 serves to efficiently inject electrons moving from the cathode 108 into the light emitting layer 105 or into the electron transport layer 106 . The electron transport layer 106 serves to efficiently transport 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 laminating or mixing one or more electron transport/injection materials, or a mixture of an electron transport/injection material and a polymeric binder.

The electron injection/transport layer is a layer responsible for injecting electrons from the cathode and transporting the electrons, and preferably has high electron injection efficiency and efficiently transports the injected electrons. For this purpose, it is preferable to use a material that has high electron affinity, high electron mobility, and excellent stability, and is unlikely to generate trap impurities during production and use. However, in the case of considering the transport balance of holes and electrons, when the role of efficiently preventing the flow of holes from the anode to the cathode side without recombination is mainly performed, even if the electron transport capacity is not so high, the luminous efficiency is improved. The effect is equivalent to that of a material having a high electron transport ability. Therefore, the electron injection/transport layer in the present embodiment may also include a function of a layer capable of effectively blocking the movement of holes.

As the material (electron transport material) forming the electron transport layer 106 or the electron injection layer 107, a compound conventionally used as an electron transport compound in photoconductive materials, an electron injection layer and an electron transport layer of an organic EL device. It can be used by selecting it arbitrarily from known compounds in use. It is also preferable to use the polycyclic aromatic compound of the present invention as a material for an electron transport layer.

As the material used for the electron transport layer or the electron injection layer, compounds comprising an aromatic ring or heteroaromatic ring composed of at least one atom selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus, pyrrole derivatives and condensed ring derivatives thereof; It is preferable to contain at least one kind selected from metal complexes having electron-accepting nitrogen. Specifically, condensed ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives represented by 4,4'-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, and naphthalimide derivatives , quinone derivatives such as anthraquinone and diphenoquinone, phosphine oxide derivatives, arylnitrile derivatives, and indole derivatives. Examples of the metal complex having electron-accepting nitrogen include hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. Although these materials are used alone, you may mix and use them with other materials.

In addition, as specific examples of other electron transfer compounds, pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone Derivatives, perylene derivatives, 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 auxin derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazoles compounds, gallium complexes, pyrazole derivatives, perfluorophenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9' -spirobifluorene, etc.), imidazopyridine derivatives, borane derivatives, benzoimidazole derivatives (tris(N-phenylbenzoimidazol-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"-terpyridin-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 oxide derivatives, bisstyryl derivatives etc. can be mentioned.

In addition, 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, and flavonol metal complexes. and benzoquinoline metal complexes.

The above materials are used alone, but may be used in combination with other materials.

Among the above materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzoimidazole derivatives, Phenanthroline derivatives, and quinolinol-based metal complexes are preferred.

The electron transport layer or electron injection layer may further contain a substance capable of reducing a material forming the electron transport layer or electron injection layer. As long as this reducing substance has a certain reducing property, various substances are used, for example, alkali metals, alkaline earth metals, rare earth metals, oxides of alkali metals, halides of alkali metals, oxides of alkaline earth metals, and alkaline earths. At least one selected from the group consisting of metal halides, rare earth metal oxides, rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, and rare earth metal organic complexes can be preferably used.

Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (2.28 eV copper), Rb (2.16 eV copper) or Cs (1.95 eV copper), Ca (2.9 eV copper), and Sr (2.0 eV copper). to 2.5 eV) or an alkaline earth metal such as Ba (copper 2.52 eV), and a substance having a work function of 2.9 eV or less is particularly preferred. Among these, a more preferable reducing substance is an alkali metal of K, Rb or Cs, even more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and the addition of a relatively small amount to the material forming the electron transport layer or the electron injection layer can improve the light emission luminance and lengthen the lifetime of the organic EL device. In addition, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more alkali metals is also preferable, and in particular, a combination containing Cs, for example, Cs and Na, Cs and K, Cs and Rb, or Cs and A combination of Na and K is preferred. By including Cs, reducing ability can be exhibited efficiently, and addition to the material forming the electron transport layer or electron injection layer can improve the luminescence brightness and lengthen the lifetime of the organic EL device.

<Cathode in organic electroluminescence device>

The cathode 108 serves to inject electrons into the light emitting layer 105 through the electron injection layer 107 and the electron transport layer 106 .

The material forming the cathode 108 is not particularly limited as long as it is a material capable of efficiently injecting electrons into the organic layer, but the same material as the material forming the anode 102 can be used. Among them, metals or alloys thereof (magnesium-silver alloy, magnesium- aluminum-lithium alloys such as indium alloys and lithium fluoride/aluminum); In order to improve device characteristics by increasing electron injection efficiency, lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low work function metals are effective. However, these low work function metals are generally unstable in air in many cases. In order to improve this point, a method is known in which, for example, an organic layer is doped with a small amount of lithium, cesium or magnesium to use an electrode having high stability. As other dopants, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. However, it is not limited to these.

Furthermore, metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, and inorganic substances such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, and hydrocarbons for electrode protection Preferred examples include laminating a polymeric compound or the like. Methods for producing these electrodes are not particularly limited as long as conduction can be achieved, such as resistance heating, electron beam evaporation, sputtering, ion plating and coating.

<Method of manufacturing organic electroluminescence device>

For each layer constituting the organic EL device, the material constituting each layer is formed into a thin film by a method such as evaporation, resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination method, printing method, spin coating method, casting method, or coating method. By doing so, it can be formed. The film thickness of each layer formed in this way is not particularly limited and can be appropriately set depending on the nature 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 type film thickness measuring device or the like. In the case of thinning using a vapor deposition method, the deposition conditions differ depending on the type of material, the target crystal structure and association structure of the film, and the like. Deposition conditions are generally boat heating temperature +50 to +400 ° C, vacuum degree 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 desirable to set appropriately within the range.

In the case of applying a direct current voltage to the organic EL element obtained in this way, the anode may be applied with + and the cathode as the polarity, and when a voltage of about 2 to 40 V is applied, the transparent or translucent electrode side (anode or cathode) , and both) can observe luminescence. In addition, this organic EL element emits light even when a pulse current or an alternating current is applied. In addition, the waveform of the alternating current to apply may be arbitrary.

Next, as an example of a method for manufacturing an organic EL device, a method for manufacturing an organic EL device composed of an anode/a hole injection layer/a hole transport layer/a light emitting layer composed of a host material and a dopant material/an electron transport layer/an electron injection layer/cathode Explain.

<Deposition method>

After fabricating an anode by forming a thin film of anode material on a suitable substrate by vapor deposition or the like, thin films of a hole injection layer and a hole transport layer are formed on the anode. A host material and a dopant material are co-evaporated thereon to form a thin film to form a light emitting layer, an electron transport layer and an electron injection layer are formed on the light emitting layer, and a thin film made of a material for the cathode is formed by a vapor deposition method or the like to form a cathode, The organic EL element which does is obtained. In addition, in fabricating the organic EL device described above, it is also possible to reverse the fabrication order and fabricate the cathode, electron injection layer, electron transport layer, light emitting layer, hole transport layer, hole injection layer and anode in this order.

<Wet film forming method>

The wet film forming method is performed by preparing a low-molecular compound capable of forming each organic layer of an organic EL element as a liquid composition for forming an organic layer, and using the same. When there is no suitable organic solvent for dissolving the low molecular weight compound, a reactive compound obtained by substituting a reactive substituent in the low molecular weight compound and a composition for forming an organic layer from a high molecular compound polymerized together with other monomers having a soluble function or a main chain polymer, etc. you can prepare

In the wet film forming method, generally, a coating film is formed by passing through an application step of applying a composition for forming an organic layer to a substrate and a drying step of removing a solvent from the applied composition for forming an organic layer. When the polymer compound has a cross-linkable substituent (also referred to as a cross-linkable polymer compound), it is further cross-linked in this drying step to form a polymer cross-linked body. Depending on the difference in the coating process, the spin coat method uses a spin coater, the slit coat method uses a slit coater, and the gravure offset, reverse offset, flexographic printing, and inkjet printers are used for the plate method. The method of doing this is called the inkjet method, and the method of spraying in the form of 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 a plurality of times using different methods and conditions. In addition, you may use other methods together, such as baking under reduced pressure, for example.

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

On the other hand, when compared with the vacuum evaporation method, the wet film formation method may be difficult to laminate. When a multilayer film is produced using a wet film forming method, it is necessary to prevent dissolution of the lower layer by the composition of the upper layer, so a composition with controlled solubility, cross-linking of the lower layer and orthogonal solvent (solvent that does not dissolve in each other), etc. this is spoken However, even if these techniques are used, there are cases where it is difficult to use the wet film formation method for coating all films.

Therefore, generally, a method of fabricating an organic EL device by using a wet film forming method for only a few layers and vacuum evaporation is employed for the rest.

For example, a procedure for fabricating an organic EL device by partially applying a wet film forming method is shown below.

(Procedure 1) Film formation by vacuum evaporation of the anode

(Procedure 2) Formation of a composition for forming a hole injection layer containing a material for a hole injection layer by a wet film forming method

(Procedure 3) Formation of a composition for forming a hole transport layer containing a material for a hole transport layer by a wet film forming method

(Procedure 4) Formation of a composition for forming a light emitting layer containing a host material and a dopant material by a wet film forming method

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

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

(Procedure 7) Film formation by vacuum evaporation of cathode

By passing through this sequence, an organic EL device composed of anode/hole injection layer/hole transport layer/light emitting layer composed of host material and dopant material/electron transport layer/electron injection layer/cathode is obtained.

Of course, the electron transport layer and the electron injection layer may also be formed by a wet film forming method using a composition for layer formation containing a material for an electron transport layer and a material for an electron injection layer, respectively. At this time, 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 the opposite order to the above procedure.

<Other Tabernacling Methods>

A laser heating drawing method (LITI) can be used for film formation of the composition for forming an organic layer. LITI is a method of heating and depositing a compound attached to a substrate with a laser, and a composition for forming an organic layer can be used for a material applied to the substrate.

<Random process>

Appropriate treatment steps, washing steps, and drying steps may be suitably incorporated before and after each step of film formation. Examples of the treatment step include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, washing treatment using an appropriate solvent, heat treatment, and the like. In addition, a series of steps for producing a bank are also mentioned.

A photolithography technique can be used for fabrication of the bank. As a bank material for which photolithography can be used, a positive type resist material and a negative type resist material can be used. In addition, patternable printing methods such as inkjet printing, gravure offset printing, reverse offset printing, and screen printing can also be used. In this case, a permanent resist material may be used.

<Composition for Forming Organic Layer Used in Wet Film Formation>

A composition for forming an organic layer is obtained by dissolving a low-molecular compound capable of forming each organic layer of an organic EL device or a high-molecular compound obtained by polymerizing the low-molecular compound in an organic solvent. For example, a composition for forming a light emitting layer includes at least one polycyclic aromatic compound (or a polymer compound thereof) as a dopant material as a first component, at least one host material as a second component, and at least one as a third component. Contains a species of organic solvent. The first component functions as a dopant component of the light emitting layer obtained from the composition, and the second component functions as a host component of the light emitting layer. The third component functions as a solvent for dissolving the first and second components in the composition, and upon application imparts a smooth and uniform surface shape by the controlled evaporation rate of the third component itself.

<Organic Solvent>

The composition for forming an organic layer contains at least one organic solvent. By controlling the evaporation rate of the organic solvent during film formation, it is possible to control and improve film formability, presence or absence of defects in the coating film, surface roughness, and smoothness. Further, in the case of film formation using the inkjet method, the meniscus stability in the pinhole of the inkjet head can be controlled to control and improve ejection properties. In addition, by controlling the drying speed of the film and the orientation of the derivative molecules, it is possible to improve the electrical characteristics, light-emitting characteristics, efficiency, and lifetime of an organic EL device having an organic layer obtained from the composition for forming an organic layer.

After film formation, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, or heating. In the case of heating, from the viewpoint of improving coating film formability, it is preferable to perform heating at a glass transition temperature (Tg) of at least one of the solutes +30°C or lower. Further, from the viewpoint of reducing the residual solvent, it is preferable to heat the glass transition point (Tg) of at least one of the solutes to -30°C or higher. Since the film is thin even when the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is sufficiently removed. Moreover, drying may be performed multiple times at different temperatures, or a plurality of 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, monocyclic ketone solvents, solvents having a diester skeleton, and Fluorine-type solvent etc. are mentioned, but it is not limited to this. In addition, a solvent may be used singly or may be mixed.

<Optional ingredients>

The composition for forming an organic layer may contain arbitrary components within a range that does not impair its properties. As an arbitrary component, a binder, surfactant, etc. are mentioned.

<Composition and physical properties of composition for forming organic layer>

The content of each component in the composition for forming an organic layer determines the good solubility, storage stability and film-forming properties of each component in the composition for forming an organic layer, the quality of a coating film obtained from the composition for forming an organic layer, and the inkjet method. It is determined in consideration of the good ejection properties in the case of use, and the good electrical characteristics, light emitting characteristics, efficiency, and lifetime of an organic EL device having an organic layer produced using the composition.

The composition for forming an organic layer can be prepared by appropriately selecting and performing stirring, mixing, heating, cooling, dissolution, dispersion, etc. of the above-mentioned components by a known method. After preparation, filtration, degassing (also referred to as degassing), ion exchange treatment, and inert gas replacement/encapsulation treatment may be appropriately selected and performed.

<Application examples of organic electroluminescent devices>

INDUSTRIAL APPLICABILITY The present invention can also be applied to a display device including an organic EL element or a lighting device including an organic EL element.

A display device or lighting device including an organic EL element can be manufactured by a known method such as connecting the organic EL element according to the present embodiment to a known drive device, and known DC drive, pulse drive, AC drive, etc. It can be driven by appropriately using the driving method of .

Examples of the display device include a panel display such as a color flat panel display, a flexible display such as a flexible color organic electroluminescent (EL) display, and the like (eg, Japanese Patent Laid-Open No. 10-335066, Japanese Unexamined Patent Publication No. 2003-321546, Japanese Unexamined Patent Publication No. 2004-281086, etc.). In addition, as a display method of a display, a matrix method, a segment method, etc. are mentioned, for example. Also, the matrix display and the segment display may coexist in the same panel.

In the matrix, pixels for display are two-dimensionally arranged in a lattice or mosaic form, and characters or images are displayed by a set of pixels. The shape or size of the pixel is determined according to the purpose. For example, for displaying images and characters on 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, pixels on the order of mm are used. do. In the case of monochrome display, pixels of the same color may be arranged, but in the case of color display, red, green, and blue pixels are arranged and displayed. In this case, there are typically a delta type and a stripe type. Incidentally, as a driving method for this matrix, either a line-sequential driving method or an active matrix may be used. Line-sequential driving has the advantage of having a simple structure, but when operating characteristics are taken into consideration, the active matrix may be superior, so it is necessary to use this also according to the purpose.

In the segment method (type), a pattern is formed to display predetermined information, and a predetermined area is illuminated. For example, the time or temperature display in a digital watch or thermometer, the operation state display of an audio device or electric cooker, and the panel display of a car etc. are mentioned.

Examples of the lighting device include lighting devices such as indoor lighting, backlights of liquid crystal display devices, and the like (for example, Japanese Patent Laid-Open No. 2003-257621, Japanese Patent Laid-Open No. 2003-277741, Japanese Patent). Publication No. 2004-119211, etc.). Backlights are mainly used for the purpose of improving the visibility of display devices that do not emit light, and are used in liquid crystal display devices, clocks, audio devices, automobile panels, display panels, and signs. In particular, considering that it is difficult to reduce the thickness of a liquid crystal display device, especially a backlight for a computer where thinning is a problem, because the conventional method consists of a fluorescent lamp or a light guide plate, the backlight using the light emitting element according to the present embodiment is thin. and is characterized by being lightweight.

3-2. other organic device

The polycyclic aromatic compound according to the present invention can be used for fabrication of an organic field effect transistor or an organic thin film solar cell in addition to the organic electroluminescent device described above.

[Example]

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited thereto. First, synthesis examples of polycyclic aromatic compounds are described below.

Synthesis of compound (1-1)

Under a nitrogen atmosphere, 66.1 g of 1,3-dichloro-2-nitrobenzene, 40 g of phenylboronic acid, tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ ) 15.2 g, 139.3 g of tripotassium phosphate , 4.2 g of tetrabutylammonium bromide (TBAB), 400 ml of toluene and 40 ml of water were placed in a flask, and the mixture was refluxed for 4 hours while stirring. After cooling the reaction solution to room temperature, water and toluene were added and separated, and then the organic layer was purified by a silica gel short pass column (eluent: toluene). Subsequently, purification was performed by silica gel column chromatography (eluent: toluene/heptane = 1/4) to obtain 58.7 g of an intermediate compound 3-chloro-2-nitro-1,1'-biphenyl.

Under a nitrogen atmosphere, 31.5 g of 3-chloro-2-nitro-1,1'-biphenyl, 123.8 g of triphenylphosphine, and 285 ml of 1,2,4-trichlorobenzene were placed in a flask, stirred, and refluxed for 15 hours. . After completion of the reaction, the solvent was distilled off under reduced pressure, and then purified by NH2 silica gel column chromatography (eluent: toluene/heptane = 1/4) to obtain 19.8 g of an intermediate compound 1-chloro-9H-carbazole. .

Under a nitrogen atmosphere, 1-chloro-9H-carbazole (10 g), 1-chloro-2-iodobenzene (17.7 g), copper (6.3 g), potassium carbonate (27.4) g, 18-crown-6-ether ( 1.3 g) and 1,2-dichlorobenzene (100 ml) were put in a flask, and the mixture was refluxed for 20 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was purified by a silica gel short pass column (eluent: toluene). The obtained crude product was purified by silica gel column chromatography (eluent: toluene/heptane = 1/4) to obtain 7.8 g of intermediate compound 1-chloro-9-(2-chlorophenyl)-9H-carbazole.

Under a nitrogen atmosphere, 8.3 g of 1-chloro-9-(2-chlorophenyl)-9H-carbazole, 7.7 g of N,N-diphenylbenzene-1,2-diamine, 0.3 g of palladium acetate, and 2-dicyclohexyl 1.1 g of phosphino-2',6'-dimethoxy-1,1'-biphenyl (Sphos), 7.7 g of sodium t-butoxide (NaOtBu), and 116 ml of xylene were put in a flask and refluxed for 16 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and water and toluene were added and separated. Thereafter, the organic layer was purified with a silica gel short pass column (eluent: toluene), followed by silica gel column chromatography (eluent: toluene/heptane = 1/4), and further purified by sublimation to obtain the target compound (1- 1) (5.4 g) was obtained.

The structure of the compound of Formula (1-1) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 6.97-7.06 (m, 8H), 7.14-7.15 (m, 3H), 7.25-7.38 (m, 10H), 7.71 (d, 1H), 7.87 (d, 1H) ), 7.93 (d, 1H), 8.54 (d, 1H).

Synthesis of compounds (1-10)

Under a nitrogen atmosphere, 8.3 g of 1-chloro-9-(2-chlorophenyl)-9H-carbazole, 5.4 g of N-phenylbenzene-1,2-diamine, 0.3 g of palladium acetate, 2-dicyclohexylphosphino- 1.1 g of 2',6'-dimethoxy-1,1'-biphenyl (Sphos), 7.7 g of sodium t-butoxide (NaOtBu), and 116 ml of xylene were placed in a flask and refluxed for 16 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and water and toluene were added and separated. Thereafter, the organic layer was purified by a silica gel short pass column (eluent: toluene), followed by silica gel column chromatography (eluent: toluene/heptane = 1/4), and 4-phenyl-4,9-dihydrodibenzo [5,6:8,9][1,4,7]triazonino[3,2,1-jk]carbazole (3.2 g) was obtained.

Under a nitrogen atmosphere, 4-phenyl-4,9-dihydrodibenzo[5,6:8,9][1,4,7]triazonino[3,2,1-jk]carbazole 1.3 g, 9 1.8g of 9'-(5-bromo-1,3-phenylene)bis(9H-carbazole), 0.03g of palladium acetate, 0.9g of tritertiarybutylphosphine, 1.9g of potassium phosphate and 10ml of xylene were added to a flask and refluxed for 8 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was purified by a silica gel short pass column (eluent: toluene). The obtained crude product was washed with Solmics solvent and reprecipitated several times with heptane. Furthermore, purification was performed by silica gel column chromatography (eluent: toluene/heptane = 1/3), followed by sublimation purification to obtain the target compound (1-10) (1.3 g).

The structure of the compound of Formula (1-10) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 6.95 (d, 2H), 7.01-7.06 (m, 3H), 7.13 (s, 2H), 7.15 (s, 1H), 7.16-7.17 (m, 7H), 7.23-7.42 (m, 12H), 7.68-7.69 (m, 5H), 7.87 (d, 1H), 7.96 (d, 1H), 8.30 (d, 4H), 8.53 (d, 1H).

Synthesis of compounds (1-13)

Under a nitrogen atmosphere, 4-phenyl-4,9-dihydrodibenzo[5,6:8,9][1,4,7]triazonino[3,2,1-jk]carbazole 2.1 g, 55 1.24 g of sodium hydride (NaH) and 77 ml of dimethylformamide (DMF) were put in a flask and stirred at room temperature for 1 hour. After that, 3.8 g of 2-chloro-4,6-diphenyl-1,3,5-triazine was added, and the mixture was further stirred at room temperature for 64 hours. After completion of the reaction, water was gradually added while cooling in an ice-water bath, followed by extraction with ethyl acetate. Subsequently, the crude product obtained by distilling off the solvent in the organic layer under reduced pressure was purified by NH ₂ silica gel column chromatography (eluent: toluene/heptane = 1/2 (volume ratio)), followed by reprecipitation with Solmics solvent several times, followed by sublimation purification. to obtain the target compound (1-13) (1.1 g).

The structure of the compound of Formula (1-13) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 6.95 (d, 2H), 7.02-7.06 (m, 3H), 7.15-7.16 (m, 3H), 7.23-7.26 (m, 4H), 7.34-7.37 (m , 4H), 7.48 (m, 6H), 7.69 (d, 1H), 7.84 (d, 1H), 7.92 (d, 1H), 8.37 (d, 4H), 8.57 (d, 1H).

Synthesis of compound (1-68)

Under a nitrogen atmosphere, 13.1 g of 2-bromo-1-chloro-3-fluorobenzene, 7.5 g of 2-aminophenol, 21.6 g of potassium carbonate and 90 ml of 1-methyl-2-pyrrolidone were placed in a flask and heated at 150 ° C. The mixture was heated and stirred for 6 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and water and ethyl acetate were added and separated. Thereafter, purification was performed by silica gel column chromatography (eluent: toluene/heptane = 3/1) to obtain 15.3 g of the intermediate compound 2-(2-bromo-3-chlorophenoxy)aniline.

Under a nitrogen atmosphere, 12.6 g of 2-(2-bromo-3-chlorophenoxy)aniline, [1,1'-bis(diphenylphosphino)ferrocene]palladium(II)dichloridedichloromethane complex (1:1 ) (Pd(dppf)Cl ₂ -CH ₂ Cl ₂ ) 1.0g, sodium t-butoxide (NaOtBu) 8.1g and toluene 315ml were put in a flask, and the mixture was refluxed for 2 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and water and toluene were added and separated. Thereafter, the organic layer was purified by a silica gel short pass column (eluent: toluene) and then purified by silica gel column chromatography (eluent: toluene/heptane = 1/6) to obtain 6.3 g of an intermediate compound 1-chloro-10H-phenoxazine got

Under a nitrogen atmosphere, 50 g of 2-bromoaniline, 44.7 g of (2-fluorophenyl)boronic acid, dichlorobis[di-t-butyl(4-dimethylaminophenyl)phosphino]palladium(II) (Pd-132, Johnson Massey) 8.2 g, tripotassium phosphate 185.1 g, tetrabutylammonium bromide (TBAB) 4.7 g, toluene 600 ml and water 100 ml were placed in a flask, and the mixture was refluxed for 4 hours while stirring. After cooling the reaction liquid to room temperature, water and toluene were added and liquid-separated. Thereafter, purification was performed by silica gel column chromatography (eluent: toluene) to obtain 51.5 g of an intermediate compound 2'-fluoro-[1,1'-biphenyl]-2-amine.

Under a nitrogen atmosphere, 5.8 g of 1-chloro-10H-phenoxazine, 5.5 g of 2'-fluoro-[1,1'-biphenyl]-2-amine, 0.3 g of palladium acetate, 2-dicyclohexylphosphino- 1.1 g of 2',6'-dimethoxy-1,1'-biphenyl (Sphos), 7.7 g of sodium t-butoxide (NaOtBu), and 116 ml of xylene were placed in a flask and refluxed for 16 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and water and toluene were added and separated. Thereafter, the organic layer was purified by a silica gel short pass column (eluent: toluene) and then purified by silica gel column chromatography (eluent: toluene/heptane = 1/4) to obtain an intermediate compound 5H-dibenzo[5,6:7 3.5 g of ,8][1,4]diazonino[3,2,1-kl]phenoxazine was obtained.

Under a nitrogen atmosphere, 2.3 g of 5H-dibenzo[5,6:7,8][1,4]diazonino[3,2,1-kl]phenoxazine, 0.84 g of copper, 3.6 g of potassium carbonate and iodobenzene 66ml was put into a flask and refluxed for 6 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was purified by a silica gel short pass column (eluent: toluene). The obtained crude product was washed with Solmics solvent and reprecipitated several times with heptane. Furthermore, purification was performed by silica gel column chromatography (eluent: toluene/heptane = 1/3), followed by sublimation purification to obtain the target compound (1-68) (2.3 g).

The structure of the compound of formula (1-68) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 7.89 (d, 2H), 7.27 (t, 2H), 7.16 (t, 2H), 7.05 (d, 2H), 6.98 (d, 2H), 6.82 to 6.77 ( m, 3H), 6.63 (t, 1H), 6.52-6.45 (m, 3H), 6.39 (d, 2H), 6.34 (d, 1H).

Synthesis of compound (1-85)

Under a nitrogen atmosphere, 5H-dibenzo[5,6:7,8][1,4]diazonino[3,2,1-kl]phenoxazine 1.0 g, 9,9'-(5-bromo- 1.8 g of 1,3-phenylene)bis(9H-carbazole), 0.03 g of palladium acetate, 0.9 g of tritertiary butylphosphine, 1.9 g of potassium phosphate, and 10 ml of xylene were placed in a flask and refluxed for 8 hours while stirring. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was purified by a silica gel short pass column (eluent: toluene). The obtained crude product was washed with Solmics solvent and reprecipitated several times with heptane. Further, purification was performed by silica gel column chromatography (eluent: toluene/heptane = 1/3), followed by sublimation purification to obtain the target compound (1-85) (1.1 g).

The structure of the compound of formula (1-85) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 6.62 (d, 1H), 6.81 (t, 1H), 6.88 (d, 1H), 6.98-7.03 (m, 3H), 7.10 (s, 2H), 7.15 ( s, 1H), 7.15-7.17 (m, 7H), 7.39-7.46 (m, 8H), 7.63 (d, 4H), 8.11 (d, 2H), 8.29 (d, 4H).

Synthesis of compound (1-88)

Under a nitrogen atmosphere, 1.7 g of 5H-dibenzo[5,6:7,8][1,4]diazonino[3,2,1-kl]phenoxazine, 1.24 g of 55% sodium hydride (NaH) and 77ml of dimethylformamide (DMF) was put into the flask and stirred at room temperature for 1 hour. After that, 3.8 g of 2-chloro-4,6-diphenyl-1,3,5-triazine was added, and the mixture was further stirred at room temperature for 64 hours. After completion of the reaction, water was gradually added while cooling in an ice-water bath, followed by extraction with ethyl acetate. Subsequently, the crude product obtained by distilling off the solvent in the organic layer under reduced pressure was purified by NH ₂ silica gel column chromatography (eluent: toluene/heptane = 1/2 (volume ratio)), followed by reprecipitation with Solmics solvent several times, followed by sublimation. Purification was performed to obtain the target compound (1-88) (1.2 g).

The structure of the compound of formula (1-88) was confirmed by MS spectrum and NMR measurement.

¹ H-NMR (CDCl ₃ ): δ = 6.62 (d, 1H), 6.84-6.85 (m, 2H), 6.94-7.02 (m, 3H), 7.12-7.13 (m, 3H), 7.37-7.38 (m , 4H), 7.51 (m, 6H), 8.09 (d, 2H), 8.36 (d, 4H).

Other polycyclic aromatic compounds of the present invention can be synthesized by a method according to the synthesis example described above by appropriately changing the compound of the raw material.

Next, evaluation of the basic physical properties of the compound of the present invention and fabrication and evaluation of organic EL devices using the compound of the present invention are described. However, the application of the compound of the present invention is not limited to the examples shown below, and the film thickness and constituent materials of each layer can be appropriately changed depending on the basic physical properties of the compound of the present invention.

<Evaluation of vapor deposition type organic EL device>

Examples 1-1 to 7, Examples 2-1 to 4, Examples 3-1 to 4, Examples 4-1 to 4, Comparative Example 1-1, Comparative Example 2-1, and Comparative Example 4-1 The organic EL device according to -2 was fabricated, and the external quantum efficiency at luminance of 1000 cd/m ² , and LT50 (at 500 cd/m ² when continuously driven at current density at initial luminance of 1000 cd/m ^{2 )} time) was measured.

On the other hand, in Table 1, "Host 1" corresponds to a hole-transporting host material, and "Host 2" corresponds to an electron-transporting host material.

<Comparative Example 1-1>

A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Opto Science Co., Ltd.) obtained by polishing ITO film formed to a thickness of 200 nm by sputtering to 50 nm was used as a transparent support substrate. A molybdenum evaporation boat in which this transparent support substrate was fixed to a substrate holder of a commercially available evaporation device (manufactured by Showa Vacuum Co., Ltd.), and HAT-CN, HTL-1, TcTa, ETL-1, and ET7 were placed, respectively; A boat for evaporation made of tungsten containing LiF and aluminum was installed.

Each of the following layers was sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 5×10 ^-4 Pa, and first, HAT-CN was heated and vapor-deposited to a thickness of 5 nm to form a hole injection layer. Next, HTL-1 was heated and deposited to a film thickness of 90 nm to form a hole transport layer 1, and further, TcTa was heated and deposited to a film thickness of 10 nm to form a hole transport layer 2. Next, ETL-1 and new-DABNA were simultaneously heated and deposited to a film thickness of 20 nm to form a light emitting layer. The deposition rate was adjusted so that the mass ratio of ETL-1 and new-DABNA was about 99:1. Next, ETL-1 was heated and deposited to a film thickness of 20 nm to form an electron transport layer 1, and further, ET7 was heated and deposited to a film thickness of 10 nm to form an electron transport layer 2. The deposition rate of each layer was 0.01 to 1 nm/sec. Thereafter, LiF was heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec to a film thickness of 1 nm, and then aluminum was heated and deposited to a film thickness of 100 nm to form a cathode to obtain an organic EL device. At this time, the deposition rate of aluminum was adjusted to be 1 to 10 nm/sec.

The chemical structures of the compounds used in Comparative Examples and Examples are shown below.

Meanwhile, (BN2/BSN-0230/S) was synthesized as follows.

Under a nitrogen atmosphere, boron tribromide (1.91 g, 7.6 mmol) was added dropwise to a solution of (BN2/BSN-0230/S-Pre) (1.96 g, 1.90 mmol) in o-dichlorobenzene (19 mL) at room temperature, and then , and stirred at 170°C for 4 hours. After cooling the reaction solution to room temperature, it was poured into phosphate buffer (pH 7.0), and the aqueous layer was extracted with toluene. The obtained organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by a silica gel short pass column (eluent: toluene). Further, the compound (BN2/BSN-0230/S) was obtained as a yellow solid (0.41 g, yield 21%) by heating and washing with ethyl acetate twice.

The structure of the obtained compound was confirmed by LC-MS measurement and NMR measurement.

LC-MS: [M+H+]=1038.40

^1H -NMR (500MHz, CDCl ₃ ): δ=10.20 (s, 1H), 9.10 (dd, J=7.7, 1.4Hz, 1H), 8.96 (dd, J=7.7, 1.4Hz, 1H), 7.51- 7.44(m, 7H), 7.40-7.35(m, 4H), 7.33(t, J=7.7Hz, 1H), 7.28(s, 1H), 7.24-7.16(m, 9H), 7.11-7.01(m, 11H), 6.98-6.92(m, 6H), 6.83(d, J=2.6Hz, 2H), 6.78(d, J=8.6Hz, 1H), 6.75(d, J=8.6Hz, 1H), 5.92( d, J = 2.3 Hz, 1H), 5.68-5.63 (m, 2H).

<Examples 1-1 to 7, Examples 2-1 to 4, Examples 3-1 to 4, Examples 4-1 to 4, Comparative Examples 2-1, and Comparative Examples 4-1 to 2>

Each element was fabricated by changing the hole transport layer 2, the light emitting layer, and the electron transport layer 1 of Comparative Example 1-1 to the materials and concentrations listed in Table 1.

Table 2 shows the evaluation results of each element.

In Examples 1-1 to 1-7, higher efficiency and longer element life were obtained compared to Comparative Example 1-1. Moreover, from comparison among Examples, as a host material, what has a carbazole ring or a triazine ring as a partial structure is preferable, and what has a triazine ring as a partial structure is more preferable. Moreover, when comparing the mid-membered ring moiety, one having a partial structure of compound (1-68) is preferable.

Compared with Comparative Example 2-1, Examples 2-1 to 2-4 obtained higher efficiency and longer device life. Further, from the comparison between the Examples, when used as a p-Host, those having a carbazole ring as a partial structure are preferable, and when used as an n-Host, those having a triazine ring as a partial structure are preferable, and also in the case of an intermediate ring ring. Comparing the sites, those having the partial structure of compound (1-68) are preferred.

In Examples 3-1 to 3-4, compared with Comparative Example 2-1, high efficiency and long device life were obtained. Further, from the comparison between Examples, the hole transport layer 2 preferably has a carbazole ring as a partial structure, and the electron transport layer 1 preferably has a triazine ring as a partial structure. Further, when comparing the intermediate ring moiety, compound (1 -68) is preferred.

In Examples 4-1 to 4-4, higher efficiency and longer element life were obtained compared to Comparative Example 4-1 to Comparative Example 4-2. Further, from the comparison between the Examples, when used as a p-Host, those having a carbazole ring as a partial structure are preferable, and when used as an n-Host, those having a triazine ring as a partial structure are preferable, and also in the case of an intermediate ring ring. Comparing the sites, those having the partial structure of compound (1-68) are preferred.

The compound of the present invention can be used as hole transport layer 2, host 1, host 2, or electron transport layer 1, but it is preferably used as electron transport layer 1, host 1 or host 2, and more preferably used as host 1 or host 2. and most preferably used as host 2.

100 organic electroluminescent device
101 substrate
102 anode
103 hole injection layer
104 hole transport layer
105 light emitting layer
106 electron transport layer
107 electron injection layer
108 Cathode

Claims (12)

polycyclic aromatic compounds having a structure composed of one or two or more structural units represented by the following formula (1);

In formula (1),
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;
Ring B and C may be further bonded through a single bond or linking group, when X ² is a single bond, ring C and ring D may be further bonded through a linking group, and when X ³ is a single bond, ring D and ring A are further bonded through a linking group you can do,
X ¹ , X ² and X ³ are each independently >C(-R ^XC ) ₂ , >NR ^XN , >O, >Si(-R ^XI ) ₂ , >S or a single bond, provided that X ¹ and X ² do not form a single bond at the same time,
R ^XC , R ^XN and R ^XI are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, or the same element One or two rings selected from rings A to D bonded to and together with the above elements form a ring, provided that two R ^XC may be bonded to each other, and two R ^XI are bonded to each other, may be,
At least one hydrogen in the compound or structure represented by formula (1) may be substituted with heavy hydrogen, cyano or halogen. According to claim 1,
A polycyclic aromatic compound having a structure consisting of one structural unit represented by Formula (1). According to claim 1 or 2,
A polycyclic aromatic compound in which ring A, ring B, ring C and ring D are all substituted or unsubstituted benzene rings. According to any one of claims 1 to 3,
X ¹ , X ² and X ³ are each independently >NR ^XN , >O, >S or a single bond, and R ^XN is a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl polycyclic aromatic compound . According to claim 1,
A polycyclic aromatic compound represented by any of the following formulas.

A material for an organic device containing the polycyclic aromatic compound according to any one of claims 1 to 5. An organic electroluminescent device comprising a pair of electrodes comprising 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 5. . According to claim 7,
An organic electroluminescent device in which the organic layer is a light emitting layer. According to claim 8,
The organic electroluminescent element in which the light emitting layer contains the polycyclic aromatic compound as a host material and a dopant material. According to claim 7,
The organic electroluminescent device, wherein the organic layer is an electron transport layer. According to claim 7,
The organic electroluminescent device, wherein the organic layer is a hole transport layer. A display device or lighting device comprising the organic electroluminescent device according to any one of claims 7 to 11.

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