TW201434832A - Compound, light-emitting material and organic electroluminescence device - Google Patents

Abstract

Provided is a compound useful as a light-emitting material. A compound represented by the formula: (D)n-A [wherein D represents a group represented by general formula (2) A represents a n-valent group containing a structure represented by general formula (3) and n represents an integer of 1 to 8]. [In general formulae (2) and (3), Z1 represents O, S, C=O, C(R21)(R22), Si(R23)(R24), N-Ar3 or a single bond R21 to R24 independently represent an alkyl group having 1 to 8 carbon atoms R1 to R8 independently represent a hydrogen atom or a substituent Y represents O, S or N-Ar4 and Ar3 and Ar4 independently represent an aryl group.]

Description

Compound, luminescent material and organic light-emitting element

The present invention relates to a compound which can be used as a light-emitting material and an organic light-emitting element using the same.

The industry has been actively researching to improve the luminous efficiency of organic light-emitting elements such as organic electroluminescent elements (organic EL elements). In particular, various studies have been made on improving the luminous efficiency by newly developing and combining electron transport materials, hole transport materials, and light-emitting materials constituting an organic electroluminescence device. Among them, the use of inclusion There have been several proposals for organic electroluminescent elements of oxadiazole or triazole ring compounds.

For example, Patent Document 1 discloses that the following formula indicates The oxadiazole ring compound has a high electron transport property and can improve the characteristics of the light-emitting element. It is stipulated in the following formula that Ar ¹ is an aryl group having 6 to 10 carbon atoms which may be substituted with an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms; and Ar ² is a ring-forming ring. An aryl group having 6 to 10 carbon atoms or a heteroaryl group having 4 to 9 carbon atoms, and R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, a compound having a structure other than an anthracene ring in which a ring to which Ar ² is bonded in the following general formula is not described.

[Chemical 1]

Patent Document 2 discloses that a carrier containing a triazole ring represented by the following formula has a high carrier transport property and can improve the light-emitting efficiency of the light-emitting device. It is stipulated in the following formula that Ar ¹ and Ar ² are an aryl group or a heteroaryl group, Ar ³ is an extended aryl group or a heteroaryl group, and R ¹¹ and R ¹² are a hydrogen atom, an alkyl group, an alkoxy group or an aromatic group. base. However, the compound in which the ring bonded to Ar ³ in the following formula is other than the indazole ring is not described. Further, a compound in which an indazole ring bonded to Ar ³ is further substituted with a diarylamine group is also not described.

Patent Document 3 discloses that a carrier containing a triazole ring represented by the following formula has a high carrier transport property and can improve the light-emitting efficiency of the light-emitting device. It is defined in the following formula: A is an oxygen atom or a sulfur atom, Ar ¹ and Ar ² are aryl groups having 6 to 13 carbon atoms, Ar ⁴ is an exoaryl group having 6 to 13 carbon atoms, and R ¹ to R ⁷ are A hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 13 carbon atoms. However, the compound having a structure in which a ring bonded to Ar ⁴ in the following formula has a structure other than the ring of A is not described.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-254675

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-308490

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2012-6912

The industry is so involved Compounds of the oxazolyl ring or the triazole ring have heretofore been studied, and there are several proposals for application in organic electroluminescent elements. However, the inclusion of molecules in the molecule [1] Diazole ring or triazole ring, and [2] brown Ring, thiophene Ring, brown Compounds of a specific ring structure such as a ring have not been specifically studied. Further, a compound having such two kinds of rings in a molecule is hardly known. Therefore, it is extremely difficult to accurately predict what kind of properties a compound having such a ring will exhibit. In particular, regarding the usefulness as a light-emitting material, it is also difficult to find a document that can be predicted based on the use of the light-emitting material in the cited documents 1 to 3.

The inventors of the present invention have considered the problems of the prior art and intend to include the synthetic molecules together. Diazole ring and the like The compound such as a ring is evaluated and evaluated as useful as a light-emitting material. In addition, it is also intended to deduce the general formula of a compound which can be used as a light-emitting material, and to continuously develop the composition of an organic light-emitting element having high luminous efficiency.

Efforts have been made to achieve the above objectives, and as a result, the inventors have successfully synthesized and included [1]. Diazole ring, thiadiazole ring or triazole ring, and [2] containing brown Ring, thiophene Ring, brown The compounds of the ring structure disclosed below are cyclized, and for the first time it is clear that such compounds can be used as luminescent materials. Further, it has been found that among the above compounds, there is a material which can be used as a delayed fluorescent material, and it is clear that an organic light-emitting element having high luminous efficiency can be provided at a low price. The inventors of the present invention have provided the following invention as a method for solving the above problems based on such knowledge.

[1] A compound represented by the following formula (1), formula (1) (D) n-A

In the formula (1), D is a group represented by the following formula (2), A represents a group having an n-valent structure of a structure represented by the following formula (3); and n represents a group of 1 to 8 An integer]

[In the formula (2), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond, R ²¹ ~ R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, Ar ³ represents a substituted or unsubstituted aryl group; and R ¹ to R ⁸ each independently represent a hydrogen atom or a substituent; and R ¹ and R ² and R ² are R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, R ¹ ~ At least one of R ⁸ represents a substituted or unsubstituted diarylamino group]

[In the formula (3), Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group].

[2] The compound according to [1], wherein Z ^{1 of the} formula (2) represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ) or a single bond .

[3] The compound according to [1], wherein Z ^{1 of the} formula (2) represents N-Ar ³ .

[4] The compound according to any one of [1] to [3], wherein A of the formula (1) has a structure represented by the following formula (4),

[In the formula (4), Y represents O, S or N-Ar ⁴ , and Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group].

[5] The compound according to any one of [1] to [4] wherein n of the formula (1) is an integer of any one of from 1 to 4.

[6] The compound according to any one of [1] to [3] wherein it is represented by the formula (5),

[In the general formula (5), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single The bond, R ²¹ to R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group; and Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group. Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² And R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ and R ¹⁴ , R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents a substitution. Or an unsubstituted diarylamine group, wherein when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ represents a substituted or unsubstituted diarylamine group; n1 and n2 each independently represent 0. Any integer of ~8, the sum of n1 and n2 is 1~8].

[7] The compound according to [6], wherein Z ¹ and Z ^{2 of the} formula (5) are each independently O, S, N-Ar ³ or a single bond.

[8] The compound according to [6] or [7], wherein Y of the formula (5) is O or N-Ar ⁴ .

[9] The compound according to any one of [1] to [3] wherein it is represented by the formula (6),

[In the formula (6), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond, R ²¹ ~ R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, Ar ³ represents a substituted or unsubstituted aryl group; Ar ^{1 '} represents a substituted or unsubstituted extended aryl group; and Ar ^{2 '} represents a substituted or unsubstituted group. a substituted aryl group; Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, At least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamino group].

[10] The compound according to any one of [1] to [3] wherein it is represented by the following formula (7),

[In the general formula (7), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single The bond, R ²¹ to R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group; and Ar ^1" and Ar ^{2 "} each independently represent a substituted or unsubstituted extension. An aryl group; Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ and R ¹⁴ R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents The substituted or unsubstituted diarylamine group, when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ represents a substituted or unsubstituted diarylamino group].

[11] The compound according to [10], wherein Z ^{1 of the} formula (7) is the same as Z ² , Ar ^{1 " is the} same as Ar ^{2 "} , R ¹ is the same as R ¹⁴ , and R ² is the same as R ¹³ . R ³ is the same as R ¹² , R ⁴ is the same as R ¹¹ , R ⁵ is the same as R ¹⁸ , R ⁶ is the same as R ¹⁷ , R ⁷ is the same as R ¹⁶ , and R ⁸ is the same as R ¹⁵ .

[12] The compound according to [10] or [11], wherein Z ¹ and Z ^{2 of the} formula (7) are each independently O, S or N-Ar ³ .

[13] A luminescent material comprising the compound according to any one of [1] to [12].

[14] A delayed phosphor comprising the compound according to any one of [1] to [12].

[15] An organic light-emitting device comprising a light-emitting layer containing a compound according to any one of [1] to [12] as a light-emitting material on a substrate.

[16] The organic light-emitting element according to [15], characterized in that the radiation is delayed in fluorescence.

[17] The organic light-emitting device according to [15] or [16], which is characterized in that it is an organic electroluminescence device.

The compounds of the invention are useful as luminescent materials. Further, the compound of the present invention contains radiation delayed fluorescence. The organic light-emitting element using the compound of the present invention as a light-emitting material can achieve higher luminous efficiency.

1‧‧‧Substrate

2‧‧‧Anode

3‧‧‧ hole injection layer

4‧‧‧ hole transport layer

5‧‧‧Lighting layer

6‧‧‧Electronic transport layer

7‧‧‧ cathode

Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of an organic electroluminescence device.

Figure 2 is a luminescence spectrum of a toluene solution of Compound 1 of Example 1.

Figure 3 is a graph showing the transient decay curve of the toluene solution of Compound 1 of Example 1.

Figure 4 is a luminescence spectrum of a toluene solution of Compound 2 of Example 1.

Figure 5 is a graph showing the transient decay curve of the toluene solution of Compound 2 of Example 1.

Figure 6 is a luminescence spectrum of a toluene solution of Compound 3 of Example 1.

Figure 7 is a graph showing the transient decay curve of the toluene solution of Compound 3 of Example 1.

Fig. 8 is a chart showing the luminescence spectrum of the film-type organic photoluminescence device using the compound 1 of Example 2.

Fig. 9 is a graph showing the transient decay curve of the film type organic photoluminescent device of Example 2 using Example 1.

Fig. 10 is a chart showing the luminescence spectrum of the film-type organic photoluminescence device using the compound 2 of Example 2.

Figure 11 is a diagram showing the transient state of the thin film type organic photoluminescent element using the compound 2 of Example 2. Attenuation curve.

Fig. 12 is a chart showing the luminescence spectrum of the film type organic photoluminescent device using the compound 3 of Example 2.

Figure 13 is a graph showing the luminescence spectrum of the organic electroluminescent device using Compound 1 of Example 3.

Fig. 14 is a graph showing the voltage-current density characteristics of the organic electroluminescent device using Compound 1 of Example 3.

Fig. 15 is a graph showing the current density-external quantum efficiency characteristics of the organic electroluminescent device using Compound 1 of Example 3.

Figure 16 is an luminescence spectrum of the organic electroluminescence device using Compound 2 of Example 3.

Fig. 17 is a graph showing the voltage-current density characteristics of the organic electroluminescent device using Compound 2 of Example 3.

Fig. 18 is a graph showing the current density-external quantum efficiency characteristics of the organic electroluminescent device using Compound 2 of Example 3.

Figure 19 is a graph showing the luminescence spectrum of the organic electroluminescence device using Compound 3 of Example 3.

Fig. 20 is a graph showing the current density-external quantum efficiency characteristics of the organic electroluminescent device using Compound 3 of Example 3.

Figure 21 is a luminescence spectrum of a toluene solution of Compound 5 of Example 4.

Figure 22 is a graph showing the transient decay curve of the toluene solution of Compound 5 of Example 4.

Figure 23 is an luminescence spectrum of a toluene solution of Compound 6 of Example 4.

Figure 24 is a graph showing the transient decay curve of the toluene solution of Compound 6 of Example 4.

Figure 25 is a graph showing the luminescence spectrum of the film type organic photoluminescent device of Example 5 using Compound 5.

Figure 26 is a view showing the film type organic photoluminescent device of the compound 5 of Example 5; State attenuation curve.

Fig. 27 is a chart showing the luminescence spectrum of the film type organic photoluminescent device of Example 5 using Compound 6.

Figure 28 is a graph showing the transient decay curve of the film type organic photoluminescent device of Example 5 using Compound 6.

Figure 29 is a graph showing the luminescence spectrum of the organic electroluminescence device using Compound 5 of Example 6.

Fig. 30 is a graph showing the voltage-current density characteristics of the organic electroluminescence device using the compound 5 of Example 6.

31 is a graph showing current density-external quantum efficiency characteristics of the organic electroluminescence device using Compound 5 of Example 6. FIG.

Figure 32 is an luminescence spectrum of an organic electroluminescence device using Compound 6 of Example 6.

Figure 33 is a graph showing the voltage-current density characteristics of the organic electroluminescent device using Compound 6 of Example 6.

Fig. 34 is a graph showing the current density-external quantum efficiency characteristics of the organic electroluminescent device using Compound 6 of Example 6.

The contents of the present invention are explained in detail below. The description of the constituent elements described below may be performed based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. In addition, the numerical range represented by "~" in this specification means the range containing the numerical value before and after "~" as a lower-limit and upper-limit. Further, the isotopic type of the hydrogen atom existing in the molecule of the compound used in the present invention is not particularly limited. For example, the hydrogen atom in the molecule may be ¹ H, and some or all of them may be ² H (氘D).

[Compound represented by the general formula (1)]

The compound of the present invention is characterized by having a structure represented by the following formula (1).

General formula (1) (D) n-A

In the formula (1), D is a group represented by the following formula (2), and A represents a group having an n-valent structure of the structure represented by the following formula (3).

In the formula (2), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond.

R ²¹ to R ²⁴ each independently represent an alkyl group having 1 to 8 carbon atoms. The alkyl group mentioned herein may be any of a linear form and a branched form, more preferably a carbon number of 1 to 6. As a specific example, a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group may be mentioned. Base, isobutyl, pentyl, isopentyl, hexyl. Specific examples of C(R ²¹ )(R ²² ) include C(CH ₃ )(CH ₃ ) or C(C ₂ H ₅ )(C ₂ H ₅ ) as Si(R ²³ )(R ^{24 )} Specific examples of the compound include Si(CH ₃ )(CH ₃ ) or Si(C ₂ H ₅ )(C ₂ H ₅ ).

When Z ¹ of the formula (2) is a single bond, the formula (2) becomes a group having a carbazole skeleton. At this time, at least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamine group. The substituted or unsubstituted diarylamine group may be any of R ¹ to R ⁸ , but preferably at least one of R ³ or R ⁶ is a substituted or unsubstituted diarylamine group. . The two aryl groups constituting the substituted or unsubstituted diarylamine group represented by R ¹ to R ⁸ may be the same or different from each other. The carbon number of the aryl group is preferably from 6 to 14, more preferably from 6 to 10. Specific examples thereof include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group. For the description and preferred ranges of the substituents which may be substituted on the aryl group, reference may be made to the description of the substituents which may be taken from R ¹ to R ⁸ described below and the preferred range. Preferred examples of the substituted or unsubstituted diarylamine group include diphenylamino group, bis(4-methylphenyl)amino group, and bis(3-methylphenyl)amine. A bis(3,5-dimethylphenyl)amino group or a bis(4-methylphenyl)amino group. Further, the two aryl groups of the diarylamine group may be bonded to each other to form a cyclic structure together with the nitrogen atom of the amine group. For example, a 9-carbazolyl group is mentioned.

When Z ¹ of the formula (2) is N-Ar ³ , Ar ³ represents a substituted or unsubstituted aryl group. The aromatic ring constituting the aryl group represented by Ar ³ may be a monocyclic ring or a condensed ring, and specific examples thereof include a benzene ring and a naphthalene ring. The carbon number of the aryl group is preferably from 6 to 40, more preferably from 6 to 20. For the description and preferred ranges of the substituents which may be substituted on the aryl group represented by Ar ³ , reference may be made to the description of the substituents which may be taken from the following R ¹ to R ⁸ and the preferred range.

R ¹ to R ^{8 in the} formula (2) each independently represent a hydrogen atom or a substituent. R ¹ to R ⁸ may each be a hydrogen atom. Further, when two or more substituents are used, the substituents may be the same or different. Examples of the substituent include a hydroxyl group, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, and a carbon number of 1 to 20. Alkyl substituted amine group, aryl substituted amine group having 12 to 40 carbon atoms, fluorenyl group having 2 to 20 carbon atoms, aryl group having 6 to 40 carbon atoms, heteroaryl group having 3 to 40 carbon atoms, carbon number 12 a substituted or unsubstituted carbazolyl group of ~40, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms Sulfhydrazinyl group, haloalkyl group having 1 to 10 carbon atoms, decylamino group, alkyl guanamine group having 2 to 10 carbon atoms, trialkylsulfonyl group having 3 to 20 carbon atoms, and tridecane having 4 to 20 carbon atoms The alkyl group is an alkylalkyl group, a trialkylsulfonylalkenyl group having 5 to 20 carbon atoms, a trialkylsulfonylalkynyl group having 5 to 20 carbon atoms, and a nitro group. Among these specific examples, those which may be further substituted with a substituent may be substituted. More preferred substituents are a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted carbon number of 6 to 40. An aryl group, a substituted or unsubstituted heteroaryl group having 3 to 40 carbon atoms, a substituted or unsubstituted dialkylamino group having 1 to 10 carbon atoms, or a substituted or unsubstituted carbon number of 12 to 40 Substituted diarylamine group, substituted or unsubstituted carbazolyl group having 12 to 40 carbon atoms. Further preferred substituents are a fluorine atom, a chlorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, and a carbon number. a substituted or unsubstituted dialkylamino group of 1 to 10, a substituted or unsubstituted diarylamino group having 12 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 15 carbon atoms a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

The alkyl group may be any of a linear chain, a branched form, and a cyclic form, and more preferably has a carbon number of 1 to 6. Specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a third butyl group. , pentyl, hexyl, isopropyl. The aryl group may be a monocyclic ring or a condensed ring, and specific examples thereof include a phenyl group and a naphthyl group. The alkoxy group may be any of a linear chain, a branched form, and a cyclic form, and more preferably has a carbon number of 1 to 6. Specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. , a third butoxy group, a pentyloxy group, a hexyloxy group, an isopropoxy group. The two alkyl groups of the dialkylamino group may be the same or different from each other, but are preferably the same. The two alkyl groups of the dialkylamino group may each independently be linear, branched or cyclic, and more preferably have a carbon number of 1 to 6. Specific examples include methyl group and ethyl group. Propyl, butyl, pentyl, hexyl, isopropyl. The two alkyl groups of the dialkylamino group may also be bonded to each other to form a cyclic structure together with the nitrogen atom of the amine group. The aryl group which can be used as a substituent may be a monocyclic ring or a condensed ring, and specific examples thereof include a phenyl group and a naphthyl group. The heteroaryl group may be a monocyclic ring or a condensed ring, and specific examples thereof include a pyridyl group and a fluorene group. Base, pyrimidinyl, three Base, triazolyl, benzotriazolyl. The heteroaryl group may be a group bonded via a hetero atom or a group bonded via a carbon atom constituting the heteroaryl ring. The two aryl groups of the diarylamine group may be a single ring or a condensed ring, and specific examples thereof include a phenyl group and a naphthyl group. The two aryl groups of the diarylamine group may also be bonded to each other to form a cyclic structure together with the nitrogen atom of the amine group. For example, a 9-carbazolyl group is mentioned.

In the general formula (2), R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may be bonded to each other to form a ring. Structure. The cyclic structure may be an aromatic ring or an aliphatic ring, or may be a hetero atom, and the cyclic structure may also be a condensed ring of 2 or more rings. As the hetero atom mentioned herein, it is preferably selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom. Examples of the cyclic structure to be formed include a benzene ring, a naphthalene ring, a pyridine ring, and an anthracene. Ring, pyrimidine ring, pyridyl Ring, pyrrole ring, imidazole ring, pyrazole ring, triazole ring, imidazoline ring, Oxazole ring, different An azole ring, a thiazole ring, an isothiazole ring, a cyclohexadiene ring, a cyclohexene ring, a cyclopentene ring, a cycloheptatriene ring, a cycloheptadiene ring, a cycloheptene ring or the like.

A in the formula (1) represents a group having an n-valent structure of the structure represented by the following formula (3).

In the formula (3), Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group. The aromatic ring constituting the aryl group represented by Ar ⁴ may be a monocyclic ring or a condensed ring, and specific examples thereof include a benzene ring and a naphthalene ring. The carbon number of the aryl group is preferably from 6 to 40, more preferably from 6 to 20. With regard to the description and preferred ranges of the substituents which may be substituted on the aryl group represented by Ar ³ , reference may be made to the description of the substituents which may be taken from the above R ¹ to R ⁸ and the preferred range.

In the formula (1), n represents any one of 1 to 8. n is more preferably 1 to 6, and further preferably 1 to 4. When n is 2 or more, a plurality of D are bonded to A of the formula (1). The plurality of Ds may be the same or different from each other. In the same situation, it has the advantage of easy synthesis.

When n is 1, the structure A containing the structure of the general formula (3) functioning as a receptor and acting as a Each of the D functions in the body is bonded to each other. On the other hand, when n is 2 or more, two or more bonds are bonded to A having a structure containing the general formula (3) which functions as a receptor, and D functions as a donor. When two or more Ds are bonded, there is a fear that the function as a donor body cancels each other, and the molecule cannot function effectively as a light-emitting material. However, according to the present invention, it has been found that by separately selecting A and D and combining them with each other, it is possible to provide a luminescent material having high luminous efficiency and excellent effects. The reason is considered to be that the broadening of HOMO (Highest Occupied Molecular Orbital) and LUMO (Lower Unoccupied Molecular Orbital) is controlled at a molecular level to satisfy the conditions as a luminescent material. .

A of the formula (1) is preferably one having the structure represented by the following formula (4).

In the formula (4), Y represents O, S or N-Ar ⁴ . With regard to the description of Y and the preferred range, reference may be made to the description of the general formula (3) and the preferred range.

In the formula (4), Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group. The aromatic group referred to herein means directly by the atom constituting the ring skeleton of the aromatic ring. A oxadiazole ring, a thiadiazole ring or a triazole ring bonded group. The aromatic ring may be a single ring or a condensed ring. Further, the ring skeleton atom constituting the aromatic ring may be composed only of carbon atoms, or may be a mixture of a carbon atom and a hetero atom. As the hetero atom, a nitrogen atom, an oxygen atom or a sulfur atom can be preferably exemplified. The ring skeleton of the aromatic ring of Ar ¹ and Ar ² preferably has an atomic number of 5 to 20, more preferably 5 to 12. Examples of the aromatic ring include a benzene ring or a naphthalene ring. The aromatic group represented by Ar ¹ and Ar ² may be substituted with a group other than D. For the description and preferred ranges of such substituents, reference may be made to the description of the substituents and preferred ranges of the above R ¹ to R ⁸ . Ar ¹ and Ar ² may be the same or different, but if they are the same, they have the advantage of being easy to synthesize.

There is no particular limitation on the position at which D performs bonding. For example, D may be bonded to both the aromatic group of Ar ^{1 and} the aromatic group of Ar ² , or may be bonded to only one of them. And, bonded to D of the number of keys on the aromatic group of Ar ¹ to the number D of nodes on the aromatic group Ar ² may be the same or different. If they are the same, they have the advantage of being easy to synthesize. As the preferred aspects include: Ar the aromatic group bonded with only ^one of the aspects of the D 1, Ar ¹ has 1 D of the aspect of bonding with the aromatic group Ar of ^2, Ar ¹ each bonded to the aromatic group Ar ² has the aspect of D 2, Ar ¹ has three aspects D of the respective bonded on the aromatic group Ar of ^2.

The compound represented by the formula (1) is preferably one having the structure represented by the following formula (5).

In the formula (5), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond. R ²¹ to R ²⁴ each independently represent an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group. Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group. Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group. R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent. R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ And R ¹⁴ , R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may be bonded to each other to form a cyclic structure. Wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamine group, and when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ One represents a substituted or unsubstituted diarylamine group. For the description and preferred ranges of Z ¹ , Z ² , Ar ¹ , Ar ² , Y, R ¹ to R ⁸ and R ¹¹ to R ^{18 in} the formula (5), reference may be made to the formula (2) to (4). And the preferred ranges of Z ¹ , Ar ¹ , Ar ² , Y and R ¹ to R ⁸ .

N1 and n2 in the formula (5) each independently represent any of 0 to 8. Wherein, the sum of n1 and n2 is 1-8. When n1 is an integer of 2 to 8, the n1 ring structures may be the same or different, and when n2 is any one of 2 to 8, the n2 ring structures may be the same or different.

Preferred examples of the general formula (5) include the case where Z ¹ and Z ² are each independently O, S, N-Ar ³ or a single bond, and Y is O or N-Ar ³ , Ar ¹ and the case where the aromatic ring of the aromatic group represented by Ar ² is a benzene ring. Further, a case where n1 is the same as n2 or a case where n1 is 1 and n2 is 0 may be mentioned.

The compound represented by the formula (1) is preferably one having the structure represented by the following formula (6).

[化15]

In the formula (6), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond, R ²¹ to R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group. Ar ^{1 '} represents a substituted or unsubstituted extended aryl group. Ar ^{2 '} represents a substituted or unsubstituted aryl group. Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group. R ¹ to R ⁸ each independently represent a hydrogen atom or a substituent. R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , and R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure. Wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamine group. For the description and preferred ranges of Z ¹ , Y, R ¹ to R ⁸ in the formula (6), reference may be made to the descriptions of the groups corresponding to the formulas (2) and (3) and preferred ranges.

The aryl group represented by Ar ^{1 ' of} the formula (6) preferably has a carbon number of 6 to 14 and more preferably 6 to 10 carbon atoms. For example, 1,4-phenylene, 1,3-phenylene, 2,6-anthranyl, 2,7-anthranyl, preferably 1,4-phenyl, 1,3 - Stretch phenyl. The aryl group represented by Ar ^{2 ' in} the formula (6) preferably has a carbon number of 6 to 14 in the skeleton constituting the aromatic ring, more preferably 6 to 10 carbon atoms. For example, a phenyl group and a naphthyl group are mentioned. The aryl group represented by Ar ^{1 '} and the aryl group represented by Ar ^{2 '} may also be substituted with a substituent. For the description of the substituents and preferred ranges, reference may be made to the description of the substituents and preferred ranges of the above R ¹ to R ⁸ .

The compound represented by the formula (1) is preferably one having the structure represented by the following formula (7).

In the formula (7), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond. R ²¹ to R ²⁴ each independently represent an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group. Ar ^{1 "} and Ar ^{2 "} each independently represent a substituted or unsubstituted extended aryl group. Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group. R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent. R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ And R ¹⁴ , R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may be bonded to each other to form a cyclic structure.

Wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamine group, and when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ One represents a substituted or unsubstituted diarylamine group.

For the description and preferred ranges of Z ¹ , Z ² , Y, R ¹ to R ⁸ and R ¹¹ to R ^{18 in} the general formula (7), reference may be made to Z ¹ in the general formulae (2) to (4), Description of Ar ¹ , Ar ² , Y and R ¹ to R ⁸ and preferred ranges. Further, regarding the description and preferred range of Ar ^1" and Ar ² in the formula (7), the description and preferred range of Ar ^{1 '} in the formula (6) can be referred to.

In the formula (7), Z ¹ is the same as Z ² , Ar ^{1 " is the} same as Ar ^{2 "} , R ¹ is the same as R ¹⁴ , R ² is the same as R ¹³ , R ³ is the same as R ¹² , and R ⁴ is the same as R ¹¹ R ⁵ is the same as R ¹⁸ , R ⁶ is the same as R ¹⁷ , R ⁷ is the same as R ¹⁶ , and R ⁸ is the same as R ¹⁵ .

Specific examples of the compound represented by the formula (1) are exemplified below. However, the compound represented by the formula (1) which can be used in the present invention should not be construed as being limited by the specific examples.

[化17]

[化18]

[Chemistry 19]

[Chemistry 20]

When the molecular weight of the compound represented by the formula (1) is used for forming an organic layer containing the compound represented by the formula (1) by a vapor deposition method, it is preferably 1,500 or less, more preferably 1200 or less. Further, it is preferably 1,000 or less, and more preferably 800 or less. The lower limit of the molecular weight is the molecular weight of the smallest compound represented by the formula (1).

The compound represented by the formula (1) can be formed into a film by a coating method regardless of the molecular weight. When the coating method is employed, a film having a relatively large molecular weight can be formed.

It is also considered to apply the present invention to use a compound containing a plurality of structures represented by the formula (1) in a molecule as a light-emitting material.

For example, it is considered that a polymerizable group is present in the structure represented by the formula (1), and the polymerizable group is polymerized to obtain a polymer, and the polymer is used as a light-emitting material. Specifically, it is considered that a monomer containing a polymerizable functional group in any one of A or D of the general formula (1) is polymerized alone or copolymerized with another monomer, thereby obtaining a repeating unit. The polymer is used as a luminescent material. Alternatively, it is also considered to obtain a dimer or a trimer by coupling a compound having a structure represented by the general formula (1) to each other, and these are used as a light-emitting material.

Examples of the polymer having a repeating unit having a structure represented by the formula (1) include a polymer having a structure represented by the following formula (8) or (9).

In the general formulae (8) and (9), Q represents a group including the structure represented by the formula (1), and L ¹ and L ² represent a linking group. The carbon number of the linking group is preferably from 0 to 20, more preferably from 1 to 15, and still more preferably from 2 to 10. The linking group is preferably a structure represented by -X ¹¹ -L ¹¹ -. Here, X ¹¹ represents an oxygen atom or a sulfur atom, preferably an oxygen atom. L ¹¹ represents a linking group, preferably a substituted or unsubstituted alkylene group, or a substituted or unsubstituted extended aryl group, more preferably a substituted or unsubstituted alkylene group having a carbon number of 1 to 10. A phenyl group, either substituted or unsubstituted.

In the general formulae (8) and (9), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ each independently represent a substituent. Preferably, it is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a halogen atom, more preferably a carbon number of 1 to 3 Substituted alkyl group, unsubstituted alkoxy group having 1 to 3 carbon atoms, fluorine atom, chlorine atom, further preferably unsubstituted alkyl group having 1 to 3 carbon atoms, and having 1 to 3 carbon atoms Substituted alkoxy.

The linking group represented by L ¹ and L ² may be bonded to A or D of the structure of the general formula (1) constituting Q, and R ¹ to R ⁸ and R ²¹ to R ²⁴ of the structure of the general formula (2), In any one of Ar ³ , in any one of Ar ¹ , Ar ² and Ar ⁴ of the formula (4), R ¹ to R ⁸ , R ¹¹ to R ¹⁸ and R ^{21 of the} formula (5). On any of ~R ²⁴ , Ar ¹ , Ar ² , Ar ³ , and Ar ⁴ , R ¹ to R ⁸ , R ²¹ to R ²⁴ , Ar ^{1 '} , Ar ^{2 '} , and Ar ^{3 of the} formula (6) In any of Ar ⁴ , any of R ¹ to R ⁸ , R ¹¹ to R ¹⁸ , R ²¹ to R ²⁴ , Ar ^1" , Ar ^{2 "} , Ar ³ , and Ar ⁴ of the formula (7) One. Two or more linking groups may be bonded to one Q to form a crosslinked structure or a network structure.

Specific examples of the configuration of the repeating unit include the structures represented by the following formulas (10) to (13).

[化22]

A polymer having a repeating unit containing the above equations (10) to (13) can be synthesized by introducing a hydroxyl group into any one of A or D of the structure of the general formula (1) as a link. The following compound is reacted to introduce a polymerizable group, and the polymerizable group is polymerized.

The polymer having a structure represented by the formula (1) in the molecule may be a polymer composed only of a repeating unit having a structure represented by the formula (1), or may be a repeating unit having a structure other than the above. polymer. Further, the repeating unit having the structure represented by the formula (1) contained in the polymer may be a single type or two or more types. Examples of the repeating unit having no structure represented by the formula (1) include those derived from a monomer which is usually used for copolymerization. For example, a repeating unit derived from a monomer having an ethylenically unsaturated bond such as ethylene or styrene may be mentioned.

[Synthesis method of compound represented by general formula (1)]

The compound represented by the formula (1) can be synthesized by combining known reactions. For example, it can be synthesized according to the following process.

[24] D-H+(X)n-A → (D)n-A

For the description of D, A and n in the above formula, the description corresponding to the formula (1) can be referred to. In the above formula, X represents a halogen atom, and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom, a bromine atom, and an iodine atom are preferred.

Among the compounds represented by the formula (1), for example, the compound represented by the formula (5) can be synthesized by the following scheme.

[化25]

For the description of Z ¹ , Z ² , Ar ¹ , Ar ² , Y, R ¹ to R ⁸ , R ¹¹ to R ¹⁸ , n 1 and n 2 in the above formula, the description corresponding to the formula (5) can be referred to. X in the above formula represents a halogen atom.

The reaction in the above two schemes is carried out by using a known coupling reaction, and a known reaction condition can be appropriately selected and used. For a detailed description of the above reaction, reference may be made to the synthesis examples described later. Further, the compound represented by the formula (1) can also be synthesized by combining other known synthesis reactions.

[Organic light-emitting element]

The compound represented by the formula (1) of the present invention can be used as a light-emitting material of an organic light-emitting element. Therefore, the compound represented by the formula (1) of the present invention can be effectively used as a light-emitting material for the light-emitting layer of the organic light-emitting element. The compound represented by the formula (1) contains a delayed fluorescent material (delayed phosphor) which emits delayed fluorescence. An organic light-emitting element using such a compound as a light-emitting material has a characteristic of emitting delayed fluorescence and having high luminous efficiency. The principle will be described below by taking an organic electroluminescence device as an example.

In the organic electroluminescence device, a carrier is injected into the luminescent material from the positive and negative electrodes, and a luminescent material in an excited state is generated to emit light. Generally, in the case of a carrier-injection type organic electroluminescence device, among the excitons generated, 25% are excited to excite the singlet state, and the remaining 75% are excited to the excited triplet state. Therefore, the energy utilization efficiency of the person who uses the light emitted from the triplet state, that is, the phosphor, is high. However, since the excited triplet lifetime is long, the saturation of the excited state or the energy inactivation caused by the interaction with the excited triplet exciton is often caused, and generally the quantum yield of phosphorescence is not high. On the other hand, the delayed fluorescent material is converted into an excitation single by the triplet-triplet annihilation or the absorption of thermal energy by converting the energy into an excited triplet state by inter-system crossing or the like. Heavy state, thus emitting fluorescence. Among the organic electroluminescent elements, heat-activated delayed fluorescent materials in which heat energy is absorbed are considered to be particularly useful. In the case where a delayed fluorescent material is used in an organic electroluminescence device, an exciton that excites a singlet state emits fluorescence as usual. On the other hand, the heat generated by the exciton absorption device of the triplet state is excited to perform inter-system conversion to the excited singlet state, thereby emitting fluorescence. At this time, since the light is emitted from the excited singlet state, it is the light emission at the same wavelength as the fluorescent light, and the life of the light (luminous lifetime) is changed by the transition from the self-excited triplet state to the excited singlet state. It is longer than normal fluorescent or phosphorescent light, so fluorescence with these delays is observed. It can be defined as delayed fluorescence. If the above heat-activated exciton shifting mechanism is used, the ratio of the excited singlet compound which usually produces only 25% can be raised to 25% or more by absorption of thermal energy after the carrier is injected. If a compound that emits strong fluorescence and delayed fluorescence even at a temperature lower than 100 ° C is used, the inter-system conversion of the self-excited triplet state to the excited singlet state is sufficiently generated by the heat of the device. Thereby, the radiation is delayed in fluorescence, so that the luminous efficiency can be dramatically improved.

By using the compound represented by the general formula (1) of the present invention as a light-emitting material of the light-emitting layer, it is possible to provide an excellent organic light-emitting device such as an organic photoluminescence device (organic PL device) or an organic electroluminescence device (organic EL device). element. At this time, the general formula (1) of the present invention The compound may also function as a so-called auxiliary dopant to assist in the illumination of other luminescent materials contained in the luminescent layer. That is, the compound represented by the formula (1) of the present invention contained in the light-emitting layer may be the lowest excitation singlet energy level of the host material contained in the light-emitting layer and the lowest excitation single sheet of the other light-emitting material contained in the light-emitting layer. The lowest excited singlet energy level between the heavy energy levels.

The organic photoluminescent element has a structure in which at least a light-emitting layer is formed on a substrate. Further, the organic electroluminescence device has at least an anode, a cathode, and a structure in which an organic layer is formed between the anode and the cathode. The organic layer may include at least a light-emitting layer, and may have one or more organic layers in addition to the light-emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer may also be a hole injection transport layer having a hole injection function, and the electron transport layer may also be an electron injection transport layer having an electron injection function. A structural example of a specific organic electroluminescent element is shown in FIG. In Fig. 1, 1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light-emitting layer, 6 denotes an electron transport layer, and 7 denotes a cathode.

Hereinafter, each member and each layer of the organic electroluminescence device will be described. Furthermore, the description of the substrate and the light-emitting layer also corresponds to the substrate of the organic photoluminescent device and the light-emitting layer.

(substrate)

The organic electroluminescent device of the present invention is preferably supported by a substrate. The substrate is not particularly limited as long as it is conventionally used for an organic electroluminescence device, and for example, glass, transparent plastic, quartz, ruthenium or the like can be used.

(anode)

As the anode in the organic electroluminescence device, a metal having a large work function (4 eV or more), an alloy, a conductive compound, and a mixture thereof can be preferably used as the electrode material. Specific examples of the electrode material include a conductive transparent material such as a metal such as Au, CuI, indium tin oxide (ITO), SnO ₂ or ZnO. Further, a material which can form an amorphous and transparent conductive film such as IDIXO (In ₂ O ₃ -ZnO) can also be used. The anode can be formed into a thin film of the electrode material by a method such as vapor deposition or sputtering, and a pattern of a desired shape can be formed by photolithography, or when pattern precision is not required (about 100 μm or more). A pattern is formed through a mask of a desired shape during vapor deposition or sputtering of the electrode material. Alternatively, when a material which can be applied as an organic conductive compound is used, a wet film formation method such as a printing method or a coating method may be employed. In the case where light emitted from the anode is extracted, it is preferable that the transmittance is more than 10%, and the sheet resistance as the anode is preferably several hundred Ω/□ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

(cathode)

On the other hand, as the cathode, a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, a conductive compound, and a mixture thereof can be used as the electrode material. Specific examples of the electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium/copper mixture, magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, and aluminum/aluminum oxide (Al ₂ O). ₃ ) Mixtures, indium, lithium/aluminum mixtures, rare earth metals, and the like. Among these, in terms of electron injectability and durability against oxidation, etc., it is preferred that the electron injecting metal and the work function have a value larger than the electron injecting metal and the stable metal, that is, the second metal mixture. For example, a magnesium/silver mixture, a magnesium/aluminum mixture, a magnesium/indium mixture, an aluminum/aluminum oxide (Al ₂ O ₃ ) mixture, a lithium/aluminum mixture, aluminum, or the like is preferable. The cathode can be produced by forming a thin film of the electrode materials by a method such as vapor deposition or sputtering. Further, the sheet resistance as the cathode is preferably several hundred Ω/□ or less, and the film thickness is usually selected from the range of 10 nm to 5 μm, preferably 50 to 200 nm. Further, in order to transmit the emitted light, as long as either the anode or the cathode of the organic electroluminescent element is transparent or translucent, the luminance of the light is improved, which is a preferred embodiment.

Further, by using the conductive transparent material exemplified in the description of the anode for the cathode, a transparent or translucent cathode can be produced, and by using the cathode, an anode and a cathode can be fabricated. Both have transmissive components.

(lighting layer)

The light-emitting layer is a layer in which exciton light is generated by recombination of holes and electrons injected from the anode and the cathode, and the light-emitting material may be used alone in the light-emitting layer, but preferably includes a light-emitting material and a host material. As the luminescent material, one or two or more selected from the group of compounds of the present invention represented by the formula (1) can be used. In order for the organic electroluminescent device and the organic photoluminescent device of the present invention to exhibit high luminous efficiency, it is important to enclose singlet excitons and triplet excitons generated in the luminescent material in the luminescent material. Therefore, it is preferred to use a luminescent material and a host material in the luminescent layer. As the host material, at least either of the excited singlet energy and the excited triplet energy may be used as an organic compound having a value higher than that of the luminescent material of the present invention. As a result, the singlet excitons and triplet excitons generated by the luminescent material of the present invention can be enclosed in the molecules of the luminescent material of the present invention, and the luminous efficiency can be sufficiently improved. Of course, even if singlet excitons and triplet excitons cannot be sufficiently closed, high luminous efficiency can be obtained. Therefore, as long as it is a host material capable of achieving high luminous efficiency, there is no particular restriction. Used in the present invention. In the organic light-emitting device or the organic electroluminescence device of the present invention, the light-emitting device is produced by the light-emitting material of the present invention contained in the light-emitting layer. The luminescence includes both fluorescent luminescence and delayed luminescence. However, one or a portion of the illumination may also include illumination from the host material.

In the case of using a host material, the amount of the compound of the present invention as a light-emitting material in the light-emitting layer is preferably 0.1% by weight or more, more preferably 1% by weight or more, and still more preferably 50% by weight or less. More preferably, it is 20 weight% or less, More preferably, it is 10 weight% or less.

As the host material in the light-emitting layer, an organic compound having a hole transporting ability, an electron transporting ability, and a long wavelength of light emission, and a higher glass transition temperature are preferable.

(injection layer)

The injection layer is a layer disposed between the electrode and the organic layer in order to reduce the driving voltage or increase the luminance of the light, and has a hole injection layer and an electron injection layer, which may exist in the anode and the light-emitting layer or the hole transport layer. Between, and between the cathode and the light-emitting layer or the electron transport layer. The injection layer can be set as needed.

(barrier layer)

The barrier layer is a layer that blocks charges (electrons or holes) and/or excitons present in the light-emitting layer from diffusing out of the light-emitting layer. The electron blocking layer may be disposed between the light emitting layer and the hole transport layer to block electrons from moving toward the hole transport layer and passing through the light emitting layer. Similarly, the hole blocking layer may be disposed between the light emitting layer and the electron transport layer, and the blocking hole moves toward the electron transport layer to pass through the light emitting layer. Also, a barrier layer can be used to block excitons from diffusing to the outside of the light-emitting layer. That is, the electron blocking layer and the hole blocking layer each have a function as an exciton blocking layer. The electron blocking layer or exciton blocking layer referred to in the present specification is used in the sense of a layer containing a function having an electron blocking layer and an exciton blocking layer.

(hole blocking layer)

The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer has a function of blocking electrons on one side and blocking the holes from reaching the electron transport layer, thereby increasing the probability of recombination of electrons and holes in the light-emitting layer. As the material of the hole blocking layer, a material of an electron transport layer to be described later may be used as needed.

(electronic barrier layer)

The so-called electron blocking layer has a function of transmitting holes in a broad sense. The electron blocking layer has a function of blocking electrons from reaching the hole transport layer while transmitting holes, thereby increasing the probability of recombination of electrons and holes in the light-emitting layer.

(exciton blocking layer)

The exciton blocking layer is used to block the diffusion of excitons generated by recombination of holes and electrons in the light-emitting layer to the charge transport layer, and the excitons can be efficiently enclosed in the light-emitting layer by inserting the layer. Inside, the luminous efficiency of the component can be improved. Exciton blocking layer can be combined with hair The optical layer is inserted adjacent to either one of the anode side and the cathode side, and may be simultaneously inserted on both sides. That is, in the case where the exciton blocking layer is provided on the anode side, the layer may be inserted adjacent to the light-emitting layer between the hole transport layer and the light-emitting layer, and may be applied to the light-emitting layer and the cathode when inserted on the cathode side. The layer is inserted adjacent to the luminescent layer. Further, a hole injection layer or an electron blocking layer may be provided between the anode and the exciton blocking layer adjacent to the anode side of the light-emitting layer, and may have between the cathode and the exciton blocking layer adjacent to the cathode side of the light-emitting layer. Electron injection layer, electron transport layer, hole blocking layer, and the like. In the case of arranging the barrier layer, it is preferred that at least one of the excited singlet energy and the excited triplet energy of the material used as the barrier layer is higher than the excited singlet energy and the excited triplet energy of the luminescent material.

(hole transport layer)

The hole transport layer includes a hole transport material having a function of transmitting a hole, and the hole transport layer may be provided with a single layer or a plurality of layers.

The hole transporting material may be any one of an organic substance and an inorganic substance, and may have any of the properties of injectability or transportability of a hole and barrier properties of electrons. As a known hole transporting material which can be used, for example, a triazole derivative can be cited. Diazole derivatives, imidazole derivatives, carbazole derivatives, carbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamines Derivatives, amine-substituted chalcone derivatives, An azole derivative, a styryl hydrazine derivative, an anthrone derivative, an anthracene derivative, an anthracene derivative, a decazane derivative, or an aniline copolymer, and a conductive polymer oligomer, particularly thiophene As the oligomer or the like, a porphyrin compound, an aromatic tertiary amine compound, and a styrylamine compound are preferably used, and an aromatic tertiary amine compound is more preferably used.

(electronic transport layer)

The electron transport layer includes a material having a function of transmitting electrons, and the electron transport layer may be provided with a single layer or a plurality of layers.

As the electron transporting material (and sometimes also as a hole blocking material), it is only necessary to have a function of transporting electrons injected from the cathode to the light emitting layer. Examples of the electron transporting layer which can be used include a nitro-substituted anthracene derivative, a diphenylanthracene derivative, a thiopyran dioxide derivative, a carbodiimide, a fluorenylene methane derivative, and a ruthenium. Methane and anthrone derivatives, Diazole derivatives and the like. Further, above Diazole derivative A thiadiazole derivative in which an oxygen atom of a oxazolyl ring is substituted with a sulfur atom, and a quinolin which is known to be a pull electron group Quinone ring The porphyrin derivative can also be used as an electron transporting material. Further, a polymer material in which the materials are introduced into the polymer chain or the materials are used as a main chain of the polymer may be used.

When the organic electroluminescence device is produced, not only the compound represented by the formula (1) but also a layer other than the light-emitting layer can be used. In this case, the compound represented by the formula (1) for the light-emitting layer may be the same as or different from the compound represented by the formula (1) for the layer other than the light-emitting layer. For example, a compound represented by the formula (1) may be used in the injection layer, the barrier layer, the hole barrier layer, the electron blocking layer, the exciton blocking layer, the hole transport layer, the electron transport layer, and the like. The film forming method of the layers is not particularly limited, and it can be produced by any of a dry process or a wet process.

Preferred materials which can be used for the organic electroluminescent element are specifically exemplified below. The materials which can be used in the present invention are not to be construed as being limited by the following exemplified compounds. Further, even a compound exemplified as a material having a specific function can be used as a material having other functions. Further, in the structural formulae of the following exemplified compounds, R, R' and R ₁ to R ₁₀ each independently represent a hydrogen atom or a substituent. X represents a carbon atom or a hetero atom forming a ring skeleton, n represents an integer of 3 to 5, Y represents a substituent, and m represents an integer of 0 or more.

First, preferred compounds which can also be used as a host material for the light-emitting layer are listed.

[Chem. 26]

[化27]

[化29]

[化30]

Next, an example of a preferable compound which can be used as a hole injecting material is listed.

[化31]

Next, an example of a preferred compound which can be used as a hole transporting material is listed.

[化32]

[化33]

[化34]

[化35]

[化36]

[化37]

Next, an example of a preferred compound which can be used as an electron blocking material is listed.

[化38]

Next, an example of a preferred compound which can be used as a barrier material for a hole is listed.

Next, examples of preferred compounds which can be used as electron transport materials are listed.

[化40]

[化41]

[化42]

Next, examples of preferred compounds which can be used as electron injecting materials are listed.

[化43]

Further, examples of the compound which is preferable as a material which can be added are listed. For example, it is considered to be added as a stabilizing material.

The organic electroluminescent device produced by the above method emits light by applying an electric field between the anode and the cathode of the obtained device. At this time, if the light is emitted by the excitation singlet energy, the light of the wavelength corresponding to the energy level is confirmed as the fluorescent light emission and the delayed fluorescent light emission. Further, in the case of light emission caused by the excitation triplet energy, the wavelength corresponding to the energy level is confirmed as phosphorescence. Generally, the fluorescence lifetime is shorter than that of delayed fluorescence, so the luminescence lifetime can be distinguished from that of delayed fluorescence.

On the other hand, regarding phosphorescence, a usual organic compound such as the compound of the present invention excites the triplet energy to be unstable and is converted into heat, and has a short life and immediately loses activity, so that it is hardly observed at room temperature. In order to determine the excited triplet state energy of a typical organic compound The amount can be measured by observing the luminescence under extremely low temperature conditions.

The organic electroluminescence device of the present invention can be applied to any of a single element, an element including a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an X-Y matrix. According to the present invention, an organic light-emitting device in which the light-emitting efficiency is greatly improved can be obtained by including the compound represented by the formula (1) in the light-emitting layer. The organic light-emitting element such as the organic electroluminescence device of the present invention can be further applied to various applications. For example, an organic electroluminescence display device can be produced by using the organic electroluminescence device of the present invention. For the detailed description, the "organic EL display" (Ohmsha Co., Ltd.), which is a joint venture between Jing Shi, Anda Chiba, and Murata Yoshida, can be referred to. Further, in particular, the organic electroluminescence device of the present invention can also be applied to an organic electroluminescence illumination or a backlight device which is in great demand.

[Examples]

The features of the present invention will be further specifically described below by way of Synthesis Examples and Examples. The materials, processing contents, processing procedures, and the like described below can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the invention should not be construed as being limited by the specific examples shown below.

(Synthesis Example 1) Synthesis of Compound 1

4-bromobenzhydryl chloride (68.4 mmol, 15.0 g), hydrazine monohydrate (34.2 mmol, 1.10 g), and chloroform (240 ml) were added to a nitrogen-substituted two-necked flask, and immersed in an ice bath to cool (0~5). °C) and stir for 30 minutes. Triethylamine (136.8 mmol, 13.8 g) was added dropwise thereto, and the mixture was stirred for 30 minutes and further stirred at room temperature for 12 hours. The precipitated white solid was collected by suction filtration, washed with water, and vacuum dried to obtain a target. N,N'-bis(4-bromobenzylidene)-indole of the product (yield: 9.34 g, yield: 68.6%).

N,N' -bis(4-bromobenzylidene)-hydrazine (8.8 mmol, 3.5 g), phosphorus pentachloride (19.3 mmol, 4.01 g), and toluene 35 ml were added to a nitrogen-substituted two-necked flask. Heating and refluxing were carried out for 3 hours. 35 ml of water was added thereto, and after stirring for 30 minutes, liquid separation was carried out to extract an organic layer. Anhydrous magnesium sulfate was added for dehydration, and the solvent was distilled off to obtain a yellow solid. The mixed solvent of ethanol and hexane was added thereto for washing, whereby N,N'-bis(chloro(4-bromophenyl)methylene)-indole as a target product was obtained (yield: 2.95 g, yield : 77.2%).

N,N'-bis(chloro(4-bromophenyl)methylene)-oxime (6.8 mmol, 2.95 g), aniline (6.8 mmol, 635 mg), N, N were added to a nitrogen-substituted two-necked flask. 15 ml of '-dimethylaniline was heated and refluxed for 5 hours. The reaction solution was slowly added to 50 ml of 1N diluted hydrochloric acid, and stirred for 30 minutes to precipitate a solid. The precipitated solid was collected by suction filtration, and the solid was dissolved in toluene, and then an aqueous sodium hydrogencarbonate solution was added thereto to carry out liquid separation to extract an organic layer. Anhydrous magnesium sulfate is added for dehydration, and the solvent is distilled off to obtain a solid, and the obtained solid is recrystallized by a mixed solvent of ethanol and hexane, thereby obtaining a target. The title product was 3,5-bis(4-bromophenyl)-4-phenyl-4H-1,2,4-triazole (yield: 2.25 g, yield: 72.8%).

Add 3,5-bis(4-bromophenyl)-4-phenyl-4H-1,2,4-triazole (3.30 mmol, 1.50 g), brown to a nitrogen-substituted double-necked flask (7.26 mmol, 1.33 g), potassium carbonate (21.8 mmol, 3.01 g), 40 ml of toluene, and stirred at room temperature for 10 minutes. A mixed solution of palladium (II) acetate (0.22 mmol, 49.4 mg), tri-tert-butylphosphine (0.80 mmol, 161.9 mg) and 40 ml of toluene was added thereto, and the mixture was heated and refluxed for 24 hours. After standing to cool to room temperature, chloroform and saline were added, and the organic layer was extracted by liquid separation. Anhydrous magnesium sulfate was added for dehydration, and the solvent was distilled off. Using the mixed solvent of chloroform:hexane = 1:4, the compound 1 (3,5-bis(4-N-morphine) as the target product was obtained by ruthenium column chromatography. The phenyl)-4-phenyl-4H-1,2,4-triazole) was subjected to isolation and purification (yield: 1.52 g, yield: 69.9%).

_{^{1 H-NMR (CDCl 3,}} 300MHz, TMS, δ): 5.99 (d, 4H), 6.61 (t, 4H), 6.68 (m, 8H), 7.57 (d, 4H), 8.39 (d, 4H)

MALDI-MS m/z: 584

(Synthesis Example 2) Synthesis of Compound 2

[化49]

N,N'-bis(4-bromobenzylidene)-hydrazine (3.52 mmol, 1.40 g) and phosphonium chloride (308.0 mmol, 47.2 g) were added to a nitrogen-substituted two-necked flask for 12 hours. Heat and reflux. After the reaction solution was allowed to stand to cool to room temperature, 150 ml of water was slowly added to precipitate a white solid. Sodium carbonate was added for neutralization, and the precipitated solid was collected by suction filtration. After washing with water, vacuum drying was carried out, whereby 2,5-bis(4-bromophenyl)-1,3,4- as a target product was obtained. Diazole (yield: 1.14 g, yield: 85.2%).

Add 2,5-bis(4-bromophenyl)-1,3,4- to a nitrogen-substituted two-necked flask Diazole (1.66mmol, 630.8mg), brown (3.65 mmol, 668.7 mg), potassium carbonate (11.0 mmol, 1.52 g), and 25 ml of toluene were stirred at room temperature for 10 minutes. A mixed solution of palladium (II) acetate (0.11 mmol, 25.0 mg), tri-tert-butylphosphine (0.40 mmol, 81.0 mg) and toluene 25 ml was added thereto, and the mixture was heated and refluxed for 24 hours. After standing to cool to room temperature, chloroform and saline were added, and the organic layer was extracted by liquid separation. Anhydrous magnesium sulfate was added for dehydration, and the solvent was distilled off. Compound 2 (2,5-bis(4-N-morphine) as a target product by using chloroform-tane column chromatography Phenyl)-1,3,4- The oxadiazole was subjected to isolation and purification (yield: 965.2 mg, yield: 99.5%).

_{^{1 H-NMR (CDCl 3,}} 300MHz, TMS, δ): 5.99 (d, 4H), 6.61 (t, 4H), 6.68 (m, 8H), 7.57 (d, 4H), 8.39 (d, 4H)

MALDI-MS m/z: 584

(Synthesis Example 3) Synthesis of Compound 3

N,N'-bis(4-bromobenzylidene)-hydrazine (4.00 mmol, 1.59 g), phosphorus pentasulfide (16.0 mmol, 3.56 g), and pyridine 100 ml were added to a nitrogen-substituted two-necked flask for 4 days. Heating and refluxing. After allowing to cool to room temperature, the solvent was distilled off, dichloromethane was added, and the mixture was cooled with an ice bath to precipitate a white solid. The precipitated solid was collected by suction filtration, and the filtrate was again cooled and recrystallized repeatedly. The solid obtained was vacuum dried, whereby 2,5-bis(4-bromophenyl)-1,3,4-thiadiazole as a target product was obtained (yield: 1.18 g, yield: 74.6%). .

Add 2,5-bis(4-bromophenyl)-1,3,4-thiadiazole (1.26 mmol, 500 mg), brown to a nitrogen-substituted two-necked flask (2.77 mmol, 507.5 mg), potassium carbonate (8.31 mmol, 1.15 g), 20 ml of toluene, and stirred at room temperature for 10 min. A mixed solution of palladium (II) acetate (0.08 mmol, 19.0 mg), tri-tert-butylphosphine (0.31 mmol, 62.0 mg) and toluene (20 ml) was added thereto, and the mixture was heated and refluxed for 24 hours. After standing to cool to room temperature, chloroform and saline were added, and the organic layer was extracted by liquid separation. Anhydrous magnesium sulfate was added for dehydration, and the solvent was distilled off. Compound 3 (2,5-bis(4-N-morphine) as a target product by guanidine column chromatography using chloroform The phenyl)-1,3,4-thiadiazole) was isolated and purified (yield: 745.6 mg, yield: 98.5%).

_{^{1 H-NMR (CDCl 3,}} 300MHz, TMS, δ): 6.01 (d, 4H), 6.61 (t, 4H), 6.68 (m, 8H), 7.53 (d, 4H), 8.27 (d, 4H)

MALDI-MS m/z: 601

(Synthesis Example 4) Synthesis of Compound 4

2,5-bis(4-bromophenyl)-1,3,4-thiadiazole (1.26 mmol, 500 mg), 3-diphenylaminocarbazole (2.77) was added to a nitrogen-substituted two-necked flask. Methyl, 926.3 mg), potassium carbonate (8.31 mmol, 1.15 g), 20 ml of toluene, and stirred at room temperature for 10 min. A mixed solution of palladium (II) acetate (0.08 mmol, 19.0 mg), tri-tert-butylphosphine (0.31 mmol, 62.0 mg) and toluene (20 ml) was added thereto, and the mixture was heated and refluxed for 24 hours. Place cold After leaving room temperature, chloroform and brine were added, and the organic layer was extracted by liquid separation. Anhydrous magnesium sulfate was added for dehydration, and the solvent was distilled off. The compound 4 (2,5-bis(4-N-(3-diphenylaminocarbazolyl)phenyl)-1,3,4 was used as the target product by hydrazine column chromatography using chloroform. -thiadiazole) was isolated and purified (yield: 654.8 mg, yield: 57.5%).

_{^{1 H-NMR (CDCl 3,}} 300MHz, TMS, δ): 6.96 (t, 4H), 7.12 (d, 8H), 7.23 (d, 8H), 7.27 (m, 4H), 7.44 (m, 4H), 7.51 (d, 2H), 7.78 (d, 4H), 7.94 (s, 2H), 8.01 (d, 2H), 8.29 (d, 4H)

MALDI-MS m/z: 903

(Synthesis Example 5) Synthesis of Compound 5

3-(4-bromophenyl)-5-phenyl-1,2,4- Diazole 1.00g (3.32mmol), 5,10-dihydro-5-phenylmorphine 2.87 g (11.1 mmol) and 1.84 g (13.3 mmol) of potassium carbonate were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen. To the mixture was added 10 mL of toluene and 0.50 mL of 2 mol/L of tris(t-butyl)phosphine. The mixture was stirred at 80 ° C for 10 hours under a nitrogen atmosphere. After stirring, 10 mL of water and 100 mL of chloroform were added to the mixture and stirred. After stirring, the mixture was subjected to suction filtration through celite to obtain a filtrate. The organic layer of the obtained filtrate was separated from the aqueous layer, and magnesium sulfate was added to the organic layer to dry. After drying, the mixture was subjected to suction filtration to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. The solvent for the column chromatography was to use toluene first, followed by a mixed solvent of toluene: ethyl acetate = 4:1. The solid obtained by concentrating the obtained fraction was washed with a mixed solvent of acetone and methanol to obtain a powdery yellow solid in a yield of 1.30 g and a yield of 81.8%.

¹ H-NMR (500 MHz, DMSO- d ₆ ): δ (ppm) 8.42 (d, J = 8.5 Hz, 2H), 8.18 (dd, J = 8.0 Hz, 1.5 Hz, 2H), 7.72-7.65 (m, 7H), 7.55 (t, J = 7.2 Hz, 1H), 7.43 (d, J = 8.4 Hz, 2H), 6.37-6.33 (m, 4H), 5.70-5.68 (m, 2H), 5.59-5.57 (m , 2H)

(Synthesis Example 6) Synthesis of Compound 6

3-(4-Bromophenyl)-4.5-diphenyl-4H-1,2,4-triazole 1.00g (2.66mmol), 5,10-dihydro-5-phenylmorphine 2.87 g (11.1 mmol) and 1.84 g (13.3 mmol) of potassium carbonate were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen. To the mixture was added 10 mL of toluene and 0.50 mL of 2 mol/L of tris(t-butyl)phosphine. The mixture was stirred at 80 ° C for 10 hours under a nitrogen atmosphere. After stirring, 10 mL of water and 100 mL of chloroform were added to the mixture and stirred. After stirring, the mixture was subjected to suction filtration through celite to obtain a filtrate. The organic layer of the obtained filtrate was separated from the aqueous layer, and magnesium sulfate was added to the organic layer to dry. After drying, the mixture was subjected to suction filtration to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. The solvent for the column chromatography was first to use toluene, and secondly to use a mixed solvent of toluene: ethyl acetate = 2:1. The solid obtained by concentrating the obtained fraction was washed with a mixed solvent of acetone and methanol to obtain a powdery yellow solid in a yield of 940 mg and a yield of 63.8%.

^{1 H-NMR (500MHz, DMSO-} d 6): δ (ppm) 7.70-7.67 (m, 4H), 7.54-7.48 (m, 6H), 7.43-7.36 (m, 9H), 6.31-6.27 (m, 4H), 5.52-5.47 (m, 4H)

(Example 1) Production and evaluation of an organic photoluminescent device (solution)

A toluene solution (concentration: 10 ^-4 mol/L) of the compound 1 synthesized in Synthesis Example 1 was prepared, and ultraviolet light was irradiated at 300 K while introducing nitrogen gas. As a result, fluorescence having a peak wavelength of 462 nm was observed as shown in Fig. 2 . Further, after passing nitrogen gas, measurement by a small fluorescence lifetime measuring device (Quantaurus-tau manufactured by Hamamatsu Photonics Co., Ltd.) was performed, and the transient decay curve shown in Fig. 3 was obtained (τ1 = 3.26 μs, τ 2 = 31.00 μs). ). The transient decay curve is a result of measuring the luminescence lifetime obtained by measuring the process in which the excitation light hits the compound to gradually lose the luminescence intensity. In the case of luminescence (fluorescence or phosphorescence) of one of the usual components, the luminescence intensity is attenuated by a single exponential function. This means that it is linearly attenuated when the vertical axis of the graph is a semi log. In the transient decay curve of the compound 1 shown in Fig. 3, the above-mentioned straight line forming component (fluorescence) was observed at the initial stage of observation, but the component which deviated from the linearity appeared after several μ second. This is the luminescence of the delayed component, and the signal added to the initial component becomes a dragging curve on the long-term side. By measuring the luminescence lifetime in this manner, it was confirmed that the compound 1 is an illuminant containing a retardation component in addition to the fluorescent component. The photoluminescence quantum efficiency of Compound 1 in a toluene solution was measured at 300 K by an absolute PL quantum yield measuring device (Quantaurus-QY manufactured by Hamamatsu Photonics Co., Ltd.), and it was 15.2% after passing nitrogen gas.

Substituting Compound 2 synthesized in Synthesis Example 2 for Compound 1 was carried out in the same manner. Preparation and evaluation of toluene solution. Fig. 4 shows the luminescence spectrum, and Fig. 5 shows the transient decay curve after passing nitrogen gas (τ1 = 0.02 μs, τ2 = 13.3 μs). The photoluminescence quantum efficiency was 43.1% after passing nitrogen gas.

The compound 3 synthesized in Synthesis Example 3 was used instead of Compound 1, and the production and evaluation of the toluene solution were carried out in the same manner. Fig. 6 shows the luminescence spectrum, and Fig. 7 shows the transient decay curve after passing nitrogen gas (τ1 = 16.25 ns, τ2 = 18.42 ns).

(Example 2) Production and evaluation of organic photoluminescent device (film)

The compound 1 and DPEPO (bis(2-(diphenylphosphino)-phenyl)ether oxide were vapor-deposited from different evaporation sources under vacuum conditions of 5.0×10 ^-4 Pa by vacuum evaporation method, double (2-Diphenylphosphinylphosphine) diphenyl ether) A film having a concentration of Compound 1 of 6.0% by weight was formed at a thickness of 100 nm at 0.3 nm/sec to prepare an organic photoluminescence device. The luminescence spectrum obtained by using the same measuring apparatus as in Example 1 is shown in Fig. 8. Further, the transient decay curve shown in Fig. 9 was obtained by measurement of a small fluorescence lifetime measuring device (Quantaurus-tau manufactured by Hamamatsu Photonics Co., Ltd.) at 300K. It was confirmed that it is a thermally active type delayed fluorescence in which the fluorescence component is delayed as the temperature is lowered. The photoluminescence quantum efficiency was 42.6% at 300K.

An organic photoluminescent device was produced by using Compound 2 instead of Compound 1, and evaluation was performed in the same manner. Fig. 10 shows the luminescence spectrum, and Fig. 11 shows the transient decay curve. It was confirmed that it is a thermally active type delayed fluorescence in which the fluorescence component is delayed as the temperature is lowered. The photoluminescence quantum efficiency was 83.8% at 300K.

Further, an organic photoluminescent device was produced by using Compound 3 instead of Compound 1, and evaluation was performed in the same manner. Figure 12 shows the transient decay curve. It was confirmed that it is a thermally active type delayed fluorescence in which the fluorescence component is delayed as the temperature is lowered. The photoluminescence quantum efficiency was 68.5% at 300K.

(Comparative Example 1) Production and evaluation of organic photoluminescent device (film)

The following Comparative Compound 1 was used instead of Compound 1, even in the same manner as in Example 2. The method was tested, and delayed fluorescence was not confirmed, and the quantum efficiency was also low.

(Example 3) Production and evaluation of organic electroluminescent elements

Each film was laminated on a glass substrate on which an anode including indium tin oxide (ITO) having a film thickness of 100 nm was formed at a vacuum of 5.0 × 10 ^-4 Pa by a vacuum deposition method. First, α-NPD (N, N'-dinaphthyl-N, N'-diphenylbenzidine, N, N'-dinaphthyl-N,N'-diphenylbenzidine) having a thickness of 30 nm is formed on ITO. mCP (N, N'-dicarbazolyl-3, 5-benzene, N, N'-dicarbazolyl-3,5-benzene) having a thickness of 10 nm was formed thereon. Next, Compound 1 and DPEPO were co-evaporated from different vapor deposition sources to form a layer having a thickness of 15 nm as a light-emitting layer. At this time, the concentration of the compound 1 was 6.0% by weight. Next, DPEPO having a thickness of 10 nm was formed, and TPBi (1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 1,3,5-tris(1-phenyl-) having a thickness of 40 nm was formed. 1H-benzimidazol-2-yl)benzene), and further vacuum-depositing 0.8 nm lithium fluoride (LiF), followed by evaporation of aluminum (Al) having a thickness of 100 nm, thereby forming a cathode, thereby preparing an organic electroluminescence element.

The manufactured organic electroluminescent device was measured using a semiconductor parameter analyzer (manufactured by Agilent Technologies, Inc.: E5273A), an optical power meter measuring device (manufactured by Newport: 1930C), and an optical spectroscope (manufactured by Ocean Optics: USB2000). As a result, as shown in Fig. 13, the light emission at 456 nm was confirmed. The voltage-current density characteristics are shown in Fig. 14, and the current density-external quantum efficiency characteristics are shown in Fig. 15. An organic electroluminescent device using Compound 1 as a luminescent material achieves a higher external quantum of 8.66% effectiveness. Assuming that an organic electroluminescence device with an ideal balance is prepared using a fluorescent material having a luminescence quantum efficiency of 100%, if the light extraction efficiency is 20 to 30%, the external quantum efficiency of the luminescence is 5 to 7.5%. This value is generally considered to be the theoretical limit of the external quantum efficiency of an organic electroluminescent device using a fluorescent material. The organic electroluminescence device of the present invention using the compound 1 is extremely excellent in achieving a higher external quantum efficiency exceeding a theoretical limit value.

An organic electroluminescence device was produced in the same manner using Compound 2 instead of Compound 1. Among them, TPBi having a thickness of 65 nm was formed. The light emission spectrum of the produced organic electroluminescence device is shown in Fig. 16, the voltage-current density characteristic is shown in Fig. 17, and the current density-external quantum efficiency characteristic is shown in Fig. 18. The organic electroluminescent device using Compound 2 as a light-emitting material achieved a higher external quantum efficiency of 14.87%.

An organic electroluminescence device was produced in the same manner using Compound 3 instead of Compound 1. The luminescence spectrum of the produced organic electroluminescence device is shown in Fig. 19, and the current density-external quantum efficiency characteristics are shown in Fig. 20. The organic electroluminescent element using Compound 3 as a light-emitting material achieved a higher external quantum efficiency of 10.0%.

(Example 4) Production and evaluation of organic photoluminescent device (solution)

A toluene solution (concentration: 10 ^-4 mol/L) of the compound 5 synthesized in Synthesis Example 5 was prepared, and ultraviolet light was irradiated at 300 K while introducing nitrogen gas. As a result, fluorescence having a peak wavelength of 505 nm was observed as shown in Fig. 21 . Further, after passing nitrogen gas, measurement by a small fluorescence lifetime measuring device (Quantaurus-tau manufactured by Hamamatsu Photonics Co., Ltd.) was carried out, and the transient decay curve shown in Fig. 22 was obtained. Fluorescence with an excitation lifetime of 0.00897 μs and delayed fluorescence of 0.491 μs were observed. The photoluminescence quantum efficiency of Compound 5 in a toluene solution was measured by an absolute PL quantum yield measuring apparatus (Quantaurus-QY manufactured by Hamamatsu Photonics Co., Ltd.) at 300 K, and was 18.7% after nitrogen gas was passed.

The production and evaluation of the toluene solution were carried out in the same manner by using the compound 6 synthesized in Synthesis Example 6 instead of the compound 5. Figure 23 shows the luminescence spectrum, and Figure 24 shows the flow of nitrogen. Transient decay curve. Fluorescence with an excitation lifetime of 0.0061 μs and delayed fluorescence of 3.39 μs were observed. The photoluminescence quantum efficiency was 34.7% after the introduction of nitrogen.

(Example 5) Production and evaluation of organic photoluminescent device (film)

The compound 5 and CBP (4,4'-bis(carbazol-9-yl)biphenyl were vapor-deposited from different evaporation sources under vacuum conditions of 5.0×10 ^-4 Pa by vacuum evaporation. 4,4'-bis(carbazol-9-yl)biphenyl), a film having a concentration of compound 5 of 6.0% by weight was formed at a thickness of 100 nm at 0.3 nm/sec to prepare an organic photoluminescence device. The luminescence spectrum obtained by using the same measuring apparatus as in Example 4 is shown in Fig. 25. Further, the transient decay curve shown in Fig. 26 was obtained by measurement of a small fluorescence lifetime measuring device (Quantaurus-tau manufactured by Hamamatsu Photonics Co., Ltd.) at 300K. Fluorescence with an excitation lifetime of 0.392 μs and delayed fluorescence of 4.05 μs were observed. The photoluminescence quantum efficiency is 45% at 300K.

An organic photoluminescent device was produced by using Compound 6 instead of Compound 5, and evaluation was performed in the same manner. Fig. 27 shows the luminescence spectrum, and Fig. 28 shows the transient decay curve. Fluorescence with an excitation lifetime of 0.0068 μs and delayed fluorescence of 6.13 μs were observed. The photoluminescence quantum efficiency was 23.6% at 300K.

(Comparative Example 2) Production and evaluation of organic photoluminescent device (film)

The following Comparative Compound 2 was used instead of Compound 5, and even if it was tested in the same manner as in Example 5, delayed fluorescence was not confirmed, and quantum efficiency was also low.

(Example 6) Production and evaluation of organic electroluminescent elements

Each film was laminated on a glass substrate on which an anode including indium tin oxide (ITO) having a film thickness of 100 nm was formed at a vacuum of 5.0 × 10 ^-4 Pa by a vacuum deposition method. First, α-NPD having a thickness of 40 nm was formed on ITO. Next, the compound 5 and CBP were co-evaporated from different vapor deposition sources to form a layer having a thickness of 30 nm as a light-emitting layer. At this time, the concentration of the compound 5 was set to 6.0% by weight. Next, TPBi having a thickness of 60 nm was formed, and lithium fluoride (LiF) of 0.8 nm was vacuum-deposited, followed by vapor deposition of aluminum (Al) having a thickness of 80 nm, thereby forming a cathode, thereby preparing an organic electroluminescence device.

The manufactured organic electroluminescent device was measured using a semiconductor parameter analyzer (manufactured by Agilent Technologies, Inc.: E5273A), an optical power meter measuring device (manufactured by Newport: 1930C), and an optical spectroscope (manufactured by Ocean Optics: USB2000). As a result, as shown in Fig. 29, luminescence at 560 nm was confirmed. The voltage-current density characteristics are shown in Fig. 30, and the current density-external quantum efficiency characteristics are shown in Fig. 31. The organic electroluminescent element using Compound 5 as a luminescent material achieved a higher external quantum efficiency of 8.9%.

An organic electroluminescence device was produced in the same manner using Compound 6 instead of Compound 5. Among them, TPBi having a thickness of 65 nm was formed. The luminescence spectrum map 32 of the produced organic electroluminescence device, the voltage-current density characteristic diagram 33, and the current density-external quantum efficiency characteristics are shown in Fig. 34. The organic electroluminescent element using Compound 5 as a light-emitting material achieved a high external quantum efficiency of 9.9%.

[化55]

[Industrial availability]

The compound of the present invention represented by the formula (1) can be used as a luminescent material. Therefore, the compound of the present invention can be effectively used as a light-emitting material for an organic light-emitting element such as an organic electroluminescence device. Since the compound of the present invention also contains radiation-delayed fluorescence, it is also possible to provide an organic light-emitting element having high luminous efficiency. Therefore, the present invention has high industrial availability.

1‧‧‧Substrate

2‧‧‧Anode

3‧‧‧ hole injection layer

4‧‧‧ hole transport layer

5‧‧‧Lighting layer

6‧‧‧Electronic transport layer

7‧‧‧ cathode

Claims (17)

A compound represented by the following formula (1): (1) (D) nA [In the formula (1), D is a group represented by the following formula (2), and A represents a formula (3) The base of the n-valent structure of the represented structure; n represents any integer from 1 to 8] [In the formula (2), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond, R ²¹ ~ R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, Ar ³ represents a substituted or unsubstituted aryl group; and R ¹ to R ⁸ each independently represent a hydrogen atom or a substituent; and R ¹ and R ² and R ² are R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, R ¹ ~ At least one of R ⁸ represents a substituted or unsubstituted diarylamino group] [Chemical 2] [In the formula (3), Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group]. The compound of claim 1, wherein Z ^{1 of the} formula (2) represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ) or a single bond. The compound of claim 1, wherein Z ^{1 of the} formula (2) represents N-Ar ³ . The compound according to any one of claims 1 to 3, wherein A of the formula (1) has a structure represented by the following formula (4), [In the formula (4), Y represents O, S or N-Ar ⁴ , and Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group]. The compound according to any one of claims 1 to 3, wherein n of the formula (1) is an integer of any one of 1 to 4. The compound of any one of claims 1 to 3, which is represented by the formula (5), [Chemical 4] [In the general formula (5), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single The bond, R ²¹ to R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group; and Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic group. Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² And R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ and R ¹⁴ , R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents a substitution. Or an unsubstituted diarylamine group, wherein when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ represents a substituted or unsubstituted diarylamine group; n1 and n2 each independently represent 0. Any integer of ~8, the sum of n1 and n2 is 1~8]. The compound of claim 6, wherein each of Z ¹ and Z ^{2 of the} formula (5) is independently O, S, N-Ar ³ or a single bond. The compound of claim 6, wherein Y of the formula (5) is O or N-Ar ⁴ . The compound according to any one of claims 1 to 3, which is represented by the formula (6), [Chemical 5] [In the formula (6), Z ¹ represents O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single bond, R ²¹ ~ R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, Ar ³ represents a substituted or unsubstituted aryl group; Ar ^{1 '} represents a substituted or unsubstituted extended aryl group; and Ar ^{2 '} represents a substituted or unsubstituted group. a substituted aryl group; Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, At least one of R ¹ to R ⁸ represents a substituted or unsubstituted diarylamino group]. The compound according to any one of claims 1 to 3, which is represented by the following formula (7), [In the general formula (7), Z ¹ and Z ² each independently represent O, S, C=O, C(R ²¹ )(R ²² ), Si(R ²³ )(R ²⁴ ), N-Ar ³ or a single The bond, R ²¹ to R ²⁴ each independently represents an alkyl group having 1 to 8 carbon atoms, and Ar ³ represents a substituted or unsubstituted aryl group; and Ar ^1" and Ar ^{2 "} each independently represent a substituted or unsubstituted extension. An aryl group; Y represents O, S or N-Ar ⁴ , and Ar ⁴ represents a substituted or unsubstituted aryl group; R ¹ to R ⁸ and R ¹¹ to R ¹⁸ each independently represent a hydrogen atom or a substituent; R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹³ and R ¹⁴ R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , R ¹⁷ and R ¹⁸ may each be bonded to each other to form a cyclic structure; wherein, when Z ¹ is a single bond, at least one of R ¹ to R ⁸ represents The substituted or unsubstituted diarylamine group, when Z ² is a single bond, at least one of R ¹¹ to R ¹⁸ represents a substituted or unsubstituted diarylamino group]. The compound of claim 10, wherein Z ^{1 of the} formula (7) is the same as Z ² , Ar ^{1 " is the} same as Ar ^{2 "} , R ¹ is the same as R ¹¹ , R ² is the same as R ¹² , and R ³ is the same as R ¹³ R ⁴ is the same as R ¹⁴ , R ⁵ is the same as R ¹⁵ , R ⁶ is the same as R ¹⁶ , R ⁷ is the same as R ¹⁷ , and R ⁸ is the same as R ¹⁸ . The compound of claim 10 or 11, wherein Z ¹ and Z ^{2 of the} formula (7) are each independently O, S or N-Ar ³ . A luminescent material comprising a compound according to any one of claims 1 to 12. A delayed phosphor comprising the compound of any one of claims 1 to 12. An organic light-emitting element characterized in that it has a light-emitting layer containing a compound according to any one of claims 1 to 12 as a light-emitting material on a substrate. The organic light-emitting element of claim 15, which emits radiation delayed fluorescence. An organic light-emitting element according to claim 15 or 16, which is an organic electroluminescence element.