Organic electroluminescent device and method for producing the same

Abstract

Provided is an organic EL element that realizes low-voltage characteristics with high efficiency. Comprised is a light-emitting layer including compounds of (1) and (2) and a dopant. X is N or CR3 with at least one being N. R1 is (1b), R2 is (1c), and R3 is an alkyl group, etc. Y is O, S, NR4, CR5R6, where R4to R6 is an alkyl group, etc., and one of R7 to R14 bonds with a ring of (1). * is the bonding position with the ring of (1), and rings C, D are aromatic rings that condense with an adjacent ring. R15, R16, and R17 are synonymous with R3 (a, b are substitution numbers). R19 is synonymous with R4, and R20 to R27 are CR3, CR28 or N, with at least one being CR28, and R28 is expression (2b). Z is O, S, NR37, CR38R39, where R37 to R39 are synonymous with R4, and one of R29 to R36 bonds with a ring of (2), and the other is CR3 or N.

Description

[Technical field]

[0001] The present invention relates to an organic electroluminescent device (hereinafter referred to as an organic EL device), and more particularly to an organic EL device containing a specific mixed host material. [Background technology]

[0002] When a voltage is applied to an organic EL element, holes are injected from the anode and electrons are injected from the cathode into the light-emitting layer. In the light-emitting layer, the injected holes and electrons recombine to generate excitons. At this time, singlet excitons and triplet excitons are generated in a ratio of 1:3 due to the statistical laws of electron spin. It is said that the internal quantum efficiency of fluorescent organic EL elements that use emission from singlet excitons is limited to 25%. On the other hand, it is known that the internal quantum efficiency of phosphorescent organic EL elements that use emission from triplet excitons can be increased to 100% if intersystem crossing from singlet excitons is efficiently performed.

[0003] More recently, highly efficient organic EL elements utilizing delayed fluorescence have been developed. For example, Patent Document 1 discloses an organic EL element utilizing the TTF (Triplet-Triplet Fusion) mechanism, which is one of the mechanisms of delayed fluorescence. The TTF mechanism utilizes the phenomenon in which singlet excitons are generated by the collision of two triplet excitons, and it is believed that the internal quantum efficiency can be theoretically increased to 40%. However, since the efficiency is lower than that of phosphorescent organic EL elements, further improvement in efficiency and low voltage characteristics are required.

[0004] Furthermore, Patent Document 2 discloses an organic EL element that utilizes the TADF (Thermally Activated Delayed Fluorescence) mechanism. The TADF mechanism utilizes the phenomenon in which reverse intersystem crossing occurs from triplet excitons to singlet excitons in a material with a small energy difference between the singlet level and the triplet level, and is believed to be able to theoretically increase the internal quantum efficiency to 100%.

[0005] However, in both mechanisms, there is room for improvement in both efficiency and lifespan, and there is also a demand for improvements in reducing the driving voltage.

[0006] On the other hand, Patent Documents 3 and 4 disclose the use of an indolocarbazole compound substituted with a condensed heterocycle as a host material.

[0007] Patent Documents 5 and 6 disclose the use of an indolocarbazole compound as a mixed host.

[0008] However, none of these methods can be said to be sufficient, and further improvements in efficiency and voltage are desired. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] WO2010 / 134350 No. [Patent Document 2] WO2011 / 070963 [Patent Document 3] WO2013 / 137001 issue [Patent Document 4] WO2013 / 122402 issue [Patent Document 5] WO2016 / 023608 issue [Patent Document 6] WO2018 / 198844 Summary of the Invention [Problem to be solved by the invention]

[0010] In order to apply an organic EL element to a display element such as a flat panel display, it is necessary to improve the luminous efficiency of the element and at the same time ensure sufficient stability during operation. In view of the above-mentioned current situation, the object of the present invention is to provide a practically useful organic EL element that has high efficiency and realizes low-voltage characteristics.

[0011] As a result of extensive investigations, the present inventors have found that an organic electroluminescent device using a specific mixed host material in the light-emitting layer can solve the above problems, and have thus completed the present invention.

[0012] The present invention is an organic electroluminescent device having a plurality of organic layers between an opposing anode and cathode, the organic layers including at least one light-emitting layer, the light-emitting layer including a compound represented by general formula (1), a compound represented by general formula (2), and a dopant. [ka]

[0013] where X is N or CR 3 and at least one of X represents N. 1 is expressed by the following formula (1b), and R 2 is expressed by the following formula (1c). 3 are independently hydrogen 、 It represents halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups have a hydrogen atom, the hydrogen atom may be substituted with a halogen.

[0014] [ka] where Y is O, S, or NR 4 , C.R. 5 R 6Represents R 4 ~R 6 are each independently hydrogen 、 It represents an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with a halogen. R 8 is a carbon atom connected to the ring of the general formula (1), R 7 、R 9 ~R 14 teeth Each independently CR 3 , or N, R 3 is as mentioned above, and R 3 When multiple are present, they may be the same or different. [ka] Here, * represents the position of bonding with the ring of the general formula (1), and ring C represents an aromatic ring represented by formula (C1) which is fused at any position of two adjacent rings. Ring D represents a five-membered ring represented by formula (D1) which is fused at any position of two adjacent rings. R 15 , R 16 and R 17 are each independently , hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with a deuterium or a halogen. 15 、R 16 and R 17 teeth, When a plurality of each of them is present, they may be the same or different. a, b, and c represent the number of substitutions, and each of a and b independently represents an integer of 1 to 4, and c represents an integer of 1 to 2. R 18 is R 4 is synonymous with.

[0015] [ka] Here, R 19 is R 4 Synonymous with R. 20 ~R 27are each independently, CR 3 ’ , C.R. 28 Or N 、 At least one CR 28 It is expressed as R 28 is expressed by the following formula (2b). R 3 ’ , R 28 When there are a plurality of each, they may be the same or different. R 3 ' represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. [ka] where Z is O, S, NR 37 , C.R. 38 R 39 R 37 ~R 39 R each independently represents hydrogen, deuterium, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups have a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. 29 ~R 36 any one of which is a carbon atom bonded to the ring of general formula (2), and the others are each independently CR 3 ’ , or N. R 3 ’ is as mentioned above, R 3 ’ When multiple are present, they may be the same or different.

[0016] Formula (1b) is R 7 , or R 8 It is preferable that R is linked to the ring of the general formula (1) via any one of the following: 8 It is preferable that the ring is linked to the ring of general formula (1) by the formula (1).

[0017] In formula (1b), Y is preferably O or S.

[0018] Regarding formula (1c), preferably, it is represented by any one of the following formulas (11) to (15).

Chemical formula

[0019] Also, regarding general formula (2), preferably, it is represented by any one of the following general formulas (21) to (29).

Chemical formula

[0020] Regarding general formula (2), more preferably, it is represented by any one of general formulas (21) to (23).

[0021] In general formulas (21) to (23), preferably, R 19 , R 37 and R 38 are a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked.

[0022] Preferred embodiments of the organic electroluminescent device of the present invention are shown below. That is, the organic electroluminescent device according to the present invention has a mixed host containing two types of compounds and includes a light-emitting layer having a dopant. Among these, as the mixed host, with respect to the total of the compound represented by the general formula (1) and the compound represented by the general formula (2), the proportion of the compound represented by the general formula (1) is preferably 10 wt% or more and less than 70 wt%, and more preferably 20 wt% or more and less than 60 wt%. Further, the light-emitting dopant is preferably an organometallic complex containing at least one metal selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold, or a thermally activated delayed fluorescence emitting dopant.

[0023] Further, in manufacturing the above organic electroluminescent device, it is preferable to have a step of mixing the compound represented by the general formula (1) and the compound represented by the general formula (2) to form a preliminary mixture, and then vapor-depositing a host material containing this to form a light-emitting layer.

[0024] In the manufacturing method of the above organic electroluminescent device, it is suitable that the difference in the 50% weight loss temperature between the first host and the second host is within 20°C.

Effects of the Invention

[0025] In order to improve device characteristics, it is necessary that the materials used in the organic layer have high durability against charges, and in particular, in the light-emitting layer, it is important to suppress the leakage of excitons and charges to the surrounding layers. To suppress this charge / exciton leakage, it is effective to improve the bias of the light-emitting region in the light-emitting layer, and for this purpose, it is necessary to control the injection amount of both charges (electrons / holes) into the light-emitting layer or the transport amount of both charges in the light-emitting layer within a preferable range. Here, the compound represented by the general formula (1) used in the present invention has a structure in which two or more different fused aromatic groups are bonded to a nitrogen-containing six-membered ring. This improves the charge transportability and durability against charges, and an organic EL device that operates stably even at a low voltage can be prepared. On the other hand, the carbazole compound represented by the general formula (2) has particularly high hole injection transportability, and the hole injection transportability can be controlled at a high level by changing the bonding style of the carbazole ring and the type and number of substituents on the skeleton. Therefore, by combining the compound represented by the general formula (1), the amount of both charges injected into the organic layer can be adjusted to a preferred range, and the bias of the light-emitting region in the light-emitting layer can be improved. In particular, in the case of a delayed fluorescent EL device or a phosphorescent EL device, since the lowest excited triplet energy is high enough to trap the excitation energy generated in the light-emitting layer, there is no energy outflow from the light-emitting layer, and an organic EL device that is highly efficient and has a long life can be prepared even at a low voltage. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of an organic EL element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The organic EL device of the present invention has a structure in which an anode, an organic layer, and a cathode are laminated on a substrate, and at least one of the organic layers has an emitting layer formed using a predetermined material for organic electroluminescent devices. That is, the organic EL device has an organic layer consisting of multiple layers between an anode and a cathode facing each other, and at least one of the multiple layers is an emitting layer, and there may be multiple emitting layers. At least one of the emitting layers is an emitting layer consisting of a vapor deposition layer containing a compound represented by general formula (1) (hereinafter referred to as a first host), a compound represented by general formula (2) (hereinafter referred to as a second host), and a luminescent dopant.

[0028] That is, the first host contained in the light emitting layer is selected from the compounds represented by general formula (1), and the second host is selected from the compounds represented by general formula (2).

[0029] In the general formula (1), X is N or CR 3 At least one of X represents N. At least one of X represents N, but it is preferable that two or more of X represent N, and it is more preferable that all of X represent N. 1 is expressed by formula (1b), and R 2 is expressed by equation (1c).

[0030] In the general formula (1), R 3 are independently hydrogen 、 halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which these or these aromatic rings are linked together. When these groups have a hydrogen atom, the hydrogen atom but Although it may be substituted with a halogen, it is preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together, and more preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic hydrocarbon groups and aromatic heterocyclic groups are linked together.

[0031] In this specification, the linking aromatic group refers to a group in which aromatic rings of aromatic hydrocarbon groups and / or aromatic heterocyclic groups are linked by a single bond. Specifically, it refers to 2 to 5 aromatic rings of substituted or unsubstituted aromatic hydrocarbon groups having 6 to 24 carbon atoms linked together, 2 to 5 aromatic rings of substituted or unsubstituted aromatic heterocyclic groups having 3 to 17 carbon atoms linked together, or 2 to 5 aromatic rings of these aromatic hydrocarbon groups and aromatic heterocyclic groups linked together. These may be linked in a straight chain or branched chain, and the aromatic rings may be the same or different.

[0032] In formula (1b), Y is O, S, NR 4 , C.R. 5 R 6 Y represents O, S, or NR 4 is preferable, and O or S is more preferable.

[0033] R 4 ~R 6 are each independently hydrogen 、 It represents an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups have a hydrogen atom, the hydrogen atom but Although it may be substituted with a halogen, it is preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which these or 2 to 5 of these aromatic rings are linked together, and more preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together.

[0034] R 8 is a carbon atom connected to the ring of the general formula (1), R 7 、R 9 ~R 14 teeth , each independently CR 3 , or N, R 3 is as mentioned above, and R 3 When there are multiple R, they may be the same or different. 7 ~R 14 Of these, N is preferably 2 or less, and N is more preferably 0 or 1.

[0035] In formula (1b), R 7 , or R 8 It is preferable that R is linked to the ring of general formula (1) through any one of the following: 8 is more preferably linked to the ring of general formula (1).

[0036] In formula (1c), * indicates the position of bonding to general formula (1), ring C is an aromatic ring represented by formula (C1) fused at any position to two adjacent rings, and ring D is a five-membered ring represented by formula (D1) fused at any position to two adjacent rings.

[0037] R 15 , R 16 and R 17 are each independently It represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with deuterium or halogen. In formula (1c), R 15 , R 16 and R 17 When a plurality of each of these is present, they may be the same or different. In formula (D1), R 18 is R 4 is synonymous with.

[0038] a and b in formula (1c) and c in formula (C1) each represent the number of substitutions, and each independently a and b represent an integer of 1 to 4, and c represents an integer of 1 to 2. Preferably, a and b are an integer of 1 or 2, and c is 1.

[0039] The second host is represented by the above general formula (2).

[0040] In the general formula (2), R 19 is R 3is synonymous with.

[0041] In addition, in the general formula (2), R 20 ~R 27 are each independently, CR 3 ’ , C.R. 28 or N, R 3 ’ As mentioned above, at least one CR 28 It is expressed as R 20 ~R 27 Of these, N is preferably 2 or less, and N is more preferably 0 or 1.

[0042] Of these, R 28 is expressed by formula (2b). R, R 28 When there are a plurality of each, they may be the same or different.

[0043] In formula (2b), Z is O, S, NR 37 , C.R. 38 R 39 R 37 ~R 39 are each independently R 4 Synonymous with R. 29 ~R 36 one of which is a carbon atom bonded to the ring of general formula (2), and the others are each independently CR 3 ’ , or N. 29 ~R 36 Among these, N is preferably 2 or less, and N is more preferably 0 or 1. R 3 ’ is as mentioned above, R 3 ’ When multiple are present, they may be the same or different.

[0044] In formulas (21) to (23), R 19 , and R 37each independently represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted or an unsubstituted aromatic heterocyclic group having 3 to 18 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together, and when these groups have a hydrogen atom, the hydrogen atom may be substituted with deuterium or halogen. However, the aromatic heterocyclic group is preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 18 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together, and more preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together.

[0045] Formulas (21) to (29) preferably have at least one p-BiPh (biphenyl) group, and more specifically, R 19 , R 37 and R 38 It is preferable that either one of the above has a p-BiPh group.

[0046] In formulas (21) to (23), R 38each independently represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted It refers to a substituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 18 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together, but is preferably hydrogen, deuterium, an aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 18 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together, and is more preferably hydrogen, deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together.

[0047] R 19 , R 37 and R 38Specific examples of when is an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyl group having 1 to 20 carbon atoms include methyl, ethyl, propyl, butyl ... alkyl groups such as ethyl, pentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl; aralkyl groups such as phenylmethyl, phenylethyl, phenylicosyl, naphthylmethyl, anthranylmethyl, phenanthrenylmethyl, and pyrenylmethyl; alkenyl groups such as vinyl, propenyl, butenyl, pentenyl, decenyl, and icosenyl; ethynyl, propargyl, butynyl, and pentynyl. alkynyl groups such as decynyl and icosynyl; dialkylamino groups such as dimethylamino, ethylmethylamino, diethylamino, dipropylamino, dibutylamino, dipentynylamino, didecylamino and diicosylamino; diarylamino groups such as diphenylamino, naphthylphenylamino, dinaphthylamino, dianthranylamino, diphenanthrenylamino and dipyrenylamino; diphenylmethylamino, diphenylethylamino, phenylmethylphenylethylamino, dinaphthylmethylamino, dianthranylmethylamino and diphenanthrenylamino; diarylmethylamino groups, acyl groups such as acetyl, propionyl, butyryl, valeryl, and benzoyl, acyloxy groups such as acetyloxy, propionyloxy, butyryloxy, valeryloxy, and benzoyloxy, alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonyloxy, and decanyloxy, alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, and pentoxycarbonyl, methoxycarbonyloxy,Examples of the alkyl group include alkoxycarbonyloxy groups such as ethoxycarbonyloxy, propoxycarbonyloxy, butoxycarbonyloxy, and pentoxycarbonyloxy, alkylsulfoxy groups such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, and pentylsulfonyl, cyano, nitro, fluoro, and tosyl groups. Preferred examples include an alkyl group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a diarylamino group having two aromatic hydrocarbon groups having 6 to 15 carbon atoms, a cyano group, a fluoro group, and a tosyl group.

[0048] R 19 , R 37 and R 38Specific examples of when is an aromatic hydrocarbon group or an aromatic heterocyclic group include an aromatic group obtained by removing one H from benzene, naphthalene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. Preferred are aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, oxadiazole, quinoline, isoquinoline, quinoxaline, quinazoline, oxadiazole, thiadiazole, benzotriazine, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, or benzothiadiazole. More preferred are aromatic groups derived from benzene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, oxazole, or oxadiazole.

[0049] Specific examples of the compound represented by formula (1) are shown below, but the compound is not limited to these. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0050] Specific examples of the compound represented by formula (2) are shown below, but the compound is not limited thereto. [ka] [ka] [ka]

[0051] The light-emitting layer of the organic electroluminescent device of the present invention contains a compound represented by general formula (1), a compound represented by general formula (2), and a dopant, and may contain other components such as an aliphatic organic compound, an aromatic hydrocarbon compound, an aromatic heterocyclic compound, an organometallic complex, etc. When other components are contained, the total proportion of other compounds in the light-emitting layer is preferably less than 30 wt%, more preferably less than 10 wt%.

[0052] The ratio of the compound represented by general formula (1) to the total of the compound represented by general formula (1) and the compound represented by general formula (2) is preferably 10 wt % or more and less than 70 wt %, and more preferably 20 wt % or more and less than 60 wt %.

[0053] The luminescent dopant is preferably an organometallic complex containing at least one metal selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold, or a thermally activated delayed fluorescent dopant material.

[0054] The light-emitting layer of the organic electroluminescent device of the present invention may be formed by deposition from a deposition source, or may be formed by dissolving or dispersing in a solvent and then by a spin coating method, a bar coating method, a spray method, an ink-jet method, a printing method or the like.

[0055] When forming the light-emitting layer of the organic electroluminescent element of the present invention by a vapor deposition method, the materials can be vapor-deposited from different vapor deposition sources, but it is preferable to premix them before vapor deposition to form a premixture, and then vapor-deposit the premixture from one vapor deposition source at the same time to form the light-emitting layer. In this case, the premixture may contain a light-emitting dopant material required to form the light-emitting layer or other hosts used as necessary, but if there is a large difference in the temperature at which the desired vapor pressure is obtained, it is preferable to vapor-deposit them from different vapor deposition sources.

[0056] When the light-emitting layer of the organic electroluminescent device of the present invention is formed by a printing method, the compound represented by general formula (1), the compound represented by general formula (2), and a dopant are dissolved or dispersed in a solvent to form a light-emitting layer ink, and then a film can be formed by the above-mentioned printing method.

[0057] Next, the structure of the organic EL element of the present invention will be described with reference to the drawings, but the structure of the organic EL element of the present invention is not limited thereto.

[0058] FIG. 1 is a cross-sectional view showing an example of the structure of a general organic EL element used in the present invention, in which 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light-emitting layer, 6 is an electron transport layer, and 7 is a cathode. The organic EL element of the present invention may have an exciton blocking layer adjacent to the light-emitting layer, or an electron blocking layer between the light-emitting layer and the hole injection layer. The exciton blocking layer can be inserted on either the anode side or the cathode side of the light-emitting layer, or both can be inserted at the same time. The organic EL element of the present invention has an anode, a light-emitting layer, and a cathode as essential layers, but may have a hole injection transport layer and an electron injection transport layer in addition to the essential layers, and may further have a hole blocking layer between the light-emitting layer and the electron injection transport layer. The hole injection transport layer means either or both of the hole injection layer and the hole transport layer, and the electron injection transport layer means either or both of the electron injection layer and the electron transport layer.

[0059] It is also possible to have the reverse structure to that shown in FIG. 1, that is, to stack the cathode 7, the electron transport layer 6, the light-emitting layer 5, the hole transport layer 4, and the anode 2 on the substrate 1 in this order. In this case as well, layers can be added or omitted as necessary.

[0060] -substrate- The organic EL device of the present invention is preferably supported by a substrate. There are no particular limitations on the substrate, and any substrate that has been conventionally used for organic EL devices, such as glass, transparent plastic, quartz, etc., can be used.

[0061] -anode- As the anode material in an organic EL element, a material consisting of a metal, an alloy, an electrically conductive compound, or a mixture thereof, each having a large work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, CuI, indium tin oxide (ITO), SnO 2 ZnO and other conductive transparent materials. 2 O 3 A material capable of forming an amorphous transparent conductive film, such as ZnO, may be used. The anode may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering, and forming a pattern of a desired shape by a photolithography method. Alternatively, when pattern accuracy is not required (about 100 μm or more), a pattern may be formed through a mask of a desired shape during vapor deposition or sputtering of the electrode material. Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film formation method such as a printing method or a coating method may be used. When light is to be emitted from this anode, it is desirable to make the transmittance larger than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. The film thickness depends on the material, but is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

[0062] -cathode- On the other hand, as the cathode material, a material consisting of a metal (electron injecting metal) with a small work function (4 eV or less), an alloy, an electrically conductive compound, or a mixture of these is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3) mixture, indium, lithium / aluminum mixture, rare earth metals, etc. Among these, from the viewpoint of electron injection property and durability against oxidation, etc., a mixture of an electron injection metal and a second metal having a larger work function value and being stable than the electron injection metal, for example, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide mixture, a lithium / aluminum mixture, aluminum, etc. are suitable. The cathode can be produced by forming a thin film of these cathode materials by a method such as deposition or sputtering. The sheet resistance of the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In addition, in order to transmit the emitted light, if either the anode or the cathode of the organic EL element is transparent or semitransparent, the luminance of the emitted light is improved, which is advantageous.

[0063] In addition, after forming the above metal in a thickness of 1 to 20 nm as the cathode, a conductive transparent material as described in the explanation of the anode is formed thereon, whereby a transparent or semitransparent cathode can be fabricated. By applying this, an element in which both the anode and cathode are transparent can be fabricated.

[0064] -Emitting layer- The light-emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from the anode and cathode, respectively, and contains a compound represented by general formula (1), a compound represented by general formula (2), and a light-emitting dopant material.

[0065] The compound represented by the general formula (1) and the compound represented by the general formula (2) are preferably used as a host material for the light-emitting layer. The compound represented by the general formula (1) may be used alone or in combination with two or more kinds. Similarly, the compound represented by the general formula (2) may be used alone or in combination with two or more kinds. If necessary, one or more known host materials may be used in combination, but the amount of the host material used is 50 wt % or less, preferably 25 wt % or less, based on the total amount of the host materials including the compound represented by general formula (1) and the compound represented by general formula (2).

[0066] When the compound represented by the general formula (1) and the compound represented by the general formula (2) are premixed and used, in order to reproducibly fabricate an organic EL device having good characteristics, it is necessary to determine the 50% weight loss temperature (T 50 ) should be as small as possible. The 50% weight loss temperature is the temperature at which the weight is reduced by 50% when the temperature is raised from room temperature to 550°C at a rate of 10°C per minute in TG-DTA measurement under reduced pressure (1 Pa) of nitrogen gas flow. It is believed that vaporization by evaporation or sublimation occurs most actively around this temperature.

[0067] The difference in the 50% weight loss temperature between the compound represented by general formula (1) and the compound represented by general formula (2) is preferably within 30° C., more preferably within 20° C. As a premixing method, a known method such as pulverization mixing can be used, but it is desirable to mix as uniformly as possible. The difference in the 50% weight loss temperature refers to an absolute value.

[0068] When multiple types of hosts are used, each host can be evaporated from a different evaporation source, or the hosts can be premixed before evaporation to form a premixture, allowing multiple types of hosts to be evaporated simultaneously from one evaporation source.

[0069] The premixing method is preferably a method that can mix as uniformly as possible, and examples of the method include pulverization and mixing, heating and melting under reduced pressure or in an inert gas atmosphere such as nitrogen, and sublimation, but is not limited to these methods.

[0070] When a phosphorescent dopant is used as the light-emitting dopant material, the phosphorescent dopant may contain an organometallic complex containing at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. 5 The iridium complexes described in the above publication are preferably used, but are not limited thereto.

[0071] The light-emitting layer may contain one or more phosphorescent dopant materials. The content of the phosphorescent dopant material is preferably 0.1 to 30 wt %, and more preferably 1 to 20 wt %, based on the host material.

[0072] The phosphorescent dopant material is not particularly limited, but specific examples include the following. [ka] [ka]

[0073] When a fluorescent dopant is used as the light-emitting dopant material, examples of the fluorescent dopant include, but are not limited to, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyrrolidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidine compounds, various metal complexes typified by metal complexes of 8-quinolinol derivatives, metal complexes of pyrromethene derivatives, rare earth complexes, and transition metal complexes; polymer compounds such as polythiophene, polyphenylene, and polyphenylenevinylene; and organic silane derivatives. Preferred are condensed aromatic derivatives, styryl derivatives, diketopyrrolopyrrole derivatives, oxazine derivatives, pyrromethene metal complexes, transition metal complexes, or lanthanoid complexes, and more preferred are naphthalene, pyrene, chrysene, triphenylene, benzo[c]phenanthrene, benzo[a]anthracene, pentacene, perylene, fluoranthene, acenaphthofluoranthene, dibenzo[a,j]anthracene, dibenzo[a,h]anthracene, benzo[a]naphthalene, hexacene, naphtho[2,1-f]isoquinoline, α-naphthalenephenanthridine, phenanthroxazole, quinolino[6,5-f]quinoline, benzothiophanthrene, etc. These may have an alkyl group, an aryl group, an aromatic heterocyclic group, or a diarylamino group as a substituent.

[0074] The light-emitting layer may contain one or more types of fluorescent dopant materials. The content of the fluorescent dopant material is preferably 0.1 to 20%, and more preferably 1 to 10%, relative to the host material.

[0075] When a thermally activated delayed fluorescent dopant is used as the luminescent dopant material, examples of the thermally activated delayed fluorescent dopant include, but are not limited to, metal complexes such as tin complexes and copper complexes, indolocarbazole derivatives described in WO2011 / 070963, cyanobenzene derivatives and carbazole derivatives described in Nature 2012,492,234, phenazine derivatives, oxadiazole derivatives, triazole derivatives, sulfone derivatives, phenoxazine derivatives and acridine derivatives described in Nature Photonics 2014,8,326, and the like.

[0076] The thermally activated delayed fluorescent dopant material is not particularly limited, but specific examples include the following. [ka] [ka]

[0077] The light-emitting layer may contain only one type of thermally activated delayed fluorescent dopant material, or may contain two or more types. The thermally activated delayed fluorescent dopant may be mixed with a phosphorescent dopant or a fluorescent dopant. The content of the thermally activated delayed fluorescent dopant material is preferably 0.1 to 50%, more preferably 1 to 30%, relative to the host material.

[0078] -Injection layer- The injection layer is a layer provided between an electrode and an organic layer to reduce the driving voltage and improve the luminance of light emitted, and includes a hole injection layer and an electron injection layer, and may be provided between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. The injection layer can be provided as necessary.

[0079] -Hole blocking layer- A hole blocking layer, in a broad sense, has the function of an electron transport layer and is made of a hole blocking material that has the function of transporting electrons but has an extremely low ability to transport holes, and by transporting electrons while blocking holes, it is possible to improve the probability of recombination of electrons and holes in the light-emitting layer.

[0080] The hole blocking layer may be made of any known material for a hole blocking layer, but it is preferable that the layer contains a compound represented by formula (1).

[0081] -Electron blocking layer- In a broad sense, the electron blocking layer functions as a hole transport layer, and can increase the probability of recombination of electrons and holes in the light emitting layer by blocking electrons while transporting holes.

[0082] As the material for the electron blocking layer, a known material for the electron blocking layer can be used, and a material for the hole transport layer described later can also be used as necessary. The thickness of the electron blocking layer is preferably 3 to 100 nm, more preferably 5 to 30 nm.

[0083] -Exciton blocking layer- The exciton blocking layer is a layer for preventing excitons generated by the recombination of holes and electrons in the light-emitting layer from diffusing into the charge transport layer, and the insertion of this layer makes it possible to efficiently confine excitons in the light-emitting layer, thereby improving the luminous efficiency of the device. In a device in which two or more light-emitting layers are adjacent to each other, the exciton blocking layer can be inserted between two adjacent light-emitting layers.

[0084] The material of the exciton blocking layer may be any known material, such as 1,3-dicarbazolylbenzene (mCP) or bis(2-methyl-8-quinolinolato)-4-phenylphenolatoaluminum(III) (BAlq).

[0085] -Hole transport layer- The hole transport layer is made of a hole transport material having a function of transporting holes, and the hole transport layer may be provided as a single layer or multiple layers.

[0086] The hole transport material has either hole injection or transport or electron barrier properties, and may be either organic or inorganic. Any of the conventionally known compounds may be selected and used for the hole transport layer. Examples of such hole transport materials include porphyrin derivatives, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, particularly thiophene oligomers, etc., but it is preferable to use porphyrin derivatives, arylamine derivatives, and styrylamine derivatives, and it is more preferable to use arylamine compounds.

[0087] -Electron transport layer- The electron transport layer is made of a material having a function of transporting electrons, and the electron transport layer may be provided as a single layer or as a multi-layer.

[0088] The electron transport material (which may also serve as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer. For the electron transport layer, any of the conventionally known compounds may be selected and used, and examples of such compounds include polycyclic aromatic derivatives such as naphthalene, anthracene, and phenanthroline, tris(8-quinolinolato)aluminum(III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole derivatives, benzothiazole derivatives, and indolocarbazole derivatives. Furthermore, polymeric materials in which these materials are introduced into the polymer chain or in which these materials form the main chain of the polymer may also be used. EXAMPLES

[0089] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples, and can be implemented in various forms without departing from the gist of the present invention.

[0090] The compounds used in the examples and comparative examples are shown below. [ka]

[0091] Table 1 shows the 50% weight loss temperature (T 50 Here, the 50% weight loss temperature was determined by measuring the temperature at which the weight was reduced by 50% when the temperature was raised from room temperature to 550°C at a rate of 10°C per minute in a TG-DTA measurement under reduced pressure (1 Pa) with a nitrogen gas flow.

[0092] [Table 1]

[0093] Example 1 Each thin film was deposited on a glass substrate with an anode made of ITO with a thickness of 110 nm by vacuum deposition at a vacuum degree of 4.0×10 -5 First, HAT-CN was formed as a hole injection layer to a thickness of 25 nm on ITO, and then NPD was formed as a hole transport layer to a thickness of 30 nm. Next, HT-1 was formed as an electron blocking layer to a thickness of 10 nm. Next, compound (1)-1 was used as the first host, compound (2)-1 was used as the second host, and Ir(ppy) was used as the emitting dopant. 3 were co-evaporated from different evaporation sources to form a 40 nm thick light-emitting layer. 3The co-deposition was performed under the deposition conditions that the concentration of the first host was 10 wt%, the concentration of the mixed host consisting of the first host and the second host was 90 wt%, and the weight ratio of the first host to the second host was 30:70. Next, ET-1 was formed to a thickness of 20 nm as an electron transport layer. Furthermore, LiF was formed to a thickness of 1 nm as an electron injection layer on the electron transport layer. Finally, Al was formed to a thickness of 70 nm as a cathode on the electron injection layer to prepare an organic EL device.

[0094] Examples 2 to 8 An organic EL device was produced in the same manner as in Example 1, except that the compounds shown in Table 1 were used as the first host and the second host. It should be noted that Example 8 is a reference example.

[0095] Examples 9-10 An organic EL device was produced in the same manner as in Example 1, except that the first host and the second host were mixed in advance to prepare a preliminary mixture, which was then evaporated from one evaporation source.

[0096] Example 11 An organic EL device was produced in the same manner as in Example 1, except that the first host and the second host were co-deposited at a weight ratio of 40:60.

[0097] Example 12 An organic EL device was produced in the same manner as in Example 9, except that the first host and the second host were mixed in advance to give a weight ratio of 50:50 to prepare a preliminary mixture, and then the preliminary mixture was evaporated from a single evaporation source.

[0098] Comparative Examples 1-2 An organic EL device was produced in the same manner as in Example 1, except that the compound shown in Table 1 was used alone as the host. The thickness of the light-emitting layer and the concentration of the light-emitting dopant were the same as in Example 1.

[0099] Comparative Example 3 An organic EL device was produced in the same manner as in Example 1, except that compound A was used as the first host.

[0100] Comparative Example 4 In Examples 9 to 10 in which the first host and the second host were premixed to form a preliminary mixture, an organic EL element was fabricated in the same manner as in Example 1, except that Compound A was used for the first host and Compound (2)-3 was used for the second host.

[0101] The evaluation results of the fabricated organic EL elements are shown in Table 1. In the table, the luminance, driving voltage, and luminous efficiency are values at a driving current of 20 mA / cm 2 and are initial characteristics. LT70 is the time required for the initial luminance to decay to 70% and represents the lifetime characteristics.

[0102] [Table 2]

Claims

1. An organic electroluminescent device having a plurality of organic layers between an anode and a cathode, the organic layers including at least one light-emitting layer, the light-emitting layer including a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a dopant: 【Chemistry 1】 [wherein X is N or CR ３ and at least one of X represents N. １ is represented by the following formula (1b), and R ２ is expressed by the following formula (1c): ３ independently represent a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with a halogen.] 【Chemistry 2】 [wherein Y is O, S, NR ４ , C.R. ５ R ６ Represents R ４ ~R ６ R each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with a halogen. ８ is a carbon atom connected to the ring of the general formula (1), and R ７ , R ９ ~R １４ are each independently CR ３ , or N; R ３ is as described above, and R ３ When multiple are present, they may be the same or different. 【Chemistry 3】 [Here, * represents the position of bonding with the ring of the general formula (1), ring C represents an aromatic ring represented by formula (C1) which is fused at any position of two adjacent rings. Ring D represents a five-membered ring represented by formula (D1) which is fused at any position of two adjacent rings. R １５ , R １６ and R １７ each independently represent hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with a deuterium or a halogen. １５ , R １６ and R １７ When multiple of each of R are present, they may be the same or different. a, b, and c represent the number of substitutions, a and b each independently represent an integer of 1 to 4, and c represents an integer of 1 to 2. R １８ is R ４ However, R 3 , R 4 to R 6 , and R 18 do not include deuterium.] 【Chemistry 4】 [Here, R １９ represents hydrogen, deuterium, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. R ２０ ~R ２７ are each independently ３ ', C.R. ２８ or N, and at least one is CR ２８ and R ２８ is represented by the following formula (2b): ３ ', R ２８ When there are a plurality of R, they may be the same or different. ３ ' represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with deuterium or halogen.] 【Chemistry 5】 [wherein Z is O, S, NR ３７ , C.R. ３８ R ３９ represents R ３７ ~R ３９ each independently represents hydrogen, deuterium, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. R ２９ ~R ３６ any one of which is a carbon atom bonded to the ring of the general formula (2), and the others are each independently ３ ', or N. ３ ' is as described above, and R ３ When there are multiple ', they may be the same or different.

2. 2. The organic electroluminescent device according to claim 1, wherein, in the formula (1b), Y is O or S.

3. 2. The organic electroluminescent device according to claim 1, wherein the formula (1c) is represented by any one of the following formulas (11) to (15). 【Chemistry 6】 [Here, R １５ ~R １８ have the same meanings as those in formula (1c).

4. 4. The organic electroluminescent device according to claim 1, wherein the general formula (2) is represented by any one of the following general formulas (21) to (29): 【Chemistry 7】 [Here, R １９ is the same as that of the general formula (2), and R ３７ , and R ３８ has the same meaning as in formula (2b).

5. 5. The organic electroluminescent device according to claim 4, wherein the general formula (2) is represented by any one of the general formulas (21) to (23).

6. In the general formulas (21) to (23), R １９ , and R ３７ The organic electroluminescent device according to claim 4 or 5, wherein is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted linking aromatic group in which 2 to 5 of these aromatic rings are linked together.

7. 6. The organic electroluminescent device according to claim 1, wherein the dopant is a phosphorescent dopant or a delayed fluorescent dopant.

8. A mixed composition comprising a compound represented by the following general formula (1) and a compound represented by the following general formula (2): 【Chemistry 8】 [wherein X is N or CR ３ and at least one of X represents N. １ is represented by the following formula (1b), and R ２ is expressed by the following formula (1c): ３ each independently represent a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with a halogen.] 【Chemistry 9】 [wherein Y is O, S, NR ４ , C.R. ５ R ６ Represents R ４ ~R ６ R each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with a halogen. ８ is a carbon atom connected to the ring of the general formula (1), and R ７ , R ９ ~R １４ are each independently CR ３ , or N; R ３ is as described above, and R ３ When there are a plurality of, they may be the same or different. 【Chemistry 10】 [Here, * represents the position of bonding with the ring of the general formula (1), ring C represents an aromatic ring represented by formula (C1) which is fused at any position of two adjacent rings. Ring D represents a five-membered ring represented by formula (D1) which is fused at any position of two adjacent rings. R １５ , R １６ and R １７ each independently represent hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with a deuterium or a halogen. １５ , R １６ and R １７ When multiple of each of R are present, they may be the same or different. a, b, and c represent the number of substitutions, and each of a and b independently represents an integer of 1 to 4, and c represents an integer of 1 to 2. １８ is R ４ However, R 3 , R 4 to R 6 , and R 18 do not include deuterium.] 【Chemistry 11】 [Here, R １９ represents hydrogen, deuterium, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. R ２０ ~R ２７ are each independently ３ ', C.R. ２８ or N, and at least one is CR ２８ and R ２８ is represented by the following formula (2b). ３ ', R ２８ When there are a plurality of R, they may be the same or different. ３ ' represents hydrogen, deuterium, a halogen, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, a dialkylamino group having 2 to 40 carbon atoms, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. In addition, when these groups have a hydrogen atom, the hydrogen atom may be substituted with deuterium or halogen.] 【Chemistry 12】 [wherein Z is O, S, NR ３７ , C.R. ３８ R ３９ represents R ３７ ~R ３９ R each independently represents hydrogen, deuterium, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 24 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which 2 to 5 of these aromatic rings are linked together. When these groups contain a hydrogen atom, the hydrogen atom may be substituted with deuterium or a halogen. ２９ ~R ３６ any one of which is a carbon atom bonded to the ring of the general formula (2), and the others are each independently ３ ', or N. ３ ' is as described above, and R ３ When there are multiple ', they may be the same or different.

9. The general formula (1) is R ７ , or R ８ The mixed composition according to claim 8, wherein the compound is bonded by any one of the following methods.

10. The general formula (1) is R ８ The mixture composition according to claim 8, wherein the compound is bonded by

11. The compound represented by the general formula (1) and the compound represented by the general formula (2) have a 50% weight loss temperature difference of 20°C or less. The mixed composition according to any one of claims 8 to 10.

12. A method for producing an organic electroluminescent device, comprising producing a light-emitting layer using the mixed composition according to any one of claims 8 to 11.

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