CPC H10K 85/6572 (2023.02) [C07D 209/86 (2013.01); C09K 11/06 (2013.01); C09K 2211/1018 (2013.01); H10K 50/11 (2023.02); H10K 2101/10 (2023.02); H10K 2101/90 (2023.02)] | 21 Claims |
1. An organic electroluminescent device having an anode, a cathode, and at least one organic layer that contains a light-emitting layer between the anode and the cathode, wherein:
the light-emitting layer contains at least a first organic compound, a second organic compound and a third organic compound satisfying the following formula (A), the second organic compound is a delayed fluorescent material represented by the following general formula (1), and the third organic compound is a light-emitting material:
ES1(A)>ES1(B)>ES1(C) Formula (A)
wherein ES1(A) represents a lowest excited singlet energy level of the first organic compound, ES1(B) represents a lowest excited singlet energy level of the second organic compound, ES1(C) represents a lowest excited singlet energy level of the third organic compound;
(A)m-L-(D)n General Formula (1)
wherein L represents an (m+n)-valent aromatic linking group of a single ring; A represents a group having a positive Hammett's σp value, or a phenyl group, provided that one or two of A's are a cyano group; D represents a group having a negative Hammett's σp value except a phenyl group; m represents an integer of 1 or more; n represents an integer of 2 or more; when m is 2 or more, plural A's may be the same as or different from each other; two of plural D's are groups containing an aromatic ring common to them but having a different structure; and all the hydrogen atoms in the general formula (1) may be 1H, and all or a part of them may be 2H.
|