| 摘要 |
PROBLEM TO BE SOLVED: To provide: a phosphorescent substance that has a high efficiency and stability, a narrow spectrum, and an improved processability; and a device.SOLUTION: Provided is a phosphorescent substance having a formula (I) in which: M is a metal having an atomic weight higher than 40; A and B are each independently a 5- or 6-membered aromatic or heteroaromatic ring, and A-B represents a combined pair of aromatic or heteroaromatic rings coordinated to the metal via a nitrogen atom on ring A and a sphybrid carbon atom on ring B; R, R, R, R, Rare each independently selected from the group consisting of unsubstitution, alkyl, hetero-alkyl, aryl, or heteroaryl group; each of Rand Rrepresents one or more substituent, and may together form a fused ring; at least one of Rand Rcomprises a branched alkyl group having a branch at a position farther than the position α of the carbonyl group; m is an oxidation state of the metal; n is an integer smaller than m and is at least 1.SELECTED DRAWING: Figure 3 |
