An organic light emitting element produced by using a light emitting composition that contains both a first compound having a PBHT value more than 0.730 and a second compound having Esi lower than that of the first compound and ΔEST less than 0.20 eV is excellent in durability. Esi is the lowest excited singlet energy level, ΔEST is the difference between the lowest excited singlet energy level and the lowest excited triplet energy level.
使用同时含有 P
BHT 值大于 0.730 的第一种化合物和 Esi 低于第一种化合物且 ΔEST 小于 0.20 eV 的第二种化合物的发光组合物生产的有机发光元件具有优异的耐久性。Esi 是最低激发单电子能级,ΔEST 是最低激发单电子能级与最低激发三电子能级之差。