ORGANIC ELECTROLUMINESCENT DEVICE

摘要

An organic electroluminescent device comprises a luminescent layer (3). The main material of the luminescent layer (3) comprises one of thermal activation delayed fluorescent materials, the main material is doped with dye, and the dye comprises at least one phosphorescent dye. The difference (ΔEST) between a triplet state energy level and a singlet state energy level is relatively small for the thermal activation delayed fluorescent material. The material is used as the fluorescent main part, and a part of a triplet state exciton energy level is transferred to a singlet state exciton, and the quantity of overall triplet state excitons is relatively small, so that the concentration of the triplet state excitons is reduced, and a recombination zone becomes narrow; therefore, the probability that an exciton enters a charge transport layer is effectively reduced, and narrowing of the recombination zone effectively prevents an N-type dopant from spreading to an exciton recombination zone. In addition, as the main material is used, the device corresponds to a relatively low working voltage.