公开(公告)号：US10566542B2

公开(公告)日：2020-02-18

申请号：US15541357

申请日：2015-12-22

申请人： BEIJING VISIONOX TECHNOLOGY CO., LTD. ,  TSINGHUA UNIVERSITY

发明人： Lian Duan ,  Yong Qiu ,  Guohui Zhang ,  Man Li ,  Dongdong Zhang ,  Yonglan Hu

IPC分类号： H01L51/00 ,  C09K11/06 ,  H01L51/50 ,  H01L51/52

摘要： The present invention discloses an organic electroluminescence device, comprising a luminescent layer, wherein, a host material of the luminescent layer comprises a thermally activated delayed fluorescence material, the host material is doped by a dye, and the dye comprises at least one phosphorescent dye. The present invention employs a thermally activated delayed fluorescence material, whose difference between the triplet state energy level and the singlet state energy level (ΔEST) is relatively small. The present invention employs the material as the phosphorescence host, so part of the triplet state exciton level transfers to the singlet state excitons, and the amount of the overall triplet state excitons is smaller. Therefore, the concentration of the triplet state excitons decreases, and the recombination region becomes narrower, which effectively reduces the probability of excitons entering the charge transport layer, and at the same time the narrowing of the recombination region effective prevents the diffusion of N-type dopants into the exciton recombination region. Additionally, by employing the host material, the device corresponds to a low working voltage.