公开(公告)号：US20240130153A1

公开(公告)日：2024-04-18

申请号：US18470908

申请日：2023-09-20

Applicant: The Regents of the University of Michigan

Inventor： Stephen R. Forrest ,  Haonan ZHAO ,  Jongchan KIM

IPC: H10K50/15 ,  H10K50/125 ,  H10K50/18 ,  H10K59/80

CPC classification number: H10K50/15 ,  H10K50/125 ,  H10K50/181 ,  H10K59/80516 ,  H10K2102/302

Abstract: Disclosed are methods, designs and materials for extending the device operational lifetime of the phosphorescent organic light emitting devices (OLEDs) such as thermally activated delayed fluorescence (TADF) OLEDs. Applying a graded cohost or co-doped emission layer (EML) in the organic layers, both charge transport and charge balance can be precisely engineered to generate a uniform exciton/exciplex profile, preventing the early deaths due to the dense hot-excited states in the device. This invention is aimed at the short lifetime problem of the high efficient phosphorescent OLEDs and TADF OLEDs, especially in the white, blue and deep blue applications.