Date：2017-06-12 |
Views：1560 |
【Academic writing Sharing 20170612】 |
A Sterically Shielded Electron Transporting Material for nearly 100% Internal Quantum Efficiency and Long Lifetime in Thermally Activated Delayed Fluorescent and Phosphorescent OLEDs
Article excerpt is from: Dongdong Zhang, Pengcheng Wei, Deqiang Zhang, and Lian Duan
Appl. Mater. Interfaces, 2017, in press
A novel design strategy for ETMs, that is sterically shielding the low T1 units to realize good exciton confinement. Thanks to the short-range interaction of the Dexter energy transfer, the large steric side groups of the low T1 ETM can hinder the triplet excitons of the emitters from being quenched by the low triplet energy of the ETM effectively. High mobility, excellent stability and good exciton blocking property were achieved simultaneously in an anthracene based ETM, BPBiPA. EQEmax as high as 21.3% was observed in the sky-blue TADF device utilizing BPBiPA as the ETM, with EQE remaining 21.2% at 1000 cd/m2 and 17.8% at 5000 cd/m2. For green phosphorescent organic light-emitting diodes based on BPBiPA, EQEmax as high as 25.5%, a low turn-on voltage of 2.3 V as well as a long T90 (time to 90% of the initial luminance) of over 400 h at an initial luminance of 5000 cd/m2 were achieved.
