Benzoylpyridine-based TADF emitters with AIE feature for efficient non-doped OLEDs by both evaporation and solution process

Abstract

Fluorescent materials taking both advantages of evaporation and solution processes are urgently explored for the development of efficient and simplified organic light-emitting diodes (OLEDs). Furthermore, it is another huge challenge for such materials to achieve excellent electroluminescence performances in non-doped OLEDs. Herein, two new emitters, named as PyB-DPAC and PyB-DMAC with 4-benzoylpyridine moiety as the electron acceptor and 9,9-diphenyl-9,10-dihydroacridine or 9,9-dimethyl-9,10-dihydroacridine as the electron donor were synthesized and explored. Both emitters exhibit distinct TADF character, typical AIE feature and relatively high photoluminescence quantum yields. Accordingly, we demonstrated efficient non-doped vacuum-deposited OLED based on the PyB-DPAC with a maximum external quantum efficiency (EQE) up to 9.7%, and meanwhile an extremely low efficiency roll-off of 1.7% at a high brightness of 1000 cd m−2. In addition, an impressive EQE of 11.1% can be realized from the solution-processed non-doped devices with the using of PyB-DPAC emitter. These affirmative results manifest that TADF emitters incorporate with the benzoylpyridine acceptor enabling a promising molecular design strategy in adapt to the non-doped evaporation- and solution-processed highly efficient OLEDs.