Efficient thermally activated delayed fluorescent emitter based on a spiro-type benzo[b]acridine donor and a benzophenone acceptor?

Journal of Materials Chemistry C Pub Date: 2022-11-01 DOI: 10.1039/D2TC03421B

Abstract

A novel spiro-type donor 5H-spiro[benzo[b]acridine-12,9′-fluorene] (SPBAC) and a thermally activated delayed fluorescence (TADF) emitter bis(4-(5H-spiro[benzo[b]acridine-12,9′-fluoren]-5-yl)phenyl)methanone (2SPBAC-BP) were synthesized for a high efficiency organic light-emitting diode (OLED). The naphthalene moiety can introduce the local excited triplet (3LED) state into the 2SPBAC-BP molecule. 3LED can enhance the spin–orbit coupling (SOC) between the lowest triplet excited state (T1) and the lowest singlet excited state (S1), working as an intermediate between the two charge transfer states (3CT and 1CT) for efficient triplet exciton utilization. Using this strategy, a doped film of 20 wt% 2SPBAC-BP in the PPF host exhibits a high photoluminescence quantum yield of 72%, and the organic light-emitting diode (OLED) based on 2SPBAC-BP displays a high EQE of 26.4%, a current efficiency (CE) of 86.8 cd A?1, and a power efficiency (PE) of 85.2 lm W?1.

Graphical abstract: Efficient thermally activated delayed fluorescent emitter based on a spiro-type benzo[b]acridine donor and a benzophenone acceptor
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