New aggregation-induced delayed fluorescent materials for efficient OLEDs with high stabilities of emission color and efficiency

Abstract

Thermally activated delayed fluorescence (TADF) can harvest both singlet and triplet excitons to achieve high electroluminescence (EL) efficiency for organic light-emitting diodes (OLEDs). However, many TADF emitters generally suffer from severe emission quenching and exciton annihilation at high voltages or luminance. To address this issue, in this work, two new luminogens, CDBP-BP-PXZ and CDBP-BP-DMAC, consisting of an electron-withdrawing benzoyl group and electron-donating 9,9′-(2,2′-dimethyl-[1,1′-biphenyl]-4,4′-diyl)bis(9H-carbazole) and phenoxazine/9,9-dimethyl-9,10-dihydroacridine are synthesized and characterized. They exhibit high thermal and electrochemical stabilities and show interesting aggregation-induced delayed fluorescence properties. They exhibit good EL performances in nondoped and doped OLEDs with high electroluminescence (EL) efficiencies, very small efficiency roll-offs and high emission color stability. The excellent EL performance of both luminogens disclose their good application potential in practical display and lighting devices.