An effective design strategy for thermally activated delayed fluorescence emitters with aggregation-induced emission to enable sky-blue OLEDs that achieve an EQE of nearly 30%
Hui Dai, Yaohui Liang, Xiang Long, Tianyi Tang, Haozhi Xie, Zhiwei Ma, Gaoyu Li, Zhan Yang, Juan Zhao, Zhenguo Chi
Abstract
Pure organic thermally activated delayed fluorescence (TADF) materials hold great promise for efficient organic light-emitting diodes (OLEDs), yet developing high-performance blue TADF materials that integrate short delayed lifetime with aggregation-induced emission (AIE) properties remains a significant challenge. In this study, we developed three highly-efficient blue TADF emitters (32clCBP, 32clCXT and 32PclCXT) featuring AIE character by integrating rigid π-extended donors with different acceptors. Notably, the doped 32PclCXT film achieved an exceptionally high photoluminescence quantum efficiency of up to 99% and a short delayed lifetime of 1.4 µs. Furthermore, the fabricated OLEDs based on 32PclCXT exhibited an impressive external quantum efficiency of 29.9% in the sky-blue region, along with low roll-off at high luminance. Therefore, this work establishes a new strategy for developing high-efficiency blue TADF materials and devices.