Xihao Yang, Yongxu Hu, Xiaoyu Guo, Jingsheng Miao, He Liu, Chuluo Yang
) excited states, fast reverse intersystem crossing, and efficient triplet exciton utilization. In contrast, TSCT-dominated BOCC shows slower RISC and reduced exciton recycling. Consequently, BOtC-based OLEDs achieve deep-blue emission (CIE: 0.157, 0.047) and a high external quantum efficiency (EQE) of 14.4%, whereas BOCC-based devices display a lower EQE of 6.5%. This work establishes TBCT/TSCT hybridization control as a general strategy to simultaneously achieve high efficiency and ultrahigh color purity in blue TADF emitters, providing guidance for next-generation display applications.