摘要
Purely organic hybrid afterglow materials that combine thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) provide a useful platform for studying triplet-involved excited-state dynamics and developing multifunctional emitters. Herein, three helical carbazolocarbazole (CCz) emitters, CCzTRZ, CCzPTC, and CCzPPC, were developed to investigate the influence of acceptor strength on hybrid afterglow behavior. CCzTRZ exhibits a long-lived RTP with a duration of up to 3 s. Increasing the electron-accepting ability reduced the singlet-triplet energy difference (ΔEST) and promoted reverse intersystem crossing (RISC), leading to enhanced TADF contribution and shortened afterglow lifetimes through accelerated triplet upconversion. Comprehensive photophysical studies revealed the evolution of hybrid TADF-RTP characteristics across the series. Organic light-emitting diode (OLED) devices based on the three emitters were further fabricated to evaluate their electroluminescence performance. The optimized CCzPPC-based OLED achieved a maximum external quantum efficiency (EQEmax) of 12%. This work demonstrates an effective acceptor engineering strategy for tuning hybrid afterglow dynamics in helical CCz systems.