“Hot-exciton” fluorescent materials can efficiently convert triplet excitons into singlet excitons through a path from high-lying triplet excited states (T_n, n > 1) to singlet excited states (S_m, m ≥ 1). The fast reverse intersystem crossing (RISC) process of the hot-exciton channel promotes a high exciton utilization efficiency (EUE) and reduces the efficiency roll-off (η_roll-off) caused by the accumulation of low-lying triplet excitons (T₁). Herein, a pure-blue-emitting molecule, PICNAnCz, exhibiting hot-exciton fluorescent emission is proposed. The optimized PICNAnCz-based nondoped organic light-emitting diode (OLED) device achieves a high external quantum efficiency of 9.05% corresponding to a large EUE of 87% and a low η_roll-off of 13%, achieving both high efficiency and a small η_roll-off. The maximum current efficiency and power efficiency of the nondoped device are 9.07 cd A⁻¹ and 5.76 lm W⁻¹, respectively. The nondoped device shows a novel blue electroluminescence (EL) emission with a peak wavelength of 448 nm and Commission Internationale de l’Eclairage coordinates of (0.16, 0.11). These results are among the best reported for hot-exciton blue-emitting materials for nondoped blue fluorescent OLEDs. The excellent EL performance is attributed to the nanosecond-scale RISC process from the high-lying triplet excited state (T₂) to the lowest singlet excited state (S₁).

“热激子”的荧光材料可以有效地通过将路径转换三重态激子到单线态激子从高地势三重激发态（T _Ñ，Ñ > 1）单线激发态（S_米，米≥1）。热激子信道的快速反向系间窜越（RISC）处理促进了高激子的利用效率（EUE）和降低了效率滚降（η_滚降引起的低洼三重态激子的积累）（T ₁）。在此，提出了呈现热激子荧光发射的纯蓝色发射分子PICNAnCz。经过优化的基于PICNAnCz的非掺杂有机发光二极管（OLED）器件可实现9.05％的高外部量子效率，对应于87％的大EUE和13％的低η_滚降，从而实现了高效率和小体积η_滚降。非掺杂器件的最大电流效率和功率效率为9.07 cd A ^-1和5.76 lm W ^-1， 分别。未掺杂的器件显示出新颖的蓝色电致发光（EL）发射，峰值波长为448 nm，国际照明委员会坐标为（0.16，0.11）。这些结果是用于非掺杂蓝色荧光OLED的热激蓝色发射材料的最佳报道。优异的EL性能归因于从高三线态激发态（T ₂）到最低单线态激发态（S ₁）的纳秒级RISC工艺。