An approach for achieving deep blue thermally activated delayed fluorescence (TADF) is presented. A simple carbazole-pyrimidine compound Cbz-PYR with near-UV emission and simultaneous room-temperature phosphorescence (RTP) was selectively modified by lowering the singlet state energy, simultaneously preserving high triplet energy. The modified compound tCbz-mPYRs was shown to be efficient TADF emitter with 0.5 solid-state emission yield and peak wavelength of 428 nm. When used in OLED device, tCbz-mPYRs based OLED showed electroluminescence with 8.7% external quantum efficiency (EQE) and Commission Internationale de l’Eclairage (CIE) coordinates of (0.16; 0.12).

提出了一种实现深蓝色热激活延迟荧光（TADF）的方法。通过降低单重态能量，同时保留高三重态能量，可以选择性地修饰具有近紫外线发射并同时具有室温磷光（RTP）的简单咔唑-嘧啶化合物Cbz-PYR。改性后的化合物tCbz-mPYRs被证明是高效的TADF发射体，其固态发射率为0.5，峰值波长为428 nm。当用于OLED器件时，基于tCbz-mPYRs的OLED表现出电致发光，具有8.7％的外部量子效率（EQE）和国际照明委员会（CIE）坐标为（0.16; 0.12）。