Blue thermally activated delayed fluorescent emitters are promising for the next generation of organic light-emitting diodes, yet their performance still cannot meet the requirements for commercialization. Here we establish a design rule for highly efficient and stable thermally activated delayed fluorescent emitters by introducing an auxiliary acceptor that could delocalize electron distributions, enhancing molecular stability in both the negative polaron and triplet excited state, while also accelerating triplet-to-singlet up-conversion and singlet radiative processes simultaneously. Proof-of-concept thermally activated delayed fluorescent compounds, based on a multi-carbazole-benzonitrile structure, exhibit near-unity photoluminescent quantum yields, short-lived delays and improved photoluminescent and electroluminescent stabilities. A deep-blue organic light-emitting diode using one of these molecules as a sensitizer for a multi-resonance emitter achieves a remarkable time to 95% of initial luminance of 221 h at an initial luminance of 1,000 cd m⁻², a maximum external quantum efficiency of 30.8% and Commission Internationale de l’Eclairage coordinates of (0.14, 0.17).

蓝色热激活延迟荧光发射器有望成为下一代有机发光二极管，但其性能仍无法满足商业化要求。在这里，我们通过引入一种可以使电子分布离域的辅助受体，增强了负极化子和三重态激发态下的分子稳定性，同时还加速了三重态到单重态的上转换和单重态辐射过程，从而建立了高效和稳定的热激活延迟荧光发射器的设计规则。基于多咔唑-苯腈结构的概念验证热激活延迟荧光化合物表现出近乎统一的光致发光量子产率、短寿命延迟以及改进的光致发光和电致发光稳定性。使用其中一个分子作为多谐振发射器敏化剂的深蓝色有机发光二极管在 1,000 cd ^m-2 的初始亮度下实现了 221 h 初始亮度的 95%，最大外部量子效率为 30.8%，国际委员会 （0.14， 0.17）。