Novel boron-and sulfur-doped polycyclic aromatic hydrocarbon as multiple resonance emitter for ultrapure blue thermally activated delayed fluorescence polymers

• 作者: Fan Chen Lei Zhao Xingdong Wang Qingqing Yang Weili Li Hongkun Tian Shiyang Shao Lixiang Wang Xiabin Jing Fosong Wang
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: COMMUNICATIONS
• 页码范围: 547-551
• 页数: 5页
• 语种: 英文

摘要

Boron (B)-and sulfur (S)-doped polycyclic aromatic hydrocarbons (PAHs) are developed as a novel kind of multiple resonance emitters for ultrapure blue thermally activated delayed fluorescence (TADF) polymers with narrowband electroluminescence.The combination of electron-deficient B atom and electron-rich S atom in PAH can form an intramolecular push-pull electronic system in a rigid aromatic framework,leading to reduced singlet-triplet energy splitting and limited structure relaxation of excited states.The critical roles of S atom in determining emission properties with respect to the oxygen analogues are in two aspects: (i) reducing energy bandgap to shift emission from human-eye-insensitive ultraviolet zone to blue region,and (ii) promoting reverse intersystem crossing process by heavy-atom effect to activate TADF effect The resulting polymer containing B,S-doped PAH as emitter and acridan as host exhibits efficient blue electroluminescence at 458 nm with small full-width at half-maximum of 31 nm,representing the first example for ultrapure TADF polymer with narrowband electroluminescence.