Mesityl‐Functionalized Multi‐Resonance Organoboron Delayed Fluorescent Frameworks with Wide‐Range Color Tunability for Narrowband OLEDs
Xiang Wang, Yuewei Zhang, Hengyi Dai, Guomeng Li, Meihui Liu, Guoyun Meng, Xuan Zeng, Tianyu Huang, Lu Wang, Qian Peng, Dezhi Yang, Dongge Ma, Dongdong Zhang, Lian Duan
Abstract
Abstract Polycyclo‐heteraborin multi‐resonance (MR) emitters are promising for high color‐purity organic light‐emitting diodes (OLEDs). Here, unlike the most common heteroatom ternary‐doped (X/B/N) frameworks, a binary‐doped (B/N) skeleton is reported with a large energy band for wide‐range color tunability. Based on this parent‐segment, a “one‐pot” catalyst‐free borylation method is developed which generates deep blue to pure green MR emitters from readily available starting materials, with peaks at 426–532 nm and full‐width‐at‐half‐maxima of 27–38 nm. Impressively, a maximum external quantum efficiency of nearly 40 % is recorded for the corresponding device with Commission Internationale de l′Eclairage coordinates of (0.14, 0.16), representing the state‐of‐the‐art performances. This work presents a new paradigm and synthesis of B/N‐doped MR emitters and will motivate the study of other novel frameworks.