Authors: Jian‐Rong Wu, Yue‐Jian Yang, Shi‐Jie Ge, Yang‐Kun Qu, Hong‐Yan Yan, Hai‐Xiao Jiang, Yin Liu, Dong‐Ying Zhou, Liang‐Sheng Liao, Zuo‐Quan Jiang
Published: 2025-05-30
Source: Full article
AbstractDeveloping the modified skeleton of multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters can feasibly regulate their optoelectronic properties. However, research on MR‐TADF materials incorporating B─N covalent bonds remains relatively limited. Herein, a strategy is first proposed utilizing the twin‐spiro conformation, a dispirofluorene acridine skeleton (DSAF), via the amine‐directed double borylation for framework fusion to construct MR‐TADF emitters, DSAF‐TBDPA and DSAF‐TBCz. B─N covalent bonds and twin‐spiro fusion are employed to enhance the structural rigidity of the molecular framework. Furthermore, the introduction of a twin‐spiro structure imparts steric hindrance, thereby weakening the π–π interactions and mitigating exciton quenching. As a result, DSAF‐TBDPA and DSAF‐TBCz exhibit narrowband emission with a full width at half maximum of 20 and 19 nm. The doped organic light‐emitting diodes (OLEDs) based on DSAF‐TBDPA and DSAF‐TBCz exhibit maximum external quantum efficiencies (EQEmax) of 27.2% and 30.8%, respectively. These results underscore that molecular design tactics not only expand the diversity of MR frameworks but also deliver critical insights for the design of high‐performance OLED emitters.