Chinese Journal of Organic Chemistry ›› 2024, Vol. 44 ›› Issue (6): 2006-2013.DOI: 10.6023/cjoc202312006 Previous Articles     Next Articles

ARTICLES

基于七元环三芳胺给体的蓝光热活化延迟荧光材料的构筑

李治, 李祯龙, 刘俊杰, 憨卫国, 游劲松, 宾正杨*()   

  1. 四川大学化学学院 成都 610065
  • 收稿日期:2023-12-07 修回日期:2024-01-23 发布日期:2024-02-19
  • 基金资助:
    国家自然科学基金(22275127)

Construction of Blue Thermally Activated Delayed Fluorescence Materials Based on the Heptagonal Triarylamine Donor

Zhi Li, Zhenlong Li, Junjie Liu, Weiguo Han, Jingsong You, Zhengyang Bin*()   

  1. College of Chemistry, Sichuan University, Chengdu 610065
  • Received:2023-12-07 Revised:2024-01-23 Published:2024-02-19
  • Contact: * E-mail: binzhengyang@scu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(22275127)

The development of efficient blue light-emitting materials is a crucial yet challenging task in organic light-emitting diodes (OLED). Two novel blue light-emitting molecules, TRZCz-TPA and TRZ-TPA, have been designed and synthesized based on the heptagonal 9H-tripheno[b,d,f]nitrozoafluorene (TPA) donor. Their thermal stability, electrochemical properties, photophysical properties, and device performances were characterized. TRZCz-TPA and TRZ-TPA both exhibit blue emission in toluene solution with emission peaks at 455 and 440 nm, respectively. In contrast to TRZ-TPA, which exhibits through-bond charge transfer (TBCT) from the TPA donor to the diphenyltriazine (TRZ) acceptor, TRZCz-TPA, featuring two adjacent 3,6-di-tert-butylcarbazole (tBuCz) donors near the TRZ acceptor, demonstrates through-space charge transfer (TSCT) from the tBuCz donors to the TRZ acceptor. This leads to a remarkable reduction in the singlet-triplet energy gap (ΔEST) from 0.53 eV to 0.04 eV, thereby displaying thermally activated delayed fluorescence (TADF) properties. Additionally, tBuCz donor with large steric hindrance effectively suppresses aggregation-induced quenching in the aggregated state. Consequently, TRZCz-TPA achieves a photoluminescence quantum yield (PLQY) of 42.0% and a maximum external quantum efficiency (EQEmax) of 10.4% in OLED devices, significantly outperforming TRZ-TPA (PLQY=6.5%, EQEmax=3.7%).

Key words: organic light-emitting diodes, thermally activated delayed fluorescence, through-bond charge transfer, through- space charge transfer, heptagonal triarylamine donor