高等学校化学学报 ›› 2024, Vol. 45 ›› Issue (10): 20240282.doi: 10.7503/cjcu20240282

• 物理化学 • 上一篇    下一篇

重原子效应对MR-TADF分子三重态和上转换性能的影响

魏亚雄(), 易凯, 段豆豆, 许新胜()   

  1. 安徽师范大学物理与电子信息学院, 光电信息材料功能调控与应用安徽省重点实验室, 芜湖 241002
  • 收稿日期:2024-06-11 出版日期:2024-10-10 发布日期:2024-08-21
  • 通讯作者: 魏亚雄,许新胜 E-mail:yaxiongwei@ahnu.edu.cn;xxsheng@mail.ahnu.edu.cn
  • 基金资助:
    芜湖市应用基础研究项目(2022jc13);国家自然科学基金(22203004);安徽师范大学2023年奖补学科建设项目(2023GFXK160)

Heavy Atom Effect’s Influence on the Triplet State and Upconversion Efficiency in MR-TADF Systems

WEI Yaxiong(), YI Kai, DUAN Doudou, XU Xinsheng()   

  1. Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials,School of Physics and Electronic Information,Anhui Normal University,Wuhu 241002,China
  • Received:2024-06-11 Online:2024-10-10 Published:2024-08-21
  • Contact: WEI Yaxiong, XU Xinsheng E-mail:yaxiongwei@ahnu.edu.cn;xxsheng@mail.ahnu.edu.cn
  • Supported by:
    the Applied Basic Research Project of Wuhu City, China(2022jc13);the National Natural Science Foundation of China(22203004);the Anhui Normal University 2023 Year Scholarship and Supplementary Discipline Construction Project, China(2023GFXK160)

摘要:

含有重原子的多重共振热激活延迟荧光(MR-TADF)表现出低能量损失、 强烈吸收、 高系间窜跃(ISC)效率和长三重态寿命. 本文选择3种不含重金属原子的MR-TADF分子, 分别结合氧、 硫和硒原子(BN-2O, BN-2S和BN-2Se); 利用理论计算和纳秒瞬态吸收光谱研究了这些分子的重原子效应, BN-2O, BN-2S和BN-2Se的ISC效率分别确定为39.4%, 74.7%和95.0%, 且三重态寿命均超过10 μs. 由BN-2Se和1,4-双(三异丙基硅乙炔基)萘(1,4-DTNA)组成的上转换系统在溶液中获得了高达8.7%的上转换量子产率(ΦUC, 最大值为50%), 且阈值激发强度(Ith)为1.7 mW/cm2, 低于太阳光辐照度(2.7 mW/cm2). 此外, 廉价的BN-2S和BN-2O也表现出良好的上转换量子产率, 分别为5.9%和3.9%, Ith也分别低至6.2和15 mW/cm2.

关键词: 多重共振热活化延迟荧光, 三重态-三重态湮灭上转换, 重原子效应

Abstract:

Multi-resonance thermally activated delayed fluorescence(MR-TADF) containing heavy atoms exhibits low energy loss, intense absorption, high intersystem crossing(ISC) efficiency, and long triplet state lifetime. In this work, three heavy metal-free MR-TADF molecules combined oxygen, sulfur, and selenium atoms were chosen, designated as BN-2O, BN-2S, and BN-2Se. The heavy atom effect of these compounds was studied using theoretical calculations and nanosecond transient absorption spectra. The ISC efficiencies of BN-2O, BN-2S, and BN-2Se are determined to be 39.4%, 74.7%, and 95.0%, respectively, while the triplet state lifetimes are found to exceed 10 μs. The upconversion system comprising BN-2Se/1,4-bis(triisopropylsilethynyl) naphthalene(1,4-DTNA) demonstrates a high upconversion quantum yield(ΦUC, the maximum value of 50%) of up to 8.7% in solution, with a threshold excitation intensity as low as 1.7 mW/cm2, which is lower than the solar irradiance of 2.7 mW/cm2. Additionally, the economically viable BN-2S and BN-2O show satisfactory ΦUC values of 5.9% and 3.9%, with low Ith values of 6.2 and 15 mW/cm2.

Key words: Multi-resonance thermally activated delayed fluorescence, Triplet-triplet annihilation upconversion, Heavy atom effect

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