重原子效应对MR-TADF分子三重态和上转换性能的影响  

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

作　　者：魏亚雄 易凯 段豆豆 许新胜[1] WEI Yaxiong;YI Kai;DUAN Doudou;XU Xinsheng(Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials,School of Physics and Electronic Information,Anhui Normal University,Wuhu 241002,China)

机构地区：[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

出　　处：《高等学校化学学报》2024年第10期89-96,共8页Chemical Journal of Chinese Universities

基　　金：芜湖市应用基础研究项目(批准号:2022jc13);国家自然科学基金(批准号:22203004,21927814);安徽师范大学2023年奖补学科建设项目(批准号:2023GFXK160)资助.

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10μs.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(Φ_(UC),最大值为50%),且阈值激发强度(I_(th))为1.7 mW/cm^(2),低于太阳光辐照度(2.7 mW/cm^(2)).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%,I_(th)也分别低至6.2和15 mW/cm^(2).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 10μs.The upconversion system comprising BN-2Se/1,4-bis(triisopropylsilethynyl)naphthalene(1,4-DTNA)demonstrates a high upconversion quantum yield(Φ_(UC),the maximum value of 50%)of up to 8.7%in solution,wI_(th)a threshold excitation intensity as low as 1.7 mW/cm^(2),which is lower than the solar irradiance of 2.7 mW/cm^(2).Additionally,the economically viable BN-2S and BN-2O show satisfactoryΦ_(UC)values of 5.9%and 3.9%,wI_(th)low I_(th)values of 6.2 and 15 mW/cm^(2).

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 

分 类 号：O644.12[理学—物理化学]