Bai Yunfei, Zhou Panwang, Yang Xinyu, Zhao Hongyuan, Wen Ziying, Meng Qichao, Sun Haibo, Li Chao, Yu William W, Liu Feng
Institute of Frontier Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China.
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
ACS Appl Mater Interfaces. 2025 May 21;17(20):29933-29940. doi: 10.1021/acsami.5c05396. Epub 2025 May 7.
In addition to the easy oxidation of tin(II) (Sn), the poor repeatability in synthesizing luminescent Sn-based halide perovskites can be attributed to the structural diversity among Sn compositions, with many structures failing to exhibit luminescence. Furthermore, compared to luminescent compounds, there is insufficient attention on the photophysical properties of these nonluminescent compositions, which impedes a deeper understanding of the relationship between their structures and optical properties. In this work, we report two Sn-based halide compounds, (DFPD)SnBr and (DFPD)SnBr (DFPD = 4,4-difluoropiperidinium). Both exhibit excellent air stability, with the former demonstrating a high luminescence efficiency of ∼92%, while the latter is essentially nonluminescent. Theoretical calculations suggest that the nonluminescence of (DFPD)SnBr arises from charge transfer between two adjacent [SnBr] units in the first excited state. In contrast, significant structural distortion and localization of excitons in (DFPD)SnBr indicate that its emission originates from self-trapped excitons. As a demonstration, we prepared an X-ray scintillator based on (DFPD)SnBr with a high light yield up to 27,600 ph/MeV and a low detection limit of 84.7 nGy/s, which is significantly better than the commercial LuAG/Ce scintillator (22,000 ph/MeV, 2.32 μGy/s).
除了二价锡（Sn）易于氧化外，合成发光的锡基卤化物钙钛矿时重复性差可归因于锡成分之间的结构多样性，许多结构无法表现出发光现象。此外，与发光化合物相比，这些非发光成分的光物理性质受到的关注不足，这阻碍了对其结构与光学性质之间关系的深入理解。在这项工作中，我们报道了两种锡基卤化物化合物，（DFPD）SnBr和（DFPD）SnBr（DFPD = 4,4 - 二氟哌啶鎓）。两者都表现出优异的空气稳定性，前者显示出约92%的高发光效率，而后者基本不发光。理论计算表明，（DFPD）SnBr不发光是由于在第一激发态下两个相邻的[SnBr]单元之间的电荷转移。相比之下，（DFPD）SnBr中显著的结构畸变和激子局域化表明其发射源于自陷激子。作为一个实例，我们制备了一种基于（DFPD）SnBr的X射线闪烁体，其高光产额高达27,600 ph/MeV，低检测限为84.7 nGy/s，明显优于商业LuAG/Ce闪烁体（22,000 ph/MeV，2.32 μGy/s）。
