Pan Fang, Li Jinrui, Ma Xiaoman, Nie Yang, Liu Beichen, Ye Honggang
Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 People's Republic of China
Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, School of Electronic Science and Engineering, Xi'an Jiaotong University Xi'an 710049 People's Republic of China.
RSC Adv. 2022 Jan 5;12(2):1035-1042. doi: 10.1039/d1ra08629d. eCollection 2021 Dec 22.
The all-inorganic perovskite CsPbBr has been capturing extensive attention due to its high quantum yield in luminescence devices and relatively high stability. Its luminescence is dominated by free exciton (FE) recombination but additional emission peaks were also commonly observed. In this work, a CsPbBr microcrystal sample in the orthorhombic phase was prepared by the chemical vapor deposition method. In addition to the FE peak, a broad emission peak was found in this sample and it was attributed to self-trapped excitons (STEs) based on its photophysical properties. The STE emission can only be observed below 70 K. The derived Huang-Rhys factor is ∼12 and the corresponding phonon energy is 15.3 meV. Its lifetime is 123 ns at 10 K, much longer than that of FE emission. The STE emission is thought to be an intrinsic property of CsPbBr.
全无机钙钛矿CsPbBr因其在发光器件中的高量子产率和相对较高的稳定性而备受广泛关注。其发光主要由自由激子（FE）复合主导，但也普遍观察到额外的发射峰。在这项工作中，通过化学气相沉积法制备了正交相的CsPbBr微晶样品。除了FE峰外，在该样品中还发现了一个宽发射峰，基于其光物理性质，该峰归因于自陷激子（STE）。STE发射仅在70 K以下才能观察到。推导得到的黄昆-里斯因子约为12，相应的声子能量为15.3 meV。其在10 K时的寿命为123 ns，远长于FE发射的寿命。STE发射被认为是CsPbBr的固有特性。
