Liu Xinyu, Wang Jianlin, Ma Chaojie, Huang Xudan, Liu Kaihui, Xu Zhi, Wang Wenlong, Wang Lifen, Bai Xuedong
State Key Laboratory for Surface Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Nanoscale. 2021 Jan 7;13(1):124-130. doi: 10.1039/d0nr07549c. Epub 2020 Dec 16.
All-inorganic lead halide perovskites (AILHPs) quantum dots (QDs) have been widely investigated as promising materials for optoelectronic applications because of their outstanding luminescence properties. Lead leakage, a common impurity and environmental pollution source that majorly hinders the commercialization of lead halide perovskite devices, has lately attracted considerable attention. Its detrimental influence on the luminescence performance has been widely reported. However, an in-depth experimental study of the chemistry geometry relating to lead leakage in CsPbBr QDs has been rarely reported to date. Herein, combining real-time (scanning) transmission electron microscopy ((S)TEM) with density functional theory calculations, we showed detailed atomic and electronic structure study of the phase boundaries in CsPbBr QDs during the lead leakage process. A phenomenon of two-phase coexistence was reported to be linked with the lead precipitating in CsPbBr QDs. A phase boundary between the Ruddlesden-Popper (RP) phase and conventional orthorhombic perovskite was developed when the lead particle was aggregating in the QDs. Our results suggested that in considering the detrimental exciton quenching process not only the role of lead nanoparticles should be considered but also the influence of the phase boundary on electron-hole transport is worthy of attention. The direct visualization of the delicate atomic and electronic structures associated with lead aggregation in CsPbBr sheds light on how the leakage process influences the luminescence performance and provides a potential route for suppressing the generation of environmentally harmful byproducts for advanced devices.
全无机铅卤化物钙钛矿（AILHPs）量子点（QDs）因其出色的发光性能而被广泛研究，有望用于光电子应用。铅泄漏是一种常见杂质和环境污染源，严重阻碍了铅卤化物钙钛矿器件的商业化，最近已引起相当大的关注。其对发光性能的有害影响已被广泛报道。然而，迄今为止，关于CsPbBr量子点中与铅泄漏相关的化学几何结构的深入实验研究鲜有报道。在此，我们将实时（扫描）透射电子显微镜（(S)TEM）与密度泛函理论计算相结合，展示了CsPbBr量子点在铅泄漏过程中相界的详细原子和电子结构研究。据报道，两相共存现象与CsPbBr量子点中的铅沉淀有关。当铅粒子在量子点中聚集时，在Ruddlesden-Popper（RP）相和传统正交钙钛矿之间形成了相界。我们的结果表明，在考虑有害的激子猝灭过程时，不仅应考虑铅纳米粒子的作用，相界对电子-空穴传输的影响也值得关注。与CsPbBr中铅聚集相关的精细原子和电子结构的直接可视化揭示了泄漏过程如何影响发光性能，并为抑制先进器件中环境有害副产物的产生提供了一条潜在途径。
