Department of Chemistry, Brown University, 324 Brook St. Providence, RI, 02912, USA.
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, 14853, USA.
Adv Mater. 2017 May;29(18). doi: 10.1002/adma.201606666. Epub 2017 Mar 10.
Lead halide perovskites are promising materials for a range of applications owing to their unique crystal structure and optoelectronic properties. Understanding the relationship between the atomic/mesostructures and the associated properties of perovskite materials is crucial to their application performances. Herein, the detailed pressure processing of CsPbBr perovskite nanocube superlattices (NC-SLs) is reported for the first time. By using in situ synchrotron-based small/wide angle X-ray scattering and photoluminescence (PL) probes, the NC-SL structural transformations are correlated at both atomic and mesoscale levels with the band-gap evolution through a pressure cycle of 0 ↔ 17.5 GPa. After the pressurization, the individual CsPbBr NCs fuse into 2D nanoplatelets (NPLs) with a uniform thickness. The pressure-synthesized perovskite NPLs exhibit a single cubic crystal structure, a 1.6-fold enhanced photoluminescence quantum yield, and a longer emission lifetime than the starting NCs. This study demonstrates that pressure processing can serve as a novel approach for the rapid conversion of lead halide perovskites into structures with enhanced properties.
卤铅钙钛矿由于其独特的晶体结构和光电性能，在一系列应用中具有广阔的应用前景。了解钙钛矿材料的原子/介观结构与相关性能之间的关系，对于其应用性能至关重要。本文首次详细报道了 CsPbBr 钙钛矿纳米立方体超晶格（NC-SL）的压力处理。通过使用基于同步加速器的原位小角/广角 X 射线散射和光致发光（PL）探针，在 0 到 17.5 GPa 的压力循环中，从原子和介观尺度上关联 NC-SL 结构转变与能带隙演化。加压后，单个 CsPbBr NC 融合成具有均匀厚度的 2D 纳米薄片（NPL）。与起始 NC 相比，压力合成的钙钛矿 NPL 具有单一的立方晶体结构、1.6 倍增强的光致发光量子产率和更长的发射寿命。这项研究表明，压力处理可以作为一种新方法，用于快速将卤铅钙钛矿转化为具有增强性能的结构。
