Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA and Department of Material Science and Engineering, Texas A&M University, College Station, Texas 77843, USA.
Nanoscale. 2019 Oct 21;11(39):18109-18115. doi: 10.1039/c9nr07222e. Epub 2019 Oct 2.
Here, we report that the oxidation state of gold plays a dominant role in determining the reaction products when gold halide salts are mixed with all-inorganic lead halide perovskite nanocrystals. When CsPbX nanocrystals react with Au(i) halide salts, Au nanoparticles are deposited on the surface of the perovskites through the reduction of Au ions by the surfactant ligand shell, to produce Au-CsPbX heterostructures. These heterostructures preserve comparably high photoluminescence quantum yield (PLQY) and show identical XRD diffractograms as the parent CsPbX nanocrystals. In contrast, the reaction of CsPbX nanocrystals with Au(iii) halide salts promotes complete cation exchange of Pb ions by Au ions in the nanocrystal perovskite lattice. The cation exchange products, CsAuAuBr or CsAuAuCl, show XRD patterns corresponding to a tetragonal mixed halide perovskite crystal structure and show no visible photoluminescence. This crucial dependence on the oxidation state of the Au ion informs synthetic strategies for producing and optimizing metal-perovskite heterostructures and lead-free perovskite nanoparticles.
在这里，我们报告说，金的氧化态在决定金卤化物盐与全无机铅卤钙钛矿纳米晶体混合时的反应产物方面起着主导作用。当 CsPbX 纳米晶体与 Au(i)卤化物盐反应时，通过表面活性剂配体壳还原 Au 离子，在钙钛矿表面上沉积 Au 纳米颗粒，从而产生 Au-CsPbX 异质结构。这些异质结构保持了相当高的光致发光量子产率（PLQY），并且与母体 CsPbX 纳米晶体具有相同的 XRD 图谱。相比之下，CsPbX 纳米晶体与 Au(iii)卤化物盐的反应促进了纳米晶钙钛矿晶格中 Pb 离子被 Au 离子的完全阳离子交换。阳离子交换产物 CsAuAuBr 或 CsAuAuCl 显示出对应于四方混合卤化物钙钛矿晶体结构的 XRD 图谱，并且没有可见的光致发光。Au 离子的氧化态的这种关键依赖性为生产和优化金属-钙钛矿异质结构和无铅钙钛矿纳米颗粒提供了合成策略。
