Department of Chemistry and ‡Department of Material Science and Engineering, Texas A&M University , College Station, Texas 77843, United States.
Nano Lett. 2017 Sep 13;17(9):5561-5566. doi: 10.1021/acs.nanolett.7b02355. Epub 2017 Aug 2.
We have designed a facile synthetic strategy for the selective deposition of Au metal on all-inorganic CsPbBr perovskite nanocrystals that includes the addition of PbBr salt along with AuBr salt. PbBr is necessary because the addition of Au to solutions of CsPbBr nanocrystals otherwise results in the exchange of Au ions from solution with Pb cations within the nanocrystal lattice to produce CsAuAuBr nanocrystals with a tetragonal crystal structure and a band gap of about 1.6 eV, in addition to Au metal deposition. Including excess Pb ions in solution prevents the exchange reaction. Au metal deposits on the surface of the nanocrystals to produce the Au-CsPbBr heterostructure nanoparticles with an Au particle diameter determined by the Au ion concentration. Fluorescence quenching caused by Au deposition monotonically increases with deposition size, but the fluorescence quantum yield (QY) is significantly greater than if any cation exchange has occurred. An optimized synthesis can produce Au-CsPbBr nanoparticles with 70% QY and no evidence of cation exchange.
我们设计了一种简便的合成策略，用于选择性地在全无机 CsPbBr 钙钛矿纳米晶体上沉积 Au 金属，该策略包括添加 PbBr 盐和 AuBr 盐。添加 PbBr 是必要的，因为向 CsPbBr 纳米晶体溶液中添加 Au 会导致 Au 离子从溶液中与纳米晶体晶格内的 Pb 阳离子发生交换，生成具有四方晶体结构和约 1.6eV 带隙的 CsAuAuBr 纳米晶体，此外还会沉积 Au 金属。在溶液中包含过量的 Pb 离子可以防止发生交换反应。Au 金属沉积在纳米晶体的表面上，生成具有 Au 粒径由 Au 离子浓度决定的 Au-CsPbBr 异质结构纳米粒子。由于 Au 沉积引起的荧光猝灭随着沉积尺寸的增加而单调增加，但荧光量子产率（QY）明显大于是否发生任何阳离子交换的情况。优化的合成可以产生具有 70%QY 且没有阳离子交换证据的 Au-CsPbBr 纳米粒子。
