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Probing the Stability and Band Gaps of Cs2AgInCl6 and Cs2AgSbCl6 Lead-Free Double Perovskite Nanocrystals
Chemistry of Materials ( IF 7.2 ) Pub Date : 2019-04-24 00:00:00 , DOI: 10.1021/acs.chemmater.8b04202
Jakob C. Dahl , Wojciech T. Osowiecki , Yao Cai , Joseph K. Swabeck , Yehonadav Bekenstein 1 , Mark Asta , Emory M. Chan , A. Paul Alivisatos 2
Affiliation  

Lead toxicity has sparked interest into alternative halide nanomaterials with properties similar to CsPbX3 perovskites. A promising alternative suggested from bulk studies is the family of double perovskites of the form Cs2AgMX6. Here, we report the synthesis of colloidal Cs2AgInCl6 and Cs2AgSbCl6 nanocrystals via injection of acyl halides into a metal acetate solution under atmospheric conditions and relatively mild temperatures. We demonstrate the synthesis of single-crystalline cubic nanocrystals of ca. 10 nm side length and their morphological similarities to other double perovskite nanostructures in terms of their [200] facet termination and decoration with Ag(0) smaller nanocrystallites. To compare the stabilities of the synthesized materials, we develop a titration assay based on the degradation of nanocrystals with amines as a proxy for degradation by humidity, which provides a quantifiable stability metric. This measurement shows that Cs2AgSbCl6 releases more than twice the decomposition energy compared to Cs2AgInCl6 or CsPbCl3 and degrades in the presence of approximately one molar equivalent of amine, whereas the other two materials require more than a 100-fold excess. Using facile chemical titration to quantitatively determine chemical stability provides an additional tool to aid in the basic understanding of what makes some of these materials more environmentally stable than others.

中文翻译:

探索Cs 2 AgInCl 6和Cs 2 AgSbCl 6无铅双钙钛矿纳米晶体的稳定性和带隙

铅的毒性激发了人们对替代卤化物纳米材料的兴趣,这些卤化物纳米材料具有类似于CsPbX 3钙钛矿的性质。大量研究提出的一种有前途的替代方法是Cs 2 AgMX 6形式的双钙钛矿家族。在这里,我们报告胶体Cs 2 AgInCl 6和Cs 2 AgSbCl 6的合成通过在大气条件和相对温和的温度下将酰基卤注入乙酸金属盐溶液中制备纳米晶体。我们证明了单晶立方纳米晶体的合成。10 nm的边长及其与其他双钙钛矿纳米结构的形态相似之处在于它们的[200]小平面终止和用Ag (0)较小的纳米微晶装饰。为了比较合成材料的稳定性,我们开发了一种基于胺的纳米晶体降解的滴定测定法,以作为湿度衰减的代用品,它提供了可量化的稳定性指标。此测量表明,铯2 AgSbCl 6个释放超过两倍的分解能量相比铯2 AgInCl6或CsPbCl 3并在大约一摩尔当量的胺存在下降解,而其他两种材料则需要超过100倍的过量。使用简便的化学滴定法定量确定化学稳定性提供了另一种工具,有助于基本了解这些材料中的某些材料比其他材料在环境方面更稳定的原因。
更新日期:2019-04-24
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