The impact of cation and anion pairing in ionic salts on surface defect passivation in cesium lead bromide nanocrystals
The impact of cation and anion pairing in ionic salts on surface defect passivation in cesium lead bromide nanocrystals
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DOI：
10.1039/d0tc04257a
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发表时间：
2021-01
影响因子：
6.4
通讯作者：
Lucy U. Yoon;Matthew R. Alpert;Hongxia Luo;Michael I. Schapowal;Eric N. Holmgren;Geoffrey M. Geise;Christopher Paolucci;Joshua J. Choi
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文献类型：
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作者：
Lucy U. Yoon;Matthew R. Alpert;Hongxia Luo;Michael I. Schapowal;Eric N. Holmgren;Geoffrey M. Geise;Christopher Paolucci;Joshua J. Choi
金属卤化物钙钛矿(MHP)纳米晶表面电荷陷阱的不完全钝化仍然是实现高性能光电子器件的关键障碍。由于MHPS的强离子性质，离子盐被认为是有效的表面电荷陷阱钝化配体。通过对溴化铯纳米晶(CsPbBr3 NCS)的光致发光量子产率(PLQY)和时间分辨光致发光(TRPL)的测量，我们发现离子盐的正负离子配对对陷阱钝化有显著的影响。利用密度泛函理论(DFT)计算，我们确定离子对的阳离子和阴离子之间的结合作用是决定陷阱通过效率的主要因素。
Imperfect passivation of surface charge traps on metal halide perovskite (MHP) nanocrystals remains a key obstacle to achieving higher performance in optoelectronic devices. Due to the strong ionic nature of MHPs, ionic salts have been identified as effective surface charge trap passivating ligands. In this study, based on photoluminescence quantum yield (PLQY) and time-resolved photoluminescence (TRPL) measurements on cesium lead bromide nanocrystals (CsPbBr3 NCs), we find that the pairing between cation and anion of an ionic salt results in a significant impact on trap passivation. Using density of functional theory (DFT) calculations, we identify the binding interaction between the cation and anion of the ionic pair to be a major factor in determining the trap passviation efficacy.