Atomic Structure and Electrical Activity of Grain Boundaries and Ruddlesden–Popper Faults in Cesium Lead Bromide Perovskite
Atomic Structure and Electrical Activity of Grain Boundaries and Ruddlesden–Popper Faults in Cesium Lead Bromide Perovskite
复制标题
DOI：
10.1002/adma.201805047
复制
发表时间：
2018-12
影响因子：
29.4
通讯作者：
A. Thind;G. Luo;J. Hachtel;Maria V. Morrell;S. Cho;A. Borisevich;J. Idrobo;Y. Xing;Rohan Mishra
中科院分区：
文献类型：
--
作者：
A. Thind;G. Luo;J. Hachtel;Maria V. Morrell;S. Cho;A. Borisevich;J. Idrobo;Y. Xing;Rohan Mishra
为了评估平面缺陷在卤化铅钙钛矿中的作用-廉价，多功能的半导体材料-在原子尺度上检查它们的结构（包括缺陷）并详细了解它们对电子特性的影响至关重要。在这项研究中，合成后的双折射，像差校正扫描透射电子显微镜，和第一原理计算相结合，研究不同的平面缺陷形成的CsPbBr 3纳米晶体的性质。从原子分辨率成像中观察到两种类型的普遍平面缺陷：先前未报道的富Br [001]（210）Σ 5晶界（GB）和Ruddlesden-Popper（RP）平面缺陷。第一性原理计算表明，这些平面故障都不会引起深缺陷能级，但它们的Br-缺陷对应物会。发现∑ 5GB排斥电子并吸引空穴，类似于n-p-n结，并且RP平面缺陷排斥电子和空穴，类似于半导体-绝缘体-半导体结。最后，讨论了这些发现的潜在应用及其对理解有机-无机卤化铅钙钛矿中的平面缺陷的影响，这些缺陷导致太阳能电池具有极高的光转换效率。
To evaluate the role of planar defects in lead‐halide perovskites—cheap, versatile semiconducting materials—it is critical to examine their structure, including defects, at the atomic scale and develop a detailed understanding of their impact on electronic properties. In this study, postsynthesis nanocrystal fusion, aberration‐corrected scanning transmission electron microscopy, and first‐principles calculations are combined to study the nature of different planar defects formed in CsPbBr3 nanocrystals. Two types of prevalent planar defects from atomic resolution imaging are observed: previously unreported Br‐rich [001](210)∑5 grain boundaries (GBs) and Ruddlesden–Popper (RP) planar faults. The first‐principles calculations reveal that neither of these planar faults induce deep defect levels, but their Br‐deficient counterparts do. It is found that the ∑5 GB repels electrons and attracts holes, similar to an n–p–n junction, and the RP planar defects repel both electrons and holes, similar to a semiconductor–insulator–semiconductor junction. Finally, the potential applications of these findings and their implications to understand the planar defects in organic–inorganic lead‐halide perovskites that have led to solar cells with extremely high photoconversion efficiencies are discussed.