卤化锡钙钛矿半导体的体相与表面缺陷的表征与调控

卤化物钙钛矿材料具有优异的半导体和光电转化性能，在太阳电池、光探测器和电致发光方面有广泛的应用潜力，但其发展前景仍然受制于其铅元素成分。卤化锡钙钛矿材料的多数半导体性质与卤化铅钙钛矿的类似，是活跃的新研究方向，不过面临的一个关键问题是材料中容易产生对器件性能不利的缺陷。本项目将首先使用电学和光谱方法表征CsSnX3材料缺陷的类型、密度和能级，结合理论建模计算确定材料缺陷的具体存在形式（例如体相的锡空位和表面的铯空位）。接下来，针对CsSnX3材料缺陷的特点，采用异价离子掺杂来中和或强化体相缺陷，沉积有机铵盐或稳定的金属卤化物来钝化表面缺陷。本项目将发展与CsSnX3材料缺陷有关的表征方法、理论模型和调控手段，经过不断循环改进得到体相和表面缺陷被抑制的CsSnX3材料，并考察其光电转化性能的提升效果；得到缺陷被增强的CsSnX3材料，并考察其导电性和热电转化性能的提升效果。

Halide perovskite materials are known for excellent semiconducting and optoelectronic properties, and have wide application potentials in solar cells, photodetectors, and electroluminescence, but their development prospects are still limited by their composition of the lead element. As an active new research area, tin halide perovskite materials have semiconducting properties similar with those of lead halide perovskites, but a key problem remains that the materials are prone to defects detrimental to device performance. This project will first use electrical and spectroscopic tools to characterize the type, density, and energy level of defects in CsSnX3, along with theoretical modeling to determine the specific form of the defect states, such as Sn vacancies in the bulk and Cs vacancies on the surfaces. Next, according to the characteristics of defects in CsSnX3, heterovalent ionic doping will be used to neutralize or enhance defects in the bulk, and organic ammonium salts or stable metal halides will be deposited to passivate surface defects. This project will develop characterization methods, theoretical models, and regulation methods for the defects in CsSnX3. Through repeated improvements, CsSnX3 materials with suppressed bulk and surface defects will be developed, and the beneficial effects on their photovoltaic performance will be investigated; CsSnX3 materials with enhanced defects will also be developed, and the beneficial effects of their conductivity and thermoelectric performance will be evaluated.