Influence of Defects and Synthesis Conditions on the Photovoltaic Performance of Perovskite Semiconductor CsSnI3

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• 作者：Peng Xu ; Shiyou Chen ; Hong-Jun Xiang ; Xin-Gao Gong ; Su-Huai Wei
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：26
• 期：20
• 页码：6068-6072
• 全文大小：307K
• ISSN：1520-5002

文摘

CsSnI₃ is a prototype inorganic halide perovskite that has recently been proposed as a strong candidate for photovoltaic applications because of its unique semiconductor properties. Through first-principle calculations, we show that the concentration control of intrinsic defects is critical for optimizing the photovoltaic properties of CsSnI₃. Under a Sn-poor condition, a high concentration of acceptor defects, such as Sn or Cs vacancies, can form easily and produce a high p-type conductivity and deep-level defects that can become electron鈥揾ole recombination centers, all with high energy. This condition is optimal for growing CsSnI₃ as hole-transport material in solar cells. In contrast, when Sn becomes richer, the concentration of acceptor defects decreases; therefore, the p-type conductivity may drop to a moderate level, which can increase the shunt resistance and, thus, the efficiency of the solar cells with CsSnI₃ as the light absorber material (LAM). However, under the Sn-rich condition, the concentration of a deep-level donor defect Sn_I will increase, causing electron traping and non-radiative electron鈥揾ole recombination. Therefore, we propose that a moderately Sn-rich condition is optimal when CsSnI₃ is used as the LAM. The defect properties of CsSnI₃ are general, and the underlying chemistry is expected to be applicable to other halide perovskite semiconductors.