Formation of the front-gradient bandgap in the Ag doped CZTSe thin films and solar cells

作     者：Dongxiao Wang Jianyu Wu Xiyu Liu Li Wu Jianping Ao Wei Liu Yun Sun Yi Zhang Dongxiao Wang;Jianyu Wu;Xiyu Liu;Li Wu;Jianping Ao;Wei Liu;Yun Sun;Yi Zhang

作者机构：Institute of Photoelectronic Thin Film Devices and Technology and Tianjin Key Laboratory of Thin Film Devices and Technology Nankai UniversityTianjin 300350 China School of Physical Science Nankai UniversityTianjin 300071 China 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2019年第28卷第8期

页      面：188-196,I0007页

核心收录：

学科分类：0820[工学-石油与天然气工程] 0808[工学-电气工程] 07[理学] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(51572132,61674082,61774089) Tianjin Natural Science Foundation of Key Project(16JCZDJC30700,18JCZDJC31200) YangFan Innovative and Entrepreneurial Research Team Project(2014YT02N037) 111 Project(B16027) 

主　　题：CZTSe solar cell Front Ag-gradient Elements distribution SCAPS simulation 

摘      要：The graded bandgap of kesterite based absorber layer is an important way to achieve high efficiency solar cells. Incorporation of Ag into CZTSSe thin films can adjust the bandgap and thus reduce the VOC-deficit and improve the quality of crystallization. However, the distribution of Ag is difficult to control due to the quick diffusion of Ag under the high temperature. In this study, we achieve the front Ag-gradient in kesterite structured compound films by prealloying followed by selenization process at 550 °C. AgZn3,Ag3Sn, and Sn–Ag–Cu alloy phases were formed during prealloying stage at 250 °C. After prealloying process, Ag tends to distribute at the front surface of the ACZTSe thin films. Combining the results of experiment and SCAPS simulation, the significantly VOCimprovement of devices is ascribed to the formation of the front Ag-gradient bandgap structure in the absorber layer. This facile prealloying selenization process affords a feasible method to design the graded bandgap structure absorber layers, which will promote the fabrication of high efficient graded bandgap structure solar cells.