XU Yafei, JIANG Hedong, GUO Pingchun, LI Jiake, ZHU Hua, SUN Jian, WANG Yanxiang

(Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China)

Abstract: Since the report of perovskite solar cells in 2009, after more than ten years of development, the photovoltaic conversion efficiency has increased from the initial 3.8% to 25.7%. Perovskite solar cells mainly have planar and mesoporous structures. Compared with planar structure, perovskite solar cells with mesoporous structure have more mesoporous layer. With mesoporous layer, the contact area between the perovskite layer and the electron transport layer can be increased, which accelerates the extraction and transport of electrons, thus reducing the hysteresis effect of the cells. In this study, SnO₂ mesoporous layer was prepared by using hydrothermal method and applied as the electron transport layer of perovskite solar cells. The effects of hydrothermal reaction time on performances of the mesoporous SnO₂ electron transport layer and the perovskite solar cells were evaluated. Composition, morphology, optical and optoelectronic properties of the samples were studied by using XPS, SEM, UV-Vis, J-V and IPCE. It is found that diameter of the SnO₂ nanosheets was increased from 80 nm to 270 nm and the thickness of the mesoporous SnO₂ layer was increased from 70 nm to 350 nm, when the hydrothermal reaction time was prolonged from 3 h to 9 h. When the hydrothermal reaction time was 7 h, photoelectric performance of the device was optimized, with photoelectric conversion efficiency of 14.53%, open-circuit voltage of 1.04 V, short-circuit current density of 19.29 mA·cm⁻² and fill factor of 72.57%.

Key words: perovskite solar cells; SnO₂ electron transport layer; mesoporous layer; hydrothermal method