14.31 % Power Conversion Efficiency of Sn‐Based Perovskite Solar Cells via Efficient Reduction of Sn<sup>4+</sup>
Liang Wang, Qingqing Miao, Dandan Wang, Mengmeng Chen, Hua̅n Bì, Jiaqi Liu, Ajay Kumar Baranwal, Gaurav Kapil, Yoshitaka Sanehira, Takeshi Kitamura, Tingli Ma, Zheng Zhang, Qing Shen, Shuzi Hayase
Abstract
Abstract The photoelectric properties of nontoxic Sn‐based perovskite make it a promising alternative to toxic Pb‐based perovskite. It has superior photovoltaic performance in comparison to other Pb‐free counterparts. The facile oxidation of Sn 2+ to Sn 4+ presents a notable obstacle in the advancement of perovskite solar cells that utilize Sn, as it adversely affects their stability and performance. The study revealed the presence of a Sn 4+ concentration on both the upper and lower surfaces of the perovskite layer. This discovery led to the adoption of a bi‐interface optimization approach. A thin layer of Sn metal was inserted at the two surfaces of the perovskite layer. The implementation of this intervention yielded a significant decrease in the levels of Sn 4+ and trap densities. The power conversion efficiency of the device was achieved at 14.31 % through the optimization of carrier transportation. The device exhibited operational and long‐term stability.