Surface reconstruction of wide-bandgap perovskites enables efficient perovskite/silicon tandem solar cells
Zheng Fang, Bingru Deng, Yongbin Jin, Yang Liu, Lisha Chen, Yawen Zhong, Huiping Feng, Yue Yin, Kaikai Liu, Yingji Li, Jinyan Zhang, Jiarong Huang, Qinghua Zeng, Hao Wang, Xing Yang, Jinxin Yang, Chengbo Tian, Liqiang Xie, Zhanhua Wei, Xipeng Xu
Abstract
Wide-bandgap perovskite solar cells (WBG-PSCs) are critical for developing perovskite/silicon tandem solar cells. The defect-rich surface of WBG-PSCs will lead to severe interfacial carrier loss and phase segregation, deteriorating the device’s performance. Herein, we develop a surface reconstruction method by removing the defect-rich crystal surface by nano-polishing and then passivating the newly exposed high-crystallinity surface. This method can refresh the perovskite/electron-transporter interface and release the residual lattice strain, improving the charge collection and inhibiting the ion migration of WBG perovskites. As a result, we can achieve certified efficiencies of 23.67% and 21.70% for opaque and semi-transparent PSCs via a 1.67-eV perovskite absorber. Moreover, we achieve four-terminal perovskite/silicon tandem solar cells with a certified efficiency of 33.10% on an aperture area of one square centimeter. The defect-rich surface of wide-bandgap perovskite solar cells leads to severe interfacial carrier loss and phase segregation. Here, the authors reconstruct the surface through nano-polishing followed by passivation, achieving certified efficiency of 33.1% for perovskite/silicon tandem solar cells.