Surface chemical polishing and passivation minimize non-radiative recombination for all-perovskite tandem solar cells

All-perovskite tandem solar cells show great promise but are hindered by surface defects causing non-radiative recombination in Sn-Pb mixed narrow bandgap perovskite films. This study reports a surface reconstruction strategy using 1,4-butanediamine (BDA) for polishing and ethylenediammonium diiodide (EDAI₂) for passivation. This approach eliminates Sn-related defects and passivates organic cation and halide vacancy defects, leading to high-quality Sn-Pb mixed perovskite films and minimized energy loss. Sn-Pb mixed perovskite solar cells with bandgaps of 1.32 and 1.25 eV achieved power conversion efficiencies of 22.65% and 23.32%, respectively. Two-junction all-perovskite tandem solar cells reached a certified power conversion efficiency of 28.49%.

Yongyan Pan, Jianan Wang, Zhenxing Sun, Jiaqi Zhang, Zheng Zhou, Chenyang Shi, Sanwan Liu, Fumeng Ren, Rui Chen, Yong Cai, Huande Sun, Bin Liu, Zhongyong Zhang, Zhengjing Zhao, Zihe Cai, Xiaojun Qin, Zhiguo Zhao, Yitong Ji, Neng Li, Wenchao Huang, Zonghao Liu, Wei Chen