Synergistic Effect of Sodium Cyanoborohydride in Pb-Sn Perovskite Solar Cells

Pb-Sn mixed perovskite has received extensive attention because of its high research value in environmental protection and theoretical prospects. However, the film defects brought on by the quick crystallization of Pb-Sn mixed perovskites and the facile oxidation of Sn2+ to Sn4+ are detrimental to the performance of Pb-Sn perovskite solar cells (PSCs). Here, aiming at the interface of Pb-Sn PSCs, which has been less studied, a reducing agent is first introduced on the top of Pb-Sn mixed perovskite interface. The results show that in NaBH3CN(SC), BH can suppress the oxidation of Sn2+ and C & EQUIV;N can enhance the perovskite crystallinity and passivate the surface defects. Benefitting from this synergistic effect, a champion power conversion efficiency of 21.3% is obtained for Pb-Sn PSCs. In addition, the encapsulated device can maintain good stability under maximum power point tracking conditions.

Automated summary

In this study, a reducing agent is introduced on the interface of Pb-Sn perovskite solar cells to address the quick crystallization and oxidation issues. The reducing agent effectively suppresses the oxidation of Sn2+ and improves the crystallinity and surface defects of perovskite. As a result, Pb-Sn perovskite solar cells achieve a champion power conversion efficiency of 21.3%.