Perovskite solar cells are expected to lead the next generation of photovoltaic technology, and improving the preparation quality of perovskite films through multifunctional passivation materials is the key way to promote the development of this technology. This study aims to design Lewis base sites in passivation materials and investigate the mechanism of their modified perovskites. Firstly, formic acid functionalization is used to create ordered Lewis base sites in zinc-based metal-organic frameworks. This material has a stable and ordered porous structure, fully exposed active sites, and unique optoelectronic properties, which are conducive to passivating defects in perovskite films. As a result, the defect density of the modified perovskite film is suppressed, and the moisture and thermal stability of the film are also significantly improved. The power conversion efficiency (PCE) of the modified perovskite solar cells increases by 1.5%, with the champion PCE exceeding 21%. Furthermore, different numbers of Lewis base sites can be created based on the axial substitution of phthalocyanines, which assists in studying the interactions between passivation materials and perovskites. The research results indicate that the bidentate coordination based on nitrogen and oxygen sites is most beneficial for improving the quality of perovskite films. The PCE of the modified device exceeds 23% with improved stability. The development of multifunctional passivation materials with Lewis base sites provides an experimental basis for the preparation of high-performance perovskite solar cells.

Organic-inorganic hybrid perovskite; Defect passivation; solar cells; stability; Lewis base sites