Enhancing Efficiency and Stability of Tin-Based Perovskite Solar Cells through A-Site Compositional Engineering

Tin-based perovskite solar cells (TPSCs) have attracted significant attention due to their relatively competitive performance and environmentally benign characteristics. Small-molecule additive strategies have been extensively employed to enhance TPSCs' performance through crystallization modulation and defect passivation. However, most small-molecule additives exhibit lattice deformation or spontaneous desorption from perovskite, leading to accelerated device degradation under operational thermal/electrical stresses. In this work, a component-engineering crystallization modulation strategy is developed to improve the crystallinity without introducing extraneous additives. It not only accelerates precursor nucleation during spin-coating but also promotes the formation of a two-dimensional phase at the initial annealing stage, ultimately optimizing crystal orientation and improve crystallinity. It enables a marked efficiency enhancement from 10.22% to 13.49% in TPSCs, coupled with exceptional stability showing negligible efficiency degradation after 5800 h N2 storage. This study provides critical insights into stabilizing tin-based perovskites through intrinsic material design, circumventing the stability limitations inherent in conventional additive-based approaches.