A Multi‐Additive System With Superimposed Optimization Effects by Incorporating Additives With Tailored Mechanisms for Perovskite Solar Cells

ABSTRACT Perovskite/c‐Si tandem solar cells have emerged as one of the most promising candidates for next‐generation solar cells in recent years. However, the wide‐bandgap (1.65–1.70 eV) perovskite top cells still encounter numerous challenges, such as suboptimal crystallization quality, poor stability, and interface recombination losses. In this study, the effects of four types of additives (i.e., MACl & Pb‐excess, ODADI, PMMA, and Me‐4PACz) co‐added to perovskite were investigated. Multiple mechanisms including intermediate phase‐assisted α‐phase formation, Pb anchoring, grain boundary passivation and interface modification have been discovered. Due to different interaction mechanisms and distribution areas, the optimized effects of these additives can be superimposed without interference with each other. Consequently, the crystallinity of perovskite film was optimized, the precipitation of Pb was suppressed, and the deep defect density was reduced, thus shifting the dominant recombination defect type from deep defects to shallow defects, significantly reducing non‐radiative recombination. The best PSCs (E g = 1.694 eV) fabricated through the co‐addition strategy with PCE = 21.50%, SPO = 20.73%, and stability T 90 ≈ 480 h (storage conditions: 30% humidity, 25°C) were obtained. Our research demonstrated the application potential of the multi‐additive system for the additive engineering of perovskites.