Stepwise Tailoring of Perovskite Nucleation Dynamics and Defect Formation Using a Supersaturation-Suppression Layer for Developing Efficient and Stable Perovskite Solar Cells

Tailoring crystal growth and defects in perovskites, a viable strategy for suppressing non-radiative recombination, is widely employed for developing efficient and stable perovskite solar cells (PSCs). However, simultaneous tailoring of crystal growth and defects in PSCs is challenging owing to several limitations; for example, excessive interactions between additives and perovskite precursors impede crystallization, and additive-induced impurity phases can substantially increase the defect density in perovskite films. In this study, we introduced a metal-induced supersaturation-suppression layer (SSL) as a pseudo-additive interfacial layer to tailor the crystallization dynamics and defect formation in perovskite crystals in steps. The proposed perovskite modification process involves an SSL-induced metal-halide ion reaction, which modulates the crystallization kinetics for grain growth and enables the formation of metal-halide complex anion adducts that can reduce crystalline defects and suppress non-radiative recombination while facilitating preferential perovskite crystal growth by alleviating residual strains. Because of these stepwise synergistic effects, the SSL-based PSCs exhibited significantly improved device performances (23.4%), low hysteresis losses, and enhanced atmospheric operational stability. This study utilized a metal-induced supersaturation-suppression layer (SSL) as a novel interfacial layer to regulate the crystallization dynamics and defect passivation in perovskite solar cells (PSCs). Through metal-halide ion reactions, SSL enhances crystallization kinetics, yielding enlarged perovskite grains and generating chemical adducts that reduce crystalline defects and non-radiative recombination, achieving the development of high-performance PSCs with robust operational stability.image (c) 2024 WILEY-VCH GmbH