Solvent engineering towards scalable fabrication of high-quality perovskite films for efficient solar modules

Over the last decade, remarkable progress has been made in metal halide perovskite solar cells (PSCs), which have been a focus of emerging photovoltaic techniques and show great potential for commercialization. However, the upscaling of small-area PSCs to large-area solar modules to meet the demands of practical applications remains a significant challenge. The scalable production of high-quality perovskite films by a simple, reproducible process is crucial for resolving this issue. Furthermore, the crystallization behavior in the solution-processed fabrication of perovskite films can be strongly influenced by the physicochemical properties of the precursor inks, which are significantly affected by the employed solvents and their interactions with the solutes. Thus, a comprehensive understanding of solvent engineering for fabricating perovskite films over large areas is urgently required. In this paper, we first analyze the role of solvents in the solution-processed fabrication of large-area perovskite films based on the classical crystal nucleation and growth mechanism. Recent efforts in solvent engineering to improve the quality of perovskite films for solar modules are discussed. Finally, the basic principles and future challenges of solvent system design for scalable fabrication of high-quality perovskite films for efficient solar modules are proposed.