Eco-friendly processing of perovskite solar cells in ambient air

Solvent engineering is a key aspect in the fabrication of high-quality perovskite films towards highly efficient perovskite solar cells (PSCs). However, the major solvents used in preparing the different solutions of PSC components are considered hazardous, which poses a significant threat to human beings or the environment. Besides, perovskite materials are reputed to exhibit serious environmental stability issues, limiting their production in ambient environment, thus hindering their practical applications. Therefore, it is of critical importance to develop eco-friendly strategies for fabricating PSC devices in ambient air, which will pave the way for industrial applications. In this review, the toxicity of commonly employed solvents was explored, and their greener alternatives were thoroughly examined. Advances in the development of green solvents for perovskite precursor solutions, as well as for the charge transport layers and their application in ambient environment were also discussed. Finally, an overall perspective is presented and key challenges limiting the development of eco-friendly PSC fabrication routes highlighted.