A Nontoxic NFM Solvent for High-Efficiency Perovskite Solar Cells with a Widened Processing Window.

With the steady industrialization process of the perovskite solar cells (PSCs), the toxicity of the used solvents has become a pivotal issue that needs to be addressed. Especially, the usage of N , N -dimethylformamide (DMF) solvent would pose serious environmental and health concerns. Herein, we have reported a nontoxic solvent N -formylmorpholine (NFM) to replace the toxic DMF and have achieved a higher PCE of 22.78% compared to 21.97% when DMF was adopted. Moreover, with NFM, a widened antisolvent processing window was observed, facilitating the fabrication of PSCs with high reproducibility. This solvent engineering strategy offers an important solution to prepare eco-friendly, efficient, and stable perovskite solar cells.