Fabrication of Lead-Free (CH₃NH₃)₃Bi₂I₉ Perovskite Photovoltaics in Ethanol Solvent

The toxicity of lead present in organohalide perovskites and the hazardous solvent systems used for their synthesis hinder the deployment of perovskite solar cells (PSCs). Herein, an environmentally friendly route toward bismuth-based, lead-free (CH₃NH₃)₃Bi₂I₉ perovskites that utilize ethanol as the solvent is described. Using this method, dense and homogeneous microstructures were obtained, compared to the porous, rough microstructures obtained using dimethylformamide. Photovoltaic performances were enhanced, with an open-circuit voltage of 0.84 V measured.