Authentic Alcohol‐Based Green‐Solution Processing of Stable Perovskite Solar Cells

In recent years, perovskite solar cells (PSCs) have emerged as a transformative technology for renewable energy applications, but their large‐scale industrialization is still hindered by employing toxic organic solvents. From the perspective of circular economy and green chemistry, for the first time a method for preparing perovskites using lead acetate (Pb(Ac) 2 ) is developed as the lead source and green alcohols as the solvent. the individual stages of Pb(Ac) 2 /perovskite conversion is scrutinized and elucidated the stepwise conversion mechanism, which first converts Pb(Ac) 2 to the intermediate MAPbI 3‐ x Ac x , and then to MAPbI 3 through anion exchange. As the removal of Ac − from the perovskite framework involves the rate‐determining process in slow conversion, a loose and porous Pb(Ac) 2 scaffold is carefully designed by introducing a pore‐guiding additive (NaHCO 3 ), which accelerates ion diffusion and reaction with the organic ammonium salts. Benefiting from this optimized nanostructure, the MAPbI 3 PSCs treated with NaHCO 3 reach a power conversion efficiency (PCE) of 22.03%, which is currently one of the highest values among PSCs prepared using Pb(Ac) 2 and is also comparable to the efficiency of PSCs using toxic PbI 2 /DMF system. The combination of Pb(Ac) 2 and alcohol solvents is expected to provide new insight for the environmentally friendly processing of PSCs.