Systematic optimization of perovskite solar cells via green solvent systems

Currently, the preparation of high-efficiency inverted perovskite solar cells (PSCs) is on the basis of using highly toxic solvents such as chlorobenzene as the anti-solvent of perovskite layer and the solvent of electron transport layer (ETL). There is an urgent need for greener solvents to reduce chronic health risks. Here, we proposed a green solvent system in which tetraethyl orthocarbonate was employed as an anti-solvent for the preparation of perovskite film and anisole was used as a solvent for dissolving the ETL. The PSCs processed by the green solvent engineering were demonstrated to have higher efficiencies than the chlorobenzene counterparts, achieving a champion efficiency of 18.15%. This result was benefited from the suppression of carrier recombination, owing to the improved film quality of perovskite and ETL. The adoption of the green solvent scheme will greatly reduce the health risks of researchers and employees, and shows great potential for the preparation of environmentally friendly perovskite-based optoelectronic devices.