High-performance planar perovskite solar cells: Influence of solvent upon performance

We systemically studied the influence of various precursor solvents on perovskite films and their effects on solar cell performances in p-i-n planar-structured perovskite solar cells (PSCs). For comprehensive and reasonable consideration to achieve a better solvent selection, various solvents such as dimethylformamide (DMF), gamma-butyrolactone (GBL), methyl-2-pyrrolidinone (NMP), dimethyl sulfoxide (DMSO), DMF-DMSO, GBL-DMSO, and NMP-DMSO that were well known as the most representative and effective solvent for perovskite precursor solvents were chosen, and they were all investigated and compared comprehensively on the basis of cell performances, quantum efficiencies, charge transport behaviors, intermediate-phase formation, and perovskite film morphology. These comparative investigations revealed that the DMF-DMSO can raise the device performances in planar-structured perovskite devices more largely than other solvents. More notably, an excellent power conversion efficiency of 15.05% with no distinct hysteresis was produced from the PSCs with DMF-DMSO. This approach will be a meaningful step toward a better solvent design for the realization of better-performing planar perovskite solar devices.