A binary solvent study with n-butanol and dimethyl sulfoxide on PEAI passivation of wide-bandgap perovskite solar cells

In terms of interfacial passivation of wide-bandgap perovskite solar cells, the solvent engineering strategy is one of the indispensable factors that influence the defect passivation effect. In this paper, by studying the effects of commonly used monohydric alcohol solvents on passivators, it is proposed that using n-butanol, which has low polarity and medium volatility rates, as the solvent for phenethyl ammonium iodide (PEAI) passivators is conducive to improving the passivation effect of PEAI. We further developed a simple binary solvent system with a trace amount of dimethyl sulfoxide (DMSO) in n-butanol solvent containing the passivation agent PEAI. The power conversion efficiency of the devices based on a wide-bandgap perovskite (1.68 eV) was boosted to 21.52% after surface passivation, accompanied with improved stability.