Effects of Different Solvents on the Planar Hetero-junction Perovskite Solar Cells

Abstract

The perovskite (CH₃NH₃PbI₃) films on the planar hetero-junction perovskite solar cells (PHJ-PSCs) are fabricated by “two-steps” process with the wet spin-coating method. The precursor (PbI2) solutions are compounded with 4 types of solvents: N-Methyl Pyrrolidone (NMP), γ-butyrolactone (GBL), Dimethyl Sulfoxide (DMSO) and N, N-dimethylformamide (DMF). All the solutions have the same concentration. The influences of different precursor solvents to the micro-structures of CH₃NH₃PbI₃ films and device performance are studied. Atomic force microscopy (AFM) and scanning electron microscope (SEM) are used to characterize the CH₃NH₃PbI₃ films. The results indicate that the CH₃NH₃PbI₃ film using DMF solvent possesses more rough morphology and thickest thickness. The monolithic PHJ-PSCs devices based on DMF solvent are tested under a standard one sun of simulated solar irradiation (AM1.5). The results show that the open-circuit voltage (Voc) reaches 872mV, the short-circuit current (Jsc) reaches 9.35mA/cm2, the filling factor(FF) is 0.62 and the photo-current conversion efficiency (PCE) is 5.05%. DMF is the best one among these 4 types of solvents for PHJ-PSCs.