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

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