Reducing Defects in Organic-Lead Halide Perovskite Film by Delayed Thermal Annealing Combined with KI/I(2) for Efficient Perovskite Solar Cells

This study improved quality of CH(3)NH(3)PbI(3) (MAPbI(3)) perovskite films by delaying thermal annealing in the spin coating process and introducing KI and I(2) to prepare MAPbI(3) films that were low in defects for high-efficiency perovskite solar cells. The influences of delayed thermal annealing time after coating the MAPbI(3) perovskite layer on the crystallized perovskite, the morphology control of MAPbI(3) films, and the photoelectric conversion efficiency of solar cells were investigated. The optimal delayed thermal annealing time was found to be 60 min at room temperature. The effect of KI/I(2) additives on the growth of MAPbI(3) films and the corresponding optimal delayed thermal annealing time were further investigated. The addition of KI/I(2) can improve perovskite crystallinity, and the conductivity and carrier mobility of MAPbI(3) films. Under optimized conditions, the photoelectric conversion efficiency of MAPbI(3) perovskite solar cells can reach 19.36% under standard AM1.5G solar illumination of 100 mW/cm(2).