Preparation of perovskite active layer applied for perovskite solar cell

Perovskite active layers treated by one step method with dimethylformamide (DMF) solvent is coated by using spincoater for perovskite solar cells in this work. The time of dumping toluene is controlled at the fourth and fifth second when the perovskite active layer is coated. By changing time of dumping toluene, the perovskite crystallization can be improved. The morphology and crystallization of perovskite active layer are measured by using scanning electron microscope (SEM) and X-ray diffractometer (XRD). The absorbance of perovskite active layer is measured by using UV-Vis spectrophotometer. As shown in the results of SEM, the perovskite active layer with toluene dumping time at the fifth second has more pinholes. The crystallization peaks of the perovskite measured by XRD are (110), (112), (202), (312), (224) and (314). When the dumping time of toluene is changed from the fourth second to the fifth second, the absorbance of perovskite active layer for the wavelengths from 300nm to 700nm is improved. Therefore, the photoelectric conversion efficiency (PCE) of perovskite solar cell with toluene dumping time at the fifth second is 5.29% that is better than 2.17% of the perovskite solar cell with toluene dumping at the fourth second.