| In recent years, the solar cell industry is developing rapidly. New solar cells emerge in endlessly. As excellent photovoltaic performance and lower costs, organolead-halide-perovskite-based solar cells have attracted considerable attention recently. Since 2009, the efficiency of perovskite solar cells is increasing from 3.8% to 20.1%. In this work, we focus on the study of preparation and performance of the halide perovskite CH3NH3PbI3 and CH3NH3PbI(3-x)Clx films.First, a morphology-controlled CH3NH3PbI (3-X) Clx film is synthesized via two-step solution deposition by spin-coating. The rotate speed of spin coating and soaking solution concentration are controlled in order to determine the optimum conditions. The results showed that, the conditions of two-step solution were chosen as following:spin coating speed is 4500r/min and the concentration of CH3NH3I solution is 10g/L. With this condition, the diffraction peaks of perovskite thin films are sharp relatively obtained by XRD, few impurity phases are measured. The SEM shows that the films are tightly combined together and with smooth surfaces.Secondly, the CH3NH3PbI3 films and CH3NH3PbI(3-X)Clx films were synthesized via one-step coating methods. The performances of CH3NH3PbI3 films by the two methods were compared.The results show that, the CH3NH3PbI3 films by one-step method have few impurity phases, and the reaction is completely finished. By comparison, the crystalline grains of CH3NH3PbI3 films by two-step method have more homogeneous distribution, which grains growths are better. As well as the grain size is more uniform than the one-step method. Meanwhile, the optimum drying temperature of CH3NH3PbI (3-X) Clx films by one-step method is 80 ℃. The results showed that:when the heat treatment time was 45 min, the diffraction peaks of CH3NH3PbI3 films and CH3NH3PbCl3 films are sharp relatively, so we chose the optimum conditions of CH3NH3PbI (3-x) Clx films as follows:drying time is 45 min and drying temperature is 80℃. |
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