Effective Management of Nucleation and Crystallization Processes in Perovskite Formation via Facile Control of Antisolvent Temperature

The antisolvent method has been used extensively to induce the growth of high-quality perovskite layers for efficient solar cells. However, uncontrollable nucleation and crystallization increases the risk of formation of undesirable defects. Here, we report a facile way to control the nucleation and crystallization stages in perovskite formation by changing the temperature of chlorobenzene (CB) in the antisolvent method. When CB is injected on the spinning substrate with a precursor solution, CB temperature affects the nucleation process as well as the crystallization process. As the CB temperature increases, nuclei increase in size, leading to the formation of larger perovskite crystals with fewer grain boundaries. However, too low or high a CB temperature induces several pinholes and reduces uniformity of the perovskite layer. Finally, at 35 degrees C, the lowest trap density and the highest charge carrier lifetime are obtained, and the highest efficiency of 20.9% in solution-processable SnO2 planar devices is obtained. By establishing the optimum temperature of antisolvent, constant and robust perovskite can be obtained regardless of seasons, and this study is expected to lead to highly reproducible and efficient perovskite solar cell fabrication.