Effect of spin coat speed on structure, composition and properties of perovskite films

Recently, 2D perovskite has emerged as a promising alternative material for solar cell applications because of its superior stability in wet environments. Among the various methods for preparing 2D perovskite films, spin coat is the most widely used due to its low pollution, high accuracy and energy efficiency. In this study, the effects of spin coat speed on the surface morphology, crystal structure and surface composition of 2D perovskite (BA₂MA₃Pb₄I₁₃) films are investigated using X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy and other techniques. It is found that the BA₂MA₃Pb₄I₁₃ film has large crystal size, good crystallinity and small lattice constant at a relatively low spin coat speeds. The device performance test showed that the BA₂MA₃Pb₄I₁₃ film can obtain better device performance as well. It indicated that the photovoltaic performance of perovskite solar cells can be significantly improved by optimization of the fabrication parameters during the film preparation process.