From Spin Coating to Zone Casting: Process Dependence and Challenges in Scaling Quasi-2D Perovskite Films

Abstract

Two-dimensional (2D) hybrid organic-inorganic perovskites are promising materials for photovoltaics due to their tunable optoelectronic properties and enhanced stability compared to three-dimensional (3D) perovskites. However, efficiency limitations stem from the distribution and orientation of their multi-quantum well structures, necessitating improvements in thin film fabrication methods, especially when transitioning from lab-scale to large-scale deposition. This study compares quasi-2D perovskite (BA₂MA₄Pb₅I₁₆) thin films prepared by spin-coating and zone-casting -a scalable method for large-area deposition -examining the effects of solution temperature, substrate temperature, and host solvent ratios on their structural and morphological properties. Both methods demonstrated increased crystallite size with increasing temperature, with zone-casting leading to significantly larger grains of up to 8 µm. On the other hand, spin-coating provides superior control over film orientation, leading to high photovoltaic performance of 18.1%, highlighting the need to develop new strategies for control of texture across large areas of quasi-2D perovskite layers.