Substrate geometry optimization of vapor-deposited perovskite thin film for high uniformity

초록

Metal halide-based perovskites (MHPs) have great potential in optoelectronic devices owing to their excellent properties. Currently, a majority of studies on perovskite thin films employ solution-based methods, which have limits for scalable production. While vaporbased growth of thin films is promising to this end, controlling film uniformity over large areas remains challenging. Here, we report the vapor-based growth of MHP thin films by varying the substrate geometry (e.g., horizontal vs. vertical) relative to carrier gas flow and systemically comparing the uniformity of as-fabricated films. We confirm that the vertical substrate geometry exhibits a more uniform deposition of lead iodide (PbI2) layers than the horizontal layout, thanks to the regulated carrier gas flow and substrate temperature distribution as predicted by computational fluid dynamics (CFD) simulation. Interestingly, perovskite conversion confirms that the horizontal substrate configuration yields more uniform conversion to MAPbI3, attributed to the solid-diffusion mechanism. Our results present an optimized approach to obtain highly uniform perovskite thin films via vapor deposition for scalable production.