Vapor Transport Deposition of Metal-Halide Perovskites for Photovoltaic Applications

Metal-halide perovskites are a promising semiconductor for use in optoelectronic and photovoltaic applications but require the identification of scalable manufacturing methods to achieve broad commercialization. In this work, we demonstrate solar cells based on an active layer of methylammonium lead iodide co-deposited via vapor transport deposition (VTD). VTD utilizes a hot-walled reactor operated under moderate vacuum in the range of 0.5-10 Torr. The organic and metal-halide precursors are heated and then transported by a nitrogen carrier gas to a cooled substrate where they condense and react to form a perovskite film. Our system design enables different source temperatures and carrier gas flow rates for the individual precursors, allowing for simultaneous deposition of both precursors and control over precursor ratio in the final perovskite film. This talk will discuss methods to control perovskite film morphology and phase purity by engineering VTD operating parameters including the carrier gas flow rate, chamber pressure, and substrate temperature. The impact of VTD processing conditions and film composition on solar cell performance will be described, with emphasis on tuning film composition via the substrate temperature and the precursor carrier gas flow rate ratio to optimize efficiency.