This study explores advancements in organic-inorganic lead-free perovskite materials, focusing on the film formation process during deposition by thermal evaporation for lead- and tin-based perovskites. It involves growth analysis, solar cell component preparation, and the analysis of optoelectronic properties. Key aspects include in situ X-ray diffraction for observing phase changes during growth, analysis of perovskite degradation, and development of multi-stage all-vacuum growth processes for multi-component perovskite thin films. State-of-the-art Pb-based perovskites and potential Sn-based compounds will be examined. We conduct sequential deposition/reaction processes under controlled temperature and flux variations in order to estimate reaction constants, diffusion constants, sticking coefficients, and activation energies. In situ X-ray diffraction in real-time will be the primary experimental method, providing insights into phase formation during thin film growth. A sandwich-like material structure design (e.g., PbI₂-CsI-SnI₂) will be used to analyze the perovskite's growth mechanism and diffusion model as well. Further exploration involves understanding how IA-group cations like Cs achieve thermodynamic and kinetic balance in PbI₂ and SnI₂, facilitating the formation of stable and high-quality perovskite layers. There are three possible film growth mechanisms: (a) Precursor vapor reaction: Solid-state precursor films react from the vapor phase to form the perovskite film. (b) Diffusion couple reaction: Two or more solid-state precursor films react via chemical diffusion. (c) Exchange reaction: Another component fully or partly exchanges one component (anion or cation) during annealing processes (e.g., MAPbI₃ to MAPbBr₃ exchange reaction). This study aims for solvent-free, controllable film deposition, utilizing sequential evaporation for better reproducibility. Different film growth mechanisms will be investigated, including precursor vapor reaction, diffusion couple reaction, and exchange reaction. Both Pb-based perovskites and Sn-based compounds are investigated, with a focus on reaction kinetics and diffusion. The ultimate goal is to advance toward the production of large-area, high-efficiency solar cells through physical processes, including the completion of various layers within a vacuum chamber, paving the way for stable and high-performance commercial applications in solar energy technology.

Halide Perovskites, Physical Vapor Deposition, In Situ X-Ray Diffraction, Co-evaporation, Diffusion Model, Precursor Vapor Reaction, Exchange Reaction, Perovskite Solar Cells