Simulation of Vapor Transport Deposition for Metal-Halide Perovskite Thin Films*

Metal-halide perovskites (MHPs) are among the most promising semiconductors currently being investigated for high efficiency, low-cost optoelectronics and photovoltaics. Although solution-processing techniques are mostly used to fabricate MHP thin films, vapor-based deposition processes permit additional material tunability via high level control over film composition and grain morphology. In this work, perovskite precursors are deposited by vapor transport deposition (VTD) and COMSOL Multiphysics® is used to investigate the material transport and thin film deposition. The simulation results offer insight into the fluid dynamics and mass transfer within the system through the analysis of adjustable processing parameters including carrier gas flow rate, dilution gas flow rate, source material sublimation temperature and chamber pressure. We further predict that VTD can realize a 5 to 10 times increase in deposition rate with changes in chamber pressure and dilution gas flow rate. In addition, dilution gas flow rate is found to play a significant role in film uniformity. With this understanding, VTD is used to fabricate perovskite solar cells device with power conversion efficiencies >10%.