Low-vacuum proximity-space effusion for high-rate controlled MAPbI3 growth

We tailor the Low-Vacuum Proximity-Space Effusion (LV-PSE) method for high-rate, sequential two-step evaporation of MAPbI3 perovskite films. By combining ordered PbI2 growth with enhanced MAI intercalation, LV-PSE achieves a MAPbI3 growth rate of 23 nm/min, surpassing co-deposition benchmarks, while providing better control over each precursor deposition. A short source–substrate distance (2 cm) increases local vapor flux on the substrate and enables pressure (0.8–4 × 10−2 mbar) and temperature (15–100 °C) to control the rate for producing high-quality MAPbI3 films (100–520 nm) with broad applicability. Continuous, dynamic intercalation, inherent to the LV-PSE working scheme, helps overcome thickness limitations. Using molecular dynamics with machine-learned interatomic potentials, we observe early PbI2 lattice disaggregation during MAI intercalation (nanosecond scale) before crystallization. A proof of concept for the integration of the MAPbI3 film into a p–i–n device architecture on ITO/PTAA, using evaporated C60/BCP/Ag as the top electrode, has been provided. Compared with high-vacuum PVD, LV-PSE reduces system complexity, minimizes material use and waste, and lowers maintenance needs. The study of process–material relationships offers key insights into perovskite formation mechanisms, provides an application-oriented parameterization for perovskite fabrication using advanced sublimation–evaporation tools, and can foster further technological development.