Open-Air Plasma-Deposited Multilayer Thin Film Moisture Barriers for Perovskite Solar Cells

A scalable, open-air plasma process has been developed to deposit alternating layers of conformal organosilicate and dense SiO
₂
thin film barriers to prevent moisture ingress. The in-situ low temperature process is suitable for direct deposition on thermally sensitive perovskite devices and is compatible with flexible polymeric substrates. When deposited directly on perovskite solar cells, they retain over 80% of their initial performance for over 660 hours in a 50°C 50%RH accelerated aging environment. Using optical calcium testing, low water vapor transmission rates (WVTR) on the order of 10
^-3
g/m
²
/day at an accelerated aging condition of 38°C and 90% relative humidity (RH) are achieved. The ability of the multilayer barrier to enable device resistance to humid environments is crucial towards realizing longer operating lifetimes.