Hermetic seal for perovskite solar cells: An improved plasma enhanced atomic layer deposition encapsulation

Unstable nature against moisture is one of the major issues of metallic halide perovskite solar cell application. Thin-film encapsulation is known as a powerful approach to notably enhance the operational stability of perovskite solar cells in humid environment. However, encapsulation layers with ideal gas barrier performance always require harsh fabrication conditions with high temperature and harmful precursors. For this reason, here we provide a mild encapsulation strategy to maintain the original performance of solar cell devices by utilization of ethylene glycol-induced immediate layer to minimize the damage of plasma-enhanced atomic layer deposition to perovskite solar cells. The organic-inorganic alternating encapsulation structure has exhibited a water vapor transmittance rate of 1.3 × 10⁻⁵ g m⁻²·day⁻¹, which is the lowest value among the reported thin film encapsulation layers of perovskite solar cells. Our perovskite solar cells have survived at 80% relative humidity and 30 °C for over 2000 h while preserving 96% of its initial performance.