Rapid Microwave Annealing of Perovskites: Effects on Device and Material Stability in High Humidity

ABSTRACT Moisture‐induced degradation remains a significant obstacle to the industrial use of perovskite solar cells. This study systematically investigates and compares the stability and degradation mechanisms of MAPbI 3 perovskite films processed via traditional hot‐plate annealing (HAF) and rapid microwave annealing (MAF) under high humidity. Morphological analyses show that microwave‐annealed films have notably larger grain sizes (~848 nm) compared to those from hot‐plate annealing (~247 nm). The larger grains and fewer grain boundaries in microwave‐annealed films help reduce moisture infiltration, thus delaying degradation. X‐ray diffraction analyses confirm that the formation of harmful PbI 2 and hydrated phases is slowed in microwave‐annealed samples. Optical characterizations consistently demonstrate greater moisture resistance in microwave‐annealed films, with less optical bleaching, fewer trap states, and better retention of carrier lifetime under high humidity. Performance tests show rapid efficiency losses in devices, with only 30% of the initial power conversion efficiency preserved in hot‐plate annealed devices after 6 h at over 85% relative humidity. In contrast, microwave‐annealed devices retain over 60% of their initial efficiency under the same conditions. This difference mainly results from significant reductions in photocurrent and open‐circuit voltage. Long‐term tests in low humidity environments further demonstrate the superior stability of microwave‐annealed devices, highlighting their potential for practical solar cell applications. This research presents microwave annealing as a promising technique to enhance the stability of perovskite devices and facilitate their commercial deployment. image