Rapid microwave-annealing process of hybrid perovskites to eliminate miscellaneous phase for high performance photovoltaics

Rapid processing technologies of perovskite solar cells (PSCs) offer an exciting approach to raise the rate of production. Herein, a rapid microwave-annealing process (MAP) is reported to replace the traditional hotplate annealing process (HAP) and the processing period of perovskite is reduced to less than 1 min. Benefiting from the penetrability and simultaneity of microwave irradiation, the MAP method can effectively eliminate miscellaneous phases and thus achieve >1 µm large-size crystal grains in perovskite films. These MAP treated perovskite films exhibit pure crystalline phase, long charge-carrier lifetime, and low defect density, which can substantially improve the PSC efficiency without requiring an additional enhancer/passivation layer. The inverted planar PSCs present enhanced power conversion efficiency from 18.33% (HAP) to 21.59% (MAP) and good stability of >1000 h lifetime without encapsulation under ambient conditions. In addition, MAP can be applied to a large-size (10 cm × 10 cm) perovskite film fabrication as well as a broader tolerance in environmental temperature and precursor concentration, making it a reliable method for repeatably practical fabrication of perovskite photovoltaics.