Encapsulation Techniques of Perovskite Solar Cells

Due to the rapid development of solar cells based on organic metal halide perovskite as light-absorber, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased from 3.8% to 25.5%, which exceeds that of silicon ones. In the meantime, the stability of the device has also made breakthrough progress. However, the degradation of perovskite is the primary reason which largely limits large-scale application. PSCs quickly chemically react with the water/oxygen in the air and decompose when exposed to ambient condition. It is urgently necessary to develop appropriate encapsulation techniques to isolate perovskite from external stimuli including moisture, oxygen and UV light to effectively extend lifetime. In this paper, the influences and physical mechanisms of the stability of perovskite are summarized. Then, the main encapsulation methods and technical approaches to improve and enhance the stability of perovskite are also reviewed, including traditional rigid-substrate-based encapsulation, thin film encapsulation, and advanced encapsulation strategies. Finally, it overviews the challenges and further development strategies faced by PSCs encapsulation techniques in practical applications.