Encapsulation of Perovskite Solar Cells for High Humidity Conditions

We examined different encapsulation strategies for perovskite solar cells by testing the device stability under continuous illumination, elevated temperature (85 degrees C) and ambient humidity of 65%. The effects of the use of different epoxies, protective layers and the presence of desiccant were investigated. The best stability (retention of approximate to 80% of initial efficiency on average after 48h) was obtained for devices protected by a SiO2 film and encapsulated with a UV-curable epoxy including a desiccant sheet. However, the stability of ZnO-based cells encapsulated by the same method was found to be inferior to that of TiO2-based cells. Finally, outdoor performance tests were performed for TiO2-based cells (30-90% ambient humidity). All the stability tests were performed following the established international summit on organic photovoltaic stability (ISOS) protocols for organic solar cell testing (ISOS-L2 and ISOS-O1).