Aging and characterization of high-bandgap perovskites for all thin-film tandem solar cell devices

Perovskite solar cells are ideal candidates for tandem solar cell technologies thanks to their bandgap tunability and high efficiency, but their stability needs to be improved for commercial applications. The operational stability of encapsulated PSCs with wide bandgaps suitable for regular and bifacial tandems was tested with 1-sun illumination and at different temperatures. For all temperatures, the decay in performance is due to a drop in current at MPP conditions, and XRD shows perovskite decomposition. Interestingly, open-circuit-voltage-decay measurements reveal a higher ion concentration for the degraded device, which correlates with the drop in current.