Highly stable CsFAPbIBr perovskite solar cells with dominant bulk recombination at real operating temperatures

Mixed-cation mixed-halide perovskite solar cells have been characterized in DC at different temperatures (from -20 degrees C up to 50 degrees C) and the time evolution of the device efficiency has been assessed using different degradation protocols (indoors and outdoors). The completely planar p-i-n structure is ITO/CuNiOx/PTAA/CsFAPbIBr/PCBM/PEI/Ag. Pristine current-voltage characteristics barely show hysteresis, at any temperature. Open circuit voltage decreases with temperature at a rate of -1.5 mV degrees C-1, and the obtained PCE temperature coefficient is lower than -0.001% K-1, which is an outstanding value for this emerging photovoltaic technology. Cells have been degraded under different protocols: indoors using different light/dark cycles and outdoors in a high temperature and high irradiation location. Cells show no significant decrease of the efficiency after more than 350 h of indoor light cycling and the estimated T-80 obtained for the sample degraded outdoors under high irradiation and high temperature conditions is similar to 15 days.