Learning curves from long-term outdoor testing and indoor optoelectronic characterization of perovskite mini-modules

Abstract

Improving the performance of perovskite devices is key to increasing their competitiveness against conventional sources of energy. Several perovskite and perovskite on Silicon tandems were extensively investigated both outdoors at real environmental conditions and indoors using a range of advanced optoelectronic methods (Spatially-Resolved Electroluminescence/Photoluminescence, Lock-In-Thermography, Light-Beam Induced Current, Raman and Ultrafast spectroscopy, etc.) to set-up a complete optical and electrical characterization of perovskite devices. The devices demonstrated the impact of irradiance and temperature on their major electrical parameters during outdoor testing conducted over several months in the field. Significant discrepancies on degradation rate were obtained for same perovskite architectures demonstrating the impact of material quality on long-term performance of perovskites. Exponential degradation of performance was obtained in the majority of samples under test during the first hours of light application. Performance recovery overnight and diurnal performance degradation of several perovskite samples were calculated for each day in the field demonstrating the dominant values for diurnal degradation and recovery for each perovskite structure and at different degradation stages. Seasonal dependence of the overall performance degradation is discussed and the diurnal performance degradation-to-recovery ratio is analysed.

Spatially-resolved Electroluminescence and Lock-In-Thermography methods demonstrated hotspot and shunts evolution in perovskite mini-modules after outdoor exposure. Raman spectroscopy measurements revealed the differences in chemical properties of perovskite mini- modules after outdoor exposure while Ultrafast spectroscopy demonstrated the carrier relaxation processes in the devices which are correlated with diurnal performance degradation and recovery processes.