A promising europium-based down conversion material: organic-inorganic perovskite solar cells with high photovoltaic performance and UV-light stability

Metal halide perovskite solar cells (PSCs) have been studied over the past few years and high power conversion efficiency (PCE) has been achieved. However, the adverse instability remains a key factor restricting wider application of PSCs. Herein, we report, for the first time, a viable strategy to incorporate a down conversion nanophosphor Sr2CeO4:Eu3+ (SCOE) into PSCs, and more importantly SCOE enables the PSCs with improvement in photovoltaic performance and UV-light stability. The SCOE-coated PSCs achieve a high current density of 23.70 mA cm(-2) and a high PCE of 18.95%, which are increased by 9% and 14.15%, respectively, when compared to those of control devices (without an SCOE layer). Moreover, the SCOE-based PSCs retain 80% of their initial PCE value after 70 hours under UV-light irradiation and retain 78% of their initial PCE value after 75 days under ambient environment with 20-25% relative humidity. These results suggest that the incorporated SCOE down conversion material is a functional component of PSCs which broadens the solar spectral response, improving photovoltaic performance, and reduces UV-light-induced photodegradation by converting UV light to visible light, prolonging the device stability.