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

Abstract

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.