Reduced ultraviolet light induced degradation and enhanced light harvesting using YVO4:Eu3+ down-shifting nano-phosphor layer in organometal halide perovskite solar cells

We report a simple method to mitigate ultra-violet (UV) degradation in TiO2 based perovskite solar cells (PSC) using a transparent luminescent down-shifting (DS) YVO4:Eu3+ nano-phosphor layer. The PSC coated with DS phosphor showed an improvement in stability under prolonged illumination retaining more than 50% of its initial efficiency, whereas PSC without the phosphor layer degraded to ∼35% of its initial value. The phosphor layer also provided ∼8.5% enhancement in photocurrent due to DS of incident UV photons into additional red photons. YVO4:Eu3+ layer thus served a bi-functional role in PSC by reducing photo-degradation as well as enhancing energy conversion efficiency.