Aesthetic and efficient perovskite/Si tandem solar cells using luminescent down-shifting textured anti-reflection films

Perovskite-based tandem cells are emerging as new photovoltaic (PV) cells with a high efficiency that exceeds the efficiency limit of single-junction cells. Building-integrated PVs that require high efficiency are attractive, but aesthetics play key roles in these urban applications. One of the most challenging problems with respect to aesthetic PV cells is the efficiency loss due to color tuning. Here, we demonstrate for the first time lossless full-color tunable PV cells based on the use of textured luminescent down-shifting (LDS) films with LDS dyes with ultraviolet-selective absorption. The LDS anti-reflection (AR) films improve the perovskite/Si tandem cell efficiency by reducing the loss of parasitic UV absorption of the layers above the perovskite film due to LDS effect and the loss due to cell reflection due to the textured surface. Therefore, color tuning with LDS AR films can be used to produce highly aesthetic and efficient PV cells for urban applications.