Multicolored Bifacial Perovskite Solar Cells through Top Electrode Engineering

Power generation and architectural beauty are equally important for designing efficient and esthetically appealing bifacial perovskite solar cells (PSCs). In this work, efficient and multicolored p-i-n-structured PSCs are achieved by taking advantage of a dielectric/metal/dielectric (DMD)-type (MoO₃/Ni/Ag/MoO₃) transparent counter electrode. The MoO₃/Ni underlayer effectively promotes the formation of a continuous and conductive ultrathin Ag transparent film, especially the 1 nm Ni seed layer adjusts the interface energy level between perovskite/MoO₃ and Ag, resulting in Ohmic contact of the electrode to promote charge extraction and collection. The upper MoO₃ layer with varied thicknesses realizes a spectrally selective antireflection coating, enhancing the rear-side efficiency and forming vivid rear-side colors by optical tuning. As a result, colorful bifacial perovskite solar cells with 20.6% front-side efficiency and 57.6-74.4% bifacial factor are obtained together with colorful rear-side appearance. The bifacial PSCs exhibit good stability by protection from the upper MoO₃ layer. This work highlights an effective electric and optic design of the top electrode for artistic bifacial PSCs.