Multicolored\nBifacial Perovskite Solar Cells through\nTop Electrode Engineering

Power generation and architectural\nbeauty are equally important\nfor designing efficient and esthetically appealing bifacial perovskite\nsolar cells (PSCs). In this work, efficient and multicolored p-i-n-structured\nPSCs are achieved by taking advantage of a dielectric/metal/dielectric\n(DMD)-type (MoO<sub>3</sub>/Ni/Ag/MoO<sub>3</sub>) transparent counter\nelectrode. The MoO<sub>3</sub>/Ni underlayer effectively promotes\nthe formation of a continuous and conductive ultrathin Ag transparent\nfilm, especially the 1 nm Ni seed layer adjusts the interface energy\nlevel between perovskite/MoO<sub>3</sub> and Ag, resulting in Ohmic\ncontact of the electrode to promote charge extraction and collection.\nThe upper MoO<sub>3</sub> layer with varied thicknesses realizes a\nspectrally selective antireflection coating, enhancing the rear-side\nefficiency and forming vivid rear-side colors by optical tuning. As\na result, colorful bifacial perovskite solar cells with 20.6% front-side\nefficiency and 57.6–74.4% bifacial factor are obtained together\nwith colorful rear-side appearance. The bifacial PSCs exhibit good\nstability by protection from the upper MoO<sub>3</sub> layer. This\nwork highlights an effective electric and optic design of the top\nelectrode for artistic bifacial PSCs.