Highly Efficient Bifacial Color‐Tunable Perovskite Solar Cells

Abstract Solar cells with a visually aesthetic functionality are of great importance for their smooth integration with indoor and outdoor spaces in buildings and automobiles, and portable electronic devices. Here bidirectional, colorful perovskite solar cells with high efficiency based on optical interference effects within the multilayer solar cell structure are presented. Tunable reflective colors across the whole visible region can be achieved by simply tuning the thickness of a transparent electrode of the solar cell. Same or different colors from top‐ and bottom‐sides can be easily attained by properly selecting the thickness of the transparent electrode. Absorbing a substantial fraction of the visible region of solar radiation allows the colored perovskite solar cells to accomplish high power conversion efficiencies of 16.01% and 17.68% when illuminated from the top‐ and bottom‐sides, respectively, while the reflective colors are produced by using a small proportion of the visible solar spectrum. The described scheme opens a variety of potential applications, such as power‐generating surfaces for buildings and automobiles, energy‐efficient display systems, and self‐powered wearable electronics.