High‐Efficiency Structural Coloration Enabled by Defect‐Free Block Copolymer Self‐Assembly for a Solar Cell Distributed Bragg Reflector

Abstract Solar cell coloration with minimum optical loss is increasingly required for building‐integrated photovoltaics (BIPV) in modern urban areas because of its importance harmonizing the exterior zero‐energy buildings and surroundings. A simple strategy developing a distributed Bragg reflector (DBR) designated 1D lamella‐forming polystyrene‐ b ‐poly(2‐vinylpyridine) (PS‐ ‐P2VP) films. An optimized thermal annealing process produces defect‐free lamellar microdomains oriented parallel to substrate throughout film. The selective crosslinking P2VP block swelling these films methanol solution methanesulfonic acid facilitate formation highly asymmetric gigantic lamellae, enabling entire visible‐wavelength spectrum DBR structural colors. Three representative red (R), green (G), blue (B) are produced on Si solar cell. Coloration from high‐reflectance narrow‐width results vividly colored cells minor or negligible reduction power conversion efficiency. approach photovoltaics, terms both attractive esthetic technical aspects BIPV application, offers viable method fabricating high‐performance based copolymer self‐assembly.