Synthesis of monodisperse single-crystal Cu2O spheres and their application in generating structural colors

A two-step reductive strategy is developed to synthesize monodisperse single-crystal Cu₂O solid spheres at room-temperature. The single-crystal spheres with adjustable diameter were used as building blocks to form amorphous photonic structures by spray method, which exhibits vivid colors. This may open a new way to realize large area film with vivid structure color.