Tunable antireflective characteristics enabled by small yellow leafhopper-inspired soccer ball-shaped structure arrays

Nowadays, tunable antireflective characteristics have attracted considerable attention due to growing demands in next-generation optical energy-related fields. Bioinspired by the distinctive structural geometry on small yellow leafhopper wings, this study reports reversibly switchable antireflective characteristics enabled by ambient-temperature shape memory polymer-based soccer ball-shaped structure arrays with multilayer porous structures underneath. The resulting structures behave a broadband omnidirectional antireflection performance, where the average reflectance in the visible spectrum can even be reduced by 22% for an incident angle of 75º. Interestingly, the structures can be instantaneously deformed or recovered through applying external stimuli in ambient environments. The antireflective property switches associated with the shape memory transitions deliver vast opportunities in developing smart optical devices. Moreover, the structure-shape effect and reversibility on the antireflective properties are systematically assessed in the research.