Ultra-antireflective synthetic brochosomes.

Abstract

Since the early discovery of the antireflection properties of insect compound eyes, new examples of natural antireflective coatings have been rare. Here, we report the fabrication and optical characterization of a biologically inspired antireflective surface that emulates the intricate surface architectures of leafhopper-produced brochosomes-soccer ball-like microscale granules with nanoscale indentations. Our method utilizes double-layer colloidal crystal templates in conjunction with site-specific electrochemical growth to create these structures, and is compatible with various materials including metals, metal oxides, and conductive polymers. These brochosome coatings (BCs) can be designed to exhibit strong omnidirectional antireflective performance of wavelengths from 250 to 2000 nm, comparable to the state-of-the-art antireflective coatings. Our results provide evidence for the use of brochosomes as a camouflage coating against predators of leafhoppers or their eggs. The discovery of the antireflective function of BCs may find applications in solar energy harvesting, imaging, and sensing devices.