Self-Assembled Biomimetic Antireflection Coatings

Antireflection coatings (ARCs) are widely utilized in reducing the unwanted reflection from flat-panel displays, car dashboards, optical components, and solar cells. Inspired by the microstructured cornea of some nocturnal moths, subwavelength-structured ARCs have been extensively explored. However, current lithography-based fabrication techniques in creating subwavelength features are costly and are limited by either low resolution or small sample size. Here we report several cheap and scalable bottom-up techniques for fabricating large-area moth-eye ARCs on transparent (e.g., glass and polymer) and semiconductor (e.g., Si, GaAs, and GaSb) substrates. All these techniques are based on a simple spin-coating technique that enables the creation of wafer-scale colloidal crystals with non-close-packed structures. The resulting ARCs exhibit superior broadband antireflection properties that are useful in developing high-efficiency solar cells and detectors. Two numerical methods – thin-film multilayer and rigorous coupled-wave analysis models have also been developed to simulate the specular reflection from the templated subwavelength structures.