Fly compound-eye inspired inorganic nanostructures with extraordinary visible-light responses

Inorganic bio-inspired nanomaterials, which integrate the unique properties of metal oxide nanomaterials and the features of well-evolved biological structures and functions, are a novel direction towards mining the potential of existing materials to further enhance the performance of various microelectronic and energy harvesting, conversion, and storage devices, although the facile fabrication of bio-inspired materials still remains a major challenge. We noticed that some compound eyes presented extremely strong responses to light and displayed beautiful colours and patterns, which inspired us to design novel photonic materials. In this study, we fabricated fly compound-eye inspired ZnO nanomaterials in the forms of either isolated microspheres or highly-ordered coatings grown in-situ, in which the three-zone structures were similar to the anatomical structure of the biological compound eyes, including an outermost faceted microlens array, a middle rhabdom-like channel layer, and a central hollow zone. The bio-inspired nanomaterials, as we expected, presented extraordinary visible-light response behaviour and would make it possible to capture energy across a wide solar spectrum with a single semiconductor material. This study thus paves the way to further improving the performance of the current photoelectronic and energy harvesting, conversion, and storage devices.