An Ingenious Super Light Trapping Surface Templated from Butterfly Wing Scales

Abstract

Based on the super light trapping property of butterfly Trogonoptera brookiana wings, the SiO 2 replica of this bionic functional surface was successfully synthesized using a simple and highly effective synthesis method combining a sol–gel process and subsequent selective etching. Firstly, the reflectivity of butterfly wing scales was carefully examined. It was found that the whole reflectance spectroscopy of the butterfly wings showed a lower level (less than 10 %) in the visible spectrum. Thus, it was confirmed that the butterfly wings possessed a super light trapping effect. Afterwards, the morphologies and detailed architectures of the butterfly wing scales were carefully investigated using the ultra-depth three-dimensional (3D) microscope and field emission scanning electronic microscopy (FESEM). It was composed by the parallel ridges and quasi-honeycomb-like structure between them. Based on the biological properties and function above, an exact SiO 2 negative replica was fabricated through a synthesis method combining a sol–gel process and subsequent selective etching. At last, the comparative analysis of morphology feature size and the reflectance spectroscopy between the SiO 2 negative replica and the flat plate was conducted. It could be concluded that the SiO 2 negative replica inherited not only the original super light trapping architectures, but also the super light trapping characteristics of bio-template. This work may open up an avenue for the design and fabrication of super light trapping materials and encourage people to look for more super light trapping architectures in nature.