High light absorption properties and optical structures in butterfly Heliophorus ila Lvcaenidae wing scales

Abstract

When the sunlight irradiates the surface of butterfly wings, it can be absorbed by the microstructures in the wings scales and converted into heat to maintain the butterfly’s metabolism. This phenomenon is an inspiration which is facilitating the scientific research in solar energy utilization. In this study, the absorption characteristics of seven species of butterfly were investigated using a spectrometer. It was found that the butterfly Heliophorus ila Lvcaenidae showed more efficient absorption capability (absorptivity was about at 85%) compared with other species in the wavelength range from 230 nm to 850 nm. Then, the morphology and structures of the butterfly Heliophorus ila Lvcaenidae wing scales were examined by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The results showed that there were two kinds of scales distributed on the wing surface of the butterfly Heliophorus ila Lvcaenidae. Finally, the optical mechanisms were revealed by theories of multiple reflection and resonance. It was confirmed that the hierarchical hollow nano-architectures of the scales were responsible for the high-efficiency absorption behaviour. This study could be used as a theoretical reference for subsequent bionic design of structural materials for solar energy utilization.