A low-cost, high-efficiency light absorption structure inspired by the Papilio ulysses butterfly

The nano-hole array structure in the black scales of the butterfly can be viewed as a natural solar collector. A low-cost, high-efficiency light absorption structure, inspired by the Papilio ulysses butterfly, was optimized using a finite-difference time-domain method. The results show that the nano-hole structure of Papilio ulysses contributes to light absorption. The shape of the holes affects the angular dependence of absorption. The absorption efficiency was found to be strongly affected by three parameters: H (the depth of the hole), D (the thickness of the hole-wall) and L (the size of the hole). These parameters were swept together in numerous simulations. The optimized nano-hole array saves 84% more material than a thin film of equal absorption (90%) at a wavelength of 600 nm.