In nature, in order to prevent attention from predators, the eyes of night-flying moths have evolutionarily developed an antireflective ability. The surfaces of their eyes are covered with a layer of a sub-wavelength structure that eliminates reflections of visible light. This layer allows the eyes of moths to escape detection in darkness, without reflections that could reveal the position of the moths to potential predators. In this study, we proposed a novel procedure for manufacturing a non-close-packed polystyrene (PS) nanosphere monolayer by combining the Langmuir-Blodgett (LB) deposition technique and oxygen plasma treatment. An antireflective structure was replicated from the sub-wavelength structure of moth eyes onto the surface of a glass substrate by nano-imprinting lithography; the structure also displayed hydrophobic properties. The Fresnel reflection of the replicated sub-wavelength structure is near the theoretical prediction from the effective medium theory model. The biomimetic moth-eye structure can be applied to solar cells, monitors, light-emitting diodes, and other optical devices in the future.

No abstract

Articles you may be interested inImprovement of zirconium-doped hafnium oxide high-k dielectric properties by adding molybdenum

Polystyrene (PS) opal and titania (TiO 2 ) inverse opal films were fabricated by the self-assembly colloidal crystal template technique. Based on Bragg's law, these sensors were used to detect the different concentrations of ethanol solution. The results indicated that TiO 2 inverse opal films were advantageous over PS opal film for detecting the ethanol concentration. TiO 2 inverse opal films sintered at 600˝C retained the highest sensitivity for ethanol concentration identification, since the anatase phase was transformed into the rutile phase, which resulted in an enhancement of the refractive index, i.e., an increase in the amount of the red shift.