Novel nano-structured phosphor materials cast from natural Morpho butterfly scales

Abstract

The fabrication of the first nano-structured phosphor materials, cast from scales of the Morpho pleides butterfly, are reported. The structures are obtained by infilling sections of the butterfly wings with precursor phosphor solutions, then drying the samples at 100°C, followed by firing/annealing at 700°C for 30min. During the firing of the resulting solids the natural template is sacrificed and burns off, leaving a cast of the butterfly structure that is composed of the resulting phosphor material. Two different phosphor precursor solutions were used, either the precursor water-based solution for the red Y₂O₃:Eu³⁺ phosphor or europium-doped titanium ethoxide solution, which is the precursor for the TiO₂:Eu³⁺ phosphor. In this work we have demonstrated that it is possible to reproduce fine detail in these casts, with structural features having ca. 100 nm dimensions being clearly visible. The casts of two distinct types of scale of the Morpho pleides butterfly were prepared in this work from phosphor materials. One distinct type of scale was rounded whereas the other was dentated, there being a clear difference in spacing between the longitudinal ridges for these two types. As yet, the casts manifest none of the photonic properties of the original butterfly scales. This is thought to be due to the precursor phosphor solutions not penetrating into the lamellar structures that are located between the cross-ribbing in the scales.