Tuning the Reflection Band of Ordered Nanocomposites using Direct Laser Writing

Abstract

Hierarchical ordered materials are common in Nature, where materials are organised in specific architectures across multiple scales, for enhanced properties and function-led design. Herein we demonstrate multi-tiered organisation of silica nanoparticles (NPs), by employing direct laser writing (DLW) of highly-ordered silica nanocomposites. The hierarchical arrangement is optimised for wide-gamut reflected colour across the visible range of the spectrum by controlling NP size, NP type (core-shell and core-only), NP volume threshold, and DLW fabrication parameters. The obtained microstructures were characterised using SEM, demonstrating retained ordered of non-close packed NPs, and reproducible high-resolution fabrication with sub-micron features. We use microspectroscopy to quantify the effect of microfabrication parameters on structural colour, which is supported by FIB-SEM analysis. We use a design-led approach to fabricate 3-dimensional multi-coloured images at the micro-scale. Exploiting the adaptability of the Stober process, we further synthesised and fabricated plasmonic core-shell NP nanocomposites.