Development of Nanoparticle Color Inks Enabled by Mie Resonance

Abstract

Typical pigments are composed of organic dyes that absorb a certain region of the visible light spectrum. Because excited organic dyes are not chemically stable, their colors fade over time under exposure to light. Structural color generated by optical interactions of light with nano- and micro-structures have attracted considerable research and industrial attention because the color never diminishes as long as the structure is preserved. Color pixels with highly saturated scattering colors have been produced by nanostructures, and high-resolution color printing has been achieved by using these color pixels. However, the printing is limited to a very small area (<1mm²) owing to the restriction of the nanofabrication processes. In this work, we develop a high-quality color ink composed of crystalline silicon (Si) nanoparticles for the structural coloration of an arbitrary substrate. By reducing the size distribution of colloidal Si nanoparticles, we succeeded in coloring solutions of Si nanoparticles in the blue-to-orange range. We demonstrate the structural coloration of a flexible substrate by Si nanoparticle color inks.

Graphical Abstract

(a) Schematic of Si nanoparticle -PVP composite film. (b–e) Reflectance spectra of Si nanoparticle ink and films. (f, g) Photos of Si nanoparticle-PVP composite film on PET substrate. Reprinted with permission from Ref. (Sugimoto et al., 2020) under the terms of the CC-BY 4.0 license. Copyright: (2020) The Authors, published by Willey-VCH.