Ta/NiO subwavelength bilayer for wide gamut, strong interference structural color

Abstract

In this paper we demonstrate that Ta/NiO bilayers may be use as high-efficiency, lithography free, reflective structural color filters for generating broad color gamut. Experimental results show that reflectance spectra present deep dips in the visible range, leading to strong structural colors that can be adjusted via the NiO subwavelength layer thickness. Simulation based on thin film interference theory allow to account for the experimental data. We demonstrate that the optical interference effect is still effective when the films are deposited on a flexible substrates such as paper and kapton, enabling to consider flexible color filtering applications.