Development of structural colored TiO₂ thin films by varied etching solutions

Abstract

Currently, one of the most important problems is water scarcity due to increasing population and environmental factors. Humankind can do overcome this problem by recycling polluted water. The structural colors obtained from photonic crystal structures draw the attention with fadeless bright color, combined with low toxicity and eco-friendliness. In this study, different etching/anodizing processes were applied to obtain Fabry-Perot and Photonic Crystal Ti-TiO2 structures. Structural colors owing to the morphology of the anatase phase on the surface of the samples etched with hydrochloric, sulfuric, and hydrofluoric acid-based solutions were obtained. The structural color of the formation on the titanium surfaces is related to the Fabry-Perot structures, while variations were correlated with Photonic Crystal surface morphologies. Because of the high reflectance values contributed to the structural color formation, the photocatalytic efficiency of the samples etched with acid-based solutions was found to be lower than the samples etched with basic sodium and potassium hydroxide and solutions. High-efficiency structural color reactors can be obtained by shifting the reflected wavelength range from the absorption wavelength range of the pollution material.