Printing of Highly Vivid Structural Colors on Metal Substrates with a Metal-Dielectric Double Layer

Abstract

The aesthetic functions of metals have attracted increasing attention, and their colorization is of scientific and technological significance. This study demonstrates that vivid structural colors can be produced on stainless steel and Al, which are two of the most commonly used metals. It is well known that a transparent dielectric film coated onto a substrate exhibits a rippled spectrum consisting of alternating reflectance minima and maxima due to multibeam interference, making it appear colored. However, such a film does not produce strong colors on a highly reflective metallic substrate, because the resulting interference ripple has small amplitudes. Herein, very vivid colors are generated by coating a thin metal layer over a dielectric film, where the metal layer adjusts the amount of light incident into the dielectric and strengthens the interference effect. The hue and saturation of the produced colors are controllable by changing the thicknesses of the dielectric and metallic layers. Additionally, color images are printed by locally controlling the layer thicknesses. This method has potential for various applications ranging from surface decoration and visual arts to optical filters and perfect absorbers.