Colorful Diamond‐Like Carbon Films from Different Micro/Nanostructures

Abstract The coloration is one kind of interesting and important properties of diamond‐like carbon (DLC) films, but lack of in‐depth study. The micro/nanostructure composition of material determines its macroscopic properties. Here, the Commission Internationale de I'Eclairage (CIE) color space, quantitative micro/nanostructure composition analysis, and ab initio molecular‐dynamics simulations are used to quantitatively analyze the generation mechanism for coloration of DLC films. It is found that as a typical amorphous thin film, the generation of DLC film coloration can be explained by the thin film interference and amorphous photonic crystal structural color theory, but the generation mechanisms of coloration for different types of DLC films are not the same. The micro/nanostructure in terms of hydrogen content and carbon atom state plays vital roles in the generation of DLC film structural colors and even determines whether the noniridescent structure color exists or not. These results demonstrate the possibility of utilizing the human eyes to directly distinguish different types of DLC films and accelerate the application of DLC film in energy saving, optical filter, sensor, color gradient coating, advanced luxury products, and bionics fields.