Reflective Full‐Color Structural Colors with High Brightness and High Purity Based on Ge₂Sb₂Se₄Te₁ Chalcogenide Film

Abstract This study proposes a general strategy for constructing an asymmetric Fabry–Perot structure based on an ultra‐thin composite absorber, Ni/Ge₂Sb₂Se₄Te₁, to produce reflective full‐color structural colors with high brightness and purity. The composite absorber effectively enhances the strong interference effect of thin film, which can significantly reduce the reflection bandwidth of the target band and the reflectivity of the non‐target band. Under the premise of optimizing the five‐layer base structure, full‐color structural colors can be tuned by only changing the thickness of the LaTiO₃ layer. Using the ion‐assisted electron beam evaporation technique, a simple and efficient film deposition process, six color devices (namely red, orange, yellow, green, blue, and purple) are successfully prepared with reflection peaks exceeding 90%. The chromaticity coordinates of the proposed high‐purity red, green, and blue (RGB) samples are (0.554, 0.339), (0.280, 0.600), and (0.164, 0.075), respectively. These coordinates are fairly close to the standard RGB color coordinates used in liquid crystal displays. This device has a simple structure with a novel material combination and a low production cost, which makes it feasible for mass production using just one coating run process. It has excellent application potential in various fields such as micro‐nano displays, anti‐counterfeiting measures, reflective color filters, and decorations.