Transient Structural Colors with Magnesium‐Based Reflective Filters (Advanced Optical Materials 13/2022)

Marina S. Leite and co‐workers (article number 2200159) demonstrate thin‐film‐based color filters using Mg and MgO, both biodegradable materials. The devices exhibit vivid hues spanning a broad gamut, besides angle‐insensitive chromaticity up to 40 degrees. A transient color response is attained by etching the Mg‐containing layers with water, which reveals the hue of a bottom Fabry–Pérot cavity structure. This approach enables pixels with irreversible color change as well as zero‐power consumption and low cost, while making use of non‐toxic materials.