Scalable, ultra-resistant structural colors based on network metamaterials

The feathers of the South American bird Cotinga maynana have inspired the design of a nanoscale material that exhibits brilliant colour. The colour originates from the material’s intricate structure rather than a pigment or dye. Andrea Fratalocchi of King Abdullah University of Science and Technology in Saudi Arabia and co-workers report that the material provides saturated colours in the visible region. Importantly, the colour can be observed over a very wide range of observation angles (up to 70 degrees) and persists even when the material’s surface is scratched. The nanomaterial consists of 300-nanometre-thick layers of dealloyed PtYAl metallic nanowires, which are sputtered onto SiNx/Si substrates and then coated with 60-nanometre layers of a dielectric coating of Al2O3. The resulting nanomaterial is robust, lightweight and suitable for large-area fabrication.