Recent Progress on Angle-Independent Responsive Photonic Crystals

Structural colors arising from physical interaction of incident light with periodic micro- or nanostructures are well known as photonic crystals (PCs). PCs consisted of the periodic ordered structure are easy to produce vivid structural color but the color is angle-dependent. Recently, inspired by nature, the PCs that possess amorphous structures with short-range order have attracted increasing attention, because the structural color of such PCs with short-range ordered structure is invariable along with the viewing angle. By incorporating a stimulus-responsive material into the amorphous PCs system, angle-independent and responsive photonic composite can be readily constructed. The angle-independent responsive photonic materials can be very useful in the areas of sensors and optical coatings due to their advantages of wide visibility, non-iridescent structural color, and light location. In this review, we will briefly introduce the discovery and structural characteristics of the angle-independent PCs, and the artificial fabrication of the angle-independent responsive PCs and their applications are then discussed.