Recent Progress in Responsive Structural Color

Abstract

Structural color has been regarded as an ideal alternative to pigments because of the advantages of environmental friendliness, resistance to fading, and dynamic regulation. Responsive structural color can give real-time visible feedback to external stimuli and thus has great prospects in many applications, such as displays, sensing, anticounterfeiting, information storage, and healthcare monitoring. In this Perspective, we elucidate basic concepts, controllable fabrications, and promising applications of responsive structural colors. In particular, we systematically summarize the general regulation mode of all kinds of responsive structural color systems. First, we introduce the basic chromogenic structures as well as the regulation modes of responsive structural color. Second, we present the fabrication methods of patterned structural color. Then, the promising applications of responsive structural color systems are highlighted in detail. Finally, we present the existing challenges and future perspectives on responsive structural colors.

Emerging Planar Nanostructures Involving Both Local and Nonlocal Modes

“…In addition to applications based on manipulations of the intensity, phases, and polarization states of light, implements achieved by engineering the spectrum of artificial nanostructures will be subsequently discussed. One significant application of optical artificial nanostructures is structural colors because of their distinct advantages in resolution, color purity, and stability. , Historically proposed in photonic crystals that can reflect photons with energy and momentum residing in the band gaps, structural colors are flourishing in the research field of metasurfaces. − Based on the rich local and nonlocal modes, the spectrum in the visible band can be flexibly engineered. − However, the structural colors generated by simple plasmonic and dielectric nanostructures are generally limited by the relatively low color saturations. Recently, ultrahigh-saturation structural colors were theoretically proposed and experimentally demonstrated based on multilayer TiO 2 metasurfaces .…”

Responsive Structural Colors Derived from Geometrical Deformation of Synthetic Nanomaterials

“…The structure produces optical properties due to interference diffraction and scattering. [ 142 ] The material is the medium of association between the SCM and the stimulus. According to the working conditions of the target device, the SCM can be obtained by combining the designed micro‐/nanostructure with the selected materials.…”

Cholesteric Liquid Crystal Polymeric Coatings for Colorful Artificial Muscles and Motile Humidity Sensor Skin Integrated with Magnetic Composites

“…Most of the structural colors result from ordered microstructures, including scattering, thin‐film interference, gratings, metasurfaces, total internal reflection, and photonic crystals. [ 21–24 ] As a typical kind of photonic crystals, cholesteric liquid crystals consist of rod‐like liquid crystalline mesogens and periodically align in a helical manner. [ 25 ] Cholesterics reflect the light of certain wavelength following Bragg's Law: λ = npsinθ, where λ is the central wavelength of reflected light, n is the average refractive index of liquid crystals, p represents the pitch of cholesteric liquid crystals and θ is the incidence angle.…”