When Chirophotonic Film Meets Wrinkles: Viewing Angle Independent Corrugated Photonic Crystal Paper

Abstract

Light manipulation strategies of nature have fascinated humans for centuries. In particular, structural colors are of considerable interest due to their ability to control the interaction between light and matter. Here, wrinkled photonic crystal papers (PCPs) are fabricated to demonstrate the consistent reflection of colors regardless of viewing angles. The nanoscale molecular self‐assembly of a cholesteric liquid crystal (CLC) with a microscale corrugated surface is combined. Fully polymerizable CLC paints are uniaxially coated onto a wrinkled interpenetrating polymer network (IPN) substrate. Photopolymerization of the helicoidal nanostructures results in a flexible and free‐standing PCP. The facile method of fabricating the wrinkled PCPs provides a scalable route for the development of novel chirophotonic materials with precisely controlled helical pitch and curvature dimensions. The reflection notch position of the flat PCP shifts to a lower wavelength when the viewing angle increased, while the selective reflection wavelength of wrinkled PCP is remained consistent regardless of viewing angles. The optical reflection of the 1D stripe‐wrinkled PCP is dependent on the wrinkle direction. PCPs with different corrugated directions can be patterned to reduce the angular‐dependent optical reflection of wrinkles. Furthermore, 2D wavy‐wrinkled PCP is successfully developed that exhibit directionally independent reflection of color.

Colorful Electrochromic Displays with High Visual Quality Based on Porous Metamaterials

“…To further visualize all the colors of our porous nylon-66-film-based EC device and conventional EC device for all viewing angles in a single image, we projected the reflected light of different EC devices onto a translucent hemispherical screen made of a white ping-pong ball (Figure 3d) when illuminated with a collimated white light source passing through a 4 mm circular aperture at an incident angle of 45°. [24,25] Obviously, our nylon-66-film-based EC device presents an almost uniform green appearance across the entire hemispherical screen (Figure 3e), while only a green dot the same size as the incident light spot is observed for an EC device with a traditional structure (Figure 3f), which is in good agreement with our spectral results. Consequently, the colors of our devices can be viewed at any angle in the space above them in a directionally illuminated environment with virtually no color deviation.…”

Resonant‐Cavity‐Enhanced Electrochromic Materials and Devices

“…The angular insensitivity of the devices can be improved by resorting to wrinkled or disordered structures. [184,[279][280][281] 4) Some organic electrochromic materials have exhibited ultrafast response speeds of up to video refresh rates (25-50 Hz) because of optical resonator enhancement. However, they tend to degrade easily during cyclic uses or under outdoor operating conditions.…”

Stimuli-Responsive Materials from Liquid Crystals

“…In the production of programmable LCPs, the use of grafting technologies, such as photopatterning and 3D printing, is widely employed. , This approach has significant implications for the development of advanced artificial organs, such as high-power human muscles . Notably, LCPs possess the ability to split along cracks or adjust their folding direction based on the initial orientation of the LC. ,, This distinctive characteristic allows for precise control and customization of the LCP structure, thereby opening up new possibilities for tailored applications such as wrinkle structures. , …”