Research Progress of Cholesteric Liquid Crystals with Broadband Reflection

Abstract

Cholesteric liquid crystal (ChLC) materials with broadband reflection are witnessing a significant surge in interest due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship. Nowadays, by the virtue of building self-organized nanostructures with pitch gradient or non-uniform pitch distribution, extensive work has already been performed to obtain ChLC films with a broad reflection band. This critical review systematically summarizes the optical background of the ChLCs with broadband reflection characteristics, methods to obtain broadband reflection of ChLCs, as well as the application in this area. Combined with the research status and the advantages in the field, the challenges and opportunities of applied scientific problems in the research direction are also introduced.

Temperature-Responsive Structurally Colored Fibers via Blend Electrospinning

“…The reflectance peaks decreased in intensity and broadened as the fiber mats cooled. Broadening of the reflection peak has been attributed to nonuniform pitch distribution of the LCs within multilayer polymer/LC system . Nonuniform pitch distribution may be attributed to variations in fiber size as well as slight temperature gradients within the sample between the solid surface and the surface exposed to ambient conditions.…”

“…Broadening of the reflection peak has been attributed to nonuniform pitch distribution of the LCs within multilayer polymer/LC system. 73 Nonuniform pitch distribution may be attributed to variations in fiber size as well as slight temperature gradients within the sample between the solid surface and the surface exposed to ambient conditions. The decreases in intensity are consistent with the observed decreases in brightness as the sample transitioned from blue to red.…”

Recent Advances in Electro-Optic Response of Polymer-Stabilized Cholesteric Liquid Crystals

“…Bandwidth broadening in PSCLCs has been an intensive research topic over the last decade from both an academic and practical application perspective. While a number of approaches exist to induce bandwidth broadening, electrically induced responses in PSCLCs are of great interest [ 42 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. PSCLCs employed for such studies are typically comprised of CLCs with negative Δε and an anisotropic polymer network with a strong alignment effect on the LC [ 58 , 61 ].…”

“…In these systems, focal conic domains, which readily scatter light, form. However, polymer stabilization of these systems has largely corrected this issue regarding the complex geometry of the electrodes and the scattering of the focal conic texture [ 40 , 44 , 54 , 60 ]. Another downside to interdigitated electrodes is the need for large electric fields to induce the color tuning of the CLC.…”

Recent advances in solar infrared light regulating smart windows based on organic materials

“…Again, this review focuses on systems with the active materials being organics, generally avoiding papers in which the active elements are primarily inorganic, differentiating this work from other reviews on NIR control elements. [13][14][15][16][17][18][19][20] Organics provide several potential advantages over using inorganic materials, including organics do not interfere with, among others, radio signals, GPS, or cell phones, [21] nor do they corrode. In addition, processing of organic materials often requires lower temperatures and simpler processes than inorganic materials.…”