Photo-switchable chiral liquid crystal with optical tristability enabled by a photoresponsive azo-chiral dopant

Abstract

A light-driven tristable chiral-tilted homeotropic nematic (TCHN) cell is demonstrated. The liquid-crystal cell is photo-switchable among the three stable states: the tilted-homeotropic, fingerprint, and the tilted-twist states. The inclusion of a photosensitive chiral bis(azobenzene) compound into a typical nematic liquid crystal makes the resulting material possible to switch from one to another stable state directly and reversibly owing to the photoinduced trans-cis isomerization of the azo-chiral dopant and, hence, the configurational change of the liquid crystal via the guest-host effect. By further introducing dichroic dyes into the TCHN system, we devised a polarizer-free display and light modulators. The novel TCHN composite material opens up new possible applications in light-driven optical elements and devices.

Electric switching of visible and infrared transmission using liquid crystals co-doped with plasmonic gold nanorods and dichroic dyes

“…The thermochromic LC systems are driven by higher voltages as well and suffer from nonuniform switching [19]. The dichroic dyes-based conventional guest-host LC displays which show similar response time as our system mainly function in the visible region of the light spectrum, not extending to cover the infrared region of the spectrum [22]. In contrast, we can selectively tune the IR absorbance peak through changing the aspect ratio of the inserted GNRs in these composites to modulate the radiation in many near infrared regions.…”

Color-Indicating, Label-Free, Dye-Doped Liquid Crystal Organic-Polymer-Based-Bioinspired Sensor for Biomolecule Immunodetection

“…This suggests that the DDLC biosensor may be used to estimate the concentration of most protein samples. However, the detection limit of DDLC biosensors can be improved by optimizing the birefringence and dichroic ratios of DDLC [ 29 ]. Compared with the past DDLC research [ 27 , 30 ], we use cheaper and common materials to fabricate the device and can be observed by using smart-phones without using polarizers and microscopy, which may greatly increase the possibility of commercialization and home-use.…”

Light-controlled skyrmions and torons as reconfigurable particles

“…Samples were prepared by mixing the QL-76 chiral additive (obtained from the Air Force Research Lab) [34] with an E7 nematic host (purchased from EM Industries), as the mixture is heated to the isotropic phase and agitated to ensure homogeneity. Various azo-chiral liquid crystalline materials have been previously synthesized and studied [35] and it is well-documented that an azobenzene-based chiral dopant can be reconfigured via a trans-cis isomerization upon UV-or blue-light excitation, leading to a change in the helical twisting power of the chiral dopant [35][36][37]. In our experiments, we chose to use an azobenzene-based chiral dopant QL-76 ( Fig.…”