scholarly journals Optical and electrical switching of cholesteric liquid crystals containing azo dye

RSC Advances ◽  
2017 ◽  
Vol 7 (32) ◽  
pp. 19497-19501 ◽  
Author(s):  
Seung-Won Oh ◽  
Jong-Min Baek ◽  
Sang-Hyeok Kim ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Azo Dye ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals ◽  
Electrical Switching

We propose an optically and electrically switchable cholesteric liquid crystal (ChLC) cell doped with a push–pull azo dye.

scholarly journals Fabrication of multicolored patterns based on dye-doped cholesteric liquid crystals

2019 ◽  
Vol 18 (7) ◽  
pp. 1638-1648 ◽  
Author(s):  
Linlin Xu ◽  
Hanbing Zhang ◽  
Jie Wei
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Fluorescence Enhancement ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals ◽  
Dual Mode

We developed a type of dye-doped cholesteric liquid crystal, which were used for fluorescence enhancement and dual-mode multicolor patterns.

scholarly journals Applications of Natural Purple from Dolabella auricularia: Colouration of Cholesteric Liquid Crystals

2016 ◽  
Vol 50 ◽  
pp. 1-6
Author(s):  
Yuki Kudo ◽  
Hiromasa Goto
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystal ◽  
Optical Microscope ◽  
Hydroxypropyl Cellulose ◽  
Cholesteric Liquid Crystals ◽  
Optical Texture ◽  
Sea Hare ◽  
Crystal Mixture

Hydroxypropyl cellulose (HPC) as a cholesteric liquid crystal was coloured with purple ink from Dolabella auricularia as a sea hare. Optical texture of the liquid crystal mixture was confirmed with a polarising optical microscope.

scholarly journals Nanoscale hyperspectral imaging of tilted cholesteric liquid crystal structures

Soft Matter ◽  
2019 ◽  
Vol 15 (15) ◽  
pp. 3256-3263 ◽  
Author(s):  
Aurélie Jullien ◽  
Adriana Scarangella ◽  
Umberto Bortolozzo ◽  
Stefania Residori ◽  
Michel Mitov
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Crystal Structures ◽  
Hyperspectral Imaging ◽  
Spectral Properties ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals

In tilted cholesteric liquid crystals, hyperspectral imaging reveals the correlation between the bandgap spectral properties and spatial twists.

Frustrated Structures and Pattern Formation After Thermal Quenches in Cholesteric Liquid Crystal Droplets

2021 ◽  
Author(s):  
Renan Biagio ◽  
Rodolfo Teixeira de Souza ◽  
Luiz Roberto Evangelista ◽  
Rafael S Zola
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Pattern Formation ◽  
Condensed Matter ◽  
Cholesteric Liquid Crystal ◽  
Layered Structures ◽  
Soft Condensed Matter ◽  
Cholesteric Liquid Crystals ◽  
Spherical Droplets ◽  
Complex Arrangement

The complex arrangement of layered structures in curved geometries is a ubiquitous problem in soft condensed matter systems. In general, cholesteric liquid crystals (CLCs) in spherical droplets have been studied...

Tunable Optical Filter with Variable Bandwidth Based on Cholesteric Liquid Crystal

2011 ◽  
Vol 181-182 ◽  
pp. 273-276
Author(s):  
Shi Chao Zhang ◽  
Yu Hua Huang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Incident Light ◽  
Cholesteric Liquid Crystal ◽  
Optical Filter ◽  
Tunable Filter ◽  
Cholesteric Liquid Crystals ◽  
Central Wavelength ◽  
Variable Bandwidth ◽  
Tunable Optical Filter

An optical tunable filter with variable bandwidth has been demonstrated using two cholesteric liquid crystals. The incident light was first reflected by the first cholesteric liquid crystal and then by the second one. By rotating the two cholesteric liquid crystals simultaneously, the central wavelength can be tuned. By fixing one of the cholesteric liquid crystals and rotating the other one, the bandwidth of the tunable filter can be varied. The central wavelength of the tunable optical filter can be tuned from 513.4 nm to 576.8 nm and the bandwidth is varied from 10 nm to 80 nm. This property will allow it to be widely used in many fields, including optical communications and multispectral and hyperspectral imaging systems.

Thermal and electrical wavelength tuning of Bragg reflection with ultraviolet light absorbers in polymer-stabilized cholesteric liquid crystals

2018 ◽  
Vol 6 (45) ◽  
pp. 12377-12385 ◽  
Author(s):  
Amid Ranjkesh ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Bragg Reflection ◽  
Cholesteric Liquid Crystal ◽  
Wavelength Tuning ◽  
Cholesteric Liquid Crystals ◽  
Light Absorbers ◽  
Polymer Stabilized

A dual thermal and electrical polymer-stabilized cholesteric liquid crystal has been fabricated by using ultraviolet light absorbers. The Bragg reflection can be autonomously controlled by temperature and manually by an electric field.

scholarly journals Enhanced Bandwidth Broadening of Infrared Reflector Based on Polymer Stabilized Cholesteric Liquid Crystals with Poly(N-vinylcarbazole) Used as Alignment Layer

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2238
Author(s):  
Limin Zhang ◽  
Qiumei Nie ◽  
Xiao-Fang Jiang ◽  
Wei Zhao ◽  
Xiaowen Hu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Cholesteric Liquid Crystal ◽  
Critical Role ◽  
Cholesteric Liquid Crystals ◽  
Smart Window ◽  
Alignment Layer ◽  
Thermal And Electrical Properties ◽  
Polymer Stabilized

Alignment layer plays a critical role on liquid crystal (LC) conformation for most LC devices. Normally, polyimide (PI) or polyvinyl alcohol (PVA), characterized by their outstanding thermal and electrical properties, have been widely applied as the alignment layer to align LC molecules. Here, we used a semi-conductive material poly(N-vinylcarbazole) (PVK) as the alignment layer to fabricate the cholesteric liquid crystal (CLC) device and the polymer-stabilized cholesteric liquid crystals (PSCLC)-based infrared (IR) reflectors. In the presence of ultraviolet (UV) irradiation, there are hole–electron pairs generated in the PVK layer, which neutralizes the impurity electrons in the LC–PVK junction, resulting in the reduction in the built-in electric field in the LC device. Therefore, the operational voltage of the CLC device switching from cholesteric texture to focal conic texture decreases from 45 V to 30 V. For the PSCLC-based IR reflectors with the PVK alignment layer, at the same applied electric field, the reflection bandwidth is enhanced from 647 to 821 nm, ranging from 685 to 1506 nm in the IR region, which makes it attractive for saving energy as a smart window.

scholarly journals The Propagation of the Electromagnetic Wave in Multilayers Structures Composed from Cholesteric Liquid Crystals under the Influence of the External Electric Field

2009 ◽  
Vol 19 (1) ◽  
pp. 26-32
Author(s):  
Pho Thi Nguyet Hang ◽  
Pham Thuy Dung
Keyword(s):  
Electromagnetic Wave ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
External Electric Field ◽  
Reflection Spectrum ◽  
Cholesteric Liquid Crystal ◽  
Incident Beam ◽  
Multilayer Structures ◽  
Cholesteric Liquid Crystals

The tensor solution for the electromagnetic wave being in quadrature with the surface of the cholesteric liquid crystal under the influence of the external electric field along axis of swing of crystal, has been found. Description of the reflection, transmission of the electromagnetic wave in multilayer structures composed from cholesteric liquid crystals have been shown. Futher the dependence of the reflection spectrum on the polarization of the incident beam and magnitude of the external electric field are determined.

scholarly journals Thermo-Chromic Response of Polymer Stabilized Cholesteric Liquid Crystal for Thermal Imaging

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Rishi Kumar
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermal Imaging ◽  
Cholesteric Liquid Crystal ◽  
Helical Structure ◽  
Cholesteric Liquid Crystals ◽  
Polymer Stabilized

Cholesteric liquid crystal (Ch-LC) exhibits many remarkable optical properties due to formation of a macroscopic helical structure. A low amount of monomer (5wt.%) is dispersed into cholesteric liquid crystal and get polymerized under UV radiations to form polymer stabilized cholesteric texture (PSCT). The thermo-chromic response made this device suitable for the developing applications in thermal imaging. Temperature based measurements of PSCT exploits the key property of some polymer stabilized cholesteric liquid crystals (PSCLC) to reflect definite colors at specific temperatures. The selective color of PSCT texture shifts with raise in temperature from 30oC to 85oC, which can be utilized in thermal imaging applications.

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