Electrically tunable infrared reflector with adjustable bandwidth broadening up to 1100 nm

2016 ◽  
Vol 4 (16) ◽  
pp. 6064-6069 ◽  
Author(s):  
Hitesh Khandelwal ◽  
Michael G. Debije ◽  
Timothy J. White ◽  
Albertus P. H. J. Schenning
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ethylene Glycol ◽  
Cholesteric Liquid Crystals ◽  
Anisotropic Liquid ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

A tunable infrared reflector has been fabricated using polymer stabilized cholesteric liquid crystals containing a negative dielectric, anisotropic liquid crystal and a long and flexible ethylene glycol twin crosslinker.

scholarly journals Bandwidth broadening induced by ionic interactions in polymer stabilized cholesteric liquid crystals

2014 ◽  
Vol 4 (7) ◽  
pp. 1465 ◽  
Author(s):  
Vincent P. Tondiglia ◽  
Lalgudi V. Natarajan ◽  
Christopher A. Bailey ◽  
Michael E. McConney ◽  
Kyung Min Lee ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Ionic Interactions ◽  
Cholesteric Liquid Crystals ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

Color-Tunable Mirrors Based on Electrically Regulated Bandwidth Broadening in Polymer-Stabilized Cholesteric Liquid Crystals

ACS Photonics ◽  
2014 ◽  
Vol 1 (10) ◽  
pp. 1033-1041 ◽  
Author(s):  
Kyung Min Lee ◽  
Vincent P. Tondiglia ◽  
Michael E. McConney ◽  
Lalgudi V. Natarajan ◽  
Timothy J. Bunning ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Cholesteric Liquid Crystals ◽  
Color Tunable ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

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.

Blue-shifting tuning of the selective reflection of polymer stabilized cholesteric liquid crystals

Soft Matter ◽  
2017 ◽  
Vol 13 (35) ◽  
pp. 5842-5848 ◽  
Author(s):  
Kyung Min Lee ◽  
Vincent P. Tondiglia ◽  
Nicholas P. Godman ◽  
Claire M. Middleton ◽  
Timothy J. White
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Dielectric Anisotropy ◽  
Cholesteric Liquid Crystals ◽  
Large Magnitude ◽  
Selective Reflection ◽  
Polymer Stabilized

We report on electrically-induced, large magnitude (>300 nm), and reversible tuning of the selective reflection in polymer stabilized cholesteric liquid crystals (PSCLCs) prepared from negative dielectric anisotropy nematic liquid crystal hosts.

scholarly journals Effect of Ion Concentration on the Electro-Optic Response in Polymer-Stabilized Cholesteric Liquid Crystals

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Kyung M. Lee ◽  
Timothy J. Bunning ◽  
Timothy J. White ◽  
Michael E. McConney ◽  
Nicholas P. Godman
Keyword(s):  
Liquid Crystals ◽  
Polymer Network ◽  
Ion Concentration ◽  
Cholesteric Liquid Crystals ◽  
Reflection Band ◽  
Ion Density ◽  
Electro Optic ◽  
Order Of Magnitude ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

We have previously reported that the application of a DC field can adjust the position and/or bandwidth of the selective reflection notch in polymer-stabilized cholesteric liquid crystals (PSCLCs). The proposed mechanism of these electro-optic (EO) response is ion-facilitated electromechanical deformation of the polymer stabilizing network. Accordingly, the concentration of ions trapped within the polymer network should considerably influence the EO response of PSCLC. Our prior studies have indicated that photoinitiators can increase ion density in PSCLC by an order of magnitude. Here, we isolate the contribution of ionic impurities associated with liquid crystal monomers (LCMs) by utilizing initiator-less polymerization. PSCLCs prepared with LCM with low ion concentration show bandwidth broadening of the reflection band whereas PSCLCs prepared with LCM with high ion concentration exhibit a red shifting tuning of the reflection band. The extent of the tuning or bandwidth broadening of the CLC reflection band depends on the concentration of LCMs and the chirality of the LCM.

Temperature dependent features of polymer stabilized cholesteric liquid crystals based on selected liquid crystal characteristics

Optik ◽  
2021 ◽  
Vol 230 ◽  
pp. 166354
Author(s):  
M. Khadem Sadigh ◽  
P. Naziri ◽  
M.S. Zakerhamidi ◽  
A. Ranjkesh ◽  
Tae-Hoon Yoon
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cholesteric Liquid Crystals ◽  
Temperature Dependent ◽  
Polymer Stabilized

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.

Electrically induced bandwidth broadening in polymer stabilized cholesteric liquid crystals

2011 ◽  
Vol 110 (5) ◽  
pp. 053109 ◽  
Author(s):  
V. T. Tondiglia ◽  
L. V. Natarajan ◽  
C. A. Bailey ◽  
M. M. Duning ◽  
R. L. Sutherland ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Cholesteric Liquid Crystals ◽  
Polymer Stabilized ◽  
Bandwidth Broadening

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.

scholarly journals Optical Response Associated with the Orientation and Structure of Liquid Crystals with Respect to Phosphatidylcholine Concentration

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 678
Author(s):  
Yuqi Han ◽  
Yan Jiang ◽  
Wei Guo ◽  
Bing Li ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Reflectance Spectrum ◽  
Optical Response ◽  
The Self ◽  
Cholesteric Liquid Crystals ◽  
Anchoring Effect ◽  
Self Assembling ◽  
Sensitization Effect ◽  
Structure Of Liquid

Based on the anchoring effect due to the self-assembling behavior of the phospholipid molecules at the interface between the liquid crystal and water phases on the orientation of liquid crystals, the optical response associated with the orientation and structure of liquid crystals with respect to the concentration of 1,2-didodecanoyl-sn-glycero-3-phosphocholine solution has been investigated. The optical response owing to changes in the orientation and structure of the mixed cholesteric liquid crystals with respect to the change in the concentration of phosphatidylcholine has been obtained. Moreover, the feasibility of using as-prepared mixed cholesteric liquid crystals to measure the phosphatidylcholine concentration has been verified. A methodology to measure the reflectance spectrum by using mixed cholesteric liquid crystals to sensitize the phosphatidylcholine concentration has been further realized. The sensitization effect of the mixed cholesteric liquid crystals on the measurement of phosphatidylcholine concentration was also verified.

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