Luminescent liquid crystals bearing an aggregation-induced emission active tetraphenylthiophene fluorophore

2019 ◽  
Vol 7 (16) ◽  
pp. 4828-4837 ◽  
Author(s):  
Ling-Xiang Guo ◽  
Yi-Bo Xing ◽  
Meng Wang ◽  
Ying Sun ◽  
Xue-Qin Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Aggregation Induced Emission ◽  
Liquid Crystal Materials

In this work, six novel luminescent liquid crystal materials bearing an aggregation-induced emission active tetraphenylthiophene fluorophore are described.

scholarly journals Evaluating the Concentration of Ions in Liquid Crystal Cells: Hidden Factors and Useful Techniques

Proceedings ◽  
2021 ◽  
Vol 62 (1) ◽  
pp. 10
Author(s):  
Yuriy Garbovskiy
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Fields ◽  
Measurement Techniques ◽  
Ion Concentration ◽  
Ion Generation ◽  
Concentration Of Ions ◽  
Generation Mechanisms ◽  
Crystal Cells ◽  
Liquid Crystal Materials

Many liquid crystal devices are driven by electric fields. Ions, typically present in molecular liquid crystal materials in minute quantities, can compromise the performance of mesogenic materials (in the simplest case, through a well-known screening effect). Even highly purified liquid crystals can be contaminated with ions during their production and handling. Therefore, measurements of the concentration of ions have become an important part of the material characterization of liquid crystals. Interestingly, even a brief analysis of existing publications can reveal a quite broad variability of the values of the concentration of ions measured by different research groups for the same liquid crystals. This reflects the complexity of ion generation mechanisms in liquid crystal materials and their dependence on numerous factors. In this paper, an overview of ion generation mechanisms in liquid crystals and modern ion measurement techniques is followed by the discussion of frequently overlooked factors affecting the measured values of the ion concentration. Ion-generating and ion-capturing properties of the alignment layers (or substrates) of liquid crystal cells are considered and used to evaluate a true concentration of ions in liquid crystals. In addition, practical recommendations aimed at improving the measurements of the ion density in liquid crystals are also discussed.

Photonics and lasing in liquid crystal materials

2006 ◽  
Vol 364 (1847) ◽  
pp. 2747-2761 ◽  
Author(s):  
Peter Palffy-Muhoray ◽  
Wenyi Cao ◽  
Michele Moreira ◽  
Bahman Taheri ◽  
Antonio Munoz
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Photonic Band Gap ◽  
Stop Band ◽  
Soft Materials ◽  
Modulated Phases ◽  
Photonic Band Gap Materials ◽  
Liquid Crystal Elastomers ◽  
Photon States ◽  
Liquid Crystal Materials

Owing to fundamental reasons of symmetry, liquid crystals are soft materials. This softness allows long length-scales, large susceptibilities and the existence of modulated phases, which respond readily to external fields. Liquid crystals with such phases are tunable, self-assembled, photonic band gap materials; they offer exciting opportunities both in basic science and in technology. Since the density of photon states is suppressed in the stop band and is enhanced at the band edges, these materials may be used as switchable filters or as mirrorless lasers. Disordered periodic liquid crystal structures can show random lasing. We highlight recent advances in this rapidly growing area, and discuss future prospects in emerging liquid crystal materials. Liquid crystal elastomers and orientationally ordered nanoparticle assemblies are of particular interest.

Ferroelectric Liquid Crystals For Non-Display Applications

1999 ◽  
Vol 559 ◽  
Author(s):  
W. Haase ◽  
D. Ganzke ◽  
E. P. Pozhidaev
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ferroelectric Liquid Crystal ◽  
Ferroelectric Liquid Crystals ◽  
Liquid Crystal Materials

ABSTRACTA brief review of non-display devises based on ferroelectric liquid crystals (FLC‘s) is presented. The development of ferroelectric liquid crystal materials and corresponding electrooptical elements for non-display applications have been considered.

scholarly journals Highly efficient blueish-green fluorescent OLEDs based on AIE liquid crystal molecules: from ingenious molecular design to multifunction materials

2017 ◽  
Vol 5 (16) ◽  
pp. 3999-4008 ◽  
Author(s):  
Yafei Wang ◽  
Yuanwei Liao ◽  
Christopher P. Cabry ◽  
Di Zhou ◽  
Guohua Xie ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Molecular Design ◽  
Aggregation Induced Emission ◽  
Highly Efficient ◽  
Green Fluorescent ◽  
Liquid Crystal Materials

Two novel aggregation-induced emission-based (AIE) liquid crystal materials of TPE-PBN and TPE-2PBN have been prepared and characterized.

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

scholarly journals Liquid Crystal Devices for Beam Steering Applications

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 247
Author(s):  
Rowan Morris ◽  
Cliff Jones ◽  
Mamatha Nagaraj
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Adaptive Optics ◽  
Beam Steering ◽  
Optical Components ◽  
Advantages And Disadvantages ◽  
Liquid Crystal Devices

Liquid crystals are valuable materials for applications in beam steering devices. In this paper, an overview of the use of liquid crystals in the field of adaptive optics specifically for beam steering and lensing devices is presented. The paper introduces the properties of liquid crystals that have made them useful in this field followed by a more detailed discussion of specific liquid crystal devices that act as switchable optical components of refractive and diffractive types. The relative advantages and disadvantages of the different devices and techniques are summarised.

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.

scholarly journals Optofluidic Platform Based on Liquid Crystals in X-Cut Lithium Niobate: Thresholdless All-Optical Response

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 908
Author(s):  
Fabrizio Ciciulla ◽  
Annamaria Zaltron ◽  
Riccardo Zamboni ◽  
Cinzia Sada ◽  
Francesco Simoni ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Light Intensity ◽  
Lithium Niobate ◽  
Photovoltaic Effect ◽  
Optical Control ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Threshold Behaviour ◽  
All Optical

In this study, we present a new configuration of the recently reported optofluidic platform exploiting liquid crystals reorientation in lithium niobate channels. In order to avoid the threshold behaviour observed in the optical control of the device, we propose microchannels realized in a x-cut crystal closed by a z-cut crystal on the top. In this way, the light-induced photovoltaic field is not uniform inside the liquid crystal layer and therefore the conditions for a thresholdless reorientation are realized. We performed simulations of the photovoltaic effect based on the well assessed model for Lithium Niobate, showing that not uniform orientation and value of the field should be expected inside the microchannel. In agreement with the re-orientational properties of nematic liquid crystals, experimental data confirm the expected thresholdless behaviour. The observed liquid crystal response exhibits two different regimes and the response time shows an unusual dependence on light intensity, both features indicating the presence of additional photo-induced fields appearing above a light intensity of 107 W/m2.

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