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Near complete exfoliation and reduction of lyophilized graphene oxide (GO) has been carried out at temperature as low as 400 °C. The structural characterizations of the reduced GO have been performed using X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy techniques. The morphological studies were carried out using scanning electron microscopy. The synthesized GO finds an application in improving the switching performance of a liquid crystal (LC) mixture by remarkably modifying the physical properties, such as spontaneous polarization and rotational viscosity of the ferroelectric LC (FLC) material which in turn resulted into faster response of the FLC. The present study explores the possibility of low temperature thermal reduction of GO along with its application in improving the properties of LC based display systems. [ABSTRACT FROM AUTHOR]

The dandelion like Se95In5 chalcogenide glass microparticle (CGMPs) doped ferroelectric liquid crystal (FLC) has been investigated. The electro-optical parameters of the pure and doped FLC were carried out as a function of applied voltage. The experimental response time and polarization curves for the Se95In5 CGMPs doped FLC have also been theoretically fitted. The presence of Se95In5 CGMPs affects the molecular dynamics of the FLC molecules, which was proved by the Fourier transformed infrared spectroscopy. The UV absorbance of the pure FLC material has been enhanced in the presence of CGMPs, which is analogous to the coupling between phonons of CGMPs and radiation field. The photoluminescence (PL) of the pure FLC has also been enhanced and blue shifted with the addition of Se95In5 CGMPs. The enhanced PL is attributed to the constructive interaction between low energy phonons of the CGMPs and incident photons of the monochromatic light in the LC medium. The blue shifting of PL emission is due to the enhanced optical band gap of the Se95In5 CGMPs doped FLC. The enhancement in the optical band gap of the CGMPs doped FLC was explained by the model of density states in the composite. Ultra-violet lasing, UV filtering, and optical band gap engineering are the possible applications of the investigated Se95In5 CGMPs doped FLC material. [ABSTRACT FROM AUTHOR]

Effect of ferroelectricity on the photorefractive effect of ferroelectric liquid crystal blends was investigated. The photorefractive effect of ferroelectric liquid crystal blends strongly depend on the ferroelectricity of the blend. We have prepared a series of ferroelectric liquid crystal blends that contains several concentrations of a chiral compound while keeping a constant concentration of a photoconductive moiety. The photorefractive properties of the ferroelectric liquid crystal blends were discussed with relations to the ferroelectric properties of the blends. [ABSTRACT FROM PUBLISHER]

The present study is focused on the investigations of possible effects on electro-optical properties of carbon nanotubes (CNTs) doped ferroelectric liquid crystal (FLC), W206E. The optical micrographs of nanocomposite systems reveal some topological defects. The spontaneous polarization of doped systems decreases as compared to the pure FLC. The dielectric permittivity and conductivity are decreased with increasing doping concentration of CNTs in W206E. These decrements can be attributed to the trapping of mobile ions by dopant CNTs in W206E. This study will help in the development of faster display devices based on liquid crystals with better contrast and lower threshold voltage. [ABSTRACT FROM AUTHOR]

The electrically suppressed helix ferroelectric liquid crystal (ESHFLC) electro-optical mode is characterised by the high contrast and fast response time at low driving voltage. However, the ESHFLC demands several constraints on the alignment layer and the cell gap. However, due to the fundamental characteristics of the ferroelectric liquid crystals, the cone angle decreases at higher temperatures, which is the biggest hurdle for this electro-optical mode to find the real application. In this article, we disclose a restricted polymer stabilisation (with very small polymer concentration in the mixture) for the ESHFLC without pushing other vital parameters out of the range of the constraints for ESHFLCs. The restricted polymer-stabilised ESHFLC shows large temperature range with stable high contrast, fast response time and low driving voltage, thus, it could find application in a range of the modern display and photonic devices. [ABSTRACT FROM PUBLISHER]

In this article, we reveal a theoretical and experimental illustration of the Ferroelectric liquid crystal (FLC) grating fabricated by mean of patterned alignment based on photo-alignment. The complexity related to the mismatching of the predefined alignment domains on the top and bottom substrate has been avoided by incorporating only one side photo aligned substrate while the other substrate does not have any alignment layer. Depending on the easy axis in the said alignment domains and the azimuth plane of the impinging polarized light, the diffracting element can be tuned in two modes i.e. DIFF/OFF switchable and DIFF/TRANS switchable modes, which can be applied to different applications. The diffraction profile has been illustrated theoretically that fits well with the experimental finding and thus the proposed diffraction elements with fast response time and high diffraction efficiency could find application in many modern devices. [ABSTRACT FROM AUTHOR]

Abstract: Most of ferroelectric liquid crystal (FLC) or ferroelectric mesophase show no photoluminescence (PL). But when, Cu doped ZnO (Cu-ZnO) nanoparticles (NPs) are dispersed in FLC, it shows an induced photoluminescence. This induced phenomenon of PL strongly depends on the concentration of dopant NPs. The Cu-ZnO-FLC composite system has shown two distinct emission peaks near 400nm and 650nm that correspond to the violet and red emission respectively. The characteristic features of both the emission peaks suggest their different source of origins. In the present paper, the aspects related to induced PL and its applications have been discussed. [Copyright &y& Elsevier]

Abstract: 10% Cu doped ZnO nanoparticles (NPs) prepared by hydrothermal and solvothermal method have been dispersed to the pure FLC 17/100 in 1% concentration of guest entity. Electro-optical, elastic and dielectric analysis has been made for the FLC-NPs composite system with the variation of temperature. The nature of the composite system clearly shows the alteration in FLC parameters with the dispersion of NPs. The interaction between crystalline NPs and non-crystalline ferroelectric liquid crystal matrix modifies the properties of the pure FLC system. The synthesis method of NPs is also responsible for the changes taking place in physical properties of the pure FLC. The size and surface defects of the NPs amend the FLC parameters like dielectric permittivity, relaxation frequency, relaxation strength, tilt angle, spontaneous polarization and rotational viscosity etc. The coupling of spontaneous polarization and tilting of the FLC molecules are factors responsible for the resultant electro-optical (E-O) parameters of the composite system. [Copyright &y& Elsevier]

We investigated the layer dynamics of a conventional surface-stabilized ferroelectric liquid crystal (SSFLC) using a full-optical snapshot Mueller matrix polarimeter (SMMP) based on wavelength polarization coding. Time-resolved polarimetric measurements were performed with different SSFLC samples, and a strong correlation between the polarimetric parameters and the SSFLC under electric field at different exposure times was found. It has been shown that the SMMP polarimeter is able to determine the evolution of the trajectory of the liquid crystal director between the two addressed states, the reversible motion of the smectic layer while switching, as well as the irreversible transition from chevron to bookshelf texture. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the dynamic properties of a ferroelectric liquid crystal mixture doped with silica nanoparticles using polarization current reversal method. The effect of temperature and bias field on the switching responses of silica–ferroelectric liquid crystal composites with different silica concentrations (0.01, 0.02, 0.05 and 0.1wt%) were studied and compared. Various electro-optic properties of ferroelectric liquid crystal mixture changed according to silica nanoparticles concentration. We observed about 14% decrease in spontaneous polarization and up to 17% increase in switching response for 0.01wt% silica dispersion, whereas a minor increase in the isotropic temperature of composites. The rotational viscosity and optical contrast increased with increasing silica concentration. At a 0.1wt% silica nanoparticle doping concentration, the ferroelectric liquid crystal cell showed the best electro-optic properties, such as low threshold and driving voltage, better optical contrast and low tilt angle. Our experimental results show that silica doped ferroelectric liquid crystal composites are promising materials for better optical contrast in electro-optical applications. [Copyright &y& Elsevier]

Dielectric properties of the orthoconic smectic liquid crystalline mixture W-129, which presents both antiferroelectric and ferroelectric smectic C phases, have been studied in the frequency range from 10 mHz to 100 kHz in planar aligned cells. Some important relaxation modes were detected in SmCa* and SmC* phases. Dielectric increments, distribution parameters and relaxation frequencies of these modes have been evaluated at different temperatures. From the study of dielectric spectra a great variety of relaxation responses emerges that could indicate the presence of different SmCa* subphases. [ABSTRACT FROM AUTHOR]

Abstract: In this report, we disclose the full color field sequential color (FSC) display based on electrically suppressed helix ferroelectric liquid crystals (ESHFLC). The ESHFLC mode is characterized shows high contrast, fast response time, and good shock stability. The strong constraints on anchoring energy for ESHFLC have been achieved by photoalignment of azo dye (SD1). The fast response time of 10 μs at the electric field of 6.5 V/μm gives us an opportunity to use them for 3D display as well. The proposed FSC display is characterized by 8 bit gray level, frame frequency more than 240‐Hz wide viewing angle and color triangle (130% of NTSC). [ABSTRACT FROM AUTHOR]

In this article, a method for the fabrication of Ferroelectric liquid crystal switchable grating based on photo-alignment technique has been proposed. The first order diffraction efficiency is 86% and response time is 69 μs , which is 10 times faster than the existing switchable gratings. Maximum performance can be achieved at the electric field of 7V/μm. [ABSTRACT FROM AUTHOR]

In this article, we disclose an ESHFLC display that is characterized by the out-standing optical quality with contrast 10k: 1, response time 10 μs, wide viewing angle, and low driving voltages. Thus, the proposed ESHFLC displays, with simpler fabrication procedure, have great potential and cloud offer better alternatives for the high-resolution displays technology. [ABSTRACT FROM AUTHOR]

We demonstrate a fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 μs, contrast of 7000:1 and high diffraction efficiency, at the electric field of 6 V/μm. The saturated electro-optical (EO) states up to very high frequency (≈5 kHz) are the real advantage of the proposed switchable grating, which opens several opportunities to improve the quality of existing devices and to find new applications. [ABSTRACT FROM AUTHOR]