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Since the establishment of liquid crystal display industries, larger sizes, faster response, higher contrast ratio, higher resolution and lower power consumption have become a pursuing target of various panel suppliers. Considering the marvelous viewing angle of the fringe‐field switching (FFS) mode, FFS displays with a higher contrast ratio are able to show more details in the dark pictures, resulting in a much better viewing experience. Herein, to develop the next‐generation liquid crystal (LC) materials for high‐contrast FFS panels, various high‐contrast LC (HCLC) materials were designed. By minimizing Δn and maximizing Kave, HCLCs exhibited lower light leakage in dark states, leading to a higher contrast ratio compared to the reference. Two HCLCs for improving the operation voltage, transmittance, contrast ratio and response time were developed by optimizing the properties of HCLC materials. Furthermore, FFS monitors with a contrast ratio of 2820:1 and a color gamut of 96.4% NTSC were demonstrated. [ABSTRACT FROM AUTHOR]

We proposed a method for dynamic Invocation of LC OD tables based on temperature changes to improve LC response time. A temperature sensor utilizing copper line with an accuracy of ± 1℃ was integrated within the liquid crystal cell. Temperature range 0‐40℃ was divided into three segments, each with an assigned optimal OD table, and the circuit system realized dynamic invocation of LC OD tables based on temperature changes. [ABSTRACT FROM AUTHOR]

Using a room‐temperature dip‐coating technique, we propose a cinnamate‐unit‐phosphonic‐acid‐based surfactant alignment material that can be orientated by linear polarized light. Using the technique, we can treat a substrate simply and quickly, achieving a uniform pretilt angle of approximately 86° with a low dose of polarized UV light. We examined the optical and electrical properties of the alignment material under different conditions, including pretilt angles under different irradiation doses, voltage holding ratio (VHR) and residual direct circuit (RDC) when using different solvents, stability, etc. The results show that the material has acceptable performance. Since the phosphonic acid series photosensitive materials still have much room for optimization, we believe it is a potential new generation of photosensitive surfactant alignment materials. [ABSTRACT FROM AUTHOR]

We propose a simulation method for two‐dimensional (2D) crossed‐type exit pupil expansion based on polarization volume grating (PVG) applied in diffractive waveguide holographic display. The functions of turning and decoupling of the PVG are realized through two continuous Bragg regions, and the spatial director distribution of liquid crystal is combined with RCWA to model its diffractive characteristics and ray tracing simulation. [ABSTRACT FROM AUTHOR]

16‐inch FHD+ (Full High Definition Plus, 1920*1200) LCD featuring LTPS TFTs with a new low‐resistance alloy gate metal and fast response AFFS (Advanced Fringe Field Switching) liquid crystal technology has been developed, which achieves a ClearMR value of 9000 at 480Hz frame rate and fulfills the requirement for product reliability test. These technologies, including the new gate metal TFTs and employing Fast‐Response time liquid crystal, have also been implemented in a 17.3‐inch FHD (Full High Definition, 1920*1080) gaming laptop LCD. This larger panel operates at an even higher frame rate of 660Hz and higher ClearMR values with GtG (Gray to Gray) liquid crystal response time within 1ms. These advancements mark significant progress in the field of high‐performance gaming displays. [ABSTRACT FROM AUTHOR]

Fast‐switching high‐efficiency liquid crystal grating is a key component in holographic true‐3D display systems. In this paper, we present our research and development of a 10.7" liquid crystal grating with 2‐3 millisecond switching time, close‐to‐ideal deflection efficiency, and >100 polarization contrast. The high performance is achieved by optimizing the design and process of the liquid crystal grating panel as well as the optical module stack. Several key design principles are analyzed and verified. Based on the developed liquid crystal grating, a 10.4" full‐color naked‐eye holographic 3D display prototype is successfully realized. [ABSTRACT FROM AUTHOR]

Polarization Volume Hologram (PVH) waveguide is an innovative liquid crystal‐based diffractive waveguide designed for augmented reality (AR) smart glasses, showcasing exceptional optical performance and simplified fabrication process. This presentation offers a comprehensive overview, including its working principles, advantages, performance optimization, process development, challenges and opportunities. The objective is to provide insights into PVH waveguide technology, from its inception to practical implementation. [ABSTRACT FROM AUTHOR]

This paper covers the overview of liquid crystal lenses for 3D displays and our latest technology that reduces the switching time of the LC lens. First, a binocular near‐eye DFD display system utilizing binary focus lenses including a liquid crystal layer is described. Then, we review a two‐way multiview 2D/3D display that can achieve 3D images in both landscape and portrait. Finally, for the fast switching time of LC lenses, we report a novel driving method by applying a vertical electric field that achieved 25 times faster turn‐off time than the conventional method. [ABSTRACT FROM AUTHOR]

Eye‐tracking is vital in AR/VR/MR systems for display correction, rendering, accommodation, and more. However, existing eye‐tracking solutions fall short in accuracy, efficiency, form factor, and population coverage. Using Liquid crystal polarization hologram (LCPH) for eye‐tracking purposes offers a compact form‐factor with excellent performance. [ABSTRACT FROM AUTHOR]

We report a method for controlling the viewing angle using twisted nematic liquid crystal (TN‐LC) materials for automotive display applications. We achieved switching between normal and privacy modes with the change in viewing‐angle‐dependent retardation through the reorientation of the TN‐LC molecules under crossed polarizers by applying a vertical electric field. [ABSTRACT FROM AUTHOR]

By reducing the ratio of dark lines to the extreme, and improving the transmittance at the dark line with chiral liquid crystal, we have successfully developed novel chiral VA Mode, which is the world's first. The transmittance of 4K can be increased by 14%, and 8K can be increased by more. [ABSTRACT FROM AUTHOR]

The Chiral Polymer Stabilized Vertical Alignment (C‐PS‐VA) technology enables up to 10% increase in transmittance leading to potentially lower power consumption of final devices and energy saving compared to conventional Polymer Stabilized Vertical Alignment (PS‐VA) technology. Self‐Aligned Vertical Alignment (SA‐VA) enables the simplification of the process to achieve energy saving by eliminating high‐temperature baking. This paper summarizes the recent developments of liquid crystal mixtures for C‐PS‐VA & SA‐VA technologies in terms of performance and reliability. [ABSTRACT FROM AUTHOR]

Combining a vertically aligned polarizer and a liquid crystal cell, a switchable view control filter is implemented, that on demand, changes the transmission for designated view angle areas between a high transmission and low transmission state, referred to as private and public modes of operation. The feasibility of the switchable view control concept is confirmed via simulations and measurements. [ABSTRACT FROM AUTHOR]

This paper proposes a proof‐of‐concept design for RIS made with liquid crystals (LC) and Corning glass for wireless communication applications. The proposed RIS concept consists of the specially designed copper‐coated glass substrates and liquid crystal materials that were filled in between two glass substrates. The LC layer exists between the upper and lower Corning glass sheets, and it is 20 μm thick. Although the 20 μm cell‐gap is very thin compared to the operating frequency (it is more than 100 μm in previous research), more than the 180° phase difference was achieved by applying 10 V in the designed frequency band. Our proposed concept can improve wireless communication coverage by reflecting incident electromagnetic waves in the desired direction to secure a propagation path by simply changing the alignment of LC molecules under different driving voltages. Also, conventional LCD manufacturing technology can significantly reduce costs and support larger sized capabilities, compared to incumbent semiconductor‐based electronics and printed circuit board (PCB) processing. [ABSTRACT FROM AUTHOR]

This paper presents the development of liquid crystal on silicon (LCOS) technology aimed at enhancing the image quality and reliability of projectors. Additionally, we introduce an 8K LCOS panel with a pixel pitch of 2.6 μm. Furthermore, we discuss the application prospects of the developed phase‐only spatial light modulator. [ABSTRACT FROM AUTHOR]

We have developed a reflective polarization volume grating using liquid crystal polymer for SWIR with high efficiency and a large diffraction angle. By using this grating and a lightguide system, we demonstrated a sensor system that can capture identical images simultaneously in both visible and SWIR light. [ABSTRACT FROM AUTHOR]

This developed 1.2‐inch 4K2K LCOS with 76.0 lp/mm spatial resolution can still achieve high phase accuracy and obviously enlarge field‐of‐viewing (FOV) angle compared with previous 0.55‐inch 2K1K LCOS. The holographic image quality within phase‐only LCOS not only can be improved by using higher phase accuracy and compensation technologies, but also can realize the real 3D imaging into near‐eye displays to avoid the VAC phenomena. In addition to, the holographic 4K2K LCOS (26.6mm x 15.8mm) optical design can achieve lighter optical engine and reconstructed square (26.6mm x 26.6mm) image per eye, so that it has advantages of more feasible driving condition and cost competition. As high‐speed technologies of display electronics, liquid crystal, and optical algorithm were gradually mature, the above 1.2" phase‐only LCOS with both high pixel resolution and smaller pixel pitch will be another choice into the VR & MR headsets utilized video see‐through (VST) method. Meanwhile, the 1.2" 4K2K LCOS with enhanced FOV can be alternative scheme for AR glasses using optical see‐through (OST) method before the trade‐off between volume, brightness, and FOV angle are resolved. [ABSTRACT FROM AUTHOR]

We analyze the field‐of‐view (FoV) limitations in a single‐layer, full‐color waveguide‐based augmented reality display, revealing key influences from the waveguide's refractive index, exit pupil expansion (EPE) scheme, and combiner's angular response. Based on these analyses, we propose an optimized butterfly EPE scheme with gradient‐pitch polarization volume gratings (PVGs), achieving a theoretical diagonal FoV of 54.06° with a 16:10 aspect ratio. [ABSTRACT FROM AUTHOR]

Thermotropic liquid crystals are versatile optical materials that exhibit a state of matter intermediate between liquids and solids. Their properties can change significantly with temperature, pressure, or other external factors, leading to different phases. The transport properties within these materials in different phases are still largely unexplored, and their understanding would enable exciting prospects for innovative technological advancements. High-order harmonic spectroscopy proved to be a powerful spectroscopic tool for investigating the electronic and nuclear dynamics in matter. Here, we report the first experimental observation of high-order harmonic generation in thermotropic liquid crystals in two different phase states, nematic and isotropic. We found the harmonic emission in the nematic phase to be strongly dependent on the relative orientation of the driving field polarization with respect to the liquid crystal alignment. Specifically, the harmonic yield has a maximum when the molecules are aligned perpendicularly to the polarization of the incoming radiation. Our results establish the first step for applying high-order harmonic spectroscopy as a tool for resolving ultrafast electron dynamics in liquid crystals with unprecedented temporal and spatial resolution. [ABSTRACT FROM AUTHOR]

Optoelectronic and spinoptronic technologies benefit from flexible and tunable coherent light sources combining the best properties of nano- and material-engineering to achieve favorable properties such as chiral lasing and low threshold nonlinearities. In this work we demonstrate an electrically wavelength- and polarization-tunable room temperature polariton laser due to emerging photonic spin–orbit coupling. For this purpose, we design an optical cavity filled with both birefringent nematic liquid crystal and an inorganic perovskite. Our versatile growth method of single CsPbBr3 inorganic perovskite crystals in polymer templates allows us to reach strong light–matter coupling and pump-induced condensation of exciton–polaritons resulting in coherent emission of light. The sensitivity of the liquid crystal to external voltage permits electrical tuning of the condensate energy across 7 nm; its threshold power, allowing us to electrically switch it on and off; and its state of polarization sweeping from linear to locally tilted circularly polarized emission. [ABSTRACT FROM AUTHOR]

Biochemical sensors have important applications in biology, chemistry, and medicine. Nevertheless, many biochemical sensors are hampered by intricate techniques, cumbersome procedures, and the need for labeling. In the past two decades, it has been discovered that liquid crystals can be used to achieve the optical amplification of biological interactions. By modifying recognition molecules, a variety of label-free biochemical sensors can be created. Consequently, biochemical sensors based on the amplification of liquid crystals have become one of the most promising sensors. This paper describes in detail the optical sensing principle of liquid crystals, sensing devices, and optical detection technologies. Meanwhile, the latest research findings are elucidated. Finally, the challenges and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Photoalignment by azo dye nanolayers can provide high alignment quality for large-area liquid crystal devices. Application of this technology to active optical elements for signal processing and communications is a hot topic of photonics research. In this article, we review recent demonstrations and performance of liquid crystal photonic devices, discuss the advantages of the proposed technology, and identify challenges and future prospects in the research field of photoaligned multi-domain liquid crystal structures. We believe that the developments discussed here can provide directions for future research and potential opportunities for applications of liquid crystal devices based on multi-domain photoalignment. [ABSTRACT FROM AUTHOR]

Chiral self‐assembly has often been found to be an efficient strategy for the development of high‐performance circularly polarized luminescent (CPL) materials, through the regulation of the ordered helical superstructure blocks in liquid crystal media. Here, the design and synthesis of two pairs of axially chiral emitters (BBXT‐3‐Br and BOHXT‐3‐Br) are reported based on bromoxanthone. And the chiral self‐assembled liquid crystal polymer (LCP) framework (PRM257) is demonstrated by mixing of the emitters with liquid crystal monomer (RM257) through thermal annealing and photoinitiated polymerization. Both BBXT‐3‐Br@PRM257 and BOHXT‐3‐Br@PRM257 exhibited excellent room temperature phosphorescence (RTP) properties. In addition, BBXT‐3‐Br@PRM257 enantiomers showed afterglow with an average lifetime (τ) of 162.41 ms and emitted blue CPL (λem = 450 nm, ΦFL = 1.3%, |gFL| = 0.071), although weak circularly polarized RTP (CP‐RTP) is observed. Interestingly, BOHXT‐3‐Br@PRM257 with a less conjugated system emits red RTP (τ = 98.83 ms) and also intense CP‐RTP (λem = 612 nm, ΦPhos = 0.45%, |gRTP| = 0.057). [ABSTRACT FROM AUTHOR]

Luminescent organic radicals, especially those with photoactivated circularly polarized luminescence (CPL) features, hold great significance for cutting‐edge optoelectronic applications, but their development still remains a challenge. In this study, we propose a novel strategy to achieve photoactivated CPL radicals by bonding two phosphine centers within an axial chiral system, yielding a compound of R/S‐5,5‐bis(diphenylphosphino)‐4,4′‐bibenzo[d][1,3]dioxole (R/S‐BDP). The photoactivated R/S‐BDP molecules in polymer matrix display a robust quantum yield of 19.8 % and a dissymmetry factor (glum) of 1.2×10−4, marking this work as the first example of photoactivated CPL radicals. Furthermore, the glum is improved to 1.0×10−2 by using a liquid crystal as host. Experimental and theoretical analyses reveal that R/S‐BDP molecules, endowed with double phosphine cores in axial chirality, offer a direct way for intramolecular electron transfer upon photoirradiation. This leads to the generation of radical ionic pairs, which subsequently trigger the donor‐acceptor arrangement through intermolecular electron transfer, thereby resulting in stable radical emission. The extended photoactivated BDP‐F exhibits a remarkably high quantum efficiency of 57.8%. Ultimately, the distinctive photo‐responsive CPL radical luminescence has been successfully used for information displays and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Topological defects play a central role in the physics of many materials, including magnets, superconductors, and liquid crystals. In active fluids, defects become autonomous particles that spontaneously propel from internal active stresses and drive chaotic flows stirring the fluid. The intimate connection between defect textures and active flow suggests that properties of active materials can be engineered by controlling defects, but design principles for their spatiotemporal control remain elusive. Here, we propose a symmetry-based additive strategy for using elementary activity patterns, as active topological tweezers, to create, move, and braid such defects. By combining theory and simulations, we demonstrate how, at the collective level, spatial activity gradients act like electric fields which, when strong enough, induce an inverted topological polarization of defects, akin to a negative susceptibility dielectric. We harness this feature in a dynamic setting to collectively pattern and transport interacting active defects. Our work establishes an additive framework to sculpt flows and manipulate active defects in both space and time, paving the way to design programmable active and living materials for transport, memory, and logic. [ABSTRACT FROM AUTHOR]

Polymer-dispersed liquid crystal (PDLC) film is an electrically controlled dimming film in which the orientation of the liquid crystal molecules can be changed by applying an electric field. When the liquid crystals are perpendicular to the PDLC film, the film is transparent. Birefringence occurs after light passes through the liquid crystal molecules, resulting in two beams of light with perpendicular vibration directions. Therefore, PDLC film appears hazy when viewed from the side. In this study, a polarizing film was introduced to reduce the side-view haze, and its influence on the haze at different angles and positions was investigated. Experiment results revealed that aligning the PDLC film along the polarizing film's absorption axis reduced the haze at all angles. When the polarizing film was attached to each side of the PDLC film and the absorption axis angle of the films was 0∘, a wide-viewing-angle PDLC film was obtained; at a 45∘ tilt, the haze only increased by 0.33%, and at 60∘ it maintained a clear field of view. This may be because only light in the same direction as the absorption axis passed through the film, reducing the amount of light that did not match the polymer refractive index. [ABSTRACT FROM AUTHOR]

The crystallization behavior of halide perovskites is of great significance. Fractal structures, featured by self-similarity between local morphology and global structures, have consistently captivated scientists' interest across diverse disciplines. In this study, we realized the fractal patterns in lead-free zero-dimensional (0D) Cs2InBr5(H2O) perovskites. By depositing saturated precursor droplets on silicon or glass substrates, we initiated nucleation and crystallization of 0D Cs2InBr5(H2O) crystals on the liquid's upper surface. As the solution evaporated, the remaining high-concentration solution formed self-similar fractal patterns beneath the Cs2InBr5(H2O) crystals. This anisotropic growth mechanism imparted a unique self-assembly behavior to 0D Cs2InBr5(H2O). Additionally, X-ray diffraction results confirmed distinct preferential orientations of the fractal patterns. The findings of this work provide valuable insights into the controlled crystallization behavior of lead-free perovskites and inspire further exploration of novel optoelectronic properties arising from such a unique fractal pattern. [ABSTRACT FROM AUTHOR]

Due to the ability to switch between transparent and light scattering states, polymer dispersed liquid crystals (PDLC) and polymer stabilised cholesteric liquid crystals (PSCLC) are widely used in smart windows and flexible displays. A novel double-layer optical switch fabricated from a PDLC-PVA-PSCLC structure has been developed in this study, and the optimal formulation of each layer of the structure was investigated. In addition, the effect of adding (spin-coating) nanoparticles on overall switch performance was investigated. The double-layer switch under optimal conditions achieved 89.1% UV shielding, which also possessed excellent layer-by-layer driving performance and was able to modulate the UV shielding rate according to the voltage, with a tunable range of 74.83%-94.33%. Consequently, this optical device holds great promise for significant improvement and application in smart windows and flexible displays. [ABSTRACT FROM AUTHOR]

This research delves into the synthesis and characterisation of novel liquid crystal compounds derived from benzo[b]thiophene cores, focusing on their potential applications in microwave technology. Two synthetic strategies were developed to construct rigid cores, resulting in the successful synthesis of 10 compounds with varied terminal groups and lateral substituents. Correlations between molecular structure and mesomorphic properties were elucidated through extensive comparative analysis. Birefringence measurements and quantum chemical calculations further provided insights into the optical properties and polarisability anisotropy of the synthesised compounds. The results highlight the influence of structural diversity on the compounds' suitability for microwave applications. Specifically, compounds featuring carbon–carbon triple bonds and polar terminal groups demonstrated enhanced birefringence and polarisability values, indicating their potential in microwave device fabrication. This study underscores the importance of molecular design in optimising liquid crystal materials for advanced technological applications. [ABSTRACT FROM AUTHOR]

In the present investigation, two series of biphenyl embedded Schiff base-bis esters alkyl-(E)-4-(((4'-(decyloxy)-[1,1'-biphenyl]-4-yl)methylene)amino)-benzoate, BPK-(2–18) and alkyl-(E)-4-(((4'-((4-(decyloxy)benzoyl)oxy)-[1,1'-biphenyl]-4-yl)-methylene)amino)benzoate, BPEK-(8–18) containing either terminal alkoxy biphenyl core or central biphenyl core have been synthesised and studied for their self-assembling behaviour. The compounds of both series demonstrated enantiotropic liquid crystal properties, displaying typical calamitic mesophases (Smectic A (SmA), Smectic C (SmC)) across a broad temperature range and with high thermal stability. The bimorphic behaviour of new molecules has been investigated by VT-XRD analysis. The density function theory has been done to illustrate the experimental results of the mesomorphic properties of the studied compounds. Several parameters have been calculated such as molecular geometry, dipole moment, polarisability, aspect ratio, etc. The results showed that more planar compounds will attain more packed structures leading to the formation of more ordered smectic phases. [ABSTRACT FROM AUTHOR]

This study investigates the self-assembly and phase transitions of cholesteric liquid crystals (CLCs) when confined in nanotubes, specifically focusing on the variations in their molecular structures. A dissipative particle dynamics method was used to investigate how the changes in helix radius (${r_{{\rm{LC}}}}$ r LC ) and pitch ($P$ P) affect the behaviour of the LCs. For pitches of 24, 12, and 6, the orientation order parameter (${P_2}$ P 2 ) showed distinct trends during cooling. Smaller helix radii resulted in isotropic to nematic to smectic phase transitions, whereas larger radii resulted in a novel smectic phase with spiral structures (Sm $_{\rm{s}}$ s ). Circumferential local-order parameters (${P_{2r}}$ P 2 r and ${P_{2z}}$ P 2 z ) were introduced to better characterise the phases, and a disordered spiral-structure phase (Sm $_{{\rm{s}}2}$ s 2 ) with local perturbations was observed. The transitions between isotropic, nematic, and smectic phases, highlighting the influence of the pitch and helix radius, were observed from the phase diagrams. Smaller pitches and radii prevented the formation of stable structures; however, specific combinations induced characteristic spiral structures in the smectic phase. These results provide new insights into the self-assembly of confined CLCs, which have potential applications in the design of photonic devices and LC-based sensors. This study advances our understanding of phase control in quasi-one-dimensional systems and highlights the importance of molecular variations in liquid crystal behaviour. [ABSTRACT FROM AUTHOR]

Dye-doped cholesteric liquid crystals (DDCLCs) with a homeotropic initial state are more practical due to their lower power consumption and higher security. However, achieving the homeotropic initial state necessitates the use of long-pitch DDCLCs. The conventional formula for determining the planar (P) state transmittance of DDCLCs is inadequate for calculating the P state transmittance of long-pitch DDCLCs with pronounced optical activity. Therefore, in the experimental calculations and fitting, optical activity was introduced to amend the conventional formula and expand the calculation range to include visible wavelengths (400 nm-800 nm). Following numerous validations, a modified formula for calculating the P-state transmittance of DDCLCs was derived, which yields results closer to the actual values when optical activity is significant. This modification is of great significance in the design of long-pitch DDCLCs. [ABSTRACT FROM AUTHOR]

In this work, electromagnetic propagating modes within a planar waveguide featuring a cholesteric elastomer core whose helical axis is oriented perpendicular to the planar boundaries are analysed. The Maxwell equations and the constitutive equation are used to establish a novel configuration, enabling the tuning of mechanical stress through elastic strain in the perpendicular stretching along the helix axis. The derived set of equations is numerically solved, presuming the waveguide to be surrounded by either air or a vacuum medium. The corresponding band structure and the ratio between electric and magnetic modes have been plotted as a function of angular frequency. The amplitudes of the electromagnetic field profiles are also investigated as functions of position. The ratio of Transverse Electric and Transverse Magnetic modes, along with the cut-off frequencies, is also examined as functions of strain. Finally, the mixing of transverse electric and magnetic modes to generate new eigenmodes, as well as the investigation of their propagation conditions within the waveguide, is examined in this study. [ABSTRACT FROM AUTHOR]

Most of the current highly polar rod-shaped molecules that form ferroelectric nematic (NF) phase do so only at elevated temperatures and multicomponent mixtures are generally needed to obtain a broad and room temperature range NF phase. In this work, we describe the synthesis, phase characterisation and measurement of various physical properties of a new ferroelectric nematic compound 4-[(4-nitrophenoxy)carbonyl]phenyl 2-isopropoxy-4-methoxybenzoate (RT11165). The molecular structure of RT11165 with a 2-isopropoxy group differs only by a substitution of the 2-methoxy group found in the prototype ferroelectric nematic material 4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate (RM734). This small structure change produces a rather dramatic change in phase behaviour leading to an NF phase from 63°C down to room temperature. Below about 45°C the rotational viscosity of RT11165 increases critically and the temperature dependence indicates a glass transition at ~19°C. The transparent and polar glassy state of RT11165, which should be also piezoelectric, is a good candidate for energy storage, piezoecatalysis, data storage and other applications. [ABSTRACT FROM AUTHOR]

This article is based on the Density Functional Theory (DFT) simulations approach to examine the structural and vibrational behaviour of pure 6O.6 and fluorinated 6O.6 liquid crystalline compounds. The molecular interactions of the molecules were investigated by their optimised molecular structure. Identification of significant functional groups and their dynamic behaviours are made with the help of vibrational frequencies obtained through DFT calculations. Vibrational Energy Distribution Analysis (VEDA) software was used to perform the Potential Energy Distribution (PED) function of FT-IR and Raman spectra. Furthermore, changes in vibrational peaks provide insight into structural modifications. This investigation mainly focused on analysing the different reactivity, thermodynamic parameters and non-linear optical (NLO) properties of the compounds. This also helps to open a new path for further investigations into optoelectronic applications and molecular dynamics. [ABSTRACT FROM AUTHOR]

In this study, polymer-stabilised cholesterol-based liquid crystal (PSLC) broadband reflective films were prepared by doping UV absorbers and chiral compounds in bilayer poly (methyl methacrylate) (PMMA) nanofiber films. Broadband reflection was achieved by diffusion of the UV absorber and chiral compounds in the bilayer nanofibers into the liquid crystal layer, which resulted in the formation of an inhomogeneous pitch distribution in the liquid crystal layer. To attain an optimal reflective effect, various factors such as polymer monomer concentration, concentration of chiral compounds in the spun film, diffusion temperature, diffusion time, and intensity of polymerised light were investigated. The effects of these factors on the reflective bandwidth were explored. The method significantly broadened the reflective bandwidth of the cholesteric phase liquid crystal layer, establishing the foundation for studying the combination of nanofiber films with cholesteric phase liquid crystals to form an adjustable pitch. [ABSTRACT FROM AUTHOR]

We study the Cauchy problem of the new model of the three dimensional inertial nematic electrolyte, which models the N-species charged particles diffuse and advect in the nematic liquid crystalline matrix. This new model was proposed by [Calderer MC, Golovaty D, Lavrentovich O, et al. Modeling of nematic electrolytes and nonlinear electroosmosis. SIAM J Appl Math. 2016;76:2260–2285. doi: 10.1137/16M1056225]. The inertial effect is such that the system involves a hyperbolic feature. We first derive the local existence in large initial data when the flow is isotropy, i.e. $ \lambda =1 $ λ = 1. For the anisotropy case ( $ \lambda \gt 0 $ λ > 0 , $ \lambda \neq ~1 $ λ ≠ 1), we obtain small data local solutions. Then, by seeking some further dissipative mechanisms from the elliptic structures, the local solution can be extended globally near the constant states with electro-neutrality condition. [ABSTRACT FROM AUTHOR]

Windows are used everywhere, from buildings to vehicles. Smart switchable windows are highly sought‐after in order to reduce energy consumption. An ideal smart window should have two functions. First, it should be able to control privacy. Second, it should be able to control radiant energy flow. Here, a smart window is reported that possesses the two functions. The smart window is based on a dichroic dye‐doped cholesteric liquid crystal. It exhibits two stable states in the absence of applied voltage. One of them is the planar state that is optically absorbing without haze and can control radiant energy flow. The other state is the focal conic state that is optically scattering and can control privacy. Furthermore, when voltage is applied, the liquid crystal is switched to a heliconical state, where the transmittance can be tuned continuously. Thanks to its superior performance, this smart window has a big potential for applications in architectural and vehicle windows. [ABSTRACT FROM AUTHOR]

In this review, we meticulously analyze and consolidate various techniques used for measuring the junction temperature of light-emitting diodes (LEDs) by examining recent advancements in the field as reported in the literature. We initiate our exploration by delineating the evolution of LED technology and underscore the criticality of junction temperature detection. Subsequently, we delve into two key facets of LED junction temperature assessment: steady-state and transient measurements. Beginning with an examination of innovations in steady-state junction temperature detection, we cover a spectrum of approaches ranging from traditional one-dimensional methods to more advanced three-dimensional techniques. These include micro-thermocouple, liquid crystal thermography (LCT), temperature sensitive optical parameters (TSOPs), and infrared (IR) thermography methods. We provide a comprehensive summary of the contributions made by researchers in this domain, while also elucidating the merits and demerits of each method. Transitioning to transient detection, we offer a detailed overview of various techniques such as the improved T3ster method, an enhanced one-dimensional continuous rectangular wave method (CRWM), and thermal reflection imaging. Additionally, we introduce novel methods leveraging high-speed camera technology and reflected light intensity (h-SCRLI), as well as micro high-speed transient imaging based on reflected light (μ_HSTI). Finally, we provide a critical appraisal of the advantages and limitations inherent in several transient detection methods and offer prognostications on future developments in this burgeoning field. [ABSTRACT FROM AUTHOR]

Soft robots often draw inspiration from nature to navigate different environments. Although the inching motion and crawling motion of caterpillars have been widely studied in the design of soft robots, the steering motion with local bending control remains challenging. To address this challenge, we explore modular origami units which constitute building blocks for mimicking the segmented caterpillar body. Based on this concept, we report a modular soft Kresling origami crawling robot enabled by electrothermal actuation. A compact and lightweight Kresling structure is designed, fabricated, and characterized with integrated thermal bimorph actuators consisting of liquid crystal elastomer and polyimide layers. With the modular design and reprogrammable actuation, a multiunit caterpillar-inspired soft robot composed of both active units and passive units is developed for bidirectional locomotion and steering locomotion with precise curvature control. We demonstrate the modular design of the Kresling origami robot with an active robotic module picking up cargo and assembling with another robotic module to achieve a steering function. The concept of modular soft robots can provide insight into future soft robots that can grow, repair, and enhance functionality. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of biphenyls, which are economically important pharmaceuticals, agrochemicals, and liquid crystals, is a challenging task. Current methods rely on metal‐dependent cross‐coupling reactions, which unfortunately require the use of harmful halogenated aryls and heavy metal catalysts that are toxic and difficult to remove from the final products. Recently, we have circumvented these problems by developing a metal‐free and broadly applicable photochemical method for biphenyl synthesis using UV−C light, called photosplicing. Here we present an improved method using photosensitizers in combination with UV−B, UV−A light, or sunlight. Using a high‐precision flow reactor with deep‐UV LEDs, we investigated the ability of commonly available organic photosensitizers to enhance the photosplicing reaction and identified a number of suitable photosensitizers with the required triplet energy. This method allows for easy batch synthesis of biaryls in borosilicate glassware and paves the way for their large‐scale production without the need for flow reactors. [ABSTRACT FROM AUTHOR]

Lipophilic biphenylthiophene‐ and phenanthrothiophene‐triazine compounds, BPTTn and CPTTn, respectively, were prepared by a tandem procedure involving successive Suzuki‐Miyaura coupling and Scholl cyclodehydrogenation reactions. These compounds display photoluminescence in solution and in thin film state, solvatochromism with increasing solvent's polarity, as well as acidochromism and metal ion recognition stimuli‐responsive fluorescence. Protonation of BPTT10 and CPTT10 by trifluoroacetic acid results in fluorescence quenching, which is reversibly restored once treated with triethylamine (ON‐OFF switch). DFT computational studies show that intramolecular charge transfer (ICT) phenomena occurs for both molecules, and reveal that protonation enhances the electron‐withdrawing ability of the triazine core and reduces the band gap. This acidochromic behavior was applied to a prototype fluorescent anti‐counterfeiting device. They also specifically recognize Fe3+ through coordination, and the recognition mechanism is closely related to the photoinduced electron transfer between Fe3+ and BPTT10/CPTT10. CPTTn self‐assemble into columnar rectangular (Colrec) mesophase, which can be modulated by oleic acid via the formation of a hydrogen‐bonded supramolecular liquid crystal hexagonal Colhex mesophase. Finally, CPTTn also form organic gels in alkanes at low critical gel concentration (3.0 mg/mL). Therefore, these star‐shaped triazine molecules possess many interesting features and thus hold great promises for information processing, liquid crystal semiconductors and organogelators. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomers (LCEs) are responsive materials that can undergo large reversible deformations upon exposure to external stimuli, such as electrical and thermal fields. Controlling the alignment of their liquid crystals mesogens to achieve desired shape changes unlocks a new design paradigm that is unavailable when using traditional materials. While experimental measurements can provide valuable insights into their behavior, computational analysis is essential to exploit their full potential. Accurate simulation is not, however, the end goal; rather, it is the means to achieve their optimal design. Such design optimization problems are best solved with algorithms that require gradients, i.e., sensitivities, of the cost and constraint functions with respect to the design parameters, to efficiently traverse the design space. In this work, a nonlinear LCE model and adjoint sensitivity analysis are implemented in a scalable and flexible finite element-based open source framework and integrated into a gradient-based design optimization tool. To display the versatility of the computational framework, LCE design problems that optimize both the material, i.e., liquid crystal orientation, and structural shape to reach a target actuated shapes or maximize energy absorption are solved. Multiple parameterizations, customized to address fabrication limitations, are investigated in both 2D and 3D. The case studies are followed by a discussion on the simulation and design optimization hurdles, as well as potential avenues for improving the robustness of similar computational frameworks for applications of interest. [ABSTRACT FROM AUTHOR]

A nonterminal liquid crystal epoxy monomer is used to create an epoxy–amine network with a typical diamine 4,4′diaminodiphenylmethane. The plain matrix is compared to matrices modified with inorganic fillers: TiO2 or SiO2. Conditions of the curing reaction and glass transition temperatures in the cured products are determined through differential scanning calorimetry and broadband dielectric spectroscopy. The curing process is also followed through optical and electrical observations. The dielectric response of all investigated networks reveals a segmental α-process related to structural reorientation (connected to the glass transition). In all products, a similar process associated with molecular motions of polar groups also appears. The matrix modified with TiO2 exhibits two secondary relaxation processes (β and γ). Similar processes were observed in the pure monomer. An advantage of the network with the TiO2 filler is a shorter time or lower temperature required for optimal curing conditions. The physical properties of cured matrices depend on the presence of a nematic phase in the monomer and nonterminal functional groups in the aliphatic chains. In effect, such cured matrices can have more flexibility and internal order than classical resins. Additional modifiers used in this work shift the glass transition above room temperature and influence the fragility index in both cases. [ABSTRACT FROM AUTHOR]

Four binary mixtures are isolated from the hydrogen bond liquid crystalline mesogenic complexes comprising methyl malonic acid (MM) and p-n heptyloxy benzoic acid (7BAO) abbreviated as MM + 7BAO & p-n dodecyloxy (12BAO) benzoic acid abbreviated as MM + 12BAO as the precursors exhibit rich phase polymorphism. Variation in the even set of molar proportion in steps of 0.2 leads to the formation of four binary mixtures. Each of the precursors used for the preparation of binary mixtures are treated as X and Y component whose molar ratio varies accordingly. Spectroscopic analysis of the binaries confirms the hydrogen bond existence between the binary mixtures. Phase variance and their textural observations are made through polarizing optical microscopic studies. Thermal properties possessed by these binary mixtures such as phase transition temperatures, enthalpy values, thermal equilibrium, thermal stability, order of phase transition and specific heat capacity are extensively investigated from the differential scanning thermograms obtained for the binaries prepared. These calorimetric investigations suggest the mesophases of the binaries for apt display, thermal and optical applications. [ABSTRACT FROM AUTHOR]

Plants can autonomously adjust their growth direction based on the gravitropic response to maximize energy acquisition, despite lacking nerves and muscles. Endowing soft robots with gravitropism may facilitate the development of self‐regulating systems free of electronics, but remains elusive. Herein, acceleration‐regulated soft actuators are described that can respond to the gravitational field by leveraging the unique fluidity of liquid metal in its self‐limiting oxide skin. The soft actuator is obtained by magnetic printing of the fluidic liquid metal heater circuit on a thermoresponsive liquid crystal elastomer. The Joule heat of the liquid metal circuit with gravity‐regulated resistance can be programmed by changing the actuator's pose to induce the flow of liquid metal. The actuator can autonomously adjust its bending degree by the dynamic interaction between its thermomechanical response and gravity. A gravity‐interactive soft gripper is also created with controllable grasping and releasing by rotating the actuator. Moreover, it is demonstrated that self‐regulated oscillation motion can be achieved by interfacing the actuator with a monostable tape spring, allowing the electronics‐free control of a bionic walker. This work paves the avenue for the development of liquid metal‐based reconfigurable electronics and electronics‐free soft robots that can perceive gravity or acceleration. [ABSTRACT FROM AUTHOR]

Achieving adaptive behavior in artificial systems, analogous to living organisms, has been a long-standing goal in electronics and materials science. Efforts to integrate adaptive capabilities into synthetic electronics traditionally involved a typical architecture comprising of sensors, an external controller, and actuators constructed from multiple materials. However, challenges arise when attempting to unite these three components into a single entity capable of independently coping with dynamic environments. Here, we unveil an adaptive electronic unit based on a liquid crystal polymer that seamlessly incorporates sensing, signal processing, and actuating functionalities. The polymer forms a film that undergoes anisotropic deformations when exposed to a minor heat pulse generated by human touch. We integrate this property into an electric circuit to facilitate switching. We showcase the concept by creating an interactive system that features distributed information processing including feedback loops and enabling cascading signal transmission across multiple adaptive units. This system responds progressively, in a multi-layered cascade to a dynamic change in its environment. The incorporation of adaptive capabilities into a single piece of responsive material holds immense potential for expediting progress in next-generation flexible electronics, soft robotics, and swarm intelligence. There is significant interest in developing electronic units that can perform sensing, signal processing, and actuation functions independently, similar to biological systems. Lyu et al. develop electronic units based on liquid crystal oligomer networks that exhibit adaptive behavior in response to environmental stimuli such as light and heat. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) are nanoscale renewable resources derived from lignocellulosic materials. They are known for their good optical permeability and self-assembly capability. Over the years, researchers have made great progress in developing CNC based structural color materials. However, their inherent brittleness limits their usage in applications such as optical sensors, food freshness testing, and flexible materials. To overcome these challenges, researchers have conducted extensive research to enhance the mechanical properties of CNCs, particularly their flexibility, and have achieved significant results. Creating flexible CNC based hand-shaped phase series films is a current research focus, but there are few reviews on this topic. To address this gap, the present review summarizes the primary strategies and recent research advances made in the last five years to improve the flexibility of CNC chiral phase series-type films. Furthermore, the present review provides deep insight into the various approaches to enhance the flexibility of CNCs, including polymer grafting, the introduction of small molecule additives, and co-assembly with added polymers. In addition, a detailed analysis of the advantages and disadvantages of these materials has been discussed briefly. Future research directions for developing flexible nanocellulose materials with structural color are outlined briefly. [ABSTRACT FROM AUTHOR]

An advanced tri‐substituted supramolecular material was synthesized via conversion of cyclotriveratrylene to cyclotriguaiacyclene with further esterification reaction with fluorescein unit embedded with side‐arms. All four luminescent materials exhibited columnar hexagonal type mesophase on both heating and cooling conditions. The materials with hexadecyloxy and octadecyloxy tail group exhibit liquid crystalline behavior at room temperature indicating the presence of a mesophase even under ambient conditions. By combining polarizing optical microscopy, differential scanning calorimetry, and high‐temperature X‐Ray diffraction techniques to understanding the optical, thermal, and molecular packing behavior of the compounds in the liquid crystalline state. The cyclotriguaiacyclene core with high fluorescent nature displayed columnar hexagonal type self‐assembly at room temperature. All four supramolecular mesogens showed higher thermal stability of mesophase. The computational study provides the importance of the electronic nature of the compounds. [ABSTRACT FROM AUTHOR]

Structured light refers to the light field tailored by various degrees of freedom including intensity, phase, and polarization states in both spatial and temporal domains, which may greatly vitalize the technologies in both optics, such as the next‐generation optical communication as well as subwavelength imaging and the materials science in both fabrication and characterization. The structured characteristics of the structure light need materials also with structured optical properties that can generate or manipulate structured light in a straightforward way, which can be well satisfied by liquid crystals, a soft mater that can self‐assemble into tunable ordered structures through external stimuli. This review summarizes the research progress of the liquid crystal‐based devices used in structured light generations and modulations, including the well‐established techniques in the market, like the spatial light modulator, q‐plate and the liquid crystal integrated optical metasurfaces. Especially, light‐matter interactions are discussed from the topological view of both the structured light and the liquid crystal structures. Such a perfect matching in topology makes the liquid crystal a promising star together with structured light in future optic and photonic technologies. [ABSTRACT FROM AUTHOR]