Electro-optics of blue phase liquid crystal in field-perpendicular direction

The electro-optic effect is the working principle of blue phase (BP) liquid crystals, and it describes the relationship between the field-induced birefringence of BPs and the field strength. Due to the electrostriction of BP crystals under the electric field, an orthorhombic or tetragonal crystal is usually obtained when the field is applied along one of the twofold axes of a BP crystal, leading to the optical biaxiality under electric field. Such field-induced optical biaxiality of BPs has been predicted and observed, but its dependence on the field strength has not been investigated. In this research, we analyze the electro-optics in the field-perpendicular direction by measuring the birefringence in highly ordered BP I(110) crystals perpendicular to the electric field. Results reveal that BP I crystals in the field-perpendicular direction show an electro-optic coefficient of the order of 10−10 m/V2 that may result from the large lattice deformation of BP crystals perpendicular to the electric field. Our research provides important experimental evidence for the tensorial properties of BP Kerr effect and may have important implications on the engineering of BP electro-optical devices in practical applications.Zhang Y., Yoshida H., Wang Q.H., et al. Electro-optics of blue phase liquid crystal in field-perpendicular direction. Applied Physics Letters 122, 161107 (2023); https://doi.org/10.1063/5.0142383

Transflective liquid crystal display using separate transmissive and reflective liquid crystal cells and materials with single cell gap

A transflective liquid crystal display (TLCD) using separate transmissive (T) and reflective (R) cells in which two liquid crystal materials with different birefringence changes are used. The birefringence change of the R region is half of the birefringence change of the T region. In this case, a single cell gap is possible and identical transmittance and reflectance for R and T is obtained. It is applicable to various reflective LC modes, and the fabrication methods are simple

Transflective LCD Using Multilayer Dielectric Film Transflector

A novel transflective liquid crystal display (LCD) is provided with a multilayer dielectric film transflector. The dielectric transflector is composed of alternating high and low refractive index dielectric material layers deposited directly on the inner side of the LCD substrate to avoid parallax. The transmittance of the dielectric transflector can vary from approximately 5% to approximately 95% by simply adjusting the individual dielectric layer thickness and the arrangement of layers. The thickness of the 10-layer film is approximately 700 nm, which does not affect the voltage drop on the LC. Two structures of the dielectric film using different positions of the materials of construction are provided and demonstrated. Such a transflective LCD exhibits outstanding features, such as, robust dielectric film, single cell gap, no parallax, and a simple fabrication process

Perdeuterated cyanobiphenyl liquid crystals for infrared applications

Perdeuterated 4'-pentyl-4-cyanobiphenyl (D5CB) was synthesized and its physical properties evaluated and compared to those of 5CB. D5CB retains physical properties similar to those of 5CB, such as phase transition temperatures, dielectric constants, and refractive indices. An outstanding feature of D5CB is that it exhibits a much cleaner and reduced infrared absorption. Perdeuteration, therefore, extends the usable range of liquid crystals to the mid infrared by significantly reducing the absorption in the near infrared, which is essential for telecom applications

A tetra­silver(I)ditungsten(VI) cluster with sulfide and bis­(diphenyl­phosphino)methane ligands

The asymmetric unit of the title complex, [Ag4W2S8(C25H22P2)3]·2C3H7NO, tris­[μ2-bis­(diphenyl­phosphino)meth­ane]-3:6κ2 P:P′;4:5κ2 P:P′;5:6κ2 P:P′-μ5-sulfido-2:3:4:5:6κ5 S-μ3-sulfido-1:3:4κ3 S-tetra-μ2-sulfido-1:3κ2 S;1:4κ2 S;2:5κ2 S;2:6κ2 S-disulfido-1κS,2κS-tetra­silver(I)ditungsten(VI) N,N-dimethyl­formamide disolvate, contains two [WS4]2− anions, four silver cations, three bidentate–bridging bis­(diphenyl­phosphino)methane (dppm) ligands and two N,N-dimethyl­formamide (DMF) solvent mol­ecules. The coordination geometry of each Ag atom is distorted tetra­hedral. Two Ag ions are coordinated by μ2-S and μ5-S atoms, and by two P atoms from two dppm ligands, while the other two Ag atoms are coordinated by μ2-S, μ3-S and μ5-S atoms, and by one P atom from a dppm ligand