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Optical modulation studies of multiwall carbon nanotube dispersed in hydrogen bonded ferroelectric liquid crystal mixture for electro-optic devices
摘要： Structural, optical and electrical properties of multiwall carbon nano-tubes (MWCNT) dispersed liquid crystalline (LC) mixture is extensively studied for electro-optic devices. A small amount of (0.1%) MWCNT is dispersed in cholesteryl stearate (CHS) and 4-dodecyloxybenzoic acid (12OBA) and its mixture is further characterized. Hydrogen bond between the mesogenic compounds are confirmed using FT-IR. Surface morphology and MWCNT dispersion in hydrogen bonded (HBFLC) mixture is established by SEM ferroelectric liquid crystal the mixture using polarizing optical studies. Optical studies of microscope (POM) is recognized by the induced smectic blue phase and smectic A mesogenic phases. Transition temperatures and its corresponding enthalpy values of induced mesophases are analyzed by differential scanning calorimetry (DSC). An interesting observation of optical modulation in the present MWCNT dispersed HBFLC mixture is reported using dielectric studies. Textural modification with respect to external stimulus (bias voltage) in the present HBFLC mixture is reported. Further the field induced phase transitions and improved dielectric permittivity due to the dispersion of MWCNT is also reported.
关键词： optical modulation,optical shutter,HBFLC,POM,MWCNT
更新于2025-09-23 15:21:01
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POM-based dyes featured rigidified bithiophene ?? linkers: Potential high-efficient dyes for dye-sensitized solar cells
摘要： A series of POM-based dyes with triphenylamine electron donor group, cyanoacrylic acid electron acceptor group and different π linkers of thiophene derivatives are systematically investigated to analyze the influence of rigidified bithiophene with fastening atoms (C and N) on the performance of dye-sensitized solar cells (DSSCs) based on density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The interfacial electron transfer (IET) processes are evaluated, which is less investigated previously. We can see that the electron in dyes 2, 4 and 5 are almost completely injected after 100 fs, thus leading to the fast IET. Dye 2 not only has lower interaction energy for most stable dimer configuration than dye 1, but also has larger short-circuit photocurrent density JSC and open-circuit photovoltage VOC, resulting from the insertion of POM group. Compared with dye 3 containing 2,2'-bithiophene π linker, its two counterparts (dyes 4 and 5) with rigidified bithiophene π linkers tend to accelerate IET process as well as retard the electron recombination, thus improve the performance of DSSCs. In particular, dye 4 with rigidified bithiophene π linker fastening by C atom would obtain the larger JSC and VOC than that of dye 5 with N atom rigidified bithiophene π linker.
关键词： rigidified bithiophene,POM-based dyes,interfacial electron transfer,dye-sensitized solar cells,density functional theory
更新于2025-09-23 15:21:01
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Thermal and Electro-optical Properties of Graphene Oxide/Dye-Doped Nematic Liquid Crystal
摘要： In this paper, the liquid crystalline complex systems were obtained by dispersing graphene oxide (GO) and methyl blue (MB) dye to liquid crystal mixture E7. The phase transitions and microstructural properties of the prepared liquid crystalline complex systems were investigated by differential scanning calorimeter (DSC) and polarised optical microscopy (POM). DSC and POM results showed that there was no change in the molecular structures of the complexes and they exhibited completely liquid crystalline properties during continuous heating. Also, the voltage-dependent optical transmissions of the complex systems were measured by the voltage transmittance experiments. It was found that the optical transmissions of the complex systems were not very different from the each other, but threshold voltage of the complex decreased by GO doping and increased for MB/GO doping. Furthermore, the dielectric properties of the complex systems were investigated by using impedance analyser. Dielectrically, measurements showed that the dielectric constant decreased with the dispersion of GO and GO/MB, and the critical frequency of E7 increased with doping.
关键词： POM,Graphene oxide,Electro-optic,Nematic liquid crystals
更新于2025-09-11 14:15:04
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Tetrakis(oxadiazolylphenyl)pyrazines: New St. Andrew's Cross- Shaped Liquid Crystals
摘要： π-Conjugated molecules with the shape of St. Andrews cross have been synthesized via fourfold Huisgen reaction. Four 2,5-diaryl-1,3,4-oxadiazol arms are attached to a central pyrazine nucleus. These fluorescent stars, when decorated with a rim of eight alkoxy side chains are discotic liquid crystals. Depending on the substitution pattern, the width of the liquid phase varies within a broad range of 25 °C to 250 °C. In their liquid crystalline phase, the molecules assemble in a typical hexagonal columnar supramolecular arrangement.
关键词： solvatochromism,liquid crystals,WAXS,POM,pyrazine
更新于2025-09-10 09:29:36