The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Shin-tson Wu - One of the best experts on this subject based on the ideXlab platform.
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fringe field switching with a negative Dielectric Anisotropy liquid crystal
IEEE\ OSA Journal of Display Technology, 2013Co-Authors: Yuan Chen, Fenglin Peng, Shin-tson WuAbstract:We report a high performance negative Dielectric Anisotropy (Δe) liquid crystal for fringing field switching (n-FFS) display. We compare the electro-optic characteristics of FFS cells using positive and negative Δe LCs. With comparable driving voltage and response time, the n-FFS cell has advantages in higher transmittance, single gamma curve, less cell gap sensitivity and slightly wider viewing angle. LC director deformation distribution is analyzed to explain these performance differences.
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Fringe-Field Switching with a Negative Dielectric Anisotropy Liquid Crystal
Journal of Display Technology, 2013Co-Authors: Yuan Chen, Fenglin Peng, Shin-tson WuAbstract:We report a high performance negative Dielectric Anisotropy (Δε) liquid crystal for fringing field switching (n-FFS) display. We compare the electro-optic characteristics of FFS cells using positive and negative Δε LCs. With comparable driving voltage and response time, the n-FFS cell has advantages in higher transmittance, single gamma curve, less cell gap sensitivity and slightly wider viewing angle. LC director deformation distribution is analyzed to explain these performance differences.
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high birefringence and large negative Dielectric Anisotropy phenyl tolane liquid crystals
Liquid Crystals, 2007Co-Authors: Haiqing Xianyu, Sebastian Gauza, Qiong Song, Shin-tson WuAbstract:Two phenyl‐tolane compounds with two pairs of (2,3) lateral difluoro substitutions were synthesized and their properties evaluated. These compounds exhibit a high birefringence (Δn ∼ 0.35) and a large negative Dielectric Anisotropy (Δe∼ −8). These two important features make the phenyl‐tolane compounds useful as a dopant in a negative Δe liquid‐crystal mixture to enhance the performance of the host mixture, or as a negative component in a dual‐frequency liquid‐crystal mixture to improve the Dielectric Anisotropy and birefringence and lower the crossover frequency.
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High birefringence and large negative Dielectric Anisotropy phenyl‐tolane liquid crystals
Liquid Crystals, 2007Co-Authors: Haiqing Xianyu, Sebastian Gauza, Qiong Song, Shin-tson WuAbstract:Two phenyl‐tolane compounds with two pairs of (2,3) lateral difluoro substitutions were synthesized and their properties evaluated. These compounds exhibit a high birefringence (Δn ∼ 0.35) and a large negative Dielectric Anisotropy (Δe∼ −8). These two important features make the phenyl‐tolane compounds useful as a dopant in a negative Δe liquid‐crystal mixture to enhance the performance of the host mixture, or as a negative component in a dual‐frequency liquid‐crystal mixture to improve the Dielectric Anisotropy and birefringence and lower the crossover frequency.
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12.2: Large Negative Dielectric Anisotropy and High‐Birefringence Liquid Crystals
SID Symposium Digest of Technical Papers, 2007Co-Authors: Haiqing Xianyu, Sebastian Gauza, Qiong Song, Shin-tson WuAbstract:New laterally-fluorinated biphenyl tolane liquid crystals with a large negative Dielectric Anisotropy (Δn∼−8) and high birefringence (Δn∼0.34) are developed. By doping 15 wt% of such a compound to MLC-6608 (a negative Δɛ LC mixture), the overall figure-of-merit is doubled.
F Yakuphanoglu - One of the best experts on this subject based on the ideXlab platform.
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Dielectric Anisotropy properties of nanostructure metal oxide semiconductor and 4 4 n pentylcyanobiphenyl based on nano nematic composite systems
Journal of Molecular Liquids, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy properties of SnO2, ZnO and Fe2O3 nanoparticles doped into 4-4′-n-pentylcyanobiphenyl (5CB) composite liquid crystals have been investigated. The Dielectric Anisotropy parameters and splay rotation coefficient of the 5CB nematic liquid crystal were improved by doping of SnO2, ZnO and Fe2O3 nanoparticles. The prepared nano-nematic composites exhibited p-type Δe at room temperature. The highest Δe value was found to be for Fe2O3 nanoparticles. The prepared nano-nematic composite systems exhibited an increase in the critical Dielectric Anisotropy transition frequency from 800 kHz to 1 MHz. The increase in Δe of the 5CB is due to the dipolar interaction between nanoparticles and liquid crystal molecules. The obtained results indicate that the new liquid crystals having high Dielectric Anisotropy can be prepared with the nanoparticles doping for the liquid crystal displays.
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Dielectric Anisotropy and electrical properties of the copper phthalocyanine cupc 4 4 n heptylcyanobiphenyl 7cb composite liquid crystals
Composites Part B-engineering, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) and the Dielectric Anisotropy changes from positive to negative Dielectric Anisotropy (n-type Δ ɛ ) behavior with frequency of applied electrical field. The critical frequency f c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.
Faten Alhazmi - One of the best experts on this subject based on the ideXlab platform.
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Dielectric Anisotropy properties of nanostructure metal oxide semiconductor and 4 4 n pentylcyanobiphenyl based on nano nematic composite systems
Journal of Molecular Liquids, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy properties of SnO2, ZnO and Fe2O3 nanoparticles doped into 4-4′-n-pentylcyanobiphenyl (5CB) composite liquid crystals have been investigated. The Dielectric Anisotropy parameters and splay rotation coefficient of the 5CB nematic liquid crystal were improved by doping of SnO2, ZnO and Fe2O3 nanoparticles. The prepared nano-nematic composites exhibited p-type Δe at room temperature. The highest Δe value was found to be for Fe2O3 nanoparticles. The prepared nano-nematic composite systems exhibited an increase in the critical Dielectric Anisotropy transition frequency from 800 kHz to 1 MHz. The increase in Δe of the 5CB is due to the dipolar interaction between nanoparticles and liquid crystal molecules. The obtained results indicate that the new liquid crystals having high Dielectric Anisotropy can be prepared with the nanoparticles doping for the liquid crystal displays.
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Dielectric Anisotropy and electrical properties of the copper phthalocyanine cupc 4 4 n heptylcyanobiphenyl 7cb composite liquid crystals
Composites Part B-engineering, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) and the Dielectric Anisotropy changes from positive to negative Dielectric Anisotropy (n-type Δ ɛ ) behavior with frequency of applied electrical field. The critical frequency f c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.
Fowzia Alnowaiser - One of the best experts on this subject based on the ideXlab platform.
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Dielectric Anisotropy properties of nanostructure metal oxide semiconductor and 4 4 n pentylcyanobiphenyl based on nano nematic composite systems
Journal of Molecular Liquids, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy properties of SnO2, ZnO and Fe2O3 nanoparticles doped into 4-4′-n-pentylcyanobiphenyl (5CB) composite liquid crystals have been investigated. The Dielectric Anisotropy parameters and splay rotation coefficient of the 5CB nematic liquid crystal were improved by doping of SnO2, ZnO and Fe2O3 nanoparticles. The prepared nano-nematic composites exhibited p-type Δe at room temperature. The highest Δe value was found to be for Fe2O3 nanoparticles. The prepared nano-nematic composite systems exhibited an increase in the critical Dielectric Anisotropy transition frequency from 800 kHz to 1 MHz. The increase in Δe of the 5CB is due to the dipolar interaction between nanoparticles and liquid crystal molecules. The obtained results indicate that the new liquid crystals having high Dielectric Anisotropy can be prepared with the nanoparticles doping for the liquid crystal displays.
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Dielectric Anisotropy properties of nanostructure metal oxide semiconductor and 4-4′-n-pentylcyanobiphenyl based on nano-nematic composite systems
Journal of Molecular Liquids, 2014Co-Authors: Faten Al-hazmi, Fowzia Alnowaiser, Ahmed A. Al-ghamdi, Noruh Al-senany, Fahrettin YakuphanogluAbstract:Abstract Dielectric Anisotropy properties of SnO2, ZnO and Fe2O3 nanoparticles doped into 4-4′-n-pentylcyanobiphenyl (5CB) composite liquid crystals have been investigated. The Dielectric Anisotropy parameters and splay rotation coefficient of the 5CB nematic liquid crystal were improved by doping of SnO2, ZnO and Fe2O3 nanoparticles. The prepared nano-nematic composites exhibited p-type Δe at room temperature. The highest Δe value was found to be for Fe2O3 nanoparticles. The prepared nano-nematic composite systems exhibited an increase in the critical Dielectric Anisotropy transition frequency from 800 kHz to 1 MHz. The increase in Δe of the 5CB is due to the dipolar interaction between nanoparticles and liquid crystal molecules. The obtained results indicate that the new liquid crystals having high Dielectric Anisotropy can be prepared with the nanoparticles doping for the liquid crystal displays.
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Dielectric Anisotropy and electrical properties of the copper phthalocyanine cupc 4 4 n heptylcyanobiphenyl 7cb composite liquid crystals
Composites Part B-engineering, 2014Co-Authors: Faten Alhazmi, Ahmed A Alghamdi, Noruh Alsenany, Fowzia Alnowaiser, F YakuphanogluAbstract:Abstract Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) and the Dielectric Anisotropy changes from positive to negative Dielectric Anisotropy (n-type Δ ɛ ) behavior with frequency of applied electrical field. The critical frequency f c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.
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Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-Heptylcyanobiphenyl (7CB) composite liquid crystals
Composites Part B-engineering, 2013Co-Authors: Faten Al-hazmi, Fowzia Alnowaiser, Ahmed A. Al-ghamdi, Noruh Al-senany, Fahrettin YakuphanogluAbstract:Abstract Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) and the Dielectric Anisotropy changes from positive to negative Dielectric Anisotropy (n-type Δ ɛ ) behavior with frequency of applied electrical field. The critical frequency f c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.
Fahrettin Yakuphanoglu - One of the best experts on this subject based on the ideXlab platform.
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Dielectric Anisotropy properties of nanostructure metal oxide semiconductor and 4-4′-n-pentylcyanobiphenyl based on nano-nematic composite systems
Journal of Molecular Liquids, 2014Co-Authors: Faten Al-hazmi, Fowzia Alnowaiser, Ahmed A. Al-ghamdi, Noruh Al-senany, Fahrettin YakuphanogluAbstract:Abstract Dielectric Anisotropy properties of SnO2, ZnO and Fe2O3 nanoparticles doped into 4-4′-n-pentylcyanobiphenyl (5CB) composite liquid crystals have been investigated. The Dielectric Anisotropy parameters and splay rotation coefficient of the 5CB nematic liquid crystal were improved by doping of SnO2, ZnO and Fe2O3 nanoparticles. The prepared nano-nematic composites exhibited p-type Δe at room temperature. The highest Δe value was found to be for Fe2O3 nanoparticles. The prepared nano-nematic composite systems exhibited an increase in the critical Dielectric Anisotropy transition frequency from 800 kHz to 1 MHz. The increase in Δe of the 5CB is due to the dipolar interaction between nanoparticles and liquid crystal molecules. The obtained results indicate that the new liquid crystals having high Dielectric Anisotropy can be prepared with the nanoparticles doping for the liquid crystal displays.
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Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-Heptylcyanobiphenyl (7CB) composite liquid crystals
Composites Part B-engineering, 2013Co-Authors: Faten Al-hazmi, Fowzia Alnowaiser, Ahmed A. Al-ghamdi, Noruh Al-senany, Fahrettin YakuphanogluAbstract:Abstract Dielectric Anisotropy and electrical properties of the copper phthalocyanine (CuPc): 4–4′-n-heptylcyanobiphenyl (7CB) composite liquid crystals have been investigated. Liquid crystals exhibit Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) and the Dielectric Anisotropy changes from positive to negative Dielectric Anisotropy (n-type Δ ɛ ) behavior with frequency of applied electrical field. The critical frequency f c values for the 7CB and CuPc doped 7CB liquid crystals were found to be 602 kHz and 518 kHz, respectively. This indicates that CuPc doping causes a decrease in the critical frequency. The splay elastic coefficients of the 7CB and CuPc doped 7CB liquid crystals were determined and CuPc doping increases the splay elastic coefficient of 7CB liquid crystal. The 7CB liquid crystal exhibits a voltage-controlled differential negative resistance (VCNR) behavior and CuPc doping affects significantly VCNR behavior of 7CB.
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Molecular orientation and Dielectric Anisotropy properties of 4-cyano-4′-n-heptylbiphenyl–TiO2 liquid crystal composite
Journal of Non-crystalline Solids, 2008Co-Authors: Mustafa Okutan, Fahrettin Yakuphanoglu, O. Köysal, G. OweimreenAbstract:Abstract The molecular orientation and the Dielectric Anisotropy of the nematic liquid crystal (LC) 4-cyano-4′-n-heptylbiphenyl (7CB) and of TiO2-doped 7CB have been investigated. The Dielectric properties of the LCs exhibit a relaxation peak that shifts to lower frequencies with increasing voltages. The relaxation frequencies of 7CB and 7CB/TiO2 liquid crystals were calculated and found to decrease as the bias voltage increases. This is attributed to molecular reorientation. The Dielectric Anisotropy of the LCs changes from the positive type to negative type and the static electric permittivity and Dielectric Anisotropy values were found to be lower for the 7CB/TiO2 system.
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Conductance and Dielectric Anisotropy properties of 4-cyano-4′-hexylbiphenyl-salicylaldimine compound composite liquid crystal exhibiting large positive Dielectric Anisotropy
Physica B-condensed Matter, 2007Co-Authors: Fahrettin Yakuphanoglu, Belkız Bilgin-eran, Hale Ocak, G. OweimreenAbstract:Abstract The electronic properties of 4-cyano-4′-hexylbiphenyl and salicylaldimine compound 1 liquid crystals have been investigated. The polarizing microscopy and differential scanning calorimetry results show that chiral salicylaldimine compound 1 exhibits enantiotropic smectic A* and SmC* mesophases. The novel 4- n -hexyl-4′-cyanobiphenyl/salicylaldimine compound 1 composite showed an extremely large positive Dielectric Anisotropy. The Dielectric Anisotropy of the LCs changes from positive type to negative type. The critical frequency f c values of Dielectrical Anisotropy for 4- n -hexyl-4′-cyanobiphenyl and salicylaldimine compound 1 LCs were found to be 630.50 and 813.01 kHz, respectively. The splay elastic constant K 11 values of the liquid crystals were calculated and the doping of salicylaldimine compound 1 into 4-cyano-4′-hexylbiphenyl liquid crystal increases the splay elastic constant of 6CB. The parallel conductivity σ ∥ values of the liquid crystals are higher than that of perpendicular conductivity σ ⊥ values and conductivity of the 4-cyano-4′-hexylbiphenyl decreases with doping of salicylaldimine compound 1 .
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Dielectric Anisotropy, and diffraction efficiency properties of a doped nematic liquid crystal
Dyes and Pigments, 2007Co-Authors: Fahrettin Yakuphanoglu, Mustafa Okutan, O. Köysal, Sam-rok KeumAbstract:Abstract The Dielectric Anisotropy and diffraction efficiency properties of E7 liquid crystal and SPCI-C7 doped liquid crystal composite have been investigated. The Dielectric constant components ( ɛ ∥ and ɛ ⊥ ) in the nematic phase of E7 were measured as a function of frequency. The liquid crystals exhibited Dielectrically-controlled positive Dielectric Anisotropy (p-type Δ ɛ ) with transition to negative Dielectric Anisotropy (n-type Δ ɛ ). SPCI-C7 doping lowered Dielectric Anisotropy and increased the diffraction efficiency of E7. The refractive index modulation values of E7 and E7/SPCI-C7 were Δ n = 3.9 × 10 −3 and Δ n = 6.95 × 10 −3 , respectively, and this parameter was increased by doping.