Vibrational spectra, dielectric properties, conductivity mechanisms and third order nonlinear optical properties of guanidinium 4-aminobenzoate

George, Jesby; Sasikala, V.; Joy, Lija K.; Sajan, D.; Arumanayagam, T.; Murugakoothan, P.; Vinitha, G.

doi:10.1016/j.optmat.2019.01.006

Cited by 16 publications

(2 citation statements)

References 64 publications

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“…The HOMO-LUMO energy gaps (ΔE) of BNA and 5CB molecules was calculated using DFT with B3LYP at the 6-31 + G (2d, p) basis set using Gaussian 09 software. As shown in Table 3, the calculated ΔE of BNA, 5CB, and BNA + 5CB were 3.79, 4.60, and 3.91 eV, respectively 62 . A low value of the ΔE pertains to the concluding CT interactions taking place within the molecule and causes a highly polarized electronic structure.…”

Section: Resultsmentioning

confidence: 94%

Electro-optical effects of organic N-benzyl-2-methyl-4-nitroaniline dispersion in nematic liquid crystals

Selvaraj

Karthick

Brahadeeswaran

et al. 2020

Sci Rep

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The dispersion of organic N-benzyl-2-methyl-4-nitroaniline (BNA) in nematic liquid crystals (LCs) is studied. BNA doping decreases the threshold voltage of cell because of the reduced splay elastic constant and increased dielectric anisotropy of the LC mixture. When operated in the high voltage difference condition, the BNA-doped LC cell has a fall time that is five times faster than that of the pure one because of the decrements in the threshold voltage of the cell and rotational viscosity of the LC mixture. The additional restoring force induced by the BNA's spontaneous polarization electric field (SPEF) also assists to decrease the fall time of the LC cell. The decreased viscosity can be deduced from the decrements in phase transition temperature and associated order parameter of the LC mixture. Density functional theory calculation demonstrates that the BNA dopant strengthens the absorbance for blue light, enhances the molecular interaction energy and dipole moment, decreases the molecular energy gap, and thus increases the permittivity of the LC mixture. The calculation also shows that the increased dipole moment, polarizability, and polarizability anisotropy increase the dielectric anisotropy of the LC mixture, which agrees with the experimental results well. BNA doping has a promising application to the fields of LC devices and displays. Nematic liquid crystals (LCs) are extraordinarily responsive and optically uniaxial materials. Nematic LCs have been extensively used in diverse applications, such as optical nonlinearity, optical phase modulators, microdisplays, flat panel displays, optical antennas, and optical switching, due to their electro-optical property and other admirable features 1-5. LCs with a fast response are vital in removing motion blur in moving pictures and resolving cross-talk in 3D displays 6-9. The response time of LCs should be less than 3 ms to diminish motion blur and cross-talk. Several techniques have been proposed to resolve this issue, and they include tuning the viscosity of materials 10 , varying the anchoring energy 11 , changing the electrode shape and driving scheme 12 , changing the cell gap 13 , modifying the guest-host material 14 , and applying new switching modes 15. The improvements in the electro-optical properties of LCs with the dispersion of different gust entities were presented recently. For example, Y. Dai et al. demonstrated that the incorporation of γ-Fe 2 O 3 nanoparticles into LCs results in a response time of 4.75 ms with the application of the overdriving scheme, which is three times faster than pure LCs 16. A response time of around 4 ms was obtained with the addition of a small amount of dye to a polymer-dispersed liquid crystal (PDLC) or functionalized carbon nanotubes dispersed in optically isotropic LCs. However, in this case, the excellent response speed is valid only for operation at a relatively high voltage 17,18. Blue-phase LCs have a response time of 0.5 ms, but they still have drawbacks, such as hysteresis, high operation voltage, and narrow t...

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Section: Resultsmentioning

confidence: 94%

Electro-optical effects of organic N-benzyl-2-methyl-4-nitroaniline dispersion in nematic liquid crystals

Selvaraj

Karthick

Brahadeeswaran

et al. 2020

Sci Rep

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“…Similarly, the M2C4N dopant shifts the absorbance peak of the LCs toward the long-wavelength side because the primary amine and hydroxyl groups in M2C4N strongly connect with the CN group in LCs [ 44 ]. The organic dopants shift the absorbance peaks of LC mixture toward long wavelengths, indicating they decrease the HOMO-LUMO energy bandgap (Δ E ) of LC mixture, owing to the inverse relationship between Δ E and wavelength [ 18 , 45 , 46 , 47 ]. Figure 6 c shows the measured transmission spectra of the pristine, 3 wt% BNA-doped, and 3 wt% M2C4N-doped LC cells over the visible range.…”

Section: Resultsmentioning

confidence: 99%

A Comparative Study on Electro-Optic Effects of Organic N-Benzyl-2-Methyl-4-Nitroaniline and Morpholinium 2-Chloro-4-Nitrobenzoate Doped in Nematic Liquid Crystals E7

et al. 2020

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Improvements in electro-optical responses of LC devices by doping organic N-benzyl-2-methyl-4-nitroaniline (BNA) and Morpholinium 2-chloro-4-nitrobenzoate (M2C4N) in nematic liquid crystals (LCs) have been reported in this study. BNA and M2C4N-doped LC cells have the fall time that is fivefold and threefold faster than the pristine LC cell, respectively. The superior performance in fall time of BNA-doped LC cell is attributed to the significant decrements in the rotational viscosity and threshold voltage by 44% and 25%, respectively, and a strong additional restoring force resulted from the spontaneous polarization electric field of BNA. On the other hand, the dielectric anisotropy (Δε) of LC mixture is increased by 16% and 6%, respectively, with M2C4N and BNA dopants. M2C4N dopant induces a large dielectric anisotropy, because the phenyl-amine/hydroxyl in M2C4N induces a strong intermolecular interaction with LCs. Furthermore, BNA dopant causes a strong absorbance near the wavelength of 400 nm that filters the blue light. The results indicate that M2C4N doping can be used to develop a high Δε of LC mixture, and BNA doping is appropriate to fabricate a fast response and blue-light filtering LC device. Density Functional Theory calculation also confirms that BNA and M2C4N increase the dipole moment, polarization anisotropy, and hence Δε of LC mixture.

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Studies on growth, optical, dielectric, and third-order nonlinearity of 4-methyl N-(4-chlorobenzylidene)aniline (4CBT) crystal

Ramnivasmirtha¹,

Balaji²,

Sneha³

et al. 2020

J Mater Sci: Mater Electron

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Vibrational spectra, dielectric properties, conductivity mechanisms and third order nonlinear optical properties of guanidinium 4-aminobenzoate

Cited by 16 publications

References 64 publications

Electro-optical effects of organic N-benzyl-2-methyl-4-nitroaniline dispersion in nematic liquid crystals

Electro-optical effects of organic N-benzyl-2-methyl-4-nitroaniline dispersion in nematic liquid crystals

A Comparative Study on Electro-Optic Effects of Organic N-Benzyl-2-Methyl-4-Nitroaniline and Morpholinium 2-Chloro-4-Nitrobenzoate Doped in Nematic Liquid Crystals E7

Studies on growth, optical, dielectric, and third-order nonlinearity of 4-methyl N-(4-chlorobenzylidene)aniline (4CBT) crystal

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