Spectroscopic, dielectric and nonlinear current–voltage characterization of a hydrogen-bonded liquid crystalline compound influenced via graphitic nanoflakes: An equilibrium between the experimental and theoretical studies - Université du Littoral Côte d'Opale
Article Dans Une Revue Journal of Molecular Liquids Année : 2020

Spectroscopic, dielectric and nonlinear current–voltage characterization of a hydrogen-bonded liquid crystalline compound influenced via graphitic nanoflakes: An equilibrium between the experimental and theoretical studies

Résumé

Herein, we investigate a hydrogen-bonded liquid crystal compound, namely 4-(Heptyloxy) benzoic acid (7OBA), and its composites by dispersing Graphene and reduced graphene oxide (rGO) flakes into an optimized concentration. The pristine 7OBA and its composites are characterized by different instrumental techniques like polarized optical microscopy, differential scanning calorimetry (DSC), dielectric, UV-visible, and Fourier-transform infrared (FTIR) spectroscopy. DSC thermograms of the 7OBA composites evince the down-shift in the smectic C−nematic and nematic−isotropic phase transition temperatures. The polarized optical micrographs (POMs) of composites reveal the homogeneous distribution of graphene and rGO flakes in the 7OBA compound without any aggregation. The π-π* transitions in phenyl ring of 7OBA compound and π-π* transitions in Cdouble bondC bonds of graphitic materials are superimposed to each other providing an enhanced UV absorbance nearly at 255 nm for the composites. The presence of graphene and rGO enhances the tan δ and electrical conductivity of the composites, whereas dielectric anisotropy, Δϵ, reduces as a function of temperature in comparison to the pristine 7OBA compound. The sign inversion of Δϵ has been observed for the 7OBA/rGO composite which has been explained via dipole−dipole interactions. The I−V behavior of the pristine 7OBA compound yields the ohmic I−V curve with a non-zero current at 0 V attributing to the pseudocapacitance effect, whereas, after the dispersion of graphene and rGO flakes, nonlinear diode like I−V curves having a hundred times larger conduction current were obtained. Furthermore, the molecular interactions have been analyzed by the FTIR which confirms the formation of hydrogen bonding in the 7OBA/rGO composite. At last, these experimental findings are compared with the simulated results by DFT. The experimental and theoretical simulations are commensurable to each other. The studied composites have shown their vital applications in nonlinear electronics.

Dates et versions

hal-04455837 , version 1 (13-02-2024)

Identifiants

Citer

Dharmendra Pratap Singh, Abhishek Kumar Misra, Kamal Kumar Pandey, Bhavna Pal, Narinder Kumar, et al.. Spectroscopic, dielectric and nonlinear current–voltage characterization of a hydrogen-bonded liquid crystalline compound influenced via graphitic nanoflakes: An equilibrium between the experimental and theoretical studies. Journal of Molecular Liquids, 2020, 302, pp.112537. ⟨10.1016/j.molliq.2020.112537⟩. ⟨hal-04455837⟩
10 Consultations
0 Téléchargements

Altmetric

Partager

More