BITS Faculty Publications
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Item Hydrothermal synthesis of conductive copper nanowires: effect of oleylamine and dextrose concentrations(RSC, 2025-11) Etika, Krishna ChitanyaOne-dimensional (1-D) metallic nanoparticles (i.e., nanowires, nanorods) exhibit unique properties and are useful in a variety of applications. 1-D copper nanowires (CuNWs) exhibit excellent electrical conductivity making them an economical alternative in applications that typically employ silver or gold nanowires. In this study, CuNWs were synthesized via an environmentally benign and scalable hydrothermal synthesis method using CuCl2 (CuP) as a copper precursor. Oleylamine (OAm) and dextrose (D) were employed as capping and reducing agents, respectively. The focus of this work was to investigate the influence of varying CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAm and CuP[thin space (1/6-em)]:[thin space (1/6-em)]D molar ratios during synthesis on the nanowire growth, morphology, and electrical conductivity. A series of synthesis trials were conducted by only varying CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAm or CuP[thin space (1/6-em)]:[thin space (1/6-em)]D molar ratios, while keeping all other reaction conditions constant. Morphological analysis of the synthesized products suggests that both OAm and D are essential for the formation of CuNWs. A synthesis conducted at a 1[thin space (1/6-em)]:[thin space (1/6-em)]3.75[thin space (1/6-em)]:[thin space (1/6-em)]1.1 CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAm[thin space (1/6-em)]:[thin space (1/6-em)]D molar ratio produced nanowires with average diameter of 96 nm, while higher OAm concentration resulted in CuNWs with larger diameters. X-ray diffraction analysis confirmed the crystalline nature of the synthesized CuNWs, with diffraction peaks corresponding well to those of FCC copper. The capping of CuNWs with OAm was confirmed through FTIR spectroscopy. Thermogravimetric (TGA) studies on CuNWs show that OAm content in CuNWs increases with increasing CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAm molar ratio during synthesis. The electrical conductivity of CuNW pellets was found to decrease with increasing CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAM molar ratio during synthesis. The highest conductivity of 1.38 × 105 S cm−1 was exhibited in the sample made using 1[thin space (1/6-em)]:[thin space (1/6-em)]3.75[thin space (1/6-em)]:[thin space (1/6-em)]1.1 CuP[thin space (1/6-em)]:[thin space (1/6-em)]OAm[thin space (1/6-em)]:[thin space (1/6-em)]D molar ratio. Furthermore, holding CuNWs pellets under ambient conditions for 60 days did not affect their electrical conductivity.Item Electrical conductivity and Hall conductivity of a hot and dense hadron gas in a magnetic field: a relaxation time approach(APS, 2019-05) Das, ArpanWe estimate the electrical conductivity and the Hall conductivity of a hot and dense hadron gas using the relaxation time approximation for the solution of the Boltzmann transport equation in the presence of an electromagnetic field. We investigate the temperature and the baryon chemical potential dependence of these transport coefficients in the presence of a magnetic field. The explicit calculation is performed within the ambit of the hadron resonance gas model. In general, it is observed that the electrical conductivity decreases in the presence of a magnetic field. While at vanishing magnetic field the electrical conductivity decreases monotonically with temperature, in the presence of a magnetic field the same shows a nonmonotonic behavior with a peak. The Hall conductivity, on the other hand, shows a nonmonotonic behavior with respect to the dependence on a magnetic field as well as with temperature. We argue that for a pair plasma (particle-antiparticle plasma) where 𝜇𝐵 =0 , Hall conductivity vanishes. Only for a nonvanishing baryon chemical potential, Hall conductivity has a nonzero value. We also estimate the electrical conductivity and the Hall conductivity as a function of the center of mass energy along the freeze-out curve as may be relevant for relativistic heavy-ion collision experiments.Item Electrical conductivity and Hall conductivity of a hot and dense quark gluon plasma in a magnetic field: a quasiparticle approach(APS, 2020-02) Das, ArpanWe estimate here the electrical and Hall conductivity using a quasiparticle approach for quark matter. We use a Boltzmann kinetic approach in the presence of external magnetic field. We confront the results of model calculations with lattice QCD simulations for vanishing magnetic field. In general, electrical conductivity decreases with magnetic field. The Hall conductivity on the other hand can show a nonmonotonic behavior with magnetic field due to an intricate interplay of behavior of relaxation time and strength of the magnetic field. We argue for vanishing quark chemical potential Hall conductivity vanishes and quark gluon plasma with finite quark chemical potential can show Hall effect. Both electrical conductivity and Hall conductivity increase with increasing quark chemical potential.Item Nanosheets of In2S3/S-C3N4-Dots for Solar Water-Splitting in Saline Water(ACS, 2022-10) Basu, MrinmoyeeHydrogen generation from splitting of water under the photoelectrochemical (PEC) pathway is considered as the most promising strategy for covering the upcoming fuel crisis by taking care of all environmental issues. In this context, In2S3 can be explored as it is a visible light-active semiconductor with an appropriate band alignment with the water redox potential. Herein, In2S3 nanosheets are developed by the chemical method. The nanosheets of In2S3 absorb high visible light due to the manifold inside scattering and reflection. The PEC activity of In2S3 is enhanced because of the increase in the light absorbance of the materials. In the present work, at 1.18 V versus RHE in 3.5 wt % NaCl, a maximum 2.07 mA/cm2 photocurrent density can be achieved by In2S3 nanosheets. However, In2S3 suffers strongly due to photo-corrosion. To improve the efficacy of the In2S3 nanosheets in saline water, the charge-carrier transportation ability of In2S3 is aimed to increase by decorating S-C3N4-dots on In2S3. The heterostructure of type-II is developed by sensitization of S-C3N4-dots on In2S3. It increases both the transportation of charge carriers as well as separation. In the heterostructure, the transient decay time (τ) increases, which indicates a decrease in photogenerated charge-carrier recombination. S-C3N4-dots also act as an optical antenna and increase the range of visible light absorbance of In2S3. The heterostructure can generate ∼2.38-fold higher photocurrent density of 1.18 V versus RHE in 3.5 wt % NaCl. The photoconversion efficiency of the heterostructure is 0.88% at 0.95 V versus RHE. The nanosheets of In2S3 and In2S3/S-C3N4-dots are stable, and photocurrent density is measured up to 2700 s under continuous back-illumination conditions.Item Microscopic Insights of Electrochemical Switching of Poly(benzimidazobenzophenanthroline) (BBL) Thin Film: A Molecular Dynamics Study(ACS, 2009-04) Sarbani, Ghosh; Garg, MohitCarbon nanotubes typically require the use of a dispersing or stabilizing agent to prevent significant aggregation during incorporation into a polymer matrix. These additives must be strongly associated, either covalently or physically, to achieve their purpose. In this study, multi-walled carbon nanotubes (MWNTs) were dispersed into an epoxy matrix using polyethylenimine (PEI) as a dispersant that was either covalently attached to the nanotubes or physically mixed to result in only noncovalent interaction. Epoxy composites containing covalently modified MWNTs exhibited greater storage modulus and reduced electrical conductivity.Item META Ion trapping in nematic liquid crystal by incorporating functionalised silver nanoparticles. P. 4(INIS, 2019-07) Manjuladevi, V.; Gupta, Raj KumarIn this work, the effect of functionalised silver nanoparticles (f-AgNPs) on the dielectric constant, electrical conductivity and birefringence of a rod shaped NLC 4-trans-pentyl cyclohexylcyanobenzene (5PCH) has been investigated in the planar cell as a function of temperature. The magnitude of dielectric anisotropy, elastic constants and birefringence in nanocomposites of 5PCH were enhanced with increasing concentration of f-AgNPs indicating enhancement of order parameter in the nematic medium. From the study it is observed that, the conductivity has reduced in f-AgNps nanocomposites of 5PCH compared to pure 5PCH due to the absorption of ions by f-AgNPs which is further confirmed by measuring transient current and ion transport number. So our results show that f-AgNPs can be used as ion trapping agent with other improved physical properties suitable for display devicesItem Investigation on physical properties of silver nanorod doped nematic liquid crystal(AIP, 2021-09) Manjuladevi, V.; Gupta, Raj KumarImprovement in the physical properties of nematic liquid crystals plays an important role in the performance of display devices. In the present study, the physical properties of silver nanorod (AgNR) doped nematic liquid crystal is investigated. The negligible change is observed in the value of birefringence for the lower doping concentration of AgNR in NLC. The parallel and perpendicular components of dielectric permittivity at T-TIN = −15 ° C increase with the addition of lower concentration (≤ 0.5 wt%) of silver nanorods to the NLC host. The ac conductivity decreases with the increase in the dopant concentration because of the trapping of ionic impurities of NLCItem Electrical transport in superionic thin films prepared by pulsed laser deposition(AIP, 2011) Dalvi, AnshumanSuperionic thin films are obtained using PLD technique from ion oxysalt glassy target. The structural and electrical properties of the films have been investigated. Partially amorphous nature of the films has been confirmed by X‐ray diffraction measurements. The electrical conductivity of the sample has been measured at well controlled heating rate of Conductivity temperature cycles suggest that deposited films are essentially ionic in nature.Item Li2SO4-Li2O-P2O5 Ionic glass dispersed with [Bmim] [PF6] ionic liquid: Electrical transport and thermal stability investigations(AIP, 2014-04) Dalvi, AnshumanA fast ionic composite is prepared by dispersion of Ionic liquid [Bmim][PF6] in glass matrix by mixing and through grinding. Amorphous/glassy nature of the samples is confirmed by X-Ray diffraction (XRD). Surprisingly, the electrical conductivity of the samples is found to be increasing by ∼ 2 orders of magnitude and exhibits typical Arrhenius behavior with low activation energy. DC polarization and impedance spectroscopy measurements suggest that samples are essentially ionic in nature. The conductivity isotherms were also obtained at different temperatures (T < 100 °C) and found to be appreciably stable at least for ∼ 10 days.Item Understanding of ionic transport in Ntp dispersed Na+ ion hybrid polymer nanocomposites using Xanes spectroscopy(International Atomic Energy Agency, 2018) Dalvi, AnshumanPresent investigation focuses on conductivity-structure correlation in NaTi2(PO4)2 (NTP) NASICON embedded novel hybrid polymer composites. Structural and electrical investigations suggest that for low NTP content salt ions prefer to move through polymer for electrical transport. However, for higher content, the surfaces as well as inner states of NTP crystallites facilitate the ionic conduction as suggested earlier also