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One-pot synthesis of multifunctional ZnO nanomaterials: study of superhydrophobicity and UV photosensing property
Get PDFZnO nanomaterials are synthesized using one-pot synthesis method. Equimolar solution of Zinc Nitrate hexahydrate (Zn(NO3)(2).6H(2)O) and Hexamethylenetetramine (C6H12N4) is used as a precursor for ZnO formation. Different nanostructures of ZnO are achieved by controlling the pH of the growth solution in the range 2-12 (acidic to alkali). ZnO nanostructures are evaluated for hydrophobic property using static contact angle measurement setup and UV photosensing activity. Surface morphology, structural properties and compositional analysis of ZnO nanostructures are examined by field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscope (FEG-TEM) and X-ray diffraction (XRD) measurements. Existence of ZnO wurtzite structure is confirmed from XRD study and is analyzed by Rietveld refinement method. Nanomaterials are characterized using Raman spectroscopy which confirms highest oxygen deficiency in ZnO nanorods. The material shows remarkable superhydrophobic and UV photosensing property and hence the name multifunctional. Among all morphologies grown at different pH values, ZnO nanorods show superhydrophobic nature with contact angle more than 170 degrees. Total surface energy value of ZnO nanostructures is calculated using Wendt two-component theory. Different ZnO nanostructures (with variation of pH value) are used to study UV photosensing property. Responsivity and photocurrent show a strong dependence on the morphology of ZnO
Layer-by-layer versus copolymer: Opto-electrochemical properties of 1,3,5-Tris(N-carbazolyl)benzene and EDOT based polymers
No full textPolymer deposition directly from monomer(s) is important for different applications in wide fields. Layer-by-layer thin film PTCB-layer-PEDOT was deposited by the successive electrochemical polymerization of 1,3,5-tris(N-carbazolyl)benzene (TCB) and 3,4-ethylenedioxythiophene (EDOT) using 0.1 M TBAPF(6) in CH2Cl2. For comparison purpose, copolymers P(TCB-co-EDOT) along with corresponding homopolymers (PTCB and PEDOT) were prepared systematically by electrochemical polymerization under identical conditions. A systematic study of cyclic voltammetry (CV), stability, impedance spectroscopy, spectroelectrochemistry and electrochromic properties of all the polymers are reported where applicable. The results revealed that CV and spectroelectrochemistry could be a powerful technique to characterize these polymer films. In contrast to layer-by-layer polymer, copolymer exhibits new properties compared to the corresponding homopolymers. Further, a series of copolymers P(TCB-co-EDOT) were prepared from the different molar ratio of monomers and we achieved the band gap control in the copolymers. (C) 2019 Elsevier B.V. All rights reserved
New Insights into the Triton X-100 Induced Chemical Exfoliation of MoS2 to Derive Highly Luminescent Nanosheets
Get PDFThe exfoliation of two dimensional (2D) transition metal dichalcogenides (TMDs) into mono- or few-layers without compromising their semiconductor properties has momentous interest for both point of view; fundamental studies and further implementation in practical applications. Herein, we reported a novel and inexpensive approach for high yield nanosheets from bulk MoS2 to few layers of strong luminescent MoS2 nanosheets using Triton X-100 as a surfactant with tailoring the bulk band gap 1.2 eV to 1.79 eV of few layers of nanosheets after chemical exfoliation process, which can be easily scaled-up in large quantity. The microstructural results reveal that the exfoliated nanosheets have thickness in the range of few layers and lateral dimension in the range of few hundred nanometers. Our findings may offer a new innovative one setup chemical exfoliation process to design a few layer of MoS2 nanosheets without suppressing luminescent properties, which is highly desirable for the next generation optoelectronic devices
Analysis of Extended Pile Gate Trapezoidal Bulk FinFET
No full textWith technology scaling, innovative approaches in the device design are increasingly being explored. Improving device design is one of the focus areas for meeting the demand for low power high-speed circuit design. FinFET being the most promising device structure within the nanoscale regime, different structure variants of FinFET have been proposed and successfully implemented. In this paper, bulk FinFET device design is modified with a new design approach. Two different Si bulk trapezoidal FinFET devices, one with stacked gate and another with extended stacked gate are implemented using the 3D TCAD tool. The improvement in the performance metrics is denoted after comparing it with a simple trapezoidal Bulk FinFET device. Investigated performance metrics include subthreshold slope, Drain-Induced Barrier Lowering, Leakage Current, transconductance generation factor and threshold voltage and internal capacitance across Gate-Substrate, Gate-Drain and Gate -Source terminals of the device
An efficient piezoelectric single-crystal l-argininium phosphite: structural, Hirshfeld, electrical and mechanical analyses for NLO applications
No full textl-Argininium phosphite, nonlinear optical crystal was grown by the slow evaporation solution growth technique. It crystallizes in the monoclinic system, with P2(1) space group and dimensions of unit cells are a=9.3677 angstrom, b=4.8601 angstrom and c=13.2096 angstrom. Its morphology was simulated and indexed using WinXMorph program. The contribution of different interactions in the crystal structure was discerned visually using Hirshfeld surface analysis. The positions of NMR signal () corresponding to carbon and hydrogen atoms in titled molecule were recorded using HETCOR analysis. Moreover, the titled compound's crystallinity was examined by performing omega scan. Through UV-Vis-NIR transmittance spectra, the cutoff wavelength and bandgap for titled crystal were evaluated. Its dielectric constant and losses were investigated as frequencies varied at room temperature. Furthermore, laser and shock damage threshold analysis were employed on titled compound. Its piezoelectric charge coefficient was also determined and found to be 12pC/N along (010) plane. Kurtz and Perry's technique was used to measure its second harmonic generation (SHG) efficiency, which was observed to be 20mV taking standard KDP as reference
An investigation on the growth and propitiates of KDP admixtured ADP single crystals
No full textADP:KDP (85:15) mixed crystal was grown using slow cooling technique. The crystalline perfection of the grown crystal was studied using HRXRD curve. The homogeneity of KDP along the length of mixed crystal was analysed. Low Urbach energy value of the grown crystal indicates good crystallinity of the mixed crystals. Etch pit density was found using chemical etching studies. Vickers hardness studies indicate that the quality of the mixed crystal is more stable compared to ADP. The photoconductive nature and piezoelectric coefficient of the crystal were found. The laser stability of the crystal was observed at 532?nm using Nd:YAG laser
Enhanced functional properties of soft polymer-ceramic composites by swift heavy ion irradiation
No full textThe physical and chemical properties of soft polymer-ceramic composites with 50 MeV swift heavy, Li3+ ion irradiation were studied. A solution-casting technique was employed to synthesize free standing, flexible composite films of ferroelectric polymer PVDF and ferroelectric ceramic BNBT mixtures with 0-3 connectivity. However, only 35 wt% ceramic was chosen for the study as it showed the highest dielectric constant and enhanced ferroelectric properties without irradiation. The effects of ion irradiation on the structural, microstructural, morphological, dielectric and ferroelectric properties of this particular composition were systematically investigated and conclusions were drawn. The mechanism for the enhancement of the electroactive beta-phase due to the swift heavy ion irradiation was discussed and the enhancement was well correlated with its ferroelectric and dielectric properties
Enhanced hard magnetic properties in partially-doped Mn3-xGdxGa (x <= 0.03)
No full textThe effect of partial (1-3%) rare-earth Gadolinium doping in D0(22 )Mn(3)Ga hard magnet has been investigated in this work. The Mn 3 Ga undergoes magnetic transition at T-c similar to 745 K, which decreases down to T-c similar to 715 K upon 1% Gd-doping with introduction of mixed Mn valence states, as revealed from XPS study. The hard magnetic behavior of Mn3Ga has been observed in a wide temperature range (up to T-c ). More importantly, the partial Gd-doping significantly enhances the room temperature hard magnetic properties i.e. squareness ratio (m(r)/m(s)), coercivity (H-c) and energy product (BHmax ) from 0.43, 2.73 kOe and 0.39 MGOe (Mn3Ga) to 0.57, 4.25 kOe and 0.5 MGOe (Mn2.97Gd0.03Ga), respectively. The modified Stoner-Wohlfarth model and low-field minor loop analysis reveal the nucleation hardening mechanism for the magnetization reversal. The study proposes the partial rare-earth doping as a new approach to enhance the hard magnetic properties of rare-earth free hard magnets
Enhancement of superconducting parameters of MgB2 by low energy carbon ion implantation
No full textThe aim of work is to study the effects of carbon ion implantation on enhancement of superconducting properties of MgB2. Pure MgB2 bulk samples are irradiated by carbon ion beam of energy 40 keV (beam current 1 mu A) at different fluences. After irradiation, there is enhancement in superconducting properties viz., critical current density (J(c)), critical magnetic field (H-c2), comparing to pristine sample. Estimated with Ginzburg-Landau theory method at zero kelvin, the critical magnetic field H-c2(0) for irradiated sample shows an increase of 47 T than that of 38 T reported for pristine sample. There is also a four times increase in J(c) after implantation. Improvement in grain connectivity with ion fluence is found in surface morphological studies. Raman spectroscopic studies show a shift in resonance peak related with E-2g phonon modes after irradiation. This shifting is caused due to improvement in scattering and alteration of Fermi surface in implanted samples. These results are explained in correlation with the lattice disorder
Dielectric and impedance spectroscopic study of lithium doped potassium tantalum niobium oxide
No full textThe (K0.90Li0.10) (Nb0.80Ta0.20)(0.99)Mn0.01O3 (KLTN) ceramic has been synthesized by the conventional solid-state reaction route. The Rietveld refinement X-Ray diffraction (XRD) patterns confirmed the single-phase orthorhombic crystal structure with space group Amm2. The frequency dependent electrical properties were examined by the complex dielectric and impedance spectroscopy in the temperature range 30 degrees C-500 degrees C where multiple structural phase transition was observed with high dielectric constant, low tangent loss and well saturated electric polarization. The shifting of the ferroelectric phase transition temperature by 30 degrees C in heating and cooling mode suggests the irreversible motion of the domains and domain walls and significant effects on grain boundaries on structural phase transition temperature. A series of phase transitions from orthorhombic to tetragonal (similar to 190 degrees C) and tetragonal to Cubic (similar to 390 degrees C in cooling and 420 degrees C in heating) have been obtained in the wide range of temperature. The different type of analogy such as Modulus formalism, complex impedance spectra, frequency dependent conductivity, the activation energy of charge carriers has been used to understand the microstructure-electrical properties relation