Advanced Materials Research Vol. 665

Abstract: The static dielectric constant (ε₀) and optical dielectric constant (ε = n²) of binary mixtures of 1-Propanol (1-PrOH) with N,N-Dimethylformamide (DMF) of different concentrations, prepared by volume fractions (0.0, 0.1, . 1.0) are measured at 2 MHz using precision LCR meter and Abbes refractometer respectively at different temperatures. The excess dielectric constant (ε₀)^E, Kirkwood correlation parameters (g^eff, g_F), Bruggeman parameter (f_B) are evaluated. The variations of these parameters with concentration and temperature are discussed in terms of molecular interaction between the molecular species of constituting components in these mixtures.

Abstract: Looking to the world wide crisis of energy resources it is very much important to develop an efficient and sustainable photoelectrochemical solar cell. PEC solar cell generates electrical energy from light which consists of a semiconducting photoanode and a metallic cathode immersed in an electrolyte. In present case we have investigated PEC solar cell using MoSe₂ as a working electrode and Platinum/copper as a counter electrode and combination of 0.025MI₂, 0.5MNaI, 0.5MNa₂SO₄ an electrolyte. MoSe₂ is proven to be most efficient and less corrosive semiconducting material. We have performed several experiments on present combination with all possible intensities. In this paper authors report their results and findings of PEC solar cell.

Abstract: The solar cells have been used as most promising device to convert light energy into electrical energy. In this paper authors have attempted to fabricate Photoelectrochemical solar cell with semiconductor electrode using TMDCs. The Photoelectrochemical solar cells are the solar cells which convert the solar energy into electrical energy. The photoelectrochemical cells are clean and inexhaustible sources of energy. The photoelectrochemical solar cells are fabricated using WSe₂ crystal and electrolyte solution of 0.025M I₂, 0.5M NaI, 0.5M Na₂SO₄. Here the WSe₂ crystals were grown by direct vapour transport technique. In our investigations the solar cell parameters like short circuit current (I_sc) and Open circuit voltage (V_oc) were measured and from that Fill factor (F.F.) and photoconversion efficiency (η) are investigated. The results obtained shows that the value of efficiency and fill factor of solar cell varies with the illumination intensities.

Abstract: The polymer blend of Ethyl Cellulose (EC) with Poly (vinyl) pyrrolidone (PVP) of various weight percentages at different thickness are used for measurement of dielectric permittivity, electrical conductivity and optical properties. The activation energies of the EC and its blend with PVP are obtained through measurement of dc conductivity. The samples are characterized by using X-ray diffractometer (XRD). The blends of EC with PVP in the ratio of 50:50 weight percent using FTIR over the range of wavenumber 4000-500 cm^-1. Key words: Polymer Blend, XRD, SEM, FTIR, dielectric permittivity, activation energy.

Abstract: Nanocrystalline CdS thin films were deposited on glass substrate by chemical bath deposition method using Cadmium Sulphate and Thiourea as Cd⁺² and S^-2 ion sources for different molarities i.e. 0.1 M, 0.2 M and 0.3 M. The crystallite size and lattice parameters for each sample were determined from X-Ray diffraction data using Scherrers formula. The value of the crystallite size was found to be within the range 14.7 nm-11.4 nm. The optical characterization was done by UV-Visible and photoluminescence spectroscopy. The optical band gap of the films was determined from the transmittance spectra. It was observed that when the molarity increases, the average crystallite size decreases and the band gap energy of the prepared films increases. Photoluminescence studies showed a prominent peak at around 530 nm. The radius of the nanocrystalline films had been evaluated from the absorption spectrum by using effective mass approximation formula.

Abstract: We have synthesized Ru₁Sr₂Gd_2-xCe_xCu₂O₁₀ (Ru-1222) materials using several concentrations of Ce. All ruthenocuprate compounds have been characterised by using standard X-ray diffraction (XRD) and Scanning Electron Micrographs (SEM). The concentration of Ce affects transport properties drastically. Compounds with x=0.5 remain nonsuperconducting with moderate resistivity even after annealing in different conditions. Enormous change in the normal state resistivity has been observed in different annealing conditions of Ru-1222 with x=0.5. Superconducting properties have been observed in compounds with x=0.65. The highest critical temperature obtained is 27.5K for x=0.65. In addition, the duration of annealing in flowing oxygen is found to be effective in changing the normal state resistivity for x=0.65.

Abstract: Using first principles density functional theoretical calculations within the generalized gradient approximation (GGA), the present paper reports thermal properties such as constant volume lattice specific heat, Gibbs free energy, internal energy, and entropy of Yb-pnictides such as YbN, YbP and YbAs in its rocksalt phase. The variation of lattice specific heat with temperature obeys the classical Dulong-Petits law at high temperature while at low temperature it obeys Debye T³ law. The internal energy, entropy and free energy show a gradual variation with temperature. The specific heat at constant volume at lower temperature increases as going from N to P to As. ^*Corresponding author Email: pkj@bhavuni.edu, prafullaj@yahoo.com Telephone: +91-278-2422650 Fax: +91-278-2426706