Materials Science Forum Vol. 832

Abstract: Silver nanoparticles with different radii were synthesized using silver nitrate solution added with sodium borohydride solution at different ratios. The synthesized silver nanoparticles of radii 25.3 nm, 31 nm, 33.6 nm and 37.1 nm were characterized by transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. The synthesized silver nanoparticles exhibit spherical morphology for all radii. The silver nanoparticles exhibit the plasmon resonance band between 390 nm – 400 nm. The optical trapping effect of Gaussian beam acting on a silver nanoparticle in Rayleigh regime was studied. The optical scattering and optical gradient forces were calculated for silver nanoparticles of different radii.

Abstract: The copper nanoparticles were synthesized by green technology using leaf extracts of Ocimum sanctum. The synthesized copper nanoparticles were confirmed by the change of colour after the addition of leaf extract into the copper sulfate solution. The synthesized copper was characterized by X-ray Diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. The copper nanoparticles are crystallized with FCC structure. The synthesized copper nanoparticles exhibit spherical morphology with average particle size of 20 nm. The copper nanoparticle exhibits absorption broad band between 550 nm – 575 nm. The optical trapping effect of Gaussian beam acting on a copper nanoparticle in Rayleigh regime was studied. The optical scattering and optical gradient forces were calculated for 20 nm copper particle.

Abstract: Copper oxide (CuO) nanofluids are prepared by two step method. CuO nanoparticles are prepared by sol gel method with Copper chloride as precursor and NaOH as a reducing agent. The prepared CuO nanoparticles are characterized by XRD, SEM and Particle size analyzer. XRD measurements reveal a grain size of 72nm .SEM image reveals an inhomogenous mixture of particles from 500 nm to 3500 nm with irregular morphology and few traces of CuO cones.. The particle size distribution of CuO particles is in the range of 1000-1600nm which is in accordance with the SEM results.CuO –Ethylene Glycol nanofluids are prepared by two step method by ultrasonication of obtained CuO particles.The stability of CuO nanofluid is given with a negative zeta potential of-22.5 mv.

Abstract: In this work, zinc stannate (Zn₂SnO₄) nanomaterials were synthesized as a composite system of zinc oxide and tin oxide by sol-gel via hydrolysis process for 60 hours. The effect of annealing temperature on the structural, optical and electrical performances of zinc stannate nanomaterials has been studied. XRD studies revealed that zinc stannate possess spinel cubic crystal structure and their growth in the preferred orientation (311) with characteristic temperature. The surface morphology of the zinc stannate nanomaterials were obtained by scanning electron microscope (SEM). EDAX and FTIR studies were employed to determine the chemical compositions and functional groups of the zinc stannate respectively. The optical properties of the hydrolysed zinc stannate were analysed by UV-visible and photoluminescence spectroscopy. UV-vis spectra were associated to the optical bandgap with a tunable range of 3.17-3.92 eV. PL spectra exhibit the stable broad blue-green emission around 400-600 nm with various excitation wavelengths. Complex impedance spectra reveal that the resistivity of the prepared zinc stannate nanomaterials is in the order of ~ 10⁵ Ω Cm. Hence, zinc stannate is a promising candidate for DSSC applications.

Abstract: Nanocrystalline Cd_1-XZn_XS (X=0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0) were synthesized by simple wet chemical method via co-precipitation. The formation, phase purity and crystalline size were ascertained by X-ray diffraction (XRD). The shape and surface morphology of the synthesized samples were characterized by scanning electron microscopy (SEM). The optical properties of the Cd_1-XZn_XS samples were investigated using UV-vis absorption spectroscopy and photoluminescence spectroscopy (PL) studies. The optical properties of the sample was dramatically changed by varying the composition of Cd_1-XZn_XS system, which may be due to the synergic effect originated by combining CdS and ZnS. The obtained optical behaviors suggest that the material can be suitable for the photocatalytic degradation of organic pollutants. The prsent investigation demontrated that the synthetic approach developed in this is highly reproducible and can be readily scaled up for potential industrial production.