ICMS-2017- Second International Conference on Material Science

"ICMS 2017 Conference Papers "

Effect of palladium doping on structural and optical properties of WO3 nanostructures [ ]

In this work, the effect of palladium (Pd) as dopant on the structural and optical properties of WO3 nanostructures has been discussed. Pure and Pd (0.5 %, 1 % and 1.5 %) doped WO3 nanostructures were synthesized by acid precipitation method. XRD analysis with Rietveld refinement revealed the formation of monoclinic phase for WO3 and Pd doped WO3 nanostructures which were further supported by Raman studies. It was observed that the crystallite size of WO3 nanostructures was decreased with increase in Pd concentration. FESEM micrographs showed nanoplate type morphology of pure and Pd doped WO3 nanostructures. EDX confirmed the presence of Pd dopant in WO3 nanostructures. A broadening and shifting of Raman stretching modes in Pd doped WO3 nanostructures was observed. Diffuse reflectance spectroscopy results showed a red shift in band gap with Pd doping. Photoluminescence spectra exhibited blue and violet emission which was due to direct band transition and oxygen vacancies. A small shift in the peaks of violet and blue emission with Pd doping was also observed and attributed to defect centres created with doping.

Effect of Synthesis Technique on The Structural, Electrical and Magnetic properties of zinc nanoferrite[ ]

Different chemical methods like sol-gel (ZS) and co-precipitation (ZC) technique have been employed to obtain zinc ferrite in the nanoregime, with an aim to study the effect of synthesis technique on their properties. The samples were sintered at 1000°C for 4 hr and were investigated for their various structural, electrical and magnetic characterizations. The lattice parameter, crystallite size, and X-ray density were calculated from the XRD data obtained. The samples synthesized by co-precipitation method were observed to have smaller crystallite size as compared to that of sol-gel prepared samples. Microstructure of the samples was recorded using scanning electron microscope (SEM) while the EDAX analysis confirmed the elemental composition of the sample. The dielectric measurements were also carried out using Agilant HP 4284A LCR meter as a function of frequency in the range 100 Hz - 1 MHz. The variation showed the normal dispersive behavior of ferrites. The magnetic properties were recorded using Vibrating Sample Magnetometer (VSM). Results obtained from the two techniques were analysed.

Photoluminescence from MoS2 nanostructures prepared via top-down approach[ ]

Highly crystalline nanostructures of MoS2 have been synthesized using combined process of high energy ball-milling and probe sonication. The nanostructures so formed display excitonic absorptions together with band edge absorption at ≈ 2.82 eV, sufficiently larger than band gap for a monolayer MoS2. These nanostructures exhibit photoluminescence emission that varies with the excitation wavelength, a signature of polydisperse nature of MoS2 nanostructures. Further, raman spectra revealed the presence of various first-order and second-order raman modes.

Dielectric and Optical Properties of Fe doped ZnS Nanoparticles[ ]

The optical and dielectric properties of ZnS:Fe nanoparticles have been investigated at room temperature. X-ray diffraction analysis confirms that pure and Fe doped ZnS nanoparticles transform into cubic phase and impurities such as iron clusters are absent. Band-gap energy increases with Fe doping in ZnS nanoparticles. Photoluminescence spectra show that defects increase with increase in concentration of Fe as dopant. Further, dielectric measurement shows the maximum value of dielectric constant at particular concentration of Fe in ZnS nanoparticles. Enhancement in dielectric constant is due to space charge polarization that is due to presence of higher oxidation state of Fe in ZnS nanoparticles.