T. R. Rajasekaran

PREPARATION AND CHARACTERIZATION OF Ce0.8Y0.2O2 NANOPOWDERS USING SOL-GEL METHOD

Nanopowders of Ce0.8Y0.2O2 were prepared by sol-gel via hydrolysis method for different hours. The prepared powders are characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and analyzed by UV-visible spectroscopy, Photoluminescence (PL) and Energy dispersive X-ray analysis (EDAX). Cubic fluorite structure of the prepared samples was confirmed by powder X-ray diffraction and the grain size of the prepared samples in the range of 12 to 33 nm. The functional groups of the prepared nanopowders are identified by FTIR spectra. The band gap energy obtained from the UV spectra. From the photoluminescence spectra, there is a mirror image relation between absorption and emission spectra. The purity of the prepared samples is confirmed by EDAX measurements.

Synthesis and Characterization of Zinc Stannate Nanomaterials by Sol-Gel Method

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.