Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2012-10-01

Effect of different fuels on structural, thermo and photoluminescent properties of Gd2O3 nanoparticles.

N Dhananjaya, H Nagabhushana, B M Nagabhushana, B Rudraswamy, S C Sharma, D V Sunitha, C Shivakumara, R P S Chakradhar

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 96 , 532-40, (2012)

Full Text: HTML

Abstract

Gd(2)O(3) nanoparticles (27-60 nm) have been synthesized by the low temperature solution combustion method using citric acid, urea, glycine and oxalyl dihydrazide (ODH) as fuels in a short time. The structural and luminescence properties have been carried out using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman, UV-Vis, photoluminescence (PL) and thermoluminescence (TL) techniques. The optical band gap values were estimated for as formed and 800 °C calcined samples. The band gap values in as-formed and calcined samples were found to be in the range 4.89-5.59 eV. It is observed that, the band gap values are lower for as-formed products and it has been attributed to high degree of structural defects. However, in calcined samples, structure becomes more order with reduced structure defects. Upon 270 nm excitation, deep blue UV-band at ~390nm along with blue (420-482 nm), green (532 nm) and red emission (612 nm) was observed. The 390 nm emission peak may be attributed to recombination of delocalized electron close to the conduction band with a single charged state of surface oxygen vacancy. TL measurements were carried out on Gd(2)O(3) prepared by different fuels by irradiating with γ-rays (1 kGy). A well resolved glow peak at 230 °C was observed for all the samples. It is observed that TL intensity is found to be higher in for urea fuel when compared to others. From TL glow curves the kinetic parameters were estimated using Chen's peak shape method and results are discussed in detail.Copyright © 2012 Elsevier B.V. All rights reserved.