Combustion synthesis and thermoluminescence response of near ultra-violet irradiated Mg 2 B 2 O 5 nanophosphors

Abstract

Among the various kinds of metal borates, the magnesium borate has been considered to have promising luminescence properties. The synthesis techniques and conditions have a profound effect over the defect assisted luminescence properties of phosphors. We synthesized Mg 2 B 2 O 5 nanophosphors by combustion technique using urea as fuel. The formation of Mg 2 B 2 O 5 nanophosphors was investigated by X-Ray diffraction pattern, which clearly confirms the single phase triclinic structure. In order to investigate the thermoluminescence (TL) response of Mg 2 B 2 O 5 nanophosphors for near ultra-violet (UV) radiations, the samples were exposed with wavelength of 365 nm for different durations. The TL glow curve of the samples consists of two broad peaks around 425-430 K and 570-590 K, which signifies two kinds of trapping or defect sites present in the sample. With the increase in exposure time, we observed that higher temperature peak intensity increases at the expense of lower temperature peak. The analysis by using Chen's peak shape method confirms that TL glow curve comprises of complex glow peaks, thus not suitable from radiation dosimetric point of view. However the present TL results suggest that Mg 2 B 2 O 5 nanophosphors are sensitive to near-UV radiations and further synthesis optimization may be required to make Mg 2 B 2 O 5 useful for UV dosimetry.