Abstract
The present paper reports the synthesis and characterization of Ti doped ZrO2 nanophosphors. The effects of variable concentration of titanium on thermoluminescence (TL) behaviour are studied. The samples were prepared by combustion a synthesis technique which is suitable for less time taking techniques also for large scale production for nano phosphors. The starting material used for sample preparation are Zr(NO3)3 and Ti(NO3)3 and urea used as a fuel. The prepared sample was characterized by X-ray diffraction technique (XRD) with variable concentration of Ti (0.05–0.5 mol%) there is no any phase change found with increase the concentration of Ti. Sample shows cubic structure and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM) technique for optimized concentration of dopant. The good connectivity with grains and the semi-sphere like structure was found by FEGSEM. The functional group analysis was determined by Fourier transform infrared (FTIR) spectroscopic techniques. The prepared phosphor examined by thermoluminescence technique. For recording TL glow curve every time 2 mg phosphor was irradiated by UV 254 nm source and fixed the heating rate at 5 °C s−1. Sample shows well resolved peak at 167 °C with a shoulder peak at 376 °C. The higher temperature peak shows the well stability and less fading in prepared phosphor. Also the effect of Ti concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot was studied. Sample shows linear response with dose and broaden peak with high temperature shows the more stability and less fading in TL glow curve. The linear dose response, high stability and less fading phenomenon shows the sample may be useful for thermoluminescence dosimetry application. Trapping parameters are calculated for every recorded glow curve. The prepared phosphor with optimized concentration of dopant was studied for various heating rate method. The various heating rate (3 °C s−1 to 5 °C s−1) shows shifting in TL glow peaks at higher temperature side. That is opposite behaviour shows in TL glow curve with various heating rate method. The presence of transition metal ions changes (Ti) the TL glow curve structure either enhancing or quenching the TL efficiency. These changes are a consequence of the crystalline field perturbation due to the different characteristics of the dopant ions which supposedly replaces the Zr4+ sites. The traps and the glow curve structure are also dependent upon the morphology of the surface area which in turn depends on the nanocrystallite size. The nanocrystallite size depends also on the dopant ion. Furthermore, the obtained experimental results show that the presence of dopant ions also modifies the TL recombination efficiency which was found to be different for each irradiation type and the specific exposed material. It is important to notice that using the right dopant concentration, it is possible to maximize the TL efficiency and improve sensitivity and dose linearity for a specific irradiation type. For dual TL glow curve present in the sample it is very difficult to calculate the kinetic parameters from peak shape method. The kinetic parameters are calculated by (Computerized glow curve convolution technique) CGCD technique. Keywords: Thermoluminescence, ZrO2:Ti, Combustion synthesis, CGCD, Effect of dopant concentration, Various heating rate