Low temperature synthesis, structural and dosimetric characterization of ZnAl2O4:Ce3+ nanophosphor

Abstract

Dosimetric properties of γ-irradiated ZnAl2O4:Ce3+ (1–9mol%) nanophosphors were studied and reported for the first time. The phosphor prepared by solution combustion route was well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. PXRD patterns of calcined phosphor show pure cubic phase of ZnAl2O4:Ce3+. Flake type morphology was observed from SEM studies. The particle size estimated by Scherrer’s and Williamson Hall (W–H) plots and found to be in the range 11–17nm. From photoluminescence (PL) studies two characteristic emission peaks at 363 and 480nm were observed due to 5d–4f transitions of Ce3+ ions. The thermoluminescence (TL) glow curves of ZnAl2O4:Ce3+ (1–9mol%) nanophosphor recorded two glow peaks 145 and 215°C at a warming rate of 2.5°Cs−1. The optimized TL intensity was observed for ∼5mol% Ce3+ concentration. The two TL glow peaks in the γ-irradiated (0.1–6kGy) ZnAl2O4:Ce3+ (5mol%) nanophosphor indicates that two set of traps were activated within the temperature range 145 and 215°C. The kinetic parameters (E,b,s) associated with the prominent glow peaks were estimated using Chen’s glow peak shape method. The intensity of the TL glow peak (145°C) increases linearly with increase of γ-dose upto 1kGy above which it follows sub-linear behavior. Track interaction model (TIM) was used to explain the linearity/sub linearity/saturation behavior of TL intensity. The TL glow curves show simple glow peak structure, good reusability, low fading and wide range of linearity. Hence, the optimized ZnAl2O4:Ce3+ (5mol%) nanophosphor was quite useful for radiation dosimetry and display applications.