Photoluminescence, thermoluminescence and EPR studies of solvothermally derived Ni2+ doped Y(OH)3 and Y2O3 multi-particle-chain microrods

Rod like structures of hexagonal Y(OH)3:Ni2+ and cubic Y2O3:Ni2+ phosphors have been successfully synthesized by solvothermal method. X-ray diffraction studies of as-formed product shows hexagonal phase, whereas the product heat treated at 700 °C shows pure cubic phase. Scanning electron micrographs (SEM) of Y(OH)3:Ni2+ show hexagonal rods while Y2O3:Ni2+ rods were found to consist of many nanoparticles stacked together forming multi-particle-chains. EPR studies suggest that the site symmetry around Ni2+ ions is predominantly octahedral. PL spectra show emission in blue, green and red regions due to the 3T1(3P)→3A2(3F), 1T2(1D)→3A2(3F) and 1T2(1D)→3T2(3F) transitions of Ni2+ ions, respectively. TL studies were carried out for Y(OH)3:Ni2+ and Y2O3:Ni2+ phosphor upon γ-dose for 1-6 kGy. A single well resolved glow peaks at 195 and 230 °C were recorded for Y(OH)3:Ni2+ and Y2O3:Ni2+, respectively. The glow peak intensity increases linearly up to 4 kGy and 5 kGy for Y(OH)3:Ni2+ and Y2O3:Ni2+, respectively. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were estimated by different methods. The phosphor follows simple glow peak structure, linear response with gamma dose, low fading and simple trap distribution, suggesting that it is quite suitable for radiation dosimetry.