3T1R model and tuning of thermoluminescence intensity by optimization of dopant concentration in monoclinic Gd2O3:Er3+;Yb3+ co-doped phosphor
Thermoluminescence property of a phosphor is an important parameter that helps to determine the use of a phosphor in various dosimetric applications. In this study, the thermoluminescence behaviour of a monoclinic Gd2O3:Er3+;Yb3+ nanophosphor was studied. Gd2O3:Er3+;Yb3+ nanophosphor was prepared using a combustion synthesis method. Structural characterization was carried out via X-ray diffraction and electron microscopy methods. Herein, thermoluminescence (TL) study and kinetic analysis of the UV- and gamma-irradiated phosphor was also carried out. The prepared phosphor exhibits two TL glow curves around 122 and 263 °C for UV excitation and 157 and 295 °C for gamma exposure. The effect of different parameters on the TL glow curve was investigated. The glow curve deconvolution function was applied on the tuned glow peak curve. The trapping parameters were determined for tuned glow curve peaks as well as for the deconvoluted peaks. Moreover, reproducibility of the sample was determined via 7 replicate TL measurements. The prepared sample shows good reproducibility for both UV and gamma exposure. A theoretical three trap and one recombination centre (3T1R) model was proposed to explain the concentration quenching effect on the thermoluminescence behaviour of the prepared sample.