The thermoluminescence properties of copper doped ZnS nanophosphor

In the given study, the thermoluminescence (TL) properties of copper (Cu) doped ZnS nanophosphors were investigated after beta-irradiation at room temperature (RT). The ZnS:Cu nanophosphors were prepared by spray pyrolysis method and the formation of the nanoparticles was confirmed by X-ray diffraction and scanning electron microscope (SEM) methods. It was observed that the shape of TL glow curve of this nanophosphor is not affected from the size of the particles during the growth of nanophosphor whereas its TL intensity was highly increased with a decrease in the size of particles. The glow curve has two broad TL peaks one of which is centered at about 110 °C and the other at about 170 °C for a heating rate of 1 °C/s in the temperature range from RT to 350 °C. The dose response and fading process of both peaks were examined and it was observed that the dose response of first peak first follow a good linearity and then saturate at approximately 2 kGy whereas the response of second peak continuously increases linearly with increasing dose in the investigated range of dose levels. The first peak nearly disappeared after one week storage in the dark at RT. On the other hand, the intensity of second peak was approximately reduced to 50% of its original value. The TL emission spectrum of this material has two main emission bands, namely the blue and green bands.