Thermoluminescence and photoluminescence characteristics of nanocrystalline LiNaSO₄ : Eu phosphor

Abstract

Europium doped LiNaSO4 in its nanocrystalline form has been prepared and its thermoluminescence (TL) properties are studied. The TL glow curve of the phosphor has been found to have a simple structure with a single peak at 432 K. Though the highly sensitive, commercially available TL phosphor LiF : Mg, Cu, P (TLD-700H) is about 1.5 times more sensitive than the nanocrystalline material, the sensitivity of the concerned nanomaterial is much higher (∼10 times) than the other standard phosphor TLD-100 (LiF : Mg, Ti). Compared to the conventional LiNaSO4 : Eu phosphor (prepared through a melting procedure and having particle size of 125 µm), the nano-sized phosphor has a lesser TL sensitivity. However, this reduction in TL sensitivity on decreasing the particle size from micrometres to nanometres gives a better understanding of the TL phenomenon. The order of TL kinetics for the concerned nanomaterial is also found to be different from that of the conventional material. Photoluminescence studies that have been performed on these materials throw light on the reasons for such a change in the order of kinetics. Further, fading and reusability of the concerned nanomaterial has also been studied and it has been found that the phosphor is quite suitable for radiation dosimetry.