Thermally stimulated luminescence studies of undoped and doped K 2B 4O 7 compounds

Abstract

In this paper TSL studies of undoped, Cu and Mn doped K 2B 4O 7 compounds are reported for the first time. The polycrystalline samples of undoped and doped K 2B 4O 7 were prepared by a melting method and the formation of the K 2B 4O 7 compound was confirmed by an X-ray diffraction study. The compound has orthorhombic structure at room temperature. The TSL studies of undoped K 2B 4O 7 sample show two glow peaks at 150 and 200 °C. The TSL studies of Cu doped K 2B 4O 7 sample show only one single strong TL glow peak at 120 °C whereas the TSL glow curve of Mn doped K 2B 4O 7 has one glow peak at 120 °C accompanied by a shoulder at 150 °C. Comparative TSL studies of these compounds show that the K 2B 4O 7 compound doped with Cu is the most sensitive and the TSL intensity is enhanced by about 37 times when compared with the TSL intensity of undoped K 2B 4O 7 compound whereas the addition of Mn impurity to undoped K 2B 4O 7 enhances the TSL intensity by two times. The trap parameters namely order of kinetics ( b), activation energy ( E) and frequency factor ( s) associated with the 120 °C glow peak of K 2B 4O 7:Cu phosphor were determined using isothermal decay and glow curve shape (Chen’s) methods.