Thermally stimulated luminescence studies of undoped and doped K2B4O7 compounds

In this paper TSL studies of undoped, Cu and Mn doped K2B4O7 compounds are reported for the first time. The polycrystalline samples of undoped and doped K2B4O7 were prepared by a melting method and the formation of the K2B4O7 compound was confirmed by an X-ray diffraction study. The compound has orthorhombic structure at room temperature. The TSL studies of undoped K2B4O7 sample show two glow peaks at 150 and 200 deg. C. The TSL studies of Cu doped K2B4O7 sample show only one single strong TL glow peak at 120 deg. C whereas the TSL glow curve of Mn doped K2B4O7 has one glow peak at 120 deg. C accompanied by a shoulder at 150 deg. C. Comparative TSL studies of these compounds show that the K2B4O7 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 K2B4O7 compound whereas the addition of Mn impurity to undoped K2B4O7 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 deg. C glow peak of K2B4O7:Cu phosphor were determined using isothermal decay and glow curve shape (Chen's) methods