Facile ultrasound route for the fabrication of green emitting Ba2SiO4: Eu2+ nanophosphors for display and dosimetric applications

A series of Eu2+ (1-5 mol%) activated Ba2SiO4 nanophosphors were prepared by ecofriendly ultrasound assisted sonochemical route using Epigallocatechin gallate (EGCG) extract as bio-surfactant. The obtained nanophosphors were well characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) etc. The average crystallite size was estimated using Debye-Scherer's formula and Williamson-Hall (W-H) plots and were found to be in the range 20-32 nm. The photoluminescence excitation spectrum exhibited two broad bands around 330 and 370 nm ascribed to the transitions of Eu2+ from 4f-ground state to 5d-excited state. The emission spectra showed broad band around 505 nm wavelength ascribed to 5d -> 4f allowed transition of Eu2+ ions. Thermoluminescence (TL) of Eu2+ doped Ba2SiO4 nanophosphors were investigated using gamma-irradiation in the dose range 1-6 kGy at a warming rate of 5 degrees C min(-1). The phosphors show a well resolved single glow peak at similar to 175 degrees C. The TL intensity of 155 degrees C glow peak increase linearly with gamma-dose and room temperature fading was similar to 76% which was highly useful in radiation dosimetry. The kinetic parameters (E, s) were estimated and the results were discussed. The chromaticity co-ordinates of all the prepared phosphors were located in green region, as a result Eu2+ activated Ba2SiO4 was a promising single phased phosphor for WLEDs. (C) 2017 Elsevier Ltd. All rights reserved.