Structural, photoluminescence, and thermoluminescence behaviors of Samarium doped CaWO4 phosphor

Abstract

This manuscript reports the crystal structure, photoluminescence and thermoluminescence behavior of Samarium doped CaWO4 i.e., Ca1-xSm2x/3WO4 (x: 0.01, 0.02, 0.03, 0.04, 0.05) synthesized by conventional solid state reaction method. The X-ray diffraction data are analyzed using Rietveld refinement method and showed that samples exhibit cento-symmetric tetragonal crystal structure with I41/a (No. 88) space group. The unit cell volumes are increased with rising Sm composition. The energy bandgaps of the phosphors are observed by the UV–Visible absorbance spectroscopy and found to be directly proportional to the cell volume. Photoluminescence properties are considered from the excitation as well as emission spectra. These spectra resulted that the critical quenching concentration occurred at x = 0.02 due to the dipole–dipole interactions with critical energy transfer distance of 20 Å. The color purity and correlated color temperature values of the sample can be measured from the CIE Chromaticity. It is also described the orange-red emission color of the phosphors. Lower UV dosimetry with second order kinetics is obtained from the thermoluminescence spectra of x = 0.02 with 30 min UV radiation.