Evaluation of photoluminescence and colorimetric performance of Tb3+-induced calcium tungstate ceramic

Abstract

Photoluminescence and colorimetric investigations of Ca_1−xTb_2x/3WO₄ with x vary from 0.01 to 0.05 samples made by employing the solid-state reaction routes are represented in this paper. Structural analyses of all the phosphors are done with the help of X-ray diffraction spectroscopy and denoted that they exhibit a tetragonal structure and I4₁/a space group without containing any secondary phase. Optical properties are described with the help of the UV–visible reflectance spectra. In addition, the energy bandgap values are evaluated from these spectra and the values are increased concerning the rise in the Tb contents in CaWO₄. Photoluminescence studies are done by considering PL excitation spectra as well as PL emission spectra. The critical concentration of quenching is observed at the composition x = 0.03 along with the critical distance of energy transfer is computed to be ~ 20 Å. Moreover, this distance is created by the dipole–dipole exchanges and indicated by the calculated Q value. Colorimetric analyses of the samples are done from the CIE color coordinates. The green emission color is obtained for all the materials. All the colorimetric parameters are evaluated and quantum yield efficiency for x = 0.03 Tb incorporated CaWO₄ material is obtained by exciting it with 485 nm wavelength. Average lifetime values are evaluated by analyzing the PL decay plots.

Graphical abstract

CIE chromaticity diagram of Tb-doped CaWO₄ at 485 nm EX wavelength