Spectroscopic characterization and Judd-Ofelt analysis of Europium activated calcium tungstate phosphor

Pure and Eu³⁺ activated calcium tungstate nanocrystals were synthesized successfully via a facile co precipitation method. The powder X-ray diffraction analysis revealed that CaWO₄ crystallizes in tetragonal crystal system with space group I4₁/a and the crystallite size calculated from Debye-Scherrer formula was found to be in the range 15-16 nm. The photoluminescence analysis was carried out by recording the excitation spectra and emission spectra of pure and Eu³⁺ doped samples. Moreover the colour co-ordinates of emission from the samples are found to be in red region of CIE diagram. To investigate the spectroscopic parameters of host matrix the Judd-Ofelt analysis was carried out from the emission spectrum. From the JO intensity parameters, promising spectroscopic parameters like emission cross-section, branching ratio and gain band width of the material were calculated. The photoluminescence analysis suggests the suitability of material for various opto-electronic applications. (author)