Structural and photoluminescence behavior of thermally stable Eu3+activated CaWO4 nanophosphors via Li+ incorporation

We have studied the structural and photo physical analogue of Eu3+ activated CaWO4 nanophosphors via Lithium (Li+ = 2, 5 7 and 10 at.%) ion incorporation. As-prepared (APS) samples were annealed at 900 degrees C to eliminate unwanted organic moieties present in the sample and to improve crystallinity. The samples are characterized employing X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), UV-VIS spectroscopy, photoluminescence studies and lifetime decay studies. FTIR features an absorption band at similar to 832 cm(-1), which correspond to its antisymmetric vibrations into O-W-O band in the WOE tetrahedron. CaWO4 having the scheelite type structure with C-4h point group and I4(1)/a space group. The surface morphology of the samples are studied with Scanning Electron Microscopy (SEM). Lithium Co-doped CaWO4:Eu3+ nanoparticles show red luminescence because of strong host contribution and different energy transfer rates from host to Eu3+ ions under 266 rim excitations. Lithium ion enhances the crystallinity and radiative transition rate thus results in higher emissive property. Calculated CIE coordinates of these Li+ doped 900 degrees C annealed samples under 266 nm excitation is x = 0.65 & y = 0.34, which are closer to the standard of NTSC (x = 0.67 & y = 0.33). This material may be potential candidates for white light emitting diodes. (C) 2017 Elsevier B.V. All rights reserved.