Luminescent properties of Dy ³⁺ doped CaWO ₄ and CaMoO ₄ phosphors for optical applications

This work reports the luminescent properties of Dy3+ doped CaWO4 and CaMoO4 nanophosphors synthesized successfully via a co-precipitation route. A systematic investigation was done for structural, morphological, and luminescent properties for their possible use in the fabrication of solid-state lightning devices. Compound formation was confirmed through x-ray diffraction and Rietveld refinement with effective substitution of Dy3+ ions at Ca2+ sites. Luminescence studies show that undoped CaWO4 and CaMoO4 have shown a broad emission range (300–600 nm) with a dominant blue emission peak centred at 470 nm and 485 nm. However, Dy3+ doped nano-phosphor demonstrates a well-intense yellow emission peak at 575 nm in addition to the blue emission peaks around 478 and 488 nm. The observed Internal Quantum yield for CaWO4 and CaMoO4 is 37.8% and 34%. Optical band gaps for CaWO4 and CaMoO4 were calculated as 4.99 eV and 4.91 eV, respectively, confirming appreciable UV stability. The results of CIE chromaticity confirm emission in the warm white region. Presence of characteristic emissions in the blue and yellow regions under ultraviolet (UV) excitation make it a promising material for the fabrication of white and UV LEDs.