Modified optical properties via induced cation disorder in self-activated NaMg2V3O10.

Cation disorder in the phosphor lattice could be one of the effective approaches to modify the luminescence efficiency. In this work, cation substitutions of (Mo6+→ V5+) and (Na+→ Mg2+) were conducted in the self-activated NaMg2V3O10. All the samples of Na1+xMg2-xV3-xMoxO10 (x = 0, 0.01, 0.05, 0.1, 0.2, 0.3) were prepared via solid-state reaction. The morphological properties were measured via SEM and EDS analyses. Structural Rietveld refinement was performed to investigate the microstructure in the lattices. The cation substitution brings about structural disorder in the phosphor, which exerts great modifications in the luminescence properties. NaMg2V3O10 presents an intrinsic indirect transition with a band gap of 3.22 eV. The incorporation of Mo6+ and Na+ in the lattices moves the optical absorption to a longer wavelength bringing about a narrower band gap. The luminescence intensity, thermal stability and corresponding lifetime were modified by the cation disorder in the self-activated phosphor.