Protocol for Dy3+-modified NaCaVO4 nanophosphors in solid-state lighting applications: structural and luminescence investigations

Abstract

Combustion process was used to synthesize the dysprosium (Dy³⁺)-doped sodium calcium vanadate (NaCaVO₄) phosphor. The structural, optical and morphological investigations were carried out with the dopant concentrations ranging from x = 0–3 mol% for which X-ray diffraction, photoluminescence spectroscopy, SEM and UV–Vis spectroscopy were used. We have explored that the XRD results indicate vibrant, clear and well-defined peaks that are matched to the NaCaVO₄ standard card confirming that the phosphor powder crystallized in the orthorhombic phase with space group C_mcm. From the FESEM pictures, the particles had an agglomerated morphology with irregular shapes and sizes in the nm range. The PL properties of undoped and Dy³⁺-doped NaCaVO₄ were investigated using a 310 nm excitation source to determine the suitability for use in displays. The emission spectrum exhibited two sharp peaks at 450–500 and 550–600 nm and a weak peak at 650–700 nm, which is assigned to Dy³⁺-emission transitions of ⁴F_9/2 → ⁶H_15/2 (blue), ⁴F_9/2 → ⁶H_13/2 (yellow) and ⁴F_9/2 → ⁶H_11/2 (red). Doping of NaCaVO₄ with Dy³⁺ for x = 0.25–3 mol% concentrations resulted in band gap modifications in the range of 3.341–3.866 eV. The material that we have taken up might be investigated as a new phosphor that could be activated by UV light-emitting diode (LED) light for solid-state lighting and display applications.