Structural and optical investigations of VO(II) ions doped NaCaAlPO4F3 phosphor

Abstract

VO(II) ions doped NaCaAlPO4F3 phosphor have been synthesized by solid state reaction. The prepared sample was characterized by powder X-ray diffraction (P-XRD), Optical absorption, Photoluminescence (PL), Electron Paramagnetic Resonance (EPR) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. From powder XRD data the average crystallite size and structural parameters are evaluated. The morphology of prepared sample was examined by Scanning Electron Microscope (SEM) images at different magnifications. Optical absorption spectrum showed characteristic bands corresponding to d–d transitions of VO(II) ions. EPR spectrum of prepared sample exhibited resonance signal characteristic of VO(II) ions in octahedral symmetry with tetragonal compression having C4V symmetry. The spin-Hamiltonian parameters (g and A), dipolar hyperfine coupling parameter (P) and Fermi contact interaction parameter (κ) have been evaluated. From the optical and EPR data, various molecular coefficients are evaluated, and the nature of bonding with ligands is covalent. PL spectrum exhibited visible emission at green, yellow and red regions under 420 nm photon excitation. The calculated Commission Internationale de l’Eclairage (CIE) coordinates are in yellowish green region at (0.382, 0.509). The prepared material is suitable for display devices. FT-IR spectrum marked the characteristic vibration bands of prepared phosphor material.