Synthesis and effect of Dy3+ doping on vibrational and luminescent properties of Mg2Zn(PO4)2

Dy³⁺ (0–5 mol%)-activated Mg₂Zn(PO₄)₂ phosphors were prepared via solution combustion method. Their structural, vibrational, and optical properties were investigated. The X-ray diffraction (XRD) results indicate that the synthesized sample consists of MgZn₂(PO₄)₂ and Mg₃(PO₄)₂. Fourier transformation infrared (FTIR) spectroscopy results show the existence of orthophosphate groups in the sample. The photoluminescence (PL) result suggests that the prepared samples give yellowish-white emission under UV excitation (348 nm). The optimum molar concentration (maximum emission intensity) of Dy³⁺-doped Mg₂Zn(PO₄)₂ occurs at 2 mol%, and further, the increase in concentration of dopant causes concentration quenching effect. The concentration quenching phenomenon happened because of dipole–dipole interaction between dopant ions. The optical band gap of these samples is obtained from the diffuse reflectance spectrum (DRS) and found in the range of 5.07–5.33 eV. The values of refractive index and dielectric constant of optimum concentration of Dy³⁺ ion (2 mol%) doped in the host lattice are obtained to be 1.972 and 3.889, respectively.