Photoluminescence and thermoluminescence properties of Tb3+ doped K3Gd(PO4)2 nanophosphor

Tb3+ doped nanoparticulate K3Gd(PO4)2 phosphor was prepared by combustion method using urea as a fuel. The structure, optical and luminescent properties of the phosphor were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and thermoluminescence (TL) spectroscopy. In undoped K3Gd(PO4)2, the excitation and emission peaks at 273 nm and 323 nm belongs to the 8S7/2 → 6IJ(J = 7/2) and 6PJ(J = 7/2) → 8 S7/2 transitions of Gd3+ while green emission was observed in the Tb3+ doped K3Gd(PO4)2. TL study was carried out after exposing the samples to γ-radiations (0.1–5 kGy) in the K3Gd(PO4)2:Tb3+ (1.5 mol%). The calculated kinetic parameters were compared with different methods. The band gap of the phosphor was estimated as 5.80 eV. The green shade of the Tb3+ ion with the CIE coordinates (x, y) as (0.29, 0.54) was in good agreement with the well known green phosphors.