Effect of calcination temperature on optical properties of Gd3PO7:Eu3+ nanophosphors synthesised by the combustion method. (10th November 2020) - Ngo, Khac Khong Minh
Red-emitting Gd3 PO7 :1mol%Eu 3+ nanophosphors have been successfully synthesised via straightforward combustion method. Thermal behavior of the as-synthesised samples was investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Structures, morphology and optical properties of Gd3 PO7 :1mol% Eu 3+ nanophosphors were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, and decay curve measurements. Samples were annealed at five different temperatures for 1 h. XRD analysis confirmed their monoclinic phase and the average grain sizes were calculated to be around about 20 nm. The influence of the annealing temperature on the optical properties, namely PLE, and PL spectra, as well as decay times was investigated. Under 252 nm excitation line, the strong red-emission at 615 nm due to the 5 D0 → 7 F2 transition was observed. It also shows that Eu 3+ ions in Gd3 PO7 mainly occupied noncentrosymmetric sites. The maximum intensity of 5 D0 → 7 F2 emission was recorded for the sample annealed at 900°C. It was found that increasing the annealing temperature leads to increase of the decay times from 1.3 ms to 1.5 ms for samples calcinated at 500°C and 900°C, respectively.