Tuning the color emission of Gd(PxV1−x)O4:Sm3+ phosphors via changing PO43−/VO43− proportion

A series of color-tunable phosphors of Gd(PxV1−x)O4: y at.% Sm3+ (x = 0, 0.3, 0.5, 0.7 and 0.8; y = 1, 2, 3 and 4) were prepared by traditional high-temperature solid method. The phosphors were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy, photoluminescence excitation, photoluminescence (PL) and fluorescence lifetime. XRD results suggest that the phosphors can maintain a tetragonal structure when the doping concentration of PO43− is less than 0.7 at.%. Gauss fitting analysis indicates that the excitation band of Gd(P0.5V0.5)O4: 2 at.% Sm3+ is mainly composed of charge-transfer (CT) bands of VO43− (280 nm) and ligand (O2−) to metal (Sm3+) CT transition (310 nm). A weak VO43− emission band centered at 442 nm was observed, and characteristic emission peaks of Sm3+ were also observed locating at about 564 nm, 604 nm and 645 nm, respectively. For Gd(PxV1−x)O4: 2 at.%, the intensity of broad band emission from VO43− can be regulated by changing the doping proportions of PO43−/VO43−, as PO43− may block energy transfer from VO43− to Sm3+. J–O parameters and spectroscopic parameters were also calculated in detail by fitting absorption spectrum. In consequence, the combination of VO43− emission and characteristic Sm3+ emission in different matrix of Gd(PxV1−x)O4 caused a series of color changing from orange-red to light-blue. And Gd(PxV1−x)O4: 2 at.% Sm3+ can be a good candidate for UV-activated color-tunable phosphor.