Photoluminescence properties of y at.% Eu3+-doped Gd(NbxP1-x)O4: A color-tunable orange-red phosphor

In this work, a simple method to prepare orange-red phosphor is introduced. A series of y at.% Eu3+-doped Gd(NbxP1-x)O4 (x = 0%, 1%, 2%, 3%, 4%, 5%, 6%, 10% and y = 5%, 7%, 9%, 11%, 13%, 14%, 15%) phosphors were prepared through solid reaction technique. The structure and optical properties of the phosphors were characterized using measurements of X-ray powder diffraction, photoluminescence excitation, photoluminescence and decay curves. The X-ray diffraction results revealed that the obtained phosphors possessed the same pure monoclinic phase as GdPO4 until the doping concentration of Nb5+ reached a maximum value of 5 at.%. With the high sensitivity of the 5D0→7F2 transition to the symmetry of the crystal field, the relative intensity of the two emission peaks at 596 and 615 nm could be continuously adjusted by changing the Nb5+ concentration. Moreover, Judd–Ofelt calculations performed on samples doped with different Eu3+ ions concentrations showed their promise as color-tunable orange-red phosphors. •A series of Eu3+:Gd(NbxP1-x)O4 phosphors with gap type were synthesized.•The energy transfers among Gd3+, NbO43− and Eu3+ were analyzed in detail.•Emission intensity of 596 and 615 nm can be regulated by contents of Nb5+ ions.