Structure and photoluminescent properties of green-emitting terbium-doped GdV1−xPxO4phosphor prepared by solution combustion method

Terbium-doped gadolinium orthovanadate (GdVO4:Tb3+), orthophosphate monohydrate (GdPO4•H2O:Tb3+)and orthovanadate–phosphate (GdV,PO4:Tb3+) powder phosphors were synthesized using a solution combustion method. X-Ray diffraction analysis confirmed the formation of crystalline GdVO4, GdPO4•H2OandGdV,PO4. Scanning electron microscopy images showed that the powder was composed of an agglomeration of particles of different shapes, ranging from spherical tooval to wire-like structures. The chemical elements present were confirmed by energy dispersive spectroscopy, and the stretching mode frequencies were determined by Fourier transform infrared spectroscopy. UV–visible spectroscopy spectra showed a strong absorption band with a maximum at 200nm assigned to the absorption of VO43-and minor excitation bands assigned to f→f transitions of Tb3+. Four characteristic emission peaks were observed at 491, 546, 588 and 623nm, and are attributed to 5D4 → 7Fj (j=6, 5, 4 and 3). The photoluminescent prominent green emission peak (5D4→7F5) was centred at 546nm.The structure and possible mechanism of light emission from GdV1xPxO4:% Tb3+are discussed