Tripolyphosphate as precursor for REPO(4):Eu (3+) (RE = Y, La, Gd) by a polymeric method.

A modification of the Pechini method was applied to obtain luminescent rare earth orthophosphates. The developed synthetic route is based on the ability of the tripolyphosphate anion (P(3)O(5-)(10)) to act both as a complexing agent and as an orthophosphate precursor. Heating of aqueous solutions containing RE(3+), Eu(3+), P(3)O(5-)(10), citric acid, and ethylene glycol led to polymeric resins. The ignition of these resins at different temperatures yielded luminescent orthophosphates. The produced nanosized phosphors (YPO(4):Eu(3+), (Y,Gd)PO(4):Eu(3+), and LaPO(4):Eu(3+)) were analyzed by infrared and luminescence spectroscopies, X-ray diffractometry, and scanning electron microscopy.