Hydrothermal synthesis and tunable luminescence of persimmon-like sodium lanthanum tungstate:Tb3+, Eu3+ hierarchical microarchitectures

Persimmon-like NaLa(WO4)(2) microarchitectures were prepared via hydrothermal process with using trisodium citrate (Na3Cit) as chelated reagent and characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL), and fluorescent dynamics. The influences of Na3Cit concentration, organic additivities, and reaction time on the morphologies of NaLa(WO4)(2) phosphor were studied. The results revealed that Na(3)Cit species had double functions of strong ligand and structure-directing reagent that could efficiently control the formation of persimmon-like NaLa(WO4)(2) microarchitectures. The possible mechanism for the growth of persimmon-like NaLa(WO4)(2) microarchitectures was attributed to the Ostwald ripening mechanism. The energy transfer from Tb3+ to Eu3+ in the persimmon-like NaLa(WO4)(2) phosphors was observed. The energy transfer efficiencies and emission colors can be tuned by changing the concentration of Eu3+. Finally, it was deduced that the electric dipole-dipole interaction (D-D) is the main mechanism for energy transfer between Tb3+ and Eu3+ in the persimmon-like NaLa(WO4)(2) phosphor. (C) 2012 Elsevier Inc. All rights reserved.