Synthesis and study of upconversion Lu2(WO4)3: Yb3+, Tm3+ nanoparticles synthesized by modified Pechini method

Abstract We report on Lu2(WO4)3: Yb3+, Tm3+ upconversion nanoparticles prepared via modified Pechini method, which is low-cost in comparison with analogs and allows achieving the homogenous rare earth ions (Yb3+ and Tm3+) dispersion in the host matrix. The Tm3+ doping concentration effect on structural and luminescence properties has been studied in detail. The structure of the nanoparticles was characterized by XRD and Raman spectroscopy. Both analytical methods confirmed the formation of single phase Lu2(WO4)3: Yb3+, Tm3+ nanoparticles without any impurities. It was found that thulium ions are uniformly incorporated into the tungstate structure up to a concentration of 1%. SEM images showed that prepared samples consisted of weakly agglomerated nanoparticles with an average size of about 40–80 nm. Emission and excitation spectra of all Lu2(WO4)3: xTm3+, 10% Yb3+ samples contained characteristic transitions inside Tm3+ ions. Upconversion spectra demonstrated intense infrared line (3H4–3H6) as well as weak blue 1G4–3H6 and two red (1G4–3F4, 3F2,3–3F6) bands obtained upon 974 nm excitation. Optimal Tm3+ doping concentration was found to be 0.3% for both 3H4–3H6 and 1G4–3F4 transitions. Change of chromaticity coordinates along with Tm3+ amount increase was also observed.