Sol–gel preparation and photoluminescence enhancement of Li + and Eu 3+ co-doped YPO 4 nanophosphors

Abstract

YPO 4 nanoparticles with pure monoclinic phase were successfully synthesized by a simple sol–gel method using both citric acid (CA) and ethylene diamine tetraacetic acid (EDTA) as complexing agent. Techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), as well as high-resolution transmission electron microscopy (HRTEM) have been employed to characterize the as-synthesized nanoparticles. Furthermore, the photoluminescence (PL) characterization of the Li + and Eu 3+ co-doped YPO 4 nanocrystals was carried out and the effects of the doping concentration of Li + and Eu 3+ active center concentration as well as calcination temperature on the PL properties have been studied in details. The results show that the incorporation of Li + ions into the YPO 4:Eu 3+ lattice could induce a remarkable improvement of the PL intensity. The highest emission intensity was observed with the compound of 5%Li + and 5%Eu 3+ co-doped YPO 4, whose brightness was increased by a factor of more than 2.5 in comparison with that of the YPO 4:5%Eu.