Eu3+/ Yb3+- activated nanocrystals of lanthanide phosphates

The paper presents structural and luminescence studies of two lanthanide phosphate composites codoped with different concentrations of Eu³⁺ and Yb³⁺ ions. The powders of polycrystalline phosphates were synthesized by the modified Pechini method. The composition and morphology of the samples were characterized using inductively coupled plasma atomic emission spectrometry and transmission electron microscope. The crystal structures of the powders were obtained from the powder diffraction data and were refined using the Rietveld method showing the existence of two or three phases in the materials. The absorption, excitation, and emission spectra of the phosphates have been studied. The upconversion luminescence has been observed in the Eu³⁺/Yb³⁺-doped samples and the energy transfer processes were discussed.