Structural and spectroscopic properties of Eu3 +-activated nanocrystalline tetraphosphates loaded in silica–hafnia thin film

Abstract Nanoparticles of lithium lanthanum tetraphosphates doped with different concentration of Eu 3 + ions were synthesized. The selected tetraphosphate was used to fabricate a transparent composite where nanocrystals were immobilized in a sol–gel-derived silica–hafnia amorphous film. The structural and spectroscopic properties of the systems were investigated by XRD analysis, Raman spectroscopy, and photoluminescence measurements. For all the samples with the Eu 3 + ions concentration from 1 to 100 mol% the monoclinic structure with a space group C12/c1 was determined. The mean diameter of nanocrystals determined by Scherrer equation was in the range of 40–55 nm. The luminescence of 10%Eu 3 + :LiLa(PO 3 ) 4 in silica–hafnia matrix indicated the immobilization of Eu 3 + ions into a distorted environment. The dependence of both luminescence intensity and lifetime on the Eu 3 + concentration demonstrated effective reduction of concentration quenching in the tetraphosphate nanopowders.