Preparation of SrR_2O_4:Eu~(3+) (R=Y, Lu) phosphor and its photoluminescence properties

摘要

In this work, we present a novel approach for synthesis of europium (Hl)-doped SrR_2O_4:Eu~(3+) (R=Y, Lu) superfine phosphor with a precursor prepared in water-in-oil microemulsion. The precursor of oxalates formed in a reaction between Sr(NO_3)_2-Y(NO_3)_3(Lu(NO_3)_3)-Eu(NO_3)_3 and H_2C_2O_4 in reverse microemulsions composed of OP-10, iso-pentanol, cyclohexane and water. X-ray diffraction results confirmed the formation of SrR_2O_4:Eu~(3+) and SrLu_2O_4:Eu~(3+) at 1000 deg C and 900 deg C respectively. FE-SEM images showed the superfine powder of SrR_2O_4:Eu~(3+) has a rugby-like shape and a diameter of 70-100 nm. Upon excitation with 257-272 nm UV light, all the SrR_2O_4:Eu~(3+) (R=Y, Lu) powders show bright red emission due to the 4f-4f transitions of Eu~(3+) ions, and the highest photoluminescence intensity at 618 nm for SrY_2O_4:Eu~(3+) and 615 nm for SrLu_2O_4:Eu_(3+) was found at a content of about 9 mol percent Eu~(3+) and 6 mol percent Eu~(3+) respectively. Splitting of the ~5D_0 - > ~7F_0 and ~5D_0 - > ~7F_1 emission transitions revealed that the Eu~(3+) ions occupied two nonequivalent sites in the crystalline lattice by substituting Y~(3+) or Lu~(3+) ions.