Structural characterizations and intense green upconversion emission in Yb3+, Pr3+ co-doped Y2O3 nano-phosphor

We report the structural and optical properties of Yb(3+), Pr(3+) co-doped Y2O3 nano-phosphor synthesized through solution combustion method. The structural studies reveal the nano-crystalline structure of the sample. The energy dispersive spectroscopy (EDS) measurements confirm the presence of Y, O, Pr and Yb elements in the sample. Fourier transform infrared studies show the vibrational features of the samples. The fluorescence spectra of the samples have been monitored on excitation with 976 nm and the intense green upconversion emission observed at 552 nm is due to (3)P0→(3)H5 electronic transition. The concentration of Pr(3+) ion in the sample is optimized and the fluorescence intensity is maximum at 0.08 mol% of Pr(3+). The power dependence studies reveal the involvement of two photons in the emission process. The possible mechanism of upconversion has been discussed on the basis of schematic energy level diagram. The sample annealed at higher temperature enhances the fluorescence intensity up to 8 times and this enhancement is discussed in terms of the removal of optical quenching centers. The nano-phosphor can be applicable in the field of display devices and green laser.