Green and red upconverted emission of hydrothermal synthesized Y2O3: Er3+–Yb3+ nanophosphors using different solvent ratio conditions

The solvent effect on the green and red upconversion luminescence of hydrothermal synthesized Y2O3: Er3+–Yb3+ nanophosphors is analyzed. To that purpose, five different ethanol/water solvent ratios 1:3, 1:4, 1:5, 1:6 and 1:10 with 1 mol% of Er3+ and 2 mol% of Yb3+, were considered. According to results, the intensity of the visible emission depends on the SR synthesis conditions; the highest intensity of green and red emission, from a 970 nm excitation, is presented by the sample obtained using a 1:5 solvent ratio. In order to explain the results, an analysis of decaying times was done, the influence of the solvent effect on the material structure was investigated by a diffuse reflectance characterization and the upconverted emission mechanism was derived from a power pumping study. Characterization data indicated that the solvent ratio influences the luminescence properties of nanostructured materials.