Properties of Er2O3 nanoparticles synthesized by a modified co-precipitation method

were recorded by pumping the nanoparticles at 525 nm, 805 nm, and 975 nm. However, the lumines-cence spectra show an enhancement of red emission for NIR pump wavelengths. We proposed this behavior was due to phonon-assisteddepopulation mechanisms and energy transfer processes related to the different excitation schemes.Keywords: Erbium nanoparticles; optical materials and properties; spectroscopy.PACS: 78.60.Lc; 78.67.Bf