Enhancement of up-conversion emissions in ZnO: Er3+–Yb3+ after Gd2O3 surface modification

ZnO: Er3+–Yb3+/Gd2O3 core/shell nanoparticles are synthesized via a seeded deposition process with ZnO: Er3+–Yb3+ nanoparticles as seeds and Gd2O3 as shells, respectively. Analyses on phase and structures indicate that the Gd2O3 shell is around 1 nm in thickness. Raman signals change with the increase of Gd2O3 shell deposition times, which are the synergistic results of phonon confinement effect and interface strain. Visible up-conversion (UC) emissions are observed in the seed samples, after Gd2O3 surface modification, great enhancement of the UC emissions are observed. The detail is discussed.