Synthesis, Characterization and Optical Properties of ZnO Nanoparticles Doped with Er and Yb.

This paper discusses the structure, particle morphology, and optical properties of un-doped ZnO and ZnO doped with Er³⁺ and Yb³⁺ lanthanide ion nanoparticles (NPs) through a process denominated sol-gel-hydrothermal. According to the pattern of X-ray diffraction, ZnO:Er and ZnO:Yb is formed by a single-phase wurtzite structure with crystallites sized ~65 nm on average, and Er or Yb dopant ions in the hexagonal structure of ZnO, specifically in its distorted lattice sites. The results also suggest the possible role of oxygen vacancies or O^x- (defects) in the energy transfer from ZnO to the Er or Yb ions with a decrease of 3.18 eV and 3.19 eV in bandgap values to a red shift.