Yb 3+ ‐ and Er 3+ ‐doped Y 2 O 3 microcrystals for upconversion photoluminescence and energy transfer with enhancements of near‐ultraviolet emission

Abstract Yb 3+ and Er 3+ were doped into Y 2 O 3 to form Y 2 O 3 : Yb 3+ , Er 3+ microcrystals. The effect of doping concentration of Yb 3+ was studied. The near‐ultraviolet (UV) upconversion (UC) emission spectra of Y 2 O 3 : Yb 3+ , Er 3+ were studied under 1.55‐μm excitation. The near‐UV UC emissions centered at 391 and 418 nm were enhanced by Yb 3+ under 1.55‐μm laser excitation. Er 3+ generally acts as activator and is not used as sensitizer in the reference Er 3+ ‐doped oxides. In the present upconversion process under the 1.55‐μm laser excitation, the energy transfer from Er 3+ to Yb 3+ and then Yb 3+ to Er 3+ was observed. Dopant Er 3+ acted as not only activator but also sensitizer. The energy transfer between Er 3+ and Yb 3+ enhanced the near‐UV UC emission of our materials.