Yb³⁺- and Er³⁺-doped Y₂O₃ microcrystals for upconversion photoluminescence and energy transfer with enhancements of near-ultraviolet emission

Yb³⁺ and Er³⁺ were doped into Y₂O₃ to form Y₂O₃: Yb³⁺, Er³⁺ microcrystals. The effect of doping concentration of Yb³⁺ was studied. The near-ultraviolet (UV) upconversion (UC) emission spectra of Y₂O₃: Yb³⁺, Er³⁺ were studied under 1.55-μm excitation. The near-UV UC emissions centered at 391 and 418 nm were enhanced by Yb³⁺ under 1.55-μm laser excitation. Er³⁺ generally acts as activator and is not used as sensitizer in the reference Er³⁺-doped oxides. In the present upconversion process under the 1.55-μm laser excitation, the energy transfer from Er³⁺ to Yb³⁺ and then Yb³⁺ to Er³⁺ was observed. Dopant Er³⁺ acted as not only activator but also sensitizer. The energy transfer between Er³⁺ and Yb³⁺ enhanced the near-UV UC emission of our materials.

The near-ultraviolet (UV) upconversion (UC) emission spectra of Y₂O₃:Yb³⁺, Er³⁺ microcrystalswere studied under 1.55-μm excitation. Enhancements of near-UV UC emission of Er³⁺ were observed. The energy transfer from Er³⁺ to Yb³⁺ and then Yb³⁺ to Er³⁺ was thought to be the possible mechanisms for these enhancements. The doping concentration of the Yb³⁺ ion was studied also. In the upconversion process, Er³⁺ ion is not only as activator but also as sensitizer.