Abstract: A series of Lu₂O₃ nanopowders co-doped with Yb³⁺ and Ho³⁺ were synthesized by co-precipitation method. The Yb³⁺ concentration is 1mol% and the Ho³⁺ concentration ranges from 0.5mol% to 10mol%. The Stokes and Anti-Stokes spectroscopic
properties of the prepared nanopowders were investigated, together with the relative intensities of Stokes and Anti-Stokes PL spectra dependence on the powders calcined at different temperatures. Strong green emissions were observed under the excitation of 447.5nm (Xenon Lamp) and 980nm (Laser Diode), respectively. Concentration quenching occurrs with the increase of Ho³⁺ concentration. Power studies reveal that a two-photon process is involved in the Anti-Stokes emissions and the possible upconversion mechanisms are energy transfer from Yb³⁺ to Ho³⁺. Concentration quenching and energy transfer process are confirmed by the decay time of the ⁵F₄, ⁵S₂ level under the excitation of different pump wavelength.

Key words: Lu₂O₃ nanopowders, Anti-Stokes PL, decay time, Stokes PL