Abstract

(Yb³⁺, Er³⁺) and (Yb³⁺, Tm³⁺) codoped Lu₂O₃ nanorods have been prepared by a low temperature hydrothermal procedure. Their optical behavior, in terms of luminescence and waveguiding properties was analyzed. Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied in function of the Yb³⁺ concentration. UC spectra revealed the strong development of Er^{3+ 4}F_9/2 → ⁴I_15/2 (red) and Tm^{3+ 1}G₄ → ³H₆ (blue) bands, which were favored by a high Yb³⁺ concentration. UC mechanisms privilege the population of ⁴F_9/2 and ¹G₄ emitting levels through phonon assisted energy-transfer and non-radiative relaxations, which are helped by the large phonons existing in the current nanorods. CL spectra show a moderate increase of the intensity ratio between the Er^{3+ 4}F_9/2 → ⁴I_15/2 (red) and ²H_11/2, ⁴S_3/2 → ⁴I_15/2 (green) emissions with the increase in the Yb³⁺ content, while for Yb³⁺, Tm³⁺-codoped Lu₂O₃ nanorods the dominant CL emission is Tm^{3+ 1}D₂ → ³F₄ (deep-blue). Uniform light emission along Yb³⁺, Er³⁺-codoped Lu₂O₃ rods has been observed by using SNOM photoluminescence images.

© 2011 Optical Society of America