Hydrothermal synthesis and green luminescent properties of Lu2O3:Yb3+/Ho3+ nanocubes.

Uniform and dispersive Lu 2 O 3 :Yb 3+ /Ho 3+ nanocubes have been successfully synthesized by the hydrothermal process followed by a subsequent calcination at 800 °C. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), cathodoluminescence (CL) spectra, as well as lifetimes measurements were utilized to characterize the synthesized phosphors. The as-formed RE 3+ -doped lutetium oxide precursor via the hydrothermal process as a template could transform to RE 3+ -doped Lu 2 O 3 with their original cubic morphology and slight shrinkage in the size after the post-annealing process. The formation mechanism for the lutetium oxide precursor cubes has been proposed. Under the excitation of UV light, 980-nm laser and low-voltage electron-beams, Lu 2 O 3 :Yb 3+ /Ho 3+ phosphors all show the characteristic emission of the Ho 3+ ion ( 5 F 4 , 5 S 2 → 5 I 8 transition) with green color, which is easily observed by naked eyes. The corresponding luminescent mechanisms have been discussed. Due to the excellent PL (including up-conversion and down-conversion) properties and CL properties of the Lu 2 O 3 :Yb 3+ /Ho 3+ phosphors, they are potentially applicable in fluorescent lamps, up-conversion fluorescent labels and FED devices as an efficient green phosphor.