Y2O3:Yb/Er nanotubes: Layer-by-layer assembly on carbon-nanotube templates and their upconversion luminescence properties

Well-shaped Y2O3:Yb/Er nanotubes have been successfully synthesized on a large scale via layer-by-layer (LBL) assembly on carbon nanotubes (CNTs) templates followed by a subsequent heat treatment process. The crystal structure, element analysis, morphology and upconversion luminescence properties were characterized. XRD results demonstrate that the diffraction peaks of the samples calcinated at 800 degrees C or above can be indexed to the pure cubic phase of Y2O3. SEM images indicate that a large quantity of uniform and rough nanotubes with diameters of about 30-60 nm can be observed. The as-prepared Y2O3:Yb/Er nanotubes show a strong red emission corresponding to the F-4(9/2)-I-4(15/2) transition of the Er3+ ions under excitation at 980 nm, which have potential applications in such fields as nanoscale devices, molecular catalysts, nanobiotechnology, photonics and optoelectronics. (C) 2012 Elsevier Ltd. All rights reserved.