Synthesis, novel luminescence properties, and surface-enhanced Raman scattering of Au/Y2O3: Eu3+ composite nanotubes

Y(OH)(3):Eu3+ nanotubes were synthesized by a facile hydrothermal method first, and then Au particles were grown on the surface of Y2O3: Eu3+ nanotubes by combining the vacuum extraction method and the annealing process. The composite nanotubes were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of the Au content on the photoluminescence properties of the Au/Y2O3:Eu3+ composite nanotubes were investigated in detail. In the excitation spectra of Au/Y2O3:Eu3+ monitored at 614 nm, the F-7(0)-> H-5(3) transition from Eu3+ increased with increasing Au content, while the other sharp lines originating from Eu3+ f-f electron transitions almost vanished. In the emission spectra, the spectral configurations of Eu3+ in Au/(YO3)-O-2:Eu3+ composite nanotubes varied with the excitation wavelengths. When the excitation wavelength was 256 nm, the D-5(4)-> F-7(0), D-5(7)-> F-7(0), (5)G(2)-> F-7(0), L-5(6)-> F-7(0), D-5(0)-> F-7(0), D-5(0)-> F-7(1), D-5(0)-> F-7(1), and D-5(0)-> F-7(2), D-5(0)-> F-7(3), D-5(0)-> F-7(4) transitions from Eu3+ ions in Au/Y2O3:Eu3+ were observed. When the excitation wavelength was 378 nm, the plasmon resonance peak from Au nanoparticles was observed. In addition, 4-ATP was chosen as the model molecule to examine the performance of the Au/Y2O3:Eu3+ composite nanotubes as SERS substrates. The relative intensities of the SERS spectra enhanced with the increase of Au+ : Ln(3+) ratio.