Synthesis, novel luminescence properties, and surface-enhanced Raman scattering of Au/Y_2O_3: Eu~(3+) composite nanotubes

摘要

Y(OH)_3:Eu~(3+) nanotubes were synthesized by a facile hydrothermal method first, and then Au particles were grown on the surface of Y_2O_3:Eu~(3+) 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/Y_2O_3:Eu~(3+) composite nanotubes were investigated in detail. In the excitation spectra of Au/Y_2O_3:Eu~(3+) monitored at 614 nm, the ~7F_0→~5H_3 transition from Eu~(3+) increased with increasing Au content, while the other sharp lines originating from Eu~(3+) f–f electron transitions almost vanished. In the emission spectra, the spectral configurations of Eu~(3+) in Au/Y_2O_3:Eu~(3+) composite nanotubes varied with the excitation wavelengths. When the excitation wavelength was 256 nm, the ~5D_4→~7F_0, ~5D_7→~7F_0, ~5G_2→~7F_0, ~5L_6→~7F_0, ~5D_0→~7F_0, ~5D+0→~7F_1, ~5D_0→~7F_2, ~5D_0→~7F_3, and ~5D_0→~7F_4 transitions from Eu~(3+) ions in Au/Y_2O_3:Eu~(3+) 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/Y_2O_3:Eu~(3+_ composite nanotubes as SERS substrates. The relative intensities of the SERS spectra enhanced with the increase of Au~+: Ln~(3+) ratio.