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A facile and simple route to manufacture active surface-enhanced Raman scattering (SERS) substrate based on Ag-decorated Cu2O micro/nanospheres on Cu foil was systematically investigated. Hierarchical Cu2O micro/nanostructure transfers from CuO nanosheets and Cu(OH)2 nanowires by means of thermally reducing the oxides from Cu2+ to Cu1+ at temperature of 500 °Cunder nitrogen atmosphere. The subsequent decoration of Ag on Cu2O nanostructural substrate was carried out by means of thermal evaporator deposition. Using 4-aminothiophenol (4-ATP) as probing molecules, the SERS experiments showed that the Ag-decorated Cu2O micro/nanospheres exhibit excellent detecting performance, which could be used as effective SERS substrate for ultrasensitive detection. Additionally, these novel hierarchical SERS substrates showed good reproducibility and a linear dependence between analyte concentrations and intensities, revealing the advantage of this method for easily scale-up production.

This study develops and successfully demonstrates visualization methods for the characterization of europium (Eu)-doped BaAl2O4 phosphors using X-ray nanoprobe techniques. X-ray fluorescence (XRF) mapping not only gives information on the elemental distributions but also clearly reveals the valence state distributions of the Eu2+ and Eu3+ ions. The accuracy of the estimated valence state distributions was examined by performing X-ray absorption spectroscopy (XAS) across the Eu L 3-edge (6.977 keV). The X-ray excited optical luminescence (XEOL) spectra exhibit different emission lines in the selected local areas. Their corresponding emission distributions can be obtained via XEOL mapping. The emission properties can be understood through correlation analysis. The results demonstrate that the main contribution to the luminescence intensity of the Eu-doped BaAl2O4 comes from the Eu2+ activator and the emission intensity will not be influenced by the concentration of Eu2+ or Eu3+ ions. It is anticipated that X-ray nanoprobes will open new avenues with significant characterization ability for unravelling the emission mechanisms of phosphor materials.

Surface plasmon resonance (SPR) is one of the main mechanisms of Surface Raman Enhance Scattering (SERS) and it will depend on the morphology and free carrier density of substrates, in many of discussions have been proved. Recently, the semiconductor copper(I) sulphide (Cu2S), the natural p-type semiconductor, exhibits remarkable SPR in the nearinfrared region [1] and can be regards as best candidate for active SERS substrates. In this report, the successive ionic layer adsorption and reaction (SILAR) process will be used to synthesis Cu2S nanostructures [2] from ZnO nanorods as template deposited by electrochemical reaction. To further manipulate the different carrier densities of Cu2S nanostructuress, the adjustment of Cu vacancy in Cu2S can be accomplished by thermal processes under noble gas. Taking 4-aminothiophenol (4-ATP) as probe molecule to measure the SERS performance by Cu2S nanostructures made in this fabrication and also examines the effect on SERS by adjusting Cu vacancy under an excited wavelength of 632.8 nm and light power of 15 mW. In fact, the modulation of Cu vacancy will positively correlate to the SPR frequencies and so could get the best enhancement factor under the limited condition of excited source. Therefore, our results could provide a new opportunity to use SERS to explore the molecule-semiconductor interaction, a fundamental but essential question for designing novel devices.