Templated Assembly of Gold Nanoparticles into Microscale Tubules and Their Application in Surface-Enhanced Raman Scattering

We report a simple procedure to assemble gold nanoparticles into hollow tubular morphology with micrometer scale, wherein the citrate molecule is used not only as a reducing and capping agent, but also as an assembling template. The nanostructure and growth mechanism of microtubes are explored via SEM, TEM, FTIR spectra, and UV−vis spectra studies. The incorporation of larger gold nanoparticles by electroless plating results in an increase in the diameter of microtubes from 900 nm to about 1.2 μm. The application of the microtubes before and after electroless plating in surface-enhanced Raman scattering (SERS) is investigated by using 4-aminothiophenol (4-ATP) as probe molecules. The results indicate that the microtubes both before and after electroless plating can be used as SERS substrates. The microtubes after electroless plating exhibit excellent enhancement ability.