Solid-state ionics method fabricated centimeter level high surface roughness silver nanoparticles/copper nanowires composites: Fractal theory study and SERS application

Abstract

In this work the centimeter level silver nanoparticles (AgNPs)/copper nanowires (CuNWs) composites were prepared by the solid-state ionics method and vacuum thermal evaporation method using fast ionic conductor Rb4Cu16Cl13I7 films under 15 μA direct current electric field (DCEF). The surface morphology and chemical composition of the AgNPs/CuNWs composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. The fractal dimension of the AgNPs/CuNWs composites was calculated by fractal theory and the surface enhanced Raman scattering (SERS) performance was detected by Rhodamine 6G (R6G) aqueous solutions as probe molecules. The results indicate that the macroscopic dendritic AgNPs/CuNWs composites arranged neatly near cathode with the longest length of 7 cm were prepared by the solid-state ionics method and vacuum thermal evaporation method. The diameters of CuNWs ranged from 20 to 80 nm and many regularly arranged AgNPs with the diameter from 5 to 15 nm lie in the prepared nanocomposites, which lead to the AgNPs/CuNWs composites have high surface roughness. The fractal dimension of AgNPs/CuNWs composites was 1.178 and the limiting concentrations of R6G for the prepared high surface roughness AgNPs/CuNWs SERS substrates is 10−13 mol/L.