Applied Surface Science, Vol.353, 11-16, 2015
Annealing effect: Controlled modification of the structure, composition and plasmon resonance of hybrid Au-Ag/C nanostructures
Here we present a novel approach to the synthesis of hybrid Au-Ag/C nanoparticles (NPs) which were found to be carbon nanospheres containing dispersed Au-Ag bimetallic nanoparticles (1-5 nm). The Au-Ag/C NPs were obtained by laser-induced liquid phase deposition from solutions of supramolecular complex. It was revealed that subsequent annealing procedure of Au-Ag/C NPs at various temperatures over the range 100-600 degrees C allows variation and directed control of NPs' morphology and composition (relative contents of principal components). For nanoscale carbon material the critical evaporation temperature was found to be about 300 degrees C, while for Ag and Au components - 500 degrees C and 600 degrees C accordingly. The morphology and composition variation makes possible tuning of the surface plasmon resonance characteristics that opens an efficient way of the NPs' functional properties control, like for example Surface-Enhanced Raman Scattering (SERS). It was found that the obtained hybrid Au-Ag/C NPs display pronounced SERS activity with the enhancement factor (EF) ca. 10(5). (C) 2015 Elsevier B.V. All rights reserved.