abstract
Nanoparticles of gold, silver and their bimetallic alloys have been prepared by an adapted method of reduction of the aqueous salts using sodium borohydride. It is demonstrated that the temperature and order of addition of the corresponding salt solutions influence the nanoalloys chemical arrangement giving different surface plasmon resonance behavior. The colloidal dispersions show very good Surface-Enhanced Raman Spectroscopy (SERS) signal towards rhodamine 6G. The obtained nanoparticles were then successfully deposited onto glass supports by evaporation of the respective colloids and also used as functional SERS sensors with efficient detection of trace amounts of the analyzed dye. These spectroscopic studies demonstrated that both mono and bimetallic nanoparticles show very good SERS sensitivity with the advantage of being prepared using a straightforward synthetic method in the absence of an additional stabilizer as needed for commonly used core-shell systems.
keywords
ENHANCED RAMAN-SCATTERING; NEUTRON POWDER-DIFFRACTION; SURFACE-PLASMON RESONANCE; SHELL NANOPARTICLES; AU-AG; NANOSTRUCTURES; SPECTROSCOPY; NANOCRYSTAL; ABSORPTION; REFINEMENT
subject category
Chemistry
authors
Girao, AV; Pinheiro, PC; Ferro, M; Trindade, T
our authors
Ana Violeta Girão
Junior Researcher
Marta Ascenção Carmona Ferro
Laboratory Officer
Paula Pinheiro
Research Fellowship
Tito Trindade
Full professorGroups
G1 - Porous Materials and Nanosystems
G3 - Electrochemical Materials, Interfaces and Coatings
acknowledgements
The authors thank Fundacao para a Ciencia e a Tecnologia (Portugal) for funding under the PTDC program and FEDER (PTDC/CTM/101453/2008), and for the post-doctoral grant SFRH/BPD/66407/2009 (A. V. Girao), as well as the PhD grant SFRH/BD/96731/2013 (P. C. Pinheiro). Microscopy analysis was supported by RNME-Pole University of Aveiro FCT Project REDE/1509/RME/2005.