title: Self-assembled silver nanochains for surface-enhanced Raman scattering.
abstract: Surface-enhanced Raman scattering (SERS) integrates high levels of sensitivity with spectroscopic precision and has tremendous potential for chemical and biomolecular sensing. The key to the wider application of Raman spectroscopy using roughened metallic surfaces is the development of highly enhancing substrates for analytical purposes. Here, we demonstrate a simple strategy for self-assembling silver nanochains on glass substrates for sensitive SERS substrates. The chain length of short Ag nanochains can be controlled by adjusting the concentration of cetyltrimethylammonium bromide (CTAB) and 11-mercaptoundecanoic acid (MUA). CTAB with appropriate concentration serves as the "glue" that can link the {100} facets of two neighboring Ag nanoparticles. MUA is found to be effective in "freezing up" the aggregation of Ag short chains and preventing them from further aggregating into a long chainlike network structure. The surface plasmon bands can be tuned over an extended wavelength range by controlling the length of the nanochains. The Ag monolayer, mainly composed of four-particle nanochains, exhibited the maximum SERS enhancement factor of around 2.6 x 108, indicating that a stronger SERS enhancement can be obtained in these interstitial sites of chainlike aggregated Ag nanoparticles.
authors.affiliation: Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa, Nagoya, Japan. yang.yong@nitech.ac.jp
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Jianlin
authors.initials: J
authors.lastname: Shi
authors.forename: Taiki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nogami
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: C505222:11-mercaptoundecanoic acid; D002593:Cetrimonium Compounds; D005227:Fatty Acids; D013438:Sulfhydryl Compounds; D012834:Silver; D000077286:Cetrimonium