Chemical stabilization of gold coated by silver core-shell nanoparticles via electron transfer.
Silver nanoparticles are notoriously susceptible to oxidation, yet gold nanoparticles coated in silver exhibit a unique electronic interaction that occurs at the interface of the two metals, leading to enhanced stability properties for the silver shell. In order to probe the phenomenon, the stability of gold nanoparticles coated by silver was studied in the presence of various chloride-containing electrolytes. It was found that a critical silver shell thickness of approximately 1 nm exists that cannot be oxidatively etched from the particle surface: this is in contrast to the observation of complete oxidative etching for monometallic silver nanoparticles. The results are discussed in terms of particle composition, structure and morphology before and after exposing the particles to the electrolytes. Raman analysis of the reporter molecule 3-amino-1,2,4-triazole-5-thiol adsorbed on the particle surface illustrates the feasibility of using gold coated by silver nanoparticle probes in sensing applications that require the presence of high levels of salt. The results provide insight into the manipulation of the electronic and stability properties for gold- and silver-based nanoparticles.
Japan Advanced Institute of Science and Technology, School of Materials Science, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
Cheshta
C
Shankar
Anh T N
AT
Dao
Prerna
P
Singh
Koichi
K
Higashimine
Derrick M
DM
Mott
Shinya
S
Maenosono
D002122:Calcium Chloride / Q000737:chemistry; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013057:Spectrum Analysis
D012834:Silver; D012965:Sodium Chloride; D006046:Gold; D002122:Calcium Chloride; D006851:Hydrochloric Acid