Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances
Type
ArticleAuthors
Huang, Jianfeng
Zhu, Yihan
Liu, Changxu

Zhao, Yunfeng

Liu, Zhaohui

Hedhili, Mohamed N.

Fratalocchi, Andrea

Han, Yu

KAUST Department
Advanced Membranes and Porous Materials Research CenterApplied Mathematics and Computational Science Program
Chemical Science Program
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Imaging and Characterization Core Lab
Nanostructured Functional Materials (NFM) laboratory
PRIMALIGHT Research Group
Physical Science and Engineering (PSE) Division
Date
2015-08-13Online Publication Date
2015-08-13Print Publication Date
2015-10Permanent link to this record
http://hdl.handle.net/10754/574950
Metadata
Show full item recordAbstract
Colloidal metal nanocrystals with strong, stable, and tunable localized surface plasmon resonances (SPRs) can be useful in a corrosive environment for many applications including field-enhanced spectroscopies, plasmon-mediated catalysis, etc. Here, a new synthetic strategy is reported that enables the epitaxial growth of a homogeneously alloyed AuAg shell on Au nanorod seeds, circumventing the phase segregation of Au and Ag encountered in conventional synthesis. The resulting core–shell structured bimetallic nanorods (AuNR@AuAg) have well-mixed Au and Ag atoms in their shell without discernible domains. This degree of mixing allows AuNR@AuAg to combine the high stability of Au with the superior plasmonic activity of Ag, thus outperforming seemingly similar nanostructures with monometallic shells (e.g., Ag-coated Au NRs (AuNR@Ag) and Au-coated Au NRs (AuNR@Au)). AuNR@AuAg is comparable to AuNR@Ag in plasmonic activity, but that it is markedly more stable toward oxidative treatment. Specifically, AuNR@AuAg and AuNR@Ag exhibit similarly strong signals in surface-enhanced Raman spectroscopy that are some 30-fold higher than that of AuNR@Au. When incubated with a H2O2 solution (0.5 m), the plasmonic activity of AuNR@Ag immediately and severely decayed, whereas AuNR@AuAg retained its activity intact. Moreover, the longitudinal SPR frequency of AuNR@AuAg can be tuned throughout the red wavelengths (≈620–690 nm) by controlling the thickness of the AuAg alloy shell. The synthetic strategy is versatile to fabricate AuAg alloyed shells on different shaped Au, with prospects for new possibilities in the synthesis and application of plasmonic nanocrystals.Citation
Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances 2015:n/a SmallJournal
SmallAdditional Links
http://doi.wiley.com/10.1002/smll.201501220ae974a485f413a2113503eed53cd6c53
10.1002/smll.201501220