Selective Deposition of Gold onto 40-nm Silver Nanocubes
with Excellent Plasmonic Properties and Chemical Stability
Yin Yang
School of Materials Science and Engineering
Georgia Institute of Technology
Plasmonic Nanocrystals
Structure
Property
Localized Surface Plasmon Resonance
(LSPR)
Application
Surface Enhanced Raman Scattering
(SERS)
532 nm
Excitation
Bright
Field
SERS
50 nm
LSPR
Selective Deposition of Metals on Nanoscale Template
Precursor of M2
Reducing agent
M1
M1@M2 core-shell
Homogeneous Growth
Ag seeds
Ag cubes
AgNO3
Ascorbic Acid
40 nm cubes
100 nm cubes
Y. Xia et al., J. Am. Chem. Soc. 2012, 134, 1793
Heterogeneous Growth of Bimetallic Nanocrystals
Pd seeds
Pd@Ag
AgNO3
Ascorbic Acid
100 nm
N. Zheng et al., Adv. Mater. 2011, 23, 3420
Deposition of Au on Ag Nanocubes
???
(E = 0.80 V vs SHE)
Au Deposition
(E = 0.99 V vs SHE)
0.05 mL
0.2 mL
0.6 mL
1.0 mL
Y. Xia et al., J. Am. Chem. Soc. 2004, 126, 3829
Increase amount of HAuCl4
Selective Deposition of Au on Ag Nanocubes
(Rgal)
Au 3+ + 3e − → Au 0
(Rred)
Y. Yang, J. Liu, Z. Fu and D. Qin, Submitted.
Ag@Au Core-shell Nanocubes
Rred>>Rgal
Chemical Stability of Core-Shell Nanocubes
(in 2.3% H2O2 aqueous solution)
40 nm
nanocubes
110 nm
nanocubes
Before Ag etching
After Ag etching
0.05 mL
0.2 mL
0.6 mL
Rred~Rgal
0.6 mL
Transformation of Ag Nanocubes into Ag-Au Hollow Nanostructures with Enhanced Ag Contents
to Improve SERS Activity and Chemical Stability
Y. Yang, Q. Zhang, Z.-W. Fu and D. Qin, ACS Applied Materials & Interfaces, DOI: 10.1021/am500506j
LSPR Properties of Ag-Au Nanostructures
Ag
nanocube
Ag@Au
core-shell cube
Ag-Au
hollow cube
Ag-Au
nanobox
Surface Enhanced Raman Scattering (SERS)
Probe Molecule: 1,4-Benzenedithoil
Ag-Au
hollow cube
Ag@Au
core-shell cube
Ag-Au
nanobox
Ag nanocube
SERS of Melamine with Ag-Au Hollow Nanocubes
Conclusion and Outlook
Ag
nanocube
Au 3+ + 3e − → Au 0
Ag@Au
core-shell cube
Ag-Au
hollow cube
Au-Ag
nanobox
Acknowledgement
Prof. Dong Qin
Dr. Jumei Li
Xiaojun Sun
Jiawei Zhang
Yin Yang
Prof. Zhengwen Fu
Collaborator: Professor Jimmy Liu, Physics, Arizona State University