Time-dependent surface plasmon resonance spectroscopy of silver nanoprisms in the presence of halide ions.
Herein, we find that the surface plasmon resonance (SPR) spectra of silver nanoprisms in the presence of halide ions change gradually with reaction time. The changes in the spectra correspond to the shape transformation of silver nanoprisms. There are threshold concentrations of halide ions that initiate the shape-transformation reaction. The threshold concentrations for Cl(-), Br(-), and I(-) are about 3x10(-4) M, 1x10(-6) M, and 1.5x10(-6) M, respectively. Any concentrations of the added halide ions above these thresholds can eventually etch the silver nanoprisms into nanodisks if the reaction time is long enough. The higher the concentration of the halide ions, the higher the etching rate will be. The kinetics of the shape transformation of the silver nanoprisms can be studied by recording their time-dependent surface plasmon resonance (SPR) spectra on a commercial UV/Vis-NIR spectrometer. The peak positions of in-plane dipole SPR bands of silver colloids in the presence of chloride and bromide ions can be fitted very well with the biexponential functions. We propose that the fast components of the biexponential behaviors should correlate to the truncating effect on the corners of silver nanoprisms, and the slow component should correlate to the redeposition of the truncated residues onto the basal plane of the nanoplates.
Hsu
Ming-Sheng
MS
Department of Applied Chemistry, National Chiayi University, Chiayi City, Taiwan.
Cao
Yi-Wei
YW
Wang
Hsuang-Wen
HW
Pan
Ya-Sin
YS
Lee
Bo-Hong
BH
Huang
Cheng-Liang
CL
D001965:Bromides / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D007454:Iodides / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D020349:Surface Plasmon Resonance; D013997:Time Factors
D001965:Bromides; D002712:Chlorides; D007454:Iodides; D012834:Silver