A Facile Method To Obtain Highly Stable Silver Nanoplate Colloids with Desired Surface Plasmon Resonance Wavelengths
The Journal of Physical Chemistry C, 114 (14):
6222–6227 (2010)DOI: 10.1021/jp910100k
Abstract
The extinction spectra and TEM images show that the silver nanoprisms would undergo shape transformation in the presence of 5 × 10−6 M bromide ions. In this study, HS(CH2)15CO2H (MHA) were introduced to modify the surface of silver nanoprisms. The MHA-modified silver nanoprisms can prevent the shape transformation in the presence of bromide ions with a concentration as high as 0.1 M. Furthermore, it was found that the etching process on the unmodified silver nanoprisms caused by the bromide ions can be stopped immediately by adding MHA into the colloid solution. However, the rate of the etching process in the initial stage was too fast to be stopped by adding MHA to control the silver colloid with the desired SPR wavelength. PVP-modified silver nanoprisms cannot prevent the shape evolution in high concentration bromide ions, such as 10−3 M, but can slow down the etching rate. The silver nanostructures with the desired SPR wavelength can be obtained by the following simple method: KBr was added into the PVP-modified silver nanoprism colloid to initiate the shape evolution, and after a period of time, MHA was added to terminate the etching reaction. The PVP-KBr-MHA treated silver nanostructures with various colors produced by this simple method not only have long-term stability stored at room temperature but also can prevent shape transformation in highly concentrated chloride solutions.