Identification of Additional Plasmon Mode for Triangular Gold Nanoprism

The use of anisotropic nanomaterials in applications such as biodetection,catalysis,and electronics has led to a continuously increasing interest in the development of synthetic methods for preparing new shapes.
In particular,triangular nanoprisms are a class of nanostructures that have generated intense interest due to their unusual optical properties and the recent development of new methodologies for preparing bulk quantities of them. Gold nanoprisms have been synthesized exclusively by thermal methods with varying degrees of success regarding purity and size control.The optical spectra of nanoprisms should exhibit a distinct dipole resonance as observed in isotropic spherical structures in addition to weaker higher order resonances.The identification of higher order surface plasmon resonance modes with these nanostructures is important because it provides not only greater understanding of their physical properties but also a spectroscopic fingerprint that can be used to characterize and assess the quality of such structures. Recently researchers presented a synthetic approach and separation procedure for synthesizing and isolating large quantities of gold nanoprisms with uniform edge lengths and thicknesses, which has allowed the use of UV−vis−NIR spectroscopy to observe an in-plane quadrupole resonance mode of such structures.
The researchers have develop a method for synthesizing Au nanoprisms in their purest form. The purity of such materials has allowed them to correlate their structure with their optical properties and identify the quadrupole plasmon resonance, which has never been observed in solution because of inhomogeneity and impurities found in the products formed from other preparatory procedures. In view of the high stability of gold as compared with silver, these structures should provide a route to synthesizing many technologically useful materials not attainable with their less noble analogue.