Anisotropic metal nanoparticles

Another key factor in determining the particle anisotropy was the size of the growing nanoparticle. Jana et al. have prepared different sizes of near-monodisperse spherical gold 

Anisotropic noble nanoparticle dispersions are very different in colour compared to dispersions of spherical particles. This is because the surface plasmon bands are more sensitive to particle shape than size [92]. All the metal nanorods have two absorbance maxima that correspond to the longitudinal and transverse plasmon bands. The longitudinal plasmon band strongly depends on the aspect ratio. For example, platelets have additional quadrupole bands [96]. Upon transition from nanorods to platelets, as the aspect ratio decreases, the longitudinal band is blue-shifted and the transverse band becomes broad due to overlap with the quadrupole band. In cubes, all three plasmon bands merge into a single band. In contrast, transition from nanorods to nanowires increases the aspect ratio, which produces a resultant red shift of the longitudinal band and a blue shift of transverse band [83]. 

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Murphy CJ, San TK, Gole AM, Orendorff GJX, Gou L, Hunyadi SE, Li T (2005) Anisotropic metal nanoparticles synthesis, assembly, and optical applications. J Phys Chem B 109 13857-13870... 

Hao, E., Schatz G, Hupp J (2004). Synthesis and optical properties of anisotropic metal nanoparticles. J. Fluor. 14 ... 

C. J. Murphy et al.. Anisotropic metal nanoparticles Synthesis, assembly, and optical applications. Journal of Physical Chemistry B, 109(29), 13857-13870 (2005). 

N. R. Jana and T. Pal, Anisotropic metal nanoparticles for use as surface-enhanced Raman substrates. Advanced Materials, 19(13), 1761-1765 (2007). 

The differential light scattering of anisotropic metal nanoparticles probes has been already exploited in the development of many biodiagnostic applications [9, 10]. The anisotropic growth of metal nanoparticles is attributed to one of the following mechanisms [11] ... 

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