Nanoshell

Figure 7.3 Absorption efficiencies for a 50 nm diameter nanoshell with varying aspect ratios. Reproduced from Harris [72], Copyright (2006) American Chemical Society.

The lower symmetry of nanorods (in comparison to nanoshells) allows additional flexibility in terms of the tunability of their optical extinction properties. Not only can the properties be tuned by control of aspect ratio (Figure 7.4a) but there is also an effect of particle volume (Figure 7.4b), end cap profile (Figure 7.4c), convexity of waist (Figure 7.4d), convexity of ends (Figure 7.4e) and loss of rotational symmetry (Figure 7.4f). 

Hirsch, L.R., Stafford, R.J., Bankson, J.A., Sershen, S.R., Rivera, B., Price, R.E., Hazle, J.D., Halas, N.J. and West, J.L (2003) Nanoshell-mediated near-infrared thermal therapy of tumors under magnetic resonance guidance. Proceedings of the National Academy of Sciences of the United States of America, 100, 13549-13554. 

Averitt, R.D., Sarkar, D. and Halas, N.J. (1997) Plasmon resonance shifts of Au-coated AU2S nanoshells Insight into multicomponent nanopartide growth. Physical Review Letters, 78, 4217-4220. 

Oldenburg, S.J., Jackson, J.B., Westcott, S.L. and Halas, N.J. (1999) Infrared extinction properties of gold nanoshells. Applied Physics Letters, 75, 2897-2899. 

Harris, N., Ford, M.J. and Cortie, M.B. (2006) Optimization of plasmonic heating by gold nanospheres and nanoshells. The Journal of Physical Chemistry B, 110, 10701-10707. 

F. and Buuren, T.v. (2005) Comment on Gold nanoshells improve single nanoparticle molecular sensors . Nano Letters, 5, 809-810. 

Fig. 8.16 TEM image showing nanowires formed by wrapping X-DNA with an outer nanoshell of AMP (scale bar = 500nm).

Figure 3. Various type of SERS active metallic nanostructures (a) metal-island films (b) metal-coated nanospheres (semi-nanoshells) (c) metal-coated random nanostructures and (d) polymer coatings embedded with metal nanoparticles. Inset An SEM image of silver-coated polystyrene spheres.

Pham T., Jackson J.B., Halas N.J., Lee T.R., Preparation and characterization of gold nanoshells coated with self-assembled monolayers, Langmuir 2002 18 4915-4920. 

Jackson J.B., Westcott S.L., Hirsch L.R., West J.L., Halas N.J., Controlling the surface enhanced Raman effect via the nanoshell geometry, Appl. Phys. Lett. 2003 82 257-259. 

Fig. 1 TEM images of plasmonic gold nanostructures (a) nanospheres, (b) nanorods, and (c) nanoshells. (Figure adapted from [6])...

Hirsch LR, Gobin AM, Lowery AR, Tam F, Drezek RA, Halas NJ, West JL (2006) Metal nanoshells. Annals of Biomedical Engineering 34 15-22. 

Wang YW, Xie XY, Wang XD, Ku G, Gill KL, O Neal DP, Stoica G, Wang LV (2004b) Photoacoustic tomography of a nanoshell contrast agent in the in vivo rat brain. Nano Letters 4 1689-1692. 

Z.S. Wronski, G.J.C. Carpenter, Carbon nanoshells obtained from leaching carbonyl nickel metal powders, Carbon 44(2006) 1779-1789. 

Fig. 4.15 Carbon onion. After [59]. Image credit http //www.staff.uni-mainz.de/banhart/ c-nano-structures/onions. Note compression of interlayer distances - from 0.335 nm for ordered graphite to less than 0.3 nm this is in contrast to the swelling of planes in turbostatic graphite and in carbon nanoshells [60]...

One can observe that carbon nanoshells, as consisting of small domains of graphitic sp sheets, must exhibit multitude of dangling bonds at their peripheries. These domains of stacked graphene sheets can also be seen as layered graphitic nanocrystals. The dimensions of these nanocrystals (few tenths nanometers thick by few hundred nanometers length) provide efficient constrains for mobility of n... 

Fig. 4.16 HREM image of carbon nanoshells showing that the basal planes roughly follow the curvature of the shell owing to the presence of a high density of dislocations. The image contrast of the basal planes was enhanced by use of fast Fourier transform (FFT) processing. After [60]...

Fig. 4.17 Model of a carbon nanoshell pointing to the stacks of 5-10 aligned layers within the shell. Hydrogen can possibly bond to the dangling bonds on the periphery of layered graphitic...

Loo C, Lowery A, Halas N, West J, Drezek R (2005) Immunotargeted nanoshells for integrated cancer imaging and therapy. Nano Lett 5 709-711... 

Hirsch LR, Jackson JB, Lee A, Halas NJ, West J (2003) A whole blood immunoassay using gold nanoshells. Anal Chem 75 2377-2381... 

Other scientists have also been experimenting with this effect. Jennifer L. West and her colleagues at Rice University designed small shells, nanoshells, of gold. The nanoshells have a core made of a... 

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