Optical nanospheres

Hosokawa, C., Yoshikawa, H. and Masuhara, H. (2004) Optical assembling dynamics of individual polymer nanospheres investigated by singleparticle fluorescence detection. Phys. Rev. E, 70, 061410-1-061410-7 (2005) Cluster formation of nanoparticles in an optical trap studied by fluorescence correlation spectroscopy. Phys. Rev. E, 72, 021408-1-021408-7. 

In order to investigate this effect, ordered arrays of metallic nano-islands were fabricated on glass substrates by a process of natural lithography using monodisperse polystyrene nanospheres. The metal particle dimensions were tailored in order to tune the plasmon resonance wavelength to match the spectral absorption of the fluorophore. The fluorophore, Cy5 dye, which is widely used in optical immunoassays and has a medium quantum efficiency ( 0.3), was used in this preliminary study of the plasmonic enhancement effect. 

Kuemer JM, Klimant I, Krause Ch, Preu H, Kunz W, Wolfbeis OS (2001) Inert phosphorescent nanospheres as markers for optical assays. Bioconjug Chem 12 883-889... 

Another nice example of nanostructuring an MIP layer is the work published by Wu et al. [138, 139] who developed a label-free optical sensor based on molecularly imprinted photonic polymers. Photonic crystals were prepared by self-assembly of silica nanospheres. The space between the spheres was then filled with MIP precursor solution. After polymerization, the silica was dissolved, leaving an MIP in the form of a 3D-ordered interconnected macroporous inverse polymer opal (Fig. 15). The authors were able to detect traces of the herbicide atrazine at low concentrations in aqueous solution [139]. Analyte adsorption into the binding sites resulted in a change in Bragg diffraction of the polymer characterized by a color modification (Fig. 15). 

Haynes CL, Van Duyne RP. Nanosphere lithography a versatile nanofabrication tool for studies of size-dependent nanoparticle optics. Journal of Physical Chemistry B 2001,105, 5599-5611. 

In the above sections, our attention was primarily focused on the structural and optical properties of lanthanide doped in nanoparticles such as spherical QDs. Lanthanides doped in some other novel low-dimensional nanostructures including core-shell, one-dimensional (ID) nanowires and nanotubes, two-dimensional (2D) nanofilms, hollow nanospheres, 2D nanosheets and nanodisks have also attracted extensive attention. It is expected that their unique structures could result in unusual mechanical, electronic, optical and magnetic properties. So far few papers have been reported for lanthanide ions other than Eu3+ in these materials. Much attention is focused on the optical properties of Eu3+ ions in view of their very good spectroscopic properties. 

The microemulsion method utilizes a water/oil/surfactant system to construct a micro reactor, in which NCs could be s)mthesized. The microemulsions have a wide range of applications from oil recovery fo fhe s)mfhesis of nanoparticles. Microemulsion is a system of water, oil, and surfactant, and it is an optically isotropic and thermod3mamically stable solution. At molecular scale, the microemulsion is heterogeneous with an internal structure either of nanospherical monosized droplefs (micelles or reverse micelles) or a bicontinuous phase, depending on the given temperature as well as the ratio of its constituents (Eriksson et al., 2004). The small droplets could be utilized as microreactors in order to s)mthesize the fine NCs in a controllable way. 

Abe S. and Kajikawa K., (2006) Linear and nonlinear optical properties of gold nanospheres immobilized on a metallic surface Phy, Rev. B 74 035416. 

Norton SJ, Vo-Dinh T (2008) Optical response of linear chains of metal nanospheres and nanospheroids. J Opt Soc Am A 25(ll) 2767-2775... 

Metallic nanorods are highly interesting materials from many points of view as elements in future nanoscale electronic circuits as sensors as catalysts as optical elements in future nanoscale optical devices. Gold and silver nanorods have distinct visible absorption and scattering spectra that are tunable with aspect ratio. Many workers have developed wet synthetic routes to these nanomaterials, with control of aspect ratio a key improvement compared to the synthesis of simple nanospheres. Another key area for which improvements need to be made is the understanding of the atomic arrangements of the different faces of crystalline... 

Nanosphere Lithography A Versatile Nanofabrication Tool for Studies of Size Dependent Nanoparticle Optics. 

Surface-enhanced Raman scattering detected temperature programmed desorption optical properties, nanostructure, and stability of silver film over SiO2 nanosphere. Journal of Physical Chemistry B, 105, 6907-6915. 

---