Quantum rods

Two different nanomaterials, namely colloidal core / shell Quantum Dots (QDs) and Quantum Rods (QRs) were synthesized as described in [51]. In the case of CdSe / ZnS QDs, the synthesis yielded samples emitting at Inux = 580 nm widi a spectral width of the fluorescence emission of 40 nm. CdSe quantum rods showed an emission peak centered at l x = 567 nm with similar linewidth. The NCs were subsequently dispersed in PMMA and deposited onto the substrate by spin-coating. In order to study tiie influence of the average fluorophore-metallic surface distance on the MEF efi t, several thicknesses of the active layer were investigated, finding an o(Aimum value of 35 nm, as measured from the surface of the metallic nanostructures. 

In analogy to the layered 2-D semiconductors, it is also possible to produce onedimensional (1-D) systems i.e., nanostructures with quantum confinement in two dimensions). This results in quantum wires (nanowires), quantum rods (nanorods) or nanotubes. Over the past decade this field has experienced exponential growth with about 1250 papers published in 2005 compared with none in 1994. Many important advances in the growth, characterisation and applications of 1-D systems have occurred and these are described in several reviews (Law et al, 2004 Rao et al, 2006 Lieber et al, 2007 Robertson, 2007). 

Level Structure and Band-Oflsets in Heterostructured Seeded Quantum Rods... 

L. Zhao, X. Pang, R. Adhikary, J. W. Petrich, Z. Lin, Semiconductor Anisotropic Nanocomposites Obtained by Directly Coupling Conjugated Polymers with Quantum Rods. Angewandte Chemie International Edition 2011,50,3958-3962. 

A. Fu et al., Semiconductor quantum rods as single molecule fluorescent biological labels. Nano Letters, 7(1), 179-182 (2007). 

K. T. Yong et al.. Quantum rod bioconjugates as targeted probes for confocal and two-photon fluorescence imaging of cancer cells, Nano Letters, 7(3), 761-765 (2007). 

K. T. Yong et al.. Multiplex imaging of pancreatic cancer cells by using functionalized quantum rods. Advanced Materials, 20(8), 1412-1417 (2008). 

Lifshitz, E. Bashouti, M. Kloper, V. Kigel, A. Eisen, M.S. Berger, S. (2003). Synthesis and Characterization of PbSe Quantum Wires, Multipods, Quantum Rods, and Cubes Nano Lett. 3., 6., (May 2003) 857-862, ISSN 1530-6984. 

Mokari T, Rothenbeig E, Popov 1, Costi R, Banin U (2004) Selective growth of metal tips onto semiconductor quantum rods and tetrapods. Sdence 304 1787-1790... 

Peng et al. recently reported the use of the hot-soup method to produce CdSe quantum rods (222). Changes in several experimental parameters were found to affect properties of the quantum rods such as size and aspect ratio. These parameters included ligand selection, reaction time, injection and growth temperatures, and number of injections. Controlled variations in these parameters could also be employed to change the product morphology from rod-like to nearly spherical. 

For materials with a zinc blende cubic lattice, the solution - liquid - solid (SLS) mechanism [132] has been widely used to synthesize wirelike crystallites. The SLS method is analogous to the vapor-liquid-solid (VLS) method [133], which generates single-crystal wires in relatively large quantities. Very recently, quantum rods and wires of InAs [134] and InP [135] with controllable diameters and excellent crystallinity were synthesized by the SLS method. However, the fabrication of III-V semiconductor quantum rods (QRs) remains difficult regarding the control of size, length, and size uniformity. Another difficulty with QRs synthesized by the SLS method is residual metallic catalyst spherules (Au, In) present at the rod tip. The presence of these metal catalyst particles interferes with measurements of the optical and electronic properties of the QRs. 

D. Katz, T. Wizansky, O. Millo, E. Rothenberg, T. Mokari, U. Banin, Size-dependent tunneling and optical spectroscopy of CdSe quantum rods. Phys. Rev. Lett. 89(8), 086801 (2002)... 

Kan, S., Aharoni, A., Mokaii, T., and Banin, U. (2004). Shape control of ni-V semiconductor nanocrystals Synthesis and properties of InAs quantum rods, Faraday Discuss. 125, 23-38. 

---