Optoelectronic devices, nanoscale

Duan, X. Huang, Y. Cui, Y. Wang, I Lieber, C. M. 2001. Indium phosphide nanowires as building blocks for nanoscale electronic and optoelectronic devices. Nature 409 66-69. 

Shi, Z., et al., Free-standing single-walled carbon nanotube-CdSe quantum dots hybrid ultrathin films for flexible optoelectronic conversion devices. Nanoscale, 2012. 4(15) p. 4515-4521. 

Interestingly, related polypeptide-based materials display differential electron-transfer rates depending on the orientation of the dipole of the peptide helix. This suggests that electron transfer in such systems may be controllable by externally applied potentials. Such results represent the beginning of the kind of long-range control and electron-transfer characteristics necessary for functional nanoscale optoelectronic devices. 

Fabrication is difficult, but the large-scale assembly of nanoscale building blocks into either devices (e.g. molecular electronic, or optoelectronic devices), nanostructured materials, or biomedical structures (artificial tissue, nerve-connectors, or drug delivery devices) is an even more daunting and complex problem. There are currently no satisfactory strategies... 

Electrospun nanofibers with electrical and electro-optical activities have received a great deal of interest in recent years because of their potential applications in nanoscale electronic and optoelectronic devices, for example nanowires, LEDs, photocells etc. Besides, one-dimensional (1-D) nanostmctures are the smallest dimensional stmctures for efficient transport of electrons and optical excitations. One of the potential future apphcations of conducting polymer nanofibers is as molecular wires, which are required to connect molecular devices to electrodes. For molecular devices, it is necessary to make nanowires with diameters in the order of the size of the molecular device. 

At the interface of science and technology, electronic and optoelectronic devices impact many areas of business and society, i.e. communications, computing, and medical devices and the demand for ever more compact and powerful systems is strong, exciting a growing interest in the development of nanoscale devices that could combine new functions with greatly enhanced performances. 

ZnO is an attractive material for nanoscale optoelectronic devices, as it is a wide band gap semiconductor with good carrier mobility and can be doped both n- and p-type. The electron mobility is much higher in... 

One-dimensional (ID) nanostructures have also been the focus of extensive studies because of their unique physical properties and potential to revolutionize broad areas of nanotechnology. First, ID nanostructures represent the smallest dimension structure that can efficiently transport electrical carriers and, thus, are ideally suited for the ubiquitous task of moving and routing charges (information) in nanoscale electronics and optoelectronics. Second, ID nanostructures can also exhibit a critical device function and thus can be exploited as both the wiring and device elements in architectures for functional nanosystems.20 In this regard, two material classes, carbon nanotubes2131 and semiconductor nanowires,32"42 have shown particular promise. 

The use of nanoscale constructs has given a further major boost to solar photon conversion. The scale of nanosized materials such as quantum dots and nanotubes, conventionally taken to lie in the range 1-100 nm, produces very interesting size quantisation effects in optoelectronic and other properties bandgaps shift to the blue, carrier lifetimes increase, potent catalytic properties emerge and constructs with very high surface-to-volume ratios can be made. Incorporation of nanoscale structures in photovoltaic devices allows these unique properties to be exploited, with conversion efficiencies above the detailed balance limit becoming possible in principle. 

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