A quantum dot is defined as a crystal of semiconductor compounds (e.g. CdSe. PdS) with a diameter on the order of the Bohr's extinction radius of of that compound. Quantum dots have a range of useful electrical and optical properties that diverge in character from these in bulk material. Quantum dots are between 2-15 nm wide (10-50 atoms).
Quantum dots are a new form of matter that can be considered as artificial atoms. they have linear discrete absorption spectra and photoluminescence that is tunable over a wide range from far infrared to deep ultraviolet.
Quantum dot leds (QLEDs)
Traditional LEds suffer large application restrictions due to limitations in traditional semiconductors including difficult to alter band gaps and inflexible structure. QLEDs made of quantum dots, can emit at any visible or infrared wavelength, and can be fabricated into plastic, coatings, paint, filters and other forms, allowing them to be used almost everywhere.
Optoelectronics
Desirable properties include broad photoluminecsene(PL) tunability, high PL quantum efficiency, and enhanced non linear optical properties. Applications include tunable IR-UV lasers and LEDs, display luminophores, optical electro-modulation, switches, memory storage, optical limiting, DNA sites makers, and efficient sensors of explosives and toxic materials.
quantum dots are also possible materials for making ultrafast, all optical switches and logic gates. For comparison, the ethernet generally can handle only 10 megabits
Quantum information processing
Desirable properties include enhanced spin level splitting, single electron spin manipulation, and very long spin coherence times. Applications include spin transistors, nanosized magnets, quantum computing and electron spin based memeory.
Tougher and harder cutting tools
Cutting tools made of nanocrystalline materials, such as tungsten carbide, tantalum carbide, and titanium carbide are much harder, much more wear resistant, erosion resistant and last longer than their conventional large grained counterparts. They also enable the manufacturer to machine various materials much faster, thereby increasing productivity and significantly reducing manufacturing costs hence useful for the miniaturizing of microelectronic circuits as microdrills.
High power magnets
The strength of a magnet is measured in terms of coercivity. and saturation magnetization values. These values increase with the decrease in grain size and an increase in specific surface area (surface area per unit volume of the grains) of the grains. It has been shown that magnets made of nanocrystalline yttrium-samarium cobalt grains possess very unusual magnetic properties due to their extremely large surface area. Typical applications for these high power rare earth magnets include quieter submarines, automobile alternators, land based power generators, motors for ships, Ultra sensitive analytical instruments and magnetic resonance imaging (MRI) in medical diagonastics.
Next generation computer chips
Nanomaterials help the modern electronic industry break these barriers down by providing the manufactuerers with nanocrystalline starting materials, ultra high purity materials, materials with better thermal conductivity, and longer lasting, durable interconnections (connections between various components and microprocessors).
Nano solar cells
When light hits an atom in a semiconductors, thosephotons of light with lots of energy can push an electron out of its nice stable orbital around the atom. The electron is then free to move from atom to atom, like the electrons in a piece of metal when it conducts electricity.
Using nanosize bits of semiconductors embedded in a conductive plastic maximizes the chance that an electron can escape the nanoparticle and reach the conductive plastic before it is trapped by another atom that has been also stripped of an electron. once in the plastic, the electron can travel happily through wire connecting the solar cell to cellphones, laptops etc.
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