Application of Quantum Dots
1. Quantum dots in medicine
a) According to Biju (2014), Quantum dots are utilized demandingly in the advancement of FRET-based biosensors for ultrasensitive spotting of biomolecules such as sugars, enzymes, acids, antigens and antibodies and as well in the furtherance of fluorescence. Their narrow emission band is the attribute that causes them to be capable in bio-sensing applications which allows complexes findings of antibodies, toxins or DNA strands in revealing portions of gene in DNA fingerprinting or pathogen. They also aid in a lot of conditions in applications of biosensor, constructed by organic dyes including fluorescein treated as pH sensors or FRET. Coupled through different anticancer antibodies, they also attain purposes in identifying cancer biomarkers within immune-microchannels or immunochromatographs. The unification among quantum dots’ oligonucleic acids are efficient foundation for FRET-based exposure of dye-labeled matching strands, which is parallel to the seeming plasmon-based, by means of gold NPs, unveiling of oligonucleotides. The expanse amongst the dye and the quantum dot and are the vital aspect in the susceptibility of these findings. Thus, the formulation of a FRET-based biosensor constructed of quantum dots alongside eminent hydrodynamic diameter demands cautious features of the space amid the giver and the receiver.
b) Quantum dots can also be enclosed inside a shell modified to copy organic receptors among the body and such receptors can link to specific viruses, diseases or further stuffs. Consequently, quantum dots will search and bind to the illness all together. Because of the fluorescent attribute of quantum dots, the location of the conflict is then become well evident. Likened to the expanse of the dot, the amount of receptors needed on the surface of the dot is smaller. Therefore, it leaves a great quantity of space to locate additional matters on the dot. It can comprise several medications to treat a disease the quantum dot regulated to obtain. By means of this, quantum dots can be designed to search cancer cells and accustom chemotherapy drugs straight to cancer cells to prevent poisoning of healthy cells and so the horrible fallouts concerning cancer therapies.
c) Based on Akerman et al., (2002), Larson et al., (2003), Bateman et al., (2007) and J.D. Smith et al., (2007), the Cadmium selenium–zinc sulphide quantum dots is utilized to see capillaries hundreds of micrometers deeply the skin of an alive mice. Cadmium-based quantum dots are also employed to picture cerebral vasculature while Methoxy-PEGylated quantum dot are applied to envision arterioles and capillary networks in mouse’s back limb skeletal muscle. Lewis et al., (2006), also stated that Pathological nanoparticles can correspondingly be marked fluorescently to great densities. For example, is the usage of the cowpea mosaic virus (within alive mouse and embryos of chick) as an examination that lets vibrant projecting of the vascular endothelium for capable of 72 hours and to a deepness of 500 ?m.
2. Quantum dots in photovoltaics
The pleasant appearance of utilizing quantum dots in producing solar cells dwells in various gains above early methods and they can be produced in an energy-saving room-temperature procedure as they can be formulated after excess and cheap resources that do not need massive purification as silicon makes and they can be operated to a range of low-priced and adaptable substrate necessities like weightless plastics.
Even though, using quantum dots as the foundation for solar cells is not a recent conception, the attempts to buid photovoltaic devices have not achieved so far by means of high efficiency in transforming sunlight to power.
An assuring course for quantum dot solar cells is a semiconductor ink having the aim of permitting the covering of substantial regions of solar cell substrates in a particular deposition step and thus removing tens of deposition steps essential alongside the former layer-by-layer process.
3. Graphene quantum dots
Graphene is a primarily unfolded planar shape of a carbon nanotube that has turned into an exceptionally and appealing contender material for nanoscale electronics. Researchers have proven that it is likely to create nanoscale transistors from a sole graphene crystal namely graphene quantum dots. Contrasting all additional recognized constituents, graphene stays extremely steady and conductive even if it is reduced into fragments one nanometer wide.
Moreover, Graphene quantum dots (GQDs) show significant meaning in the subjects of photovoltaics, photoelectronics, bio-imaging and bio-sensing due to their exceptional photoluminescence (PL) assets comprising low toxicity, outstanding biocompatibility and great constancy versus photoblinking and photobleaching.
4. Perovskite quantum dots
Luminescent quantum dots (LQDs), possess extreme photoluminescence quantum yields, pliable production color manipulating, and ability to process solution are ensuring for usages in lighting systems (infrared irradiation and cozy white light devoid of UV) and great class displays.
On the other hand, the market of LQDs has been restrained because of the excessively high price of their creation. At present, LQDs are formulated thru HI method demanding at high temperature and monotonous cover handling in able to progress both visual assets and permanency.
5. Quantum dot TVs and displays
Quantum dots are both photo-active (photoluminescent) and electro-active (electroluminescent). It also have unique physical properties which will be at the core of next-generation displays. Compared to organic luminescent materials used in organic light emitting diodes (OLEDs), Quantum dots-based materials have purer colors, longer lifetime, lower manufacturing cost, and lower power consumption compared to organic luminescent materials used in organic light emitting diodes (OLEDs). Another advantage of quantum dots is it can be deposited on any substance which are expected to be printable, flexible and even rollable quantum dot displays of all sizes.
6. Optical application
As of now, quantum dots attracted interest of everyone because of its interesting optical properties. QDs are being used for all kinds of applications in which those applications need the importance of the precise control of colored light. In a simple and relatively minor application, quantum dots made in a thin filter has been invented so it can fit on top of a fluorescent or LED lamp and will convert the light from a blueish color to a warmer, redder producing more attractive shade like the light produced by old-fashioned incandescent lamps. QDs can also be used as an alternative to pigments and dyes. Embedded in other materials, quantum dots also absorb incoming light of one color and producing different color which are brighter and more restraint than organic dyes.
In addition, quantum dots are also considered as part of those breakthrough technologies in the development of more efficient solar cells. In a traditional solar cell, photons of sunlight knock electrons out of a semiconductor into a circuit which use to make beneficial electric power, but its process efficiency is somewhat low. It also produce more electrons (or holes) for each photon that strikes though enable to boost the efficiency of perhaps 10 percent over conventional semiconductors. CCDs (charge-coupled devices) and CMOS sensors are the image-detecting chips in such things as digital cameras and webcams which also work the same as solar cells. It can also be use to make smaller and more systematized image sensors for applications.
7. Quantum computing
Computers get faster and smaller as time passes by. But there comes a time wherein physical limits of materials prevent computer in advancing unless there is a new development in the field of technologies. One possibility would be to store and transfer information with light as a replacement of electrons known as photonics. Optical computers could use quantum dots as the basic components in memory chips and logic gates as electronic computers use transistors
In a quantum computer, bits (binary digits) are stored by atoms individuallly, ions, electrons, or photons that are linked together and act as quantum bits called qubits. These switch of the quantum-scale can store many values contemporaneously and work on different problems in parallel. Atoms and so on are hard to control in this way but quantum dots in a larger scale would be much easier to work with. However, there is a very high degree of precision with in which one can measure the quantum particles resulting to an easily constructed quantum computer.
8. Lighting Applications
The energy emitted from quantum dots as light is close to a hundred percent of the energy put into the system. This remarkably high efficiency make quantum dots fascinating for use in lights and as individual colour pixels in a vibrant colour flat panel displays. A layer of quantum dots can be placed in between two electrically conductive layers in lighting purposes. A current applied to the quantum dots directly between these layers will produce fluoresce and will having an extremely high light source efficiency.
9. Quantum dots in a solar cell
Quantum dots have the ability to increase the efficiency of solar cells. A photon of light generates one electron in a normal solar cell. Based on some experiments, silicon quantum dots and lead sulfide quantum dots can create two electrons for a single photon of light. It also have been found that up to three electrons per photon of light a quantum dot can emit as opposed to one for standard photovoltaic panels. Therefore, it was concluded that with the use of quantum dots in solar cells could significantly change the efficiency to produce electric power.
Quantum dots are the new and innovative perspective on the traditional semiconductor. It can be synthesized to be essentially any size, and therefore produce essentially any wavelength of light. The applications of quantum dots are useful in many conditions due to their physiochemical properties that may be used in different fields and by altering their surface property, internal structures, preparation techniques, coating material etc.
The bright future will be exciting with the use of those possible applications of quantum dots.