Unit-IV Applied chemistry of nanomaterials:Application to fundamenatal studies. Industrial applications: Photographic materials, Ceramic materials, Magnetic particles for recording media, Catalysts, Fuel cells electrocatalysis,Pigments, Nanostructured materials as new chemical reagents, Nanocomposite polymers, Fluids, inks and dyes, Block copolymers and dendrimers. Analytical and Environmental chemistry of nanoparticles.

Nanomaterials and their Applications

Nanomaterial Applications using Carbon Nanotubes

Applications being developed for carbon nanotubes include adding antibodies to nanotubes to form bacteria sensors, making a composite with nanotubes that bend when electric voltage is applied bend the wings of morphing aircraft, adding boron or gold to nanotubes to trap oil spills, include smaller transistors, coating nanotubes with silicon to make anodes the can increase the capacity of Li-ion batteries by up to 10 times.

Nanomaterial Applications using Graphene

Applications being developed for graphene include using graphene sheets as electodes in ultracapacitors which will have as much storage capacity as batteries but will be able to recharge in minutes, attaching strands of DNA to graphene to form sensors for rapid disease diagnostics, replacing indium in flat screen TVs and making high strenght composite materials.

Nanomaterial Applications using Nanocomposites

Applications being developed for nanocomposites include a nanotube-polymer nanocomposite to form a scaffold which speeds up replacement of broken bones, making a graphene-epoxy nanocomposite with very high strenght-to-weight ratios, a nanocomposite made from cellulous and nanotubes used to make a flexible battery.

Nanomaterial Applications using Nanofibers

Applications being developed for nanofibers include stimulating the production of cartilage in damaged joints, piezoelectric nanofibers that can be woven into clothing to produce electricty for cell phones or other devices, carbon nanofibers that can improve the preformance flame retandant in funiture.

Nanomaterial Applications using Nanoparticles

Applications being developed for nanoparticles include deliver chemotherapy drugs directly to cancer tumors, resetting the immune system to prevent autoimmune diseases, delivering drugs to damaged regions of arteries to fight cardiovascular disease, create photocatalysts that produce hydrogen from water, reduce the cost of producing fuel cells and solar cells, clean up oil spills, water pollution and air pollution.

Nanomaterial Applications using Nanowires

Applications being developed for carbon nanotubes include using zinc oxide nanowires in a flexible solar cell, silver chloride nanowires to decompose organic molecules in polluted water, using nanowires made from iron and nickel to make dense computer memory – called “race track memo

Nanomaterials and their Applications

Nanomaterial Applications using Carbon Nanotubes

The properties of carbon nanotubes have caused researchers and companies to consider using them in several fields. The following survey of carbon nanotube applications introduces many of these uses.

Carbon Nanotubes and Energy

Researchers at the University of Delaware have demonstarted increased energy density for capacitors whit the use of carbon nanotubes in 3-D structured electrodes.

Researchers at North Carolina State University have demonstrated the use of silicon coated carbon nanotubes in anodes for Li-ion batteries. They are predicting that the use of silicon can increase the capacity of Li-ion batteries by up to 10 times. However silicon expands during a batteries discharge cycle, which can damage silicon based anodes. By depositing silicon on nanotubes aligned parallel to each other the researchers hope to prevent damage to the anode when the silicon expands.

Researchers at Los Alamos National Laboratory have demonstrated a catalyst made from nitrogen-doped carbon-nanotubes, instead of platinum. The researchers believe this type of catalyst could be used in Lithium-air batteries, which can store up to 10 times as much energy as lithium-ion batteries.

Researchers at Rice University have developed electrodes made from carbon nanotubes grown on graphene with very high surface area and very low electrical resistance. The researchers first grow graphene on a metal substrate then grow carbon nanotubes on the graphene sheet. Because the base of each nanotube is bonded, atom to atom, to the graphene sheet the nanotube-graphene structure is essentially one molecule with a huge surface area.

Using carbon nanotubes in the cathode layer of a battery that can be produced on almost any surface. The battery can be formed by simply spraying layers of paint containing the components needed for each part of the battery.

Carbon nanotubes can perform as a catalyst in a fuel cell, avoiding the use of expensive platinum on which most catalysts are based. Researchers have found that incorporating nitrogen and iron atoms into the carbon lattice of nanotubes results in nanotubes with catalytic properties.

Carbon Nanotubes In Healthcare

Researchers are improving dental implants by adding nanotubes to the surface of the implant material. They have shown that bone adheres better to titanium dioxide nanotubes than to the surface of standard titanium implants. As well they have demonstrated to the ability to load the nanotubes with anti-inflammatory drugs that can be applied directly to the area around the implant.

Reseachers at MIT have developed a sensor using carbon nanotubes embedded in a gel; that can be injected under the skin to monitor the level of nitric oxide in the bloodstream. The level of nitric oxide is important because it indicates inflamation, allowing easy monitoring of imflammatory diseases. In tests with laboratory mice the sensor remained functional for over a year.

Researchers have demonstrated artificial muscles composed of yarn woven with carbon nanotubes and filled with wax. Tests have shown that the artificial muscles can lift weights that are 200 times heavier than natural muscles of the same size.

Nanotubes bound to an antibody that is produced by chickens have been shown to be useful in lab tests to destroy breast cancer tumors. The antibody-carrying nanotubes are attracted to proteins produced by one type of breast cancer cell. Once attached to these cells, the nanotubes absorb light from an infrared laser, incinerating the nanotubes and the attached tumor.

Researchers at the University of Connecticut have developed a sensor that uses nanotubes and gold nanoparticles to detect proteins that indicate the presence of oral cancer. Tests have shown this sensor to be accurate and it provides results in less than an hour.

Carbon Nanotubes and the Environment

Carbon nanotubes are being developed to clean up oil spills. Researchers have found that adding boron atoms during the growth of carbon nanotubes causes the nanotubes to grow into a sponge like material that can absorb many times it’s weight in oil. These nanotube sponges are made to be magnetic, which should make retrieval of them easier once they are filled with oil.

Carbon nanotubes can be used as the pores in membranes to run reverse osmosis desalination plants. Water molecules pass through the smoother walls of carbon nanotubes more easily than through other types of nanopores, which requires less power. Other researchers are using carbon nanotubes to develope small, inexpensive water purification devices needed in developing countries.

Sensors using carbon nanotube detection elements are capable of detecting a range of chemical vapors. These sensors work by reacting to the changes in the resistance of a carbon nanotube in the presence of a chemical vapor.

Researchers at the Technische Universität München have demonstrated a method of spraying carbon nanotubes onto flexible plastic surfaces to produce sensors. The researchers believe that this method could produce low cost sensors on surfaces such as the plastic film wrapping food, so that the sensor could detect spoiled food.

An inexpensive nanotube-based sensor can detect bacteria in drinking water. Antibodies sensitive to a particular bacteria are bound to the nanotubes, which are then deposited onto a paper strip. When the bacteria is present it attaches to the antibodies, changing the spacing between the nanotubes and the resistance of the paper strip containing the nanotubes.

Carbon nanotubes tipped with gold nanoparticles can be used to trap oil drops polluting water. Since the gold end is attracted to water while the carbon end is attracted to oil. Therefore the nanotubes form spheres surrounding oil droplets with the carbon end pointed in, toward the oil, and the gold end pointing out, toward the water.

Carbon Nanotubes Effecting Materials

Researchers are developing materials, such as a carbon nanotube-based composite developed by NASA that bends when a voltage is applied. Applications include the application of an electrical voltage to change the shape (morph) of aircraft wings and other structures. This video from NASA gives you an idea of what a futuristic morphing aircraft might look like.

Researchers have found that carbon nanotubes can fill the voids that occur in conventional concrete. These voids allow water to penetrate concrete causing cracks, but including nanotubes in the mixstops the cracks from forming.

Researchers at MIT have developed a method to add carbon nanotubes aligned perpendicular to the carbon fibers, called nanostiching. They believe that having the nanotubes perpendicular to the carbon fibers help hold the fibers together, rather than depending upon epoxy, and significanly improve the properties of the composite.

Avalon Aviation incorporated carbon nanotubes in a carbon fiber composite engine cowling on an aerobatic aircraft to increase the strength to weight ratio. The engine cowling is highly stressed components in this aircraft, adding carbon nanotubes to the composite allowed them to reduce the weight without weakening the component.

Carbon Nanotubes and Electronics

Building transistors from carbon nanotubes enables minimum transistor dimensions of a few nanometers and the development of techniques to manufacture integrated circuits built with nanotube transistors.

Researchers at Stanford University have demonstrated a method to make functioning integrated circuits using carbon nanotubes. In order to make the circuit work they developed methods to remove metallic nanotubes, leaving only semiconducting nanotubes, as well as an algorithm to deal with misaligned nanotubes. The demonstration circuit they fabricated in the university labs contains 178 functioning transistors.

Other applications in this area include:

Carbon nanotubes used to direct electrons to illuminate pixels, resulting in a lightweight, millimeter thick “nanoemissive” display panel.
Printable electronic devices using nanotube “ink” in inkjet printers
Transparent, flexible electronic devices using arrays of nanotubes.

Carbon Nanotube Company Directory

Company	Products
Nano Lab	Functionalizied nanotubes and nanotube arrays
Bayer Material Science	Carbon nanotubes
Cheap Tubes	Carbon nanotubes

Nanomaterial Applications using Graphene

diagnostics, replacing indium in flat screen TVs and making high strenght composite materials.

The properties of graphene, carbon sheets that are only one atom thick, have caused researchers and companies to consider using this material in several fields. The following survey of research activity introduces you to many potential applications of graphene.

A Survey of Applications:

Hydrogen production without platimum. Researchers have demonstrated a catalyst made fromgraphene doped with cobalt can be used to produce hydrogen from water. The researchers at looking at this method as a low cost replacement for platimum based catalysts.

Lower cost of display screens in mobile devices. Researchers have found that graphene can replace indium-based electrodes in organic light emitting diodes (OLED). These diodes are used in electronic device display screens which require low power consumption. The use of graphene instead of indium not only reduces the cost but eliminates the use of metals in the OLED, which may make devices easier to recycle.

Lithium-ion batteries that recharge faster. These batteries use graphene on the surface of the anode surface. Defects in the graphene sheet (introduced using a heat treatment) provide pathways for the lithium ions to attach to the anode substate. Studies have shown that the time needed to recharge a battery using the graphene anode is much shorter than with conventional lithium-ion batteries.

Ultracapacitors with better performance than batteries. These ultracapacitiors store electrons on graphene sheets, taking advantage of the large surface of graphene to provide increase the electrical power that can be stored in the capacitor. Researchers are projecting that these ultracapacitors will have as much electrical storage capacity as lithium ion batteries but will be able to be recharged in minutes instead of hours.

Components with higher strength to weight ratios. Researchers have found that adding graphene to epoxy composites may result in stronger/stiffer components than epoxy composites using a similar weight of carbon nanotubes. Graphene appears to bond better to the polymers in the epoxy, allowing a more effective coupling of the graphene into the structure of the composite. This property could result in the manufacture of components with high strength to weight ratio for such uses as windmill blades or aircraft components.

Storing hydrogen for fuel cell powered cars. Researchers have prepared graphene layers to increase the binding energy of hydrogen to the graphene surface in a fuel tank, resulting in a higher amount of hydrogen storage and therefore a lighter weight fuel tank. This could help in the development of practical hydrogen fueled cars.

Lower cost fuel cells. Researchers at Ulsan National Institute of Science and Technology have demonstrated how to produce edge-halogenated graphene nanoplatelets that have good catalytic properties. The researchers prepared the nanoplatelets by ball-milling graphene flakes in the presence of chlorine, bromine or iodine. They believe these halogenated nanoplatelets could be used as a replacement for expensive platinum catalystic material in fuel cells.

Low cost water desalination: Researchers have determined that graphene with holes the size of a nanometer or less can be used to remove ions from water. They believe this can be used to desalinate sea water at a lower cost than the reverse osmosis techniques currently in use.

Lightweight natural gas tanks: Researchers at Rice University have developed a composite material using plastic and graphene nanoribbons that block the passage of gas molecules. This material may be used in applications ranging from soft drink bottles to lightweight natural gas tanks.

More efficient dye sensitized solar cells. Researchers at Michigan Technological University have developed a honeycomb like structure of graphene in which the graphene sheets are held apart by lithium carbonate. They have used this “3D graphene” to replace the platinum in a dye sensitized solar cell and achieved 7.8 percent conversion of sunlight to electricity.

Electrodes with very high surface area and very low electrical resistance. Researchers at Rice University have developed electrodes made from carbon nanotubes grown on graphene. The researchers first grow graphene on a metal substrate then grow carbon nanotubes on the graphene sheet. Because the base of each nanotube is bonded, atom to atom, to the graphene sheet the nanotube-graphene structure is essentially one molecule with a huge surface area.

Lower cost solar cells: Researchers have built a solar cell that uses graphene as a electrode while using buckyballs and carbon nanotubes to absorb light and generate electrons; making a solar cell composed only of carbon. The intention is to eliminate the need for higher cost materials, and complicated manufacturing techniques needed for conventional solar cells.

Transistors that operate at higher frequency. The ability to build high frequency transistors with graphene is possible because of the higher speed at which electrons in graphene move compared to electrons in silicon. Researchers are also developing lithography techniques that can be used to fabricate integrated circuits based on graphene.

Sensors to diagnose diseases. These sensors are based upon graphene’s large surface area and the fact that molecules that are sensitive to particular diseases can attach to the carbon atoms in graphene. For example, researchers have found that graphene, strands of DNA, and fluorescent molecules can be combined to diagnose diseases. A sensor is formed by attaching fluorescent molecules to single strand DNA and then attaching the DNA to graphene. When an identical single strand DNA combines with the strand on the graphene a double strand DNA if formed that floats off from the graphene, increasing the fluorescence level. This method results in a sensor that can detect the same DNA for a particular disease in a sample.

Membranes for more efficient separation of gases. These membranes are made from sheets ofgraphene in which nanoscale pores have been created. Because graphene is only one atom thick researchers believe that gas separation will require less energy than thicker membranes.

Chemical sensors effective at detecting explosives. These sensors contain sheets of graphene in the form of a foam which changes resistance when low levels of vapors from chemicals, such as ammonia, is present.

Graphene Company Directory

Graphene Company	Product
Angstron Materials	Graphene Supplier
Bluestone Global Tech	Graphene Supplier
CrayoNano	Semiconductor nanowires grown on graphene

Nanomaterial Applications using Nanocomposites

A nanocomposite is a matrix to which nanoparticles have been added to improve a particular property of the material. The properties of nanocomposites have caused researchers and companies to consider using this material in several fields.

A survey of the applications of nanocomposites:

The following survey of nanocomposite applications introduces you to many of the uses being explored, including:

Producing batteries with greater power output. Researchers have developed a method to make anodes for lithium ion batteries from a composite formed with silicon nanospheres and carbon nanoparticles. The anodes made of the silicon-carbon nanocomposite make closer contact with the lithium electrolyte, which allows faster charging or discharging of power.

Speeding up the healing process for broken bones. Researchers have shown that growth of replacement bone is speeded up when a nanotube-polymer nanocomposite is placed as a kind of scaffold which guides growth of replacement bone. The researchers are conducting studies to better understand how this nanocomposite increases bone growth.

Producing structural components with a high strength-to-weight ratio. For example an epoxy containing carbon nanotubes can be used to produce nanotube-polymer composite windmill blades. This results in a strong but lightweight blade, which makes longer windmill blades practical. These longer blades increase the amount of electricity generated by each windmill.

Using graphene to make composites with even higher strength-to-weight ratios. Researchers have found that adding graphene to epoxy composites may result in stronger/stiffer components than epoxy composites using a similar weight of carbon

nanotubes. Graphene appears to bond better to the polymers in the epoxy, allowing a more effective coupling of the graphene into the structure of the composite. This property could result in the manufacture of components with higher strength-to-weight ratios for such uses as windmill blades or aircraft components.

Making lightweight sensors with nanocomposites. A polymer-nanotube nanocomposite conducts electricity; how well it conducts depends upon the spacing of the nanotubes. This property allows patches of polymer-nanotube nanocomposite to act as stress sensors on windmill blades. When strong wind gusts bend the blades the nanocomposite will also bend. Bending changes the nanocomposite sensor’s electrical conductance, causing an alarm to be sounded. This alarm would allow the windmill to be shut down before excessive damage occurs.

Using nanocomposites to make flexible batteries. A nanocomposite of cellulous materials and nanotubes could be used to make a conductive paper. When this conductive paper is soaked in an electrolyte, a flexible battery is formed.

Making tumors easier to see and remove. Researchers are attempting to join magnetic nanoparticles and fluorescent nanoparticles in a nanocomposite particle that is both magnetic and fluorescent. The magnetic property of the nanocomposite particle makes the tumor more visible during an MRI procedure done prior to surgery. The fluorescent property of the nanocomposite particle could help the surgeon to better see the tumor while operating.

Nanocomposite Company Directory

Company	Product
Nanosonic	Metal Rubber™ nanocomposites
InMat	Nanocomposite coatings
Nanocyl	EPOCYL™ epoxy resins reinforced with carbon nanotubes
MesaCoat	Nanocomposite coatings
NanoComposites	Nanocomposite materials

More Nanocomposite Companies

Nanomaterial Applications using Nanofibers

A nanofiber is a fiber with a diameter of 100 nanometers or less. The properties of nanofibers have caused researchers and companies to consider using this material in several fields.

A survey of the applications of nanofibers:

Researchers are using nanofibers to capture individual cancer cells circulating in the blood stream. They use nanofibers coated with antibodies that bind to cancer cells, trapping the cancer cell for analysis.

Nanofibers can stimulate the production of cartilage in damaged joints. Three different approaches to the use of nanofibers to stimulate cartilage are being taken by researchers at John Hopkins University, at Northwestern University and at the University of Pennsylvania.

Reseachers are using nanofibers to delivery thrapeutic drugs. The have developed an elastic material that is embedded with needle like carbon nanofibers. The material is intended to be used as balloons which are inserted next diseased tissue, and then inflated. When the balloon is inflated the carbon nanofibers penetrate diseased cells and delivery therapeutic drugs.

Researchers at MIT have used carbon nanofibers to make lithium ion battery electrodes that show four times the storage capacity of current lithium ion batteries.

The next step beyond lithium-ion batteries may be lithium sulfur batteries (the cathode contains the sulfur), which have the capability of storing several times the energy of lithium-ion batteries. Researchers at Stanford University are using cathodes made up of carbon nanofibers encapsulating the sulfur.

Researchers are using nanofibers to make sensors that change color as they absorb chemical vapors. They plan to use these sensors to show when the absorbing material in a gas mask becomes saturated.

Researchers have developed piezoelectric nanofibers that are flexible enough to be woven into clothing. The fibers can turn normal motion into electricity to power your cell phone and other mobile electronic devices.

Flame retardant formed by coating the foam used in furniture with carbon nanofibers.

Nanomaterial Applications using Nanoparticles

Nanoparticles have one dimension that measures 100 nanometers or less. The properties of many conventional materials change when formed from nanoparticles. This is typically because nanoparticles have a greater surface area per weight than larger particles which causes them to be more reactive to some other molecules.

Nanoparticles are used, or being evaluated for use, in many fields. The list below introduces several of the uses under development.

Nanoparticle Applications in Medicine

The use of polymeric micelle nanoparticles to deliver drugs to tumors.

The use of polymer coated iron oxide nanoparticles to break up clusters of bacteria, possibly allowing more effective treatment of chronic bacterial infections.

The surface change of protein filled nanoparticles has been shown to affect the ability of the nanoparticle to stimulate immune responses. Researchers are thinking that these nanoparticles may be used in inhalable vaccines.

Researchers at Rice University have demonstrated that cerium oxide nanoparticles act as an antioxidant to remove oxygen free radicals that are present in a patient’s bloodstream following a traumatic injury. The nanoparticles absorb the oxygen free radicals and then release the oxygen in a less dangerous state, freeing up the nanoparticle to absorb more free radicals.

Researhers are developing ways to use carbon nanoparticles called nanodiamonds in medical applications. For example nanodiamonds with protein molecules attached can be used to increase bone growth around dental or joint implants.

Researchers are testing the use of chemotherapy drugs attached to nanodiamonds to treat brain tumors. Other researchers are testing the use of chemotherapy drugs attached to nanodiamonds to treat leukemia.

More about Nanotechnology in Medicine

Nanoparticle Applications in Manufacturing and Materials

Ceramic silicon carbide nanoparticles dispersed in magnesium produce a strong, lightweight material.

A synthetic skin, that may be used in prosthetics, has been demonstrated with both self healing capability and the ability to sense pressure. The material is a composite of nickel nanoparticles and a polymer. If the material is held together after a cut it seals together in about 30 minutes giving it a self healing ability. Also the electrical resistance of the material changes with pressure, giving it a sense ability like touch.

Silicate nanoparticles can be used to provide a barrier to gasses (for example oxygen), or moisture in a plastic film used for packaging. This could slow down the process of spoiling or drying out in food.

Zinc oxide nanoparticles can be dispersed in industrial coatings to protect wood, plastic, and textiles from exposure to UV rays.

Silicon dioxide crystalline nanoparticles can be used to fill gaps between carbon fibers, thereby strengthening tennis racquets.

Silver nanoparticles in fabric are used to kill bacteria, making clothing odor-resistant.

Nanoparticle Applications and the Environment

Researchers are using photocatalytic copper tungsten oxide nanoparticles to break down oil into biodegradable compounds. The nanoparticles are in a grid that provides high surface area for the reaction, is activated by sunlight and can work in water, making them useful for cleaning up oil spills.

Researchers are using gold nanoparticles embedded in a porous manganese oxide as a room temperature catalyst to breakdown volatile organic pollutants in air.

Iron nanoparticles are being used to clean up carbon tetrachloride pollution in ground water.

Iron oxide nanoparticles are being used to clean arsenic from water wells.

Nanoparticle Applications in Energy and Electronics

Researchers have used nanoparticles called nanotetrapods studded with nanoparticles of carbon to develop low cost electrodes for fuel cells. This electrode may be able to replace the expensive platinum needed for fuel cell catalysts.

Researchers at Georgia Tech, the University of Tokyo and Microsoft Research have developed a method to print prototype circuit boards using standard inkjet printers. Silver nanoparticle ink was used to form the conductive lines needed in circuit boards.

Combining gold nanoparticles with organic molecules creates a transistor known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor). This transistor is unusual in that it can function in a way similar to synapses in the nervous system.

A catalyst using platinum-cobalt nanoparticles is being developed for fuel cells that produces twelve times more catalytic activity than pure platinum. In order to achieve this performance, researchers anneal nanoparticles to form them into a crystalline lattice, reducing the spacing between platinum atoms on the surface and increasing their reactivity.

Researchers have demonstrated that sunlight, concentrated on nanoparticles, can produce steam with high energy efficiency. The “solar steam device” is intended to be used in areas of developing countries without electricity for applications such as purifying water or disinfecting dental instruments.

A lead free solder reliable enough for space missions and other high stress environments using copper nanoparticles.

Silicon nanoparticles coating anodes of lithium-ion batteries can increase battery power and reduce recharge time.

Semiconductor nanoparticles are being applied in a low temperature printing process that enables the manufacture of low cost solar cells.

A layer of closely spaced palladium nanoparticles is being used in a hydrogen sensor. Whenhydrogen is absorbed, the palladium nanoparticles swell, causing shorts between nanoparticles. These shorts lower the resistance of the palladium layer.

Nanoparticle Company Directory

Company	Products
CytImmune	Gold nanoparticles for targeted delivery of drugs to tumors
Invitrogen	Qdots for medical imaging
Antaria	Zinc oxide nanoparticles used in coatings to reduce UV exposure
Nanoledge	Epoxy resins strengthened with nanoparticles

Nanomaterial Applications using Nanowires

The properties of nanowires have caused researchers and companies to consider using this material in several fields.

Nanowires Applications in Energy

Researchers at MIT have developed a solar cell using graphene coated with zinc oxide nanowires. The researchers believe that this method will allow the production of low cost flexible solar cells at high enough efficiency to be competive.

Sensors powered by electricity generated by piezoelectric zinc oxide nanowires. This could allowsmall, self contained, sensors powered by mechanical energy such as tides or wind

Researchers are using a method called Aerotaxy to grow semiconducting nanowires on gold nanoparticles. They plan to use self assembly techniques to align the nanowires on a substrate; forming a solar cell or other electrical devices. The gold nanoparticles replace the silicon substrate on which conventional semiconductor based solar cells are built.

Researchers at the Nies Bohr Institute have determined that sunlight can be concentrated in nanowires due to a resonance effect. This effect can result in more efficient solar cells, allowing more of the energy from the sun to be converted to electricity.

Using light absorbing nanowires embedded in a flexible polymer film is another method being developed to produce low cost flexible solar panels.

Researchers at Lawrence Berkeley have demonstrated an inexpensive process for making solar cells. These solar cells are composed of cadmium sulfide nanowires coated with copper sulfide.

Researchers at Stanford University have grown silicon nanowires on a stainless steel substrate and demonstrated that batteries using these anodes could have up to 10 times the power density of conventional lithium ion batteries. Using silicon nanowires, instead of bulk silicon fixes a problem of the silicon cracking, that has been seen on electrodes using bulk silicon. The cracking is caused because the silicon swells it absorbs lithium ions while being recharged, and contracts as the battery is discharged and the lithium ions leave the silicon. However the researchers found that while the silicon nanowires swell as lithium ions are absorbed during discharge of the battery and contract as the lithium ions leave during recharge of the battery the nanowires do not crack, unlike anodes that used bulk silicon.

Nanowire Applications in the Enviroment

Using silver chloride nanowires as a photocatalysis to decompose organic molecules in polluted water.

Using an electrified filter composed of silver nanowires, carbon nanotubes and cotton to kill bacteria in water.

Using nanowire mats to absorb oil spill

Nanowire Applications in Electronics

Using electrodes made from nanowires that would enable flat panel displays to be flexible as well as thinner than current flat panel displays.

Using nanowires to build transistors without p-n junctions.

Using nanowires made of an alloy of iron and nickel to create dense memory devices. By applying a current magnetized sections along the length of the wire. As the magnetized sections move along the wire, the data is read by a stationary sensor. This method is called race track memory.

Using silver nanowires embedded in a polymer to make conductive layers that can flex, without damaging the conductor.

Sensors using zinc oxide nano-wire detection elements capable of detecting

M.Tech U-IV Applied chemistry of nanomaterials