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Mobile electrons multiplied in quantum dot films

Researchers of the Opto-electronic Materials section of the TU Delft and Toyota Europe have demonstrated that several mobile electrons can be produced by the absorption of a single light particle in films of coupled quantum dots. These multiple electrons can be harvested in solar cells with increased efficiency.
The researchers published their findings in the October issue of the scientific journal Nano Letters.
A way to increase the efficiency of cheap solar cells is the use of semiconductor nanoparticles, also called quantum dots. In theory, the efficiency of these cells can be increased to 44%. This is due to an interesting effect that efficiently happens in these nanoparticles: carrier multiplication. In the current solar cells, an absorbed light particle can only excite one electron, while in a quantum dot solar cell a light particle can excite several electrons. Multiplying the number of electrons results in the enhancement of current in solar cells, increasing the overall power conversion efficiency.
Carrier Multiplication
Several years ago it was demonstrated that carrier multiplication is more efficient in quantum dots than in traditional semiconductors. As a result, these quantum dots are currently heavily investigated worldwide for use in solar cells. A problem with using carrier multiplication is that the produced charges live only a very short time (around 0.00000000005 s) before they collide with each other and disappear via a decay process known as Auger recombination. The main current challenge is to proof that it is still possible to do something useful with them.
Mobile charges
The researchers from Delft have now demonstrated that even this very short time is long enough to separate the multiple electrons from each other. They prepared films of quantum dots in which the electrons can move so efficiently between the quantum dots that they become free and mobile before the time it takes to disappear via Auger recombination. In these films up to 3.5 free electrons are created per absorbed light particle. In this way, these electrons do not only survive, they are able to move freely through the material to be available for collection in a solar cell.

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Mobile electrons multiplied in quantum dot films

Redox flow batteries, a promising technology for renewable energies integration

Today there is a wide variety of energy storage technologies at very different stages of development. Among them, the Redox Flow Battery (RFB) is an innovative solution based on the use of liquid electrolytes stored in tanks and pumped through a reactor to produce energy. Tecnalia is currently working in the development of high performance RFBs.
RFB is, by its very nature, a modular and highly flexible technology with very rapid response, little environmental impact and considerable potential for cutting costs. This is the reason why Redox Flow Batteries are emerging as a very promising option for stationary storage in general and for renewable applications in particular.
Renewable energies
There is no doubt that the development of renewable energies will be a key milestone in the way towards a new environmentally-friendly energy model., However, their variability and limited predictability are posing a problem for the operation of the system and, as a result, a barrier to their massive penetration.
A clear example of these difficulties is the need to maintain backup systems that generate energy during low wind or low solar irradiance periods. On the other side, high renewable generation can lead to energy waste during low demand periods.
Redox Flow Batteries are considered as a highly adequate technology to mitigate the variability of renewable energies and to improve their dispatchability, that is, to provide the capability to regulate the output in a similar way to conventional power stations. The energy stored during periods of high renewable production can be used to compensate for the lack of generation when the weather conditions are less favourable.

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Redox flow batteries, a promising technology for renewable energies integration

Solar inverters: Losses are cut in half

A switching trick makes it possible to cut the losses of a series-production inverter in half and increase the efficiency from 96 to 98 percent. The HERIC®-topology makes it possible to achieve a world-record efficiency of more than 99 percent.
“It was a matter of minutes,” Dr. Heribert Schmidt remembers the day in spring of 2002. To find opportunities for improvement, he had often pondered about the switching plan of an inverter while in his office at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany. A sudden flash of inspiration — and a solution that was ingeniously simple came to his mind. He immediately went to get an inverter from the laboratory, laid a few new strips and installed two additional semiconductor switches. “Then it required only a little bit of work on the controls — and we already had the proof!” This is how the electrical engineer, who holds a doctorate in electrical engineering, described the revolutionary step in brief: the losses could be halved and the degree of effectiveness could be increased from 96 to 98 percent.
Key component for electricity feed
After the solar generator, the inverter is the second key component of a grid-linked photovoltaics system. Solar modules generate direct current. If the current is to be fed into the public grid, then it must be converted into grid-compatible alternating current. The inverter handles this task. Single-phase feed inverters consist of three essential parts: the buffer capacitor at the input which provides intermediate storage for the direct current from the solar generator; the inverter bridge with four semiconductor switches that “chop up” the direct current by rapidly switching on and off and as a third component, the inductor at the output that converts the alternating current into a perfect sinus current.
In a short time from the idea to the product
Heribert Schmidt knew: A large portion of the losses are caused by the return of current between the output inductor and the input capacitor. The question therefore was how to prevent this. “That’s easy,” said Heribert Schmidt after a sudden inspiration: “If I decouple the capacitor and the inductors completely from each other at certain intervals, then it is impossible for a return current to flow, and electro-magnetic disturbances cannot occur at the input as a result of voltage spikes.” He immediately had his invention patented as HERIC® topology and began to develop a new series of devices with the SUNWAYS company in Konstanz, Germany. Experts were astonished, and awards and recognition followed quickly: “By far the best device in this performance category.” In the meantime, an encompassing patent has been awarded to the basic idea and the Fraunhofer-Gesellschaft is in negotiations with additional licensees.

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Solar inverters: Losses are cut in half

Flexible films for photovoltaics

Dr. Sabine Amberg-Schwab and Dr. Klaus Noller have developed a specially coated polymer film that is ideally suited for encapsulating inorganic solar cells. Photovoltaics, displays that can be rolled up and flexible solar cells. Barrier layers,that protect thin-film solar cells from oxygen and water vapor and thus increase their useful life are an essential component. Potato chips and thin-film solar cells are common, that protect them from air and water vapor: the chips in order to stay fresh and crisp; the solar cells in order to have a useful life that is as long as possible. In some cases,glass is used to protect the active layers of the solar cells from environmental influences.

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Flexible films for photovoltaics

Scientists generates hydrogen as an energy source from ethanol and sunlight

A team of researchers from the Universitat Politècnica de Catalunya, the University of Aberdeen (Scotland) and the University of Auckland (New Zealand) uses ethanol and sunlight to generate hydrogen as an energy source.
The results of the study have been published in Nature Chemistry.
Jordi Llorca, director of the Institute of Energy Technology and researcher at the Universitat Politècnica de Catalunya’s Nanoengineering Research Centre, is one of the authors of the study, which represents a major step towards using hydrogen as an alternative to fossil fuels. In the framework of the research, a fully scalable powder photocatalyst was created that makes the hydrogen production process simpler and cheaper as it takes place at ambient temperature and pressure.
A solid photocatalyst is placed in a container with ethanol and exposed to ultraviolet light by agitation, simulating the most energetic part of the solar spectrum. The device contains a titanium dioxide semiconductor that in contact with sunlight generates electrons captured by metallic gold nanoparticles, which react with the alcohol molecules to produce hydrogen. According to Llorca, the semiconductor’s structure and the contact with the nanoparticles are crucial features in the design of the photocatalyst.
The amount of hydrogen and energy generated depends on the amount of catalyst used and the area exposed to solar radiation. Researchers have generated up to 5 litres of hydrogen per kilogram of catalyst in one minute. If 9 kg of catalyst were put in an ethanol tank and exposed to sunlight and the hydrogen generated were used to power a fuel cell, 3 kW of electricity would be obtained, an amount similar to that which is used in a home.
Llorca plans to design reactors with real-life applications such as providing electricity to the home, which he sees as an important step towards introducing hydrogen as an energy vector and gradually gaining independence from fossil fuels. One of the advantages of hydrogen compared with electricity is that it can be stored.
An economical process based on renewable resources Until now, solar-generated hydrogen techniques have largely relied on water. However, despite water being cheap and abundant, these techniques have garnered poor results and the materials they require are expensive. As an alternative, the researchers suggest using ethanol, a renewable and economical resource that is easily obtained from agricultural and forest waste (100 grams of glucose generate approximately 50 grams of ethanol).
The photocatalyst is also much cheaper and simpler to use than the materials employed in techniques with water as it uses very small gold particles, ranging in size from 2 to 12 nanometres (1 metre = 1 million nanometres). These nanoparticles capture the free electrons generated when titanium oxide — used as a support base — comes into contact with sunlight.
During the process, which is based on solar energy, the team also discovered that the size of the gold nanoparticles has no influence on the production of hydrogen, unlike what occurs during the more widespread processes in which the catalyst powder must be heated to reaction temperature (usually over 500ºC) and therefore incurs an energy cost. In addition, the catalyst is more durable because it works at ambient temperature and pressure.

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Scientists generates hydrogen as an energy source from ethanol and sunlight

Solar panels for NASA’s Juno spacecraft complete testing

The three massive solar panels that will provide power for NASA’s Juno spacecraft during its mission to Jupiter have seen their last photons of light until they are deployed in space after launch. The last of the Jupiter-bound spacecraft’s panels completed pre-flight testing at the Astrotech payload processing facility in Titusville, Fla., and was folded against the side of the spacecraft into its launch configuration Thursday, May 26. The solar-powered Juno spacecraft will orbit Jupiter’s poles 30 times to find out more about the gas giant’s origins, structure, atmosphere and magnetosphere.
“Completing the testing and stow of solar panels is always a big pre-launch milestone, and with Juno, you could say really big because our panels are really big,” said Jan Chodas, Juno’s project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “The next time these three massive solar arrays are extended to their full length, Juno will be climbing away from the Earth at about seven miles per second.”
This is the first time in history a spacecraft has used solar power so far out in space (Jupiter is five times farther from the sun than Earth). To operate on the sun’s light that far out requires solar panels about the size of the cargo section of a typical tractor-trailer you’d see on the interstate highway. Even with all that surface area pointed sunward, all three panels, which are 2.7 meters wide (9 feet), by 8.9 meters long (29 feet), will only generate about enough juice to power five standard light bulbs — about 450 watts of electricity. If the arrays were optimized to operate at Earth, they would produce 12 to 14 kilowatts of power.
In other recent events, the 106-foot-long (32-meter-long), 12.5-foot-wide (3.8-meter-wide) first stage of the United Launch Alliance Atlas V launch vehicle that will carry Juno into space arrived at the Skid Strip at Cape Canaveral Air Force Station on May 24, aboard the world’s second largest cargo aircraft — a Volga-Dnepr Antonov AN-124-100. The two-stage Atlas V, along with the five solid rocket boosters that ring the first stage, will be assembled and tested on site at Launch Complex-41 at Cape Canaveral this summer.
The launch period for Juno opens Aug. 5, 2011, and extends through Aug. 26. For an Aug. 5 liftoff, the launch window opens at 8:39 a.m. PDT (11:39 am EDT) and remains open through 9:39 a.m. PDT (12:39 p.m. EDT).
NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA’s Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA’s Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.
More information about Juno is online at http://www.nasa.gov/juno .
Note: You can learn more about the Juno mission to Jupiter by logging on to the mission’s new website. The new site was created by Juno Principal Investigator Scott Bolton in conjunction with Radical Media of New York. “It is one-stop shopping for anyone who wants to be entertained as much as informed about space science and the upcoming Juno mission,” said Bolton. This Juno website can be found at: http://missionjuno.swri.edu .

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Solar panels for NASA’s Juno spacecraft complete testing

Photosynthesis mechanics: Tapping into plants is the key to combat climate change, says scientist

Understanding the way plants use and store light to produce energy could be the key ingredient in the fight against climate change, a scientist at Queen Mary, University of London says.
Professor Alexander Ruban from Queen Mary’s School of Biological and Chemical Sciences has been studying the mechanisms behind photosynthesis, a process where plants use sunlight and carbon dioxide to produce food and release oxygen, for 30 years.
In a recent article published in Energy and Environmental Science, he analyses the complex mechanism by which higher plants absorb and store sunlight, the antenna of photosystem II.
“The photosynthetic antenna absorbs the sunlight used in the process of photosynthesis. It is an incredibly efficient mechanism, enabling not only the absorption and storage of sunlight, but also acting as a protective shield to ensure the plant absorbs just the right amount needed,” he explains.
“If we can somehow harness the capabilities of this magnificent mechanism and adapt these findings for the benefit of solar energy, our fight against climate change could become a whole lot easier.”
Professor Ruban, along with colleagues Dr Matthew Johnson and Dr Christopher, took a closer look at the mechanics behind the scenes which enable plants to absorb sunlight.
“Plants have a remarkable ability to adapt to environmental changes around them. The antenna structure in vascular plants are able to act as a regulator — they are extremely intelligent,” Professor Ruban said.
“The carotinoids, which are a group of pigments within the antenna structure, enable the antenna to regulate its absorption and shield capabilities. If we can channel this regulation and intelligence into the production of solar energy, then the future of the Earth could be a whole lot brighter.”

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Photosynthesis mechanics: Tapping into plants is the key to combat climate change, says scientist

Chemistry with sunlight: Combining electrochemistry and photovoltaics to clean up oxidation reactions

The idea is simple, says Kevin Moeller, PhD, and yet it has huge implications. All we are recommending is using photovoltaic cells (clean energy) to power electrochemical reactions (clean chemistry). Moeller is the first to admit this isn’t new science.
“But we hope to change the way people do this kind of chemistry by making a connection for them between two existing technologies,” he says.
To underscore the simplicity of the idea, Moeller and his co-authors used a $6 solar cell sold on the Internet and intended to power toy cars to run reactions described in an article published in Green Chemistry.
If their suggestion were widely adopted by the chemical industry, it would eliminate the toxic byproducts currently produced by a class of reactions commonly used in chemical synthesis — and with them the environmental and economic damage they cause.
The trouble with oxidation reactions
Moeller, a professor of chemistry in Arts & Sciences at Washington University in St. Louis, is an organic chemist, who makes and manipulates molecules made mainly of carbon, hydrogen, oxygen and nitrogen.
One important tool for synthesizing organic molecules — an enormous category that includes everything from anesthetics to yarn — is the oxidation reaction.
“They are the one tool we have that allows us to increase the functionality of a molecule, to add more “handles” to it by which it can be manipulated,” says Moeller.
“Molecules interact with each other through combinations of atoms known as functional groups,” he explains. “Ketones, alcohols or amines are all functional groups. The more functional groups you have on a molecule, the more you can control how the molecule interacts with others.”
“Oxidation reactions attach functional groups to a molecule,” he continues. “If I have a hydrocarbon that consists of nothing but carbon and hydrogen atoms bonded together, and I want to convert it to an alcohol, a ketone or an amine, I have to oxidize it.”
In an oxidation reaction, an electron is removed from a molecule. But that electron has to go somewhere, so every oxidation reaction is paired with a reduction reaction, where an electron is added to a second molecule.
The problem, says Moeller, is that “that second molecule is a waste product; it’s not something you want.”
One example, he says, is an industrial alcohol oxidation that uses the oxidant chromium to convert an alcohol into a ketone. In the process the chromium, originally chromium VI, picks up electrons and becomes chromium IV. Chromium IV is the waste product of the oxidation reaction.
In this case, there is a partial solution. Sodium periodate is used to recycle the highly toxic chromium IV. A salt, the sodium periodate dissociates in solution and the periodate ion (an iodine atom with attached oxygens) interacts with the chromium, restoring it to its original oxidation state.
The catch is that restoring the chromium destroys the periodate. In addition, the process is inefficient; three equivalents of periodate is consumed for every equivalent of desired product produced.
Seeking cleaner byproducts
“All chemical oxidations have a byproduct, says Moeller, so the question is not whether there will be a byproduct but what that byproduct will be. People have starting thinking about how they might run oxidations where the reduced byproduct is something benign.”
“If you use oxygen to do the oxidation, the byproduct is water, and that is a gentle process,” he says.
But there is a catch. Like all other molecules, oxygen has a set oxidation potential, or willingness to accept electrons. “So whatever I want to oxidize in solution has to have an oxidation potential that matches oxygen’s. If it doesn’t, I might have to change my whole reaction around to make sure I can use oxygen. And when I change the whole reaction around, maybe it doesn’t run as well as it used to. So I’m limited in what I can do,” Moeller says.
A simpler idea is also cleaner.
There’s another way to do it. “Electrochemistry can oxidize molecules with any oxidation potential, because the electrode voltage can be tuned or adjusted, or I can run the reaction in such a way that it adjusts itself. So I have tremendous versatility for doing things,” says Moeller.
Moreover, the byproduct of electrochemical oxidation is hydrogen gas, so this too is a clean process.
But again there is a catch. Electrochemistry can be only as green as the source of the electricity. If the oxidation reaction is running clean, but the electricity comes from a coal-fired plant, the problem has not been avoided, just displaced.
The answer is to use the cleanest possible energy, solar energy captured by photovoltaic cells, to run electrochemical reactions.
“That’s what the Green Chemistry article is about,” says Moeller. “It’s a proof-of-principle paper that says it’s easy to make this work, and it works just like reactions that don’t use photovoltaics, so the chemical reaction doesn’t have to be changed around.”
The next step
The Green Chemistry article demonstrated the method by directly oxidizing molecules at the electrode. No chemical reagent was used. Since writing the article, Moeller’s group has been studying how solar-powered electrochemistry might be used to recycle chemical oxidants in a clean way.
Why would manufacturers choose to use a chemical oxidant, if the voltage of the electrode can be matched to the oxidation potential of the molecule that must be oxidized?
“An electrode selects purely on oxidation potential,” Moeller explains. “A chemical reagent does not. The binding properties of the chemical reagent might differ from one part of the molecule to another. And there’s also something called steric hindrance, which means that one part of the molecule might physically block access to an oxidation site, forcing substrates to other sites on the reagent.”
“The chemistry community has learned how to use chemical reagents to make reactions selective,” he says. “The reagents are usually expensive and toxic, so they are recycled,” he says. “We are working on cleaning up reagent recycling.”
In the chromium oxidation described above, for example, chromium IV could be recycled electrochemically instead of through a reaction with periodate. Instead of periodate waste, the reaction would produce hydrogen gas as the byproduct.
“Another example is an industrial process for carrying out alcohol oxidations that convert the alcohol group to a carbonyl group,” says Moeller. This process uses TEMPO, a complex chemical reagent discovered in 1960. TEMPO is expensive so it is recycled by the addition of bleach. This regenerates the TEMPO but produces sodium chloride as a byproduct.”
In small quantities sodium chloride is table salt, but in industrial quantities it is a waste product whose disposal is costly. Once again, the TEMPO can be recycled using electrochemistry, a process that produces hydrogen as the only byproduct.
“We can’t make all of chemical synthesis cleaner by hitching solar power to electrochemistry,” Moeller says, “but we can fix the oxidation reactions that people use. And maybe that will inspire someone else to come up with simple and innovative solutions to other types of reactions they’re interested in.”

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Chemistry with sunlight: Combining electrochemistry and photovoltaics to clean up oxidation reactions

New superstrate material enables flexible, lightweight and efficient thin film solar modules

DuPont™ Kapton® colorless polyimide film, a new material currently in development for use as a flexible superstrate for cadmium telluride (CdTe) thin film photovoltaic (PV) modules, has enabled a new world record for energy conversion efficiency. A team at Empa, the Swiss Federal Laboratories for Materials Science and Technology, has demonstrated a conversion efficiency of 13.8 percent using the new colorless film, leapfrogging their previous record of 12.6 percent and nearing that of glass.
Because Kapton® film is over 100 times thinner and 200 times lighter than glass typically used for PV, there are inherent advantages in transitioning to flexible, film-based vs. rigid glass CdTe systems. High-speed and low-cost roll-to-roll deposition technologies can be applied for high-throughput manufacturing of flexible solar cells on polymer film as substrates. The new polyimide film potentially enables significantly thinner and lighter-weight flexible modules that are easier to handle and less expensive to install, making them ideal for applications including building-integrated photovoltaics.
“Rather than transporting heavy, fragile glass modules on large trucks and lifting them by crane onto rooftop PV installations, one could imagine lightweight, flexible film-based modules that could simply be rolled up for transport, and easily carried up stairs,” said Robert G. Schmidt, new business development manager, Photovoltaics — DuPont Circuit & Packaging Materials. “With record-setting efficiency established through Empa, we’re confident this flexible, lightweight and durable material has the potential to revolutionize the industry by enabling flexible design and lowering balance of system costs.”
Increase in efficiency — toward achieving grid parity
Empa’s Laboratory for Thin Films and Photovoltaics is developing high-efficiency thin film solar cells with emphasis on novel concepts for enhancing their performance, simplifying the fabrication processes, and advancing device structures for next generation of more efficient and low-cost devices. They have been doing groundbreaking work in developing and optimizing a low deposition temperature process (below 450 degrees Celsius) for high-efficiency CdTe solar cells on glass (reaching 15.6 percent efficiency) and polymer film (reaching 12.6 percent efficiency, the highest value before the recent improvement to 13.8 percent). Only a few weeks ago Tiwari’s team also set a new world record in energy efficiency (of 18.7 percent) for another type of flexible solar cells based on copper indium gallium (di)selenide (also known as CIGS).
“Finding a film that could both be transparent and withstand high processing temperatures was a challenge initially, but the new Kapton® colorless polyimide film had both the tolerance for high temperatures needed, and higher light transmittance due to its transparency that allowed it to exceed our previous world record in conversion efficiency of flexible CdTe solar cell,” said Ayodhya N. Tiwari, head of the laboratory. “As we continue to raise the standards for PV efficiency, materials make a distinct difference in the progress we make toward achieving grid parity. Of course, further development is needed for addressing cost and stability issues.” Tiwari plans to present a technical paper on the full findings at the 26th European Photovoltaic Solar Energy Conference and Exhibition in Hamburg, Germany, being held Sept. 5-9, 2011.
DuPont™ Kapton® polyimide film has made innovative design solutions possible in a range of industries over the last 45 years including aerospace, automotive and industrial applications. With a unique combination of electrical, thermal, chemical and mechanical properties that withstand extreme temperature and other demanding environments, Kapton® films have set the standards in high performance, long-term reliability and durability, and are ideally suited for applications in the PV industry. Three new Kapton® PV9100 series films were introduced for the thin film PV market in 2010, including offerings for amorphous Silicon (a-Si) modules and Copper Indium Gallium Selenide (CIGS) photovoltaic applications.

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New superstrate material enables flexible, lightweight and efficient thin film solar modules

Neutron analysis explains dynamics behind best thermoelectric materials

Neutron analysis of the atomic dynamics behind thermal conductivity is helping scientists at the Department of Energy’s Oak Ridge National Laboratory gain a deeper understanding of how thermoelectric materials work. The analysis could spur the development of a broader range of products with the capability to transform heat to electricity.
Researchers performed experiments at both of ORNL’s neutron facilities — the Spallation Neutron Source and the High Flux Isotope Reactor — to learn why the material lead telluride, which has a similar molecular structure to common table salt, has very low thermal conductivity, or heat loss — a property that makes lead telluride a compelling thermoelectric material.
“The microscopic origin of the low thermal conductivity is not well understood. Once we do understand it better we can design materials that perform better at converting heat to electricity,” said Olivier Delaire, a researcher and Clifford Shull Fellow in ORNL’s Neutron Sciences Directorate.
Delaire’s research, reported in Nature Materials, shows that an unusual coupling of microscopic vibrational modes, called phonons, is responsible for the disruption of the dynamics that transport the thermal energy in lead telluride.
In typical crystalline materials, which have a lattice-like atomic structure, the conduction of heat is enhanced by the propagation of phonons along the lattice. The atoms conduct heat by vibrating in a chain, similar to vibrations propagating along a spring.
Delaire’s team determined through analysis at the SNS that lead telluride, although having the same crystal lattice as rock salt, exhibits a strong coupling of phonons, which results in a disruption of the lattice effect and cancels the ability to conduct heat.
“The resolution of the SNS’s Cold Neutron Chopper Spectrometer, along with the high flux, have been quite important to making these time of flight measurements,” Delaire said.
By controlling thermal conductivity in thermoelectrics, less energy is dispersed and more heat can be directed to power generation. Today, thermoelectric materials are used to power the deep-space probes that explore the outer planets and solar system. Cruising beyond the range of solar collectors, the crafts’ reactor thermoelectric generators use heat from decaying radioisotopes to generate power.
New, advanced thermoelectric materials could be used to develop more earthly applications, such as vehicle exhaust systems that convert exhaust heat into electricity, reducing the need for alternators. New thermoelectric materials could also help concentrate solar energy for power generation and recover waste heat for industrial processes.
Delaire’s team performed additional neutron measurements with HFIR’s triple-axis spectrometer. Data analysis has been facilitated through collaboration with ORNL’s Materials Theory group. Samples were synthesized and characterized in ORNL’s Correlated Electrons Materials group.
The work was funded by DOE’s Office of Science as part of the Solid-State Solar-Thermal Energy Conversion Center (S3TEC) Energy Research Frontier Center.

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Neutron analysis explains dynamics behind best thermoelectric materials

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