Researchers make atoms-thick Post-It notes for solar cells and circuits: U of Chicago


23-scientistsmaSchematic diagram (left) and electron microscope image (right) of a stacked set of semiconductor films, made using the Park lab’s new technique. Credit: Park et. al./Nature

Over the past half-century, scientists have shaved silicon films down to just a wisp of atoms in pursuit of smaller, faster electronics. For the next set of breakthroughs, though, they’ll need novel ways to build even tinier and more powerful devices.

A study led by UChicago researchers, published Sept. 20 in Nature, describes an innovative method to make stacks of semiconductors just a few atoms thick. The technique offers scientists and engineers a simple, cost-effective method to make thin, uniform layers of these materials, which could expand capabilities for devices from solar cells to cell phones.

Stacking thin layers of materials offers a range of possibilities for making  with unique properties. But manufacturing such  is a delicate process, with little room for error.

“The scale of the problem we’re looking at is, imagine trying to lay down a flat sheet of plastic wrap the size of Chicago without getting any  in it,” said Jiwoong Park, a UChicago professor with the Department of Chemistry, the Institute for Molecular Engineering and the James Franck Institute, who led the study. “When the material itself is just atoms thick, every little stray atom is a problem.”

Today, these layers are “grown” instead of stacking them on top of one another. But that means the bottom layers have to be subjected to harsh growth conditions such as high temperatures while the new ones are added—a process that limits the materials with which to make them.

Park’s team instead made the films individually. Then they put them into a vacuum, peeled them off and stuck them to one another, like Post-It notes. This allowed the scientists to make films that were connected with weak bonds instead of stronger covalent bonds—interfering less with the perfect surfaces between the layers.

“The films, vertically controlled at the atomic-level, are exceptionally high-quality over entire wafers,” said Kibum Kang, a postdoctoral associate who was the first author of the study.

Kan-Heng Lee, a graduate student and co-first author of the study, then tested the films’ electrical properties by making them into devices and showed that their functions can be designed on the atomic scale, which could allow them to serve as the essential ingredient for future computer chips.

The method opens up a myriad of possibilities for such films. They can be made on top of water or plastics; they can be made to detach by dipping them into water; and they can be carved or patterned with an ion beam. Researchers are exploring the full range of what can be done with the method, which they said is simple and cost-effective.

“We expect this new  to accelerate the discovery of novel , as well as enabling large-scale manufacturing,” Park said.

 Explore further: A simple additive to improve film quality

More information: “Layer-by-layer assembly of two-dimensional materials into wafer-scale heterostructures,” Kang et. al, Nature, Sept. 20. DOI: 10.1038/nature23905

 

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How The Tesla Battery Will Benefit Marijuana Growers (Legally)


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A medium-sized commercial weed grow with around 50 lights stands to save about $13,500 in electricity costs a year with the use of two Tesla Batteries. Those will also protect the plants in case of power outages while making the operation less visible to law enforcement. Elon Musk just made growing weed easier. 

Unveiled last night, the Tesla Battery gives home owners and businesses an easy, slick, affordable way to store electricity at home. The 10kWh battery costs just $3,500 and can be “stacked” in sets of up to nine units. Larger capacity batteries of infinitely-scaleable capacity will be available to large businesses and governments. There’s three general use cases for the battery:

  1. Storing electricity purchased during cheaper, Off-peak hours for use during high-demand periods;
  2. Storing electricity generated by solar power or other renewable sources for use around the clock; and
  3. As a backup power source for when the grid goes down.

Know who uses an awful lot of electricity? Weed growers. We just called one and put him on the phone with a commercial energy use management expert to figure out how the Tesla Battery will benefit his home operation and others like it.

Our friend’s operation is small, but profitable. With eight to ten grow lights running 16-20 hours a day in his garage, as well as air-conditioning during hotter parts of the year, his monthly electricity bill is around $2,100, including his home use.

SolarEdge-Tesla-PowerwallAs a domestic consumer of electricity, he’s currently purchasing flat-rate power. In that current arrangement, the Tesla Battery would not save him money day-to-day. Where it would help would be during a power outage, where it would enable him to keep at least some of his lights on, part of the time. In total, those lights alone are using up to 250kWh of power a day, so even two 10kWh batteries could only keep some of the lights on part time.

But, that could be enough to prevent a large financial loss. “The plants start to get angry after about 72 hours without power,” the grower explains. “They won’t die, but the plants in veg will think it’s time to flower and switch over.”

In the lifecycle of a marijuana plant, the vegetative state is where the plants are growing. Depending on the individual plants and the method with which they’re being grown, this stage can last from two weeks to two months. Premature flowering would lead to smaller plants producing fewer, smaller buds and therefore a smaller crop.

The point in the plant lifecycle at which a power outage occurs, its duration and the amount of marijuana being grown will combine to determine the financial loss, but it’s safe to say that the Tesla Battery could throw growers a lifeline during extreme weather or natural disasters.

We’ve all heard stories about growers being outed by the energy intensive nature of their work. Roofs over grow rooms free of snow during winters or insanely high electricity bills have all, in those stories at least, tipped off the cops.

“It doesn’t work that way,” the grower explains. “The cops have to present a warrant to the electricity company to get your bill and, for that, they need probable cause. No, the electricity companies don’t always demand that warrant, but generally, this isn’t how it works. They’re not going through every power bill, looking for suspiciously high ones.”

One of the other touted benefits of the Battery is its ability to facilitate off-grid living. By hooking it up to solar panels, the Battery can store energy during the day, then keep your house powered throughout the night. Or your off-grid grow, maybe?

“I haven’t seen any solar-powered indoor grows yet,” says our guy. “I suspect the costs of the panels are still way too high.”

He’s right. The most powerful solar panel kit currently available at Home Depot costs $12,388 and produces only 3,800 to 8,900kWh a year. Best case scenario, that yearly total is only enough to power our buddy’s 8-10 lights for a little over a month. Look at it from a cost perspective and 10 times the price of his monthly electricity bill (lights only) nets him about 1/10th the power. And that’s before buying any batteries, Tesla or otherwise.

At this point, the real savings possible with the Tesla Battery come with scale. But not that much more.

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Our commercial energy consumption management expert sat down and ran the numbers assuming a medium-sized, 50-light commercial operation running its A/C during the day. These numbers are based on commercial electricity rates here in California, where the company is paying a premium during high-demand hours.

With two 10kWh Tesla Batteries giving this commercial grow the ability to shift some of its load to off-peak hours, savings in demand charges alone would total $8,000 a year, while use charges would lower by $5,500, for a total savings of $13,500.

Of course, even just at 50 lights, we’re talking about a multi-million dollar operation, making this sound like relative chump change. Worthwhile — the batteries would be paid for in just over 6 months of savings — but hardly revolutionary.

“Where these batteries might start to make sense for small growers is when LEDs are optimized for herb,” says our grower. He’s skeptical of the light quality produced by current LED grow lights, but sees that technology being optimized for marijuana in the near future. When it is, it could drastically lower the energy consumption of growing, reducing electricity used by the lights alone by 60 percent or more. Lower outright energy consumption will reduce the cost of growing, of course, but it also shifts the amount of consumption into a range that could be more easily handled by Tesla Batteries.

Given the current pace of marijuana legalization, the need for clandestine home grows may largely be eliminated by the time dipping energy consumption and increasing battery capacity meet in a home solar power sweet zone, but as a massive electricity consumer, it does look like the marjiuana industry is going to profit from the same Tesla Battery benefits everyone else will — reduced peak demand and increased stability during outages.

Are there ‘soon to be coming to market – more energy dense batteries’ available?

Watch this short Presentation Video

Indefinitely Wild is a new publication about adventure travel in the outdoors, the vehicles and gear that get us there and the people we meet along the way. Follow us on Facebook, Twitter, and Instagram.

MIT: Cheap – Solar Cells – On Paper



Prof. Karen Gleason has come up with a low-cost, environmentally friendly way to make solar cells on ordinary tracing paper. Photo: Len RubensteinSpring 2012

Solar Cells on Paper

Chemical engineer Karen K. Gleason would like to paper the world with solar cells. Glued to laptops, tacked onto roof tiles, tucked into pockets, lining window shades, she envisions ultrathin, ultra-flexible solar cells going where no solar cells have gone before.

Silvery blue solar cells seem to magically generate electricity from sunlight the way Rumpelstiltskin spun straw into gold but in their present form, they’re more akin to gold than straw. 


Karen Gleason develops a low-cost, environmentally friendly way to make solar cells on tracing paper, which one day might charge a cell phone.




The cost of manufacturing crystalline and thin-film solar cells with silicon, glass, and rare earth materials like tellurium and indium is high.


LEARN MORE

MIT’s New Paper Chase: Cheap – Paper Solar Cells

Gleason, the Alexander and I. Michael Kasser Professor of Chemical Engineering, has collaborated with Vladimir Bulovic, professor of electrical engineering; former chemical engineering graduate student Miles C. Barr; and others to come up with a low-cost, environmentally friendly way to make practically indestructible solar cells on ordinary tracing paper. 


One day, a paper solar cell might help us charge a cell phone. “A paper substrate is a thousand times cheaper than silicon and glass. What’s more, these solar cells can be scrunched up, folded a thousand times, and weatherproofed,” she says.

Using abundant, inexpensive organic elements like carbon, oxygen, and copper­­ — “nothing exotic,” she says — in a vacuum chamber, layers are “printed” through a process called vapor deposition, similar to frost forming on a window. At less than 120 degrees Celsius, the method is gentler and cooler than that normally used to manufacture photovoltaic materials, allowing it to be used on delicate paper, cloth, or plastic. “We repeat that five times and you end up with a solar cell,” she says; tweaking the composition of the five layers of materials determines the cells’ energy output. 

The research is funded by MITEI founding member Eni SpA, Italy’s biggest energy company, which is pursuing new advances in biofuels, solar, and other forms of alternative energy.

“The challenge of the project appealed to me,” she says. “I also thought it would be fun.” Her students display a prototype solar cell (a sheet of paper embossed with a pinstripe and chain-link design) folded into a paper airplane as a power source for an LCD clock. 
Gleason would like to see the first commercial solar paper devices hit the market in five years, but first the cells’ efficiency has to be ramped up from nearly 4 percent to at least 10 percent. (Commercial solar cells have an efficiency of around 15 percent.) MIT engineers believe this is doable

Then, the sky’s the limit — solar cells could power iPads, generate lighting inside tents, keep ski clothing toasty. 

“The paper cells’ portability could have a big impact in developing countries, where the cost of transporting solar cells has been prohibitive.

“Rather than confining solar power to rooftops or solar farms, paper photovoltaics can be used virtually anywhere, making energy ubiquitous,” Gleason says.

Researchers @Imperial College of London uncover secret of nanomaterial that makes harvesting sunlight easier


Sun Harvest Nano Material 12-researchersuGold nanoparticles chemically guided inside the hot-spot of a larger gold bow-tie nanoantenna. Credit: Imperial College London

Using sunlight to drive chemical reactions, such as artificial photosynthesis, could soon become much more efficient thanks to nanomaterials.

 

This is the conclusion of a study published today led by researchers in the Department of Physics at Imperial College London, which could ultimately help improve solar energy technologies and be used for new applications, such as using sunlight to break down harmful chemicals.

Sunlight is used to drive many processes that would not otherwise occur. For example, carbon dioxide and water do not ordinarily react, but in the process of photosynthesis, plants take these two chemicals and, using sunlight, produce oxygen and sugar.

The efficiency of this is very high, meaning much of the energy from sunlight is transferred to the chemical reaction, but so far scientists have been unable to mimic this process in manmade artificial devices.

One reason is that many molecules that can undergo with light do not efficiently absorb the light themselves. They rely on photocatalysts – materials that absorb light efficiently and then pass the energy on to the molecules to drive reactions.

In the new study, researchers have investigated an artificial photocatalyst material using nanoparticles and found out how to make it more efficient.

This could lead to better solar panels, as the energy from the Sun could be more efficiently harvested. The photocatalyst could also be used to destroy liquid or gas pollutants, such as pesticides in water, by harnessing sunlight to drive reactions that break down the chemicals into less harmful forms.

Lead author Dr Emiliano Cortés from the Department of Physics at Imperial, said: “This finding opens new opportunities for increasing the efficiency of using and storing sunlight in various technologies.

“By using these materials we can revolutionize our current capabilities for storing and using with important implications in energy conversion, as well as new uses such as destroying pollutant molecules or gases and water cleaning, among others.”

The material that the team investigated is made of metal nanoparticles – particles only billionths of a metre in diameter. Their results are published today in the Journal Nature Communications.

The team, which included researchers from the Chemistry Department at University of Duisburg-Essen in Germany led by Professor Sebastian Schlücker and theoreticians from the Rensselaer Polytechnic Institute and Harvard University at the US, showed that light-induced chemical reactions occur in certain regions over the surface of these nanomaterials.

They identified which areas of the nanomaterial would be most suitable for transferring to chemical reactions, by tracking the locations of very small gold nanoparticles (used as a markers) on the surface of the silver nanocatalytic material.

Now that they know which regions are responsible for the process of harvesting light and transferring it to chemical reactions, the team hope to be able to engineer the nanomaterial to increase these areas and make it more efficient.

Lead researcher Professor Stefan Maier said: “This is a powerful demonstration of how metallic nanostructures, which we have investigated in my group at Imperial for the last 10 years, continue to surprise us in their abilities to control light on the nanoscale.

“The new finding uncovered by Dr Cortés and his collaborators in Germany and the US opens up new possibilities for this field in the areas photocatalysis and nanochemistry.”

Explore further: Artificial leaf as mini-factory for drugs

More information: Emiliano Cortés et al. Plasmonic hot electron transport drives nano-localized chemistry, Nature Communications (2017). DOI: 10.1038/NCOMMS14880

MIT: New ‘Solar Skin’ Solar panels get a face-lift with custom Display Capabilities


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Startup aims for wider U.S. solar adoption with photovoltaic panels that can display any image.

Founded at the MIT Sloan School of Management, Sistine Solar creates custom solar panels designed to mimic home facades and other environments, as well as display custom designs, with aims of enticing more homeowners to install photovoltaic systems. Courtesy of Sistine Solar

Residential solar power is on a sharp rise in the United States as photovoltaic systems become cheaper and more powerful for homeowners. A 2012 study by the U.S. Department of Energy (DOE) predicts that solar could reach 1 million to 3.8 million homes by 2020, a big leap from just 30,000 homes in 2006.

But that adoption rate could still use a boost, according to MIT spinout Sistine Solar. “If you look at the landscape today, less than 1 percent of U.S. households have gone solar, so it’s nowhere near mass adoption,” says co-founder Senthil Balasubramanian MBA ’13.

Founded at the MIT Sloan School of Management, Sistine creates custom solar panels designed to mimic home facades and other environments, with aims of enticing more homeowners to install photovoltaic systems.

Sistine’s novel technology, SolarSkin, is a layer that can be imprinted with any image and embedded into a solar panel without interfering with the panel’s efficacy. Homeowners can match their rooftop or a grassy lawn. Panels can also be fitted with business logos, advertisements, or even a country’s flag. SolarSkin systems cost about 10 percent more than traditional panel installations. But over the life of the system, a homeowner can still expect to save more than $30,000, according to the startup.

A winner of a 2013 MIT Clean Energy Prize, Sistine has recently garnered significant media attention as a rising “aesthetic solar” startup. Last summer, one of its pilot projects was featured on the Lifetime television series “Designing Spaces,” where the panels blended in with the shingle roof of a log cabin in Hubbardston, Massachusetts.

In December, the startup installed its first residential SolarSkin panels, in a 10-kilowatt system that matches a cedar pattern on a house in Norwell, Massachusetts. Now, the Cambridge-based startup says it has 200 homes seeking installations, primarily in Massachusetts and California, where solar is in high demand.

“We think SolarSkin is going to catch on like wildfire,” Balasubramanian says. “There is a tremendous desire by homeowners to cut utility bills, and solar is finding reception with them — and homeowners care a lot about aesthetics.”

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Captivating people with solar – Who Said Solar Can’t Be Beautiful?

SolarSkin is the product of the co-founders’ unique vision, combined with MIT talent that helped make the product a reality.

Balasubramanian came to MIT Sloan in 2011, after several years in the solar-power industry, with hopes of starting his own solar-power startup — a passion shared by classmate and Sistine co-founder Ido Salama MBA ’13.

One day, the two were brainstorming at the Muddy Charles Pub, when a surprisingly overlooked issue popped up: Homeowners, they heard, don’t really like the look of solar panels. That began a nebulous business mission to “captivate people’s imaginations and connect people on an emotional level with solar,” Balasubramanian says.

Recruiting Jonathan Mailoa, then a PhD student in MIT’s Photovoltaic Research Laboratory, and Samantha Holmes, a mosaic artist trained in Italy who is still with the startup, the four designed solar panels that could be embedded on massive sculptures and other 3-D objects. They took the idea to 15.366 (Energy Ventures), where “it was drilled into our heads that you have to do a lot of market testing before you build a product,” Balasubramanian says.

That was a good thing, too, he adds, because they realized their product wasn’t scalable. “We didn’t want to make a few installations that people talk about. … We [wanted to] make solar so prevalent that within our lifetime we can see the entire world convert to 100 percent clean energy,” Balasubramanian says.

The team’s focus then shifted to manufacturing solar panels that could match building facades or street fixtures such as bus shelters and information kiosks. In 2013, the idea earned the team — then officially Sistine Solar — a modest DOE grant and a $20,000 prize from the MIT Clean Energy Prize competition, “which was a game-changer for us,” Balasubramanian says.

But, while trying to construct custom-designed panels, another idea struck: Why not just make a layer to embed into existing solar panels? Recruiting MIT mechanical engineering student Jody Fu, Sistine created the first SolarSkin prototype in 2015, leading to pilot projects for Microsoft, Starwood Hotels, and other companies in the region.

That summer, after earning another DOE grant for $1 million, Sistine recruited Anthony Occidentale, an MIT mechanical engineering student who has since helped further advance SolarSkin. “We benefited from the incredible talent at MIT,” Balasubramanian says. “Anthony is a shining example of someone who resonates with our vision and has all the tools to make this a reality.”

Imagination is the limit

SolarSkin is a layer that employs selective light filtration to display an image while still transmitting light to the underlying solar cells. The ad wraps displayed on bus windows offer a good analogy: The wraps reflect some light to display an image, while allowing the remaining light through so passengers inside the bus can see out. SolarSkin achieves a similar effect — “but the innovation lies in using a minute amount of light to reflect an image [and preserve] a high-efficiency solar module,” Balasubramanian says.

To achieve this, Occidentale and others at Sistine have developed undisclosed innovations in color science and human visual perception. “We’ve come up with a process where we color-correct the minimal information we have of the image on the panels to make that image appear, to the human eye, to be similar to the surrounding backdrop of roof shingles,” Occidentale says.

As for designs, Sistine has amassed a database of common rooftop patterns in the United States, such as asphalt shingles, clay tiles, and slate, in a wide variety of colors. “So if a homeowner says, for instance, ‘We have manufactured shingles in a barkwood pattern,’ we have a matching design for that,” he says. Custom designs aren’t as popular, but test projects include commercial prints for major companies, and even Occidentale’s face on a panel.

Currently, Sistine is testing SolarSkin for efficiency, durability, and longevity at the U.S. National Renewable Energy Laboratory under a DOE grant.

The field of aesthetic solar is still nascent, but it’s growing, with major companies such as Tesla designing entire solar-panel roofs. But, as far as Balasubramanian knows, Sistine is the only company that’s made a layer that can be integrated into any solar panel, and that can display any color as well as intricate patterns and actual images.

Companies could thus use SolarSkin solar panels to double as business signs. Municipalities could install light-powering solar panels on highways that blend in with the surrounding nature. Panels with changeable advertisements could be placed on bus shelters to charge cell phones, information kiosks, and other devices. “You can start putting solar in places you typically didn’t think of before,” Balasubramanian says. “Imagination is really the only limit with this technology.”

Energy-collecting Windows Dream One-Step Closer


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Silicon-based luminescent solar concentrator. While most of the light concentrated to the edge of the silicon-based luminescent solar concentrator is actually invisible, we can better see the concentration effect by the naked eye when the slab is illuminated by a “black light” which is composed of mostly ultraviolet wavelengths. (image: Uwe Kortshagen, University of Minnesota)

February 20, 2017

Researchers at the University of Minnesota and University of Milano-Bicocca are bringing the dream of windows that can efficiently collect solar energy one step closer to reality thanks to high tech silicon nanoparticles.

The researchers developed technology to embed the silicon nanoparticles into what they call efficient luminescent solar concentrators (LSCs). These LSCs are the key element of windows that can efficiently collect solar energy. When light shines through the surface, the useful frequencies of light are trapped inside and concentrated to the edges where small solar cells can be put in place to capture the energy.

The research is published today in Nature Photonics (“Highly efficient luminescent solar concentrators based on Earth-abundant indirect-bandgap silicon quantum dots”).

Windows that can collect solar energy, called photovoltaic windows, are the next frontier in renewable energy technologies, as they have the potential to largely increase the surface of buildings suitable for energy generation without impacting their aesthetics—a crucial aspect, especially in metropolitan areas. LSC-based photovoltaic windows do not require any bulky structure to be applied onto their surface and since the photovoltaic cells are hidden in the window frame, they blend invisibly into the built environment.

The idea of solar concentrators and solar cells integrated into building design has been around for decades, but this study included one key difference—silicon nanoparticles. Until recently, the best results had been achieved using relatively complex nanostructures based either on potentially toxic elements, such as cadmium or lead, or on rare substances like indium, which is already massively utilized for other technologies. Silicon is abundant in the environment and non-toxic. It also works more efficiently by absorbing light at different wavelengths than it emits. However, silicon in its conventional bulk form, does not emit light or luminesce.

“In our lab, we ‘trick’ nature by shrinking the dimension of silicon crystals to a few nanometers, that is about one ten-thousandths of the diameter of human hair,” said University of Minnesota mechanical engineering professor Uwe Kortshagen, inventor of the process for creating silicon nanoparticles and one of the senior authors of the study. “At this size, silicon’s properties change and it becomes an efficient light emitter, with the important property not to re-absorb its own luminescence. This is the key feature that makes silicon nanoparticles ideally suited for LSC applications.”

Using the silicon nanoparticles opened up many new possibilities for the research team.

“Over the last few years, the LSC technology has experienced rapid acceleration, thanks also to pioneering studies conducted in Italy, but finding suitable materials for harvesting and concentrating solar light was still an open challenge,” said Sergio Brovelli, physics professor at the University of Milano-Bicocca, co-author of the study, and co-founder of the spin-off company Glass to Power that is industrializing LSCs for photovoltaic windows “Now, it is possible to replace these elements with silicon nanoparticles.”

Researchers say the optical features of silicon nanoparticles and their nearly perfect compatibility with the industrial process for producing the polymer LSCs create a clear path to creating efficient photovoltaic windows that can capture more than 5 percent of the sun’s energy at unprecedented low costs.

“This will make LSC-based photovoltaic windows a real technology for the building-integrated photovoltaic market without the potential limitations of other classes of nanoparticles based on relatively rare materials,” said Francesco Meinardi, physics professor at the University of Milano-Bicocca and one of the first authors of the paper.

The silicon nanoparticles are produced in a high-tech process using a plasma reactor and formed into a powder.

“Each particle is made up of less than two thousand silicon atoms,” said Samantha Ehrenberg, a University of Minnesota mechanical Ph.D. student and another first author of the study. “The powder is turned into an ink-like solution and then embedded into a polymer, either forming a sheet of flexible plastic material or coating a surface with a thin film.”

The University of Minnesota invented the process for creating silicon nanoparticles about a dozen years ago and holds a number of patents on this technology. In 2015, Kortshagen met Brovelli, who is an expert in LSC fabrication and had already demonstrated various successful approaches to efficient LSCs based on other nanoparticle systems. The potential of silicon nanoparticles for this technology was immediately clear and the partnership was born. The University of Minnesota produced the particles and researchers in Italy fabricated the LSCs by embedding them in polymers through an industrial based method, and it worked.

“This was truly a partnership where we gathered the best researchers in their fields to make an old idea truly successful,” Kortshagen said. “We had the expertise in making the silicon nanoparticles and our partners in Milano had expertise in fabricating the luminescent concentrators. When it all came together, we knew we had something special.”

Source: University of Minnesota

 

Stanford University: Solving the “Storage Problem” for Renewable Energies: A New Cost Effective Re-Chargeable Aluminum Battery


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One of the biggest missing links in renewable energy is affordable and high performance energy storage, but a new type of battery developed at Stanford University could be the solution.

Solar energy generation works great when the sun is shining [duh…like taking a Space Mission to the Sun .. but only at night! :-)] and wind energy is awesome when it’s windy (double duh…), but neither is very helpful for the grid after dark and when the air is still. That’s long been one of the arguments against renewable energy, even if there are plenty of arguments for developing additional solar and wind energy installations without large-scale energy storage solutions in place. However, if low-cost and high performance batteries were readily available, it could go a long way toward a more sustainable and cleaner grid, and a pair of Stanford engineers have developed what could be a viable option for grid-scale energy storage.

With three relatively abundant and low-cost materials, namely aluminum, graphite, and urea, Stanford chemistry Professor Hongjie Dai and doctoral candidate Michael Angell have created a rechargeable battery that is nonflammable, very efficient, and has a long lifecycle.

“So essentially, what you have is a battery made with some of the cheapest and most abundant materials you can find on Earth. And it actually has good performance. Who would have thought you could take graphite, aluminum, urea, and actually make a battery that can cycle for a pretty long time?” – Dai

A previous version of this rechargeable aluminum battery was found to be efficient and to have a long life, but it also employed an expensive electrolyte, whereas the latest iteration of the aluminum battery uses urea as the base for the electrolyte, which is already produced in large quantities for fertilizer and other uses (it’s also a component of urine, but while a pee-based home battery might seem like just the ticket, it’s probably not going to happen any time soon).

According to Stanford, the new development marks the first time urea has been used in a battery, and because urea isn’t flammable (as lithium-ion batteries are), this makes it a great choice for home energy storage, where safety is of utmost importance. And the fact that the new battery is also efficient and affordable makes it a serious contender when it comes to large-scale energy storage applications as well.

“I would feel safe if my backup battery in my house is made of urea with little chance of causing fire.” – Dai

According to Angell, using the new battery as grid storage “is the main goal,” thanks to the high efficiency and long life cycle, coupled with the low cost of its components. By one metric of efficiency, called Coulombic efficiency, which measures the relationship between the unit of charge put into the battery and the output charge, the new battery is rated at 99.7%, which is high.WEF solarpowersavemoney-628x330

In order to meet the needs of a grid-scale energy storage system, a battery would need to last at least a decade, and while the current urea-based aluminum ion batteries have been able to last through about 1500 charge cycles, the team is still looking into improving its lifetime in its goal of developing a commercial version.

The team has published some of its results in the Proceedings of the National Academy of Sciences, under the title “High Coulombic efficiency aluminum-ion battery using an AlCl3-urea ionic liquid analog electrolyte.”

 

PNL Battery Storage Systems 042016 rd1604_batteriesGrid-scale energy storage to manage our electricity supply would benefit from batteries that can withstand repeated cycling of discharging and charging. Current lithium-ion batteries have lifetimes of only 1,000-3,000 cycles. Now a team of researchers from Stanford University, Taiwan, and China have made a research prototype of an inexpensive, safe aluminum-ion battery that can withstand 7,500 cycles. In the aluminum-ion battery, one electrode is made from affordable aluminum, and the other is composed of carbon in the form of graphite.

Read: A step towards new, faster-charging, and safer batteries

 

New organic-inorganic material creates more flexible, efficient technologies ~ For Solar Cells, Thermo-electric Devices and LED’s


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Credit: ACS

An organic-inorganic hybrid material may be the future for more efficient technologies that can generate electricity from either light or heat or devices that emit light from electricity.

Florida State University College of Engineering Assistant Professor Shangchao Lin has published a new paper in the journal ACS Nano that predicts how an organic-inorganic hybrid material called organometal halide perovskites could be more mechanically flexible than existing silicon and other inorganic materials used for , and light-emitting diodes.

In a separate study, Lin found that they might be more energy efficient as well.

“We’re addressing this from a theoretical perspective,” Lin said. “Nobody has really looked at the mechanical and thermal properties of this new material and how it could be used.”

Through mathematical simulations, Lin found that organic-inorganic hybrid perovskites should be extremely malleable and flexible. Although plenty of researchers have looked at perovskites for energy technologies, they did not think they were viable for certain devices because of their crystal structure. Scientists thought they would shatter if used for something like a solar panel.

However, Lin found that hybrid perovskites are predicted to fracture slowly through a crystalline-to-amorphous transition, which would make them very damage-tolerant.

Before mechanical failure, they might absorb twice as much elastic energy from external loading than currently used materials in electronic devices, such as silicon and gallium arsenide.

In a previous paper published in the journal Advanced Functional Materials, Lin and his team predicted that hybrid perovskites possess very due to the organic component. This could make them ideal materials for high efficiency thermoelectric energy conversion.

Specifically, his work suggested that hybrid perovskites are twice as efficient as the current state-of-art thermoelectric material, bismuth telluride, which is very expensive and composed of rare-earth elements.

“The amazing found in perovskites has put it at the frontier of material discovery,” Lin said. “Even more exciting, -based solar cells are four times as efficient, in terms of quantum yield, than polymer-based ones. They are also as efficient as the current, mainstream but are much more flexible and cheaper to make from a solution phase through a procedure very similar to inkjet printing.”

perovskite-solar-cell-generic-structure

Read More About: Will New Method of Making Perovskites Solar Cells Make Solar Energy More Efficient – Less Costly?

Lin hopes to follow these two studies by teaming with experimental chemists, material scientists and device engineers who could put his theoretical framework to the test.

“Computational materials-by-design will be a powerful predicting tool for researchers at FSU and at other universities and industry to use as they move forward in this field,” he said.

Explore further: Discovery of new crystal structure holds promise for optoelectronic devices

More information: Mingchao Wang et al. Anisotropic and Ultralow Phonon Thermal Transport in Organic-Inorganic Hybrid Perovskites: Atomistic Insights into Solar Cell Thermal Management and Thermoelectric Energy Conversion Efficiency, Advanced Functional Materials (2016). DOI: 10.1002/adfm.201600284

Jingui Yu et al. Probing the Soft and Nanoductile Mechanical Nature of Single and Polycrystalline Organic–Inorganic Hybrid Perovskites for Flexible Functional Devices, ACS Nano (2016). DOI: 10.1021/acsnano.6b05913

New class of materials could revolutionize biomedical, alternative energy industries: Cancer Therapies ~ Low Cost Solar Cells


poly-new-material-170125145735_1_540x360Polyarylboranes are a new class of materials that could be used in biomedical, personal computer and alternative energy applications. Credit: Mark Lee

Polyhedral boranes, or clusters of boron atoms bound to hydrogen atoms, are transforming the biomedical industry. These humanmade materials have become the basis for the creation of cancer therapies, enhanced drug delivery and new contrast agents needed for radioimaging and diagnosis. Now, a researcher at the University of Missouri has discovered an entirely new class of materials based on boranes that might have widespread potential applications, including improved diagnostic tools for cancer and other diseases as well as low-cost solar energy cells.

Mark Lee Jr., an assistant professor of chemistry in the MU College of Arts and Science, discovered the new class of hybrid nanomolecules by combining boranes with carbon and hydrogen. Boranes are chemically stable and have been tested at extreme heat of up to 900 degrees Celsius or 1,652 degrees Fahrenheit. It is the thermodynamic stability these molecules exhibit that make them non-toxic and attractive to the biomedical, personal computer and alternative energy industries.

“Despite their stability, we discovered that boranes react with aromatic hydrocarbons at mildly elevated temperatures, replacing many of the hydrogen atoms with rings of carbon,” Lee said. “Polyhedral boranes are incredibly inert, and it is their reaction with aromatic hydrocarbons like benzene that will make them more useful.”

Lee also showed that the attached hydrocarbons communicate with the borane core.

“The result is that these new materials are highly fluorescent in solution,” Lee said. “Fluorescence can be used in applications such as bio-imaging agents and organic light-emitting diodes like those in phones or television screens. Solar cells and other alternative energy sources also use fluorescence, so there are many practical uses for these new materials.”

Lee’s discovery is based on decades of research. Lee’s doctoral advisor, M. Frederick Hawthorne, MU Curators Distinguished Professor of Chemistry and Radiology, discovered several of these boron clusters as early as 1959. In the past, boranes have been used for medical imaging, drug delivery, neutron-based treatments for cancer and rheumatoid arthritis, catalysis and molecular motors. Borane researchers also have created a specific type of nanoparticle that selectively targets cancer cells.

“When these molecules were discovered years ago we never could have imagined that they would lead to so many advancements in biomedicine,” Lee said. “Now, my group is expanding on the scope of this new chemistry to examine the possibilities. These new materials, called ‘polyarylboranes,’ are much broader than we imagined, and now my students are systematically exploring the use of these new clusters.”


Story Source:

Materials provided by University of Missouri-Columbia. Note: Content may be edited for style and length.


Journal Reference:

  1. Mark W. Lee. Catalyst-Free Polyhydroboration of Dodecaborate Yields Highly Photoluminescent Ionic Polyarylated Clusters. Angewandte Chemie, 2017; 129 (1): 144 DOI: 10.1002/ange.201608249

Europe’s nanotechnology ‘Sunflower’ project to design and use less toxic photovoltaic materials (w/video)


Posted: Jan 27, 2017




The University Institute for Advanced Materials Research at the Universitat Jaume I (UJI) has participated in the European Project Sunflower, whose objective has been the development of organic photovoltaic materials less toxic and viable for industrial production. 

A consortium of 17 research and business institutions has carried out this European project in the field of nanotechnology for four years and with an overall budget of 14.2 million euros, with funding of 10.1 million euros from the Seventh Framework Programme of the European Commission.

An introduction to Sunflower

Researchers at Sunflower have carried out several studies, among the most successful of which there are the design of an organic photovoltaic cell that can be printed and, consequently, has great versatility. In short, “we can assure that, thanks to these works, progress has been made in the achievement of solar cells with a good performance, low cost and very interesting architectural characteristics”, states the director of the University Institute for Advanced Materials Research (INAM) Juan Bisquert.

The goals of Sunflower were very ambitious, according to Antonio Guerrero, researcher at the Department of Physics integrated in the INAM, since it was intended “not only to improve the stability and efficiency of the photovoltaic materials, but also to reduce their costs of production”. 

In fact, according to Guerrero, “the processes for making the leap from the laboratory to the industrial scale have been improved because, among others, non-halogenated solvents have been used that are compatible with industrial production methods and that considerably reduce the toxic loading of halogenates”.

“The involvement of our institute in these projects has a great interest because one of our priority lines of research is the new materials to develop renewable energies,” says Bisquert, who is also professor of Applied Physics. In addition, these consortia involve the work of academia and industry. According to the researcher, “the transfer of knowledge to society is favoured and, in this case, we demonstrate that organic materials investigated for twenty years are already close to become viable technologies”.

Change of use of plastic materials

The participation of UJI researchers at Sunflower has focused on “improving the aspect of chemical reactivity of materials or structural compatibility”, says Germà García, professor of Applied Physics and member of INAM. 

“We have worked to move from the concepts of inorganic electronics to photovoltaic cells to the part of organic electronics,” he adds. The researchers wanted to take advantage of the faculties of absorption and conduction of plastic materials and to verify its capacity of solar production, an unusual use because normally they are used as an electrical insulation.

At UJI laboratories, they have studied the organic materials, very complex devices because they have up to eight nanometric layers. “We have made advanced electrical measurements to see where the energy losses were and thus to inform producers of materials and devices in order to improve the stability and efficiency of solar cells,” explains Guerrero.

Solar energy in everyday objects

“The potential applications of organic photovoltaic technology (OPV) are numerous, ranging from mobile consumer electronics to architecture,” says the project coordinator Giovanni Nisato, from the Swiss Centre for Electronics and Microtechnology (CSEM). 

“Thanks to the results we have obtained, printed organic photovoltaics will become part of our daily lives, and will allow us to use renewable energy and respect the environment with a positive impact on our quality of life,” according to Nisato.

The European Sunflower project has been developed over 48 months with the main objective of extending the life and cost-efficiency of organic photovoltaic technology through better process control and understanding of materials. In addition, in the opinion of those responsible, the results of this research could double the share of renewable energy in its energy matrix, from 14% in 2012 to 27-30% by 2030. In fact, Sunflower has facilitated a significant increase in the use of solar energy incorporated in everyday objects.

The Sunflower consortium consists of 17 partners from across Europe: CSEM (Switzerland), DuPont Teijin Films UK Ltd (UK), Amcor Flexibles Kreuzlingen AG (Switzerland), Agfa-Gevaert NV (Belgium), Fluxim AG (Switzerland), University of Antwerp (Belgium), SAES Getters SpA (Italy), Consiglio Nazionale delle Ricerche-ISMN-Bologna (Italy), Hochschule für Life Sciences FHNW (Switzerland), Chalmers Tekniska Hoegskola AB (Sweden), Fraunhofer Institut der angewandten Forschung zur Foerderung @EV (Germany), Linköpings Universitet (Sweden), Universitat Jaume I (Spain), Genes’Ink (France), National Centre for Scientific Research (France), Belectric OPV GmbH (Germany) and Merck KGaA (Germany).

Meanwhile, the main lines of research at the INAM focus on new types of materials for clean energy devices, solar cells based on low cost compounds, such as perovskite and other organic compounds. Furthermore, INAM studies the production of fuels from sunlight, breaking water molecules and producing hydrogen and other catalytic materials in the chemical aspect, all of great importance in the context of international research.

Source: Ruvid