Breakthrough in ‘wonder’ materials paves way for flexible tech


breakthrough-2d-structures

Credit: University of Warwick

 

Gadgets are set to become flexible, highly efficient and much smaller, following a breakthrough in measuring two-dimensional ‘wonder’ materials by the University of Warwick.

Dr Neil Wilson in the Department of Physics has developed a new technique to measure the electronic structures of stacks of two-dimensional materials – flat, atomically thin, highly conductive, and extremely strong materials – for the first time.

Multiple stacked layers of 2-D materials – known as heterostructures – create highly efficient optoelectronic devices with ultrafast electrical charge, which can be used in nano-circuits, and are stronger than materials used in traditional circuits.

Various heterostructures have been created using different 2-D materials – and stacking different combinations of 2-D materials creates new with new properties.

Dr Wilson’s technique measures the electronic properties of each layer in a stack, allowing researchers to establish the optimal structure for the fastest, most efficient transfer of electrical energy.

The technique uses the photoelectric effect to directly measure the momentum of electrons within each layer and shows how this changes when the layers are combined.

The ability to understand and quantify how 2-D material heterostructures work – and to create optimal semiconductor structures – paves the way for the development of highly efficient nano-circuitry, and smaller, flexible, more wearable gadgets.

Solar power could also be revolutionised with heterostructures, as the atomically thin layers allow for strong absorption and efficient power conversion with a minimal amount of photovoltaic material.

Dr Wilson comments on the work: “It is extremely exciting to be able to see, for the first time, how interactions between atomically thin layers change their electronic structure. This work also demonstrates the importance of an international approach to research; we would not have been able to achieve this outcome without our colleagues in the USA and Italy.”

Dr Wilson worked formulated the technique in collaboration with colleagues in the theory groups at the University of Warwick and University of Cambridge, at the University of Washington in Seattle, and the Elettra Light Source, near Trieste in Italy.

Understanding how interactions between the atomic layers change their required the help of computational models developed by Dr Nick Hine, also from Warwick’s Department of Physics.

Explore further: Model accurately predicts the electronic properties of a combination of 2-D semiconductors

More information: Neil R. Wilson et al. Determination of band offsets, hybridization, and exciton binding in 2D semiconductor heterostructures, Science Advances (2017). DOI: 10.1126/sciadv.1601832

 

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Elon Musk: Solar Panels Will Be Your New Roof … And His Vision for a ‘Solar Future’


Solar Cells 041115 organicsemic

Elon Musk has confirmed the next step in the evolution of sustainable energy: Rather than adding solar panels to an existing roof, the panels will BE the roof. What seems like an obvious progression for this technology is actually a unique move in the market.

The news came out of SolarCity‘s conference call yesterday, covering its second quarter financial results, as reported by Electrek. Following SolarCity CEO Lyndon Rive’s reference to 2 new products expected in 2017, Musk jumped in to add “It’s a solar roof, as opposed to modules on a roof… think this is really a fundamental part of achieving differentiated product strategy, where you have a beautiful roof. It’s not a thing on the roof. It is the roof.”

Rive added that this will allow solar city to access a new market, citing that 5 million new roofs are installed each year in the US alone. Additionally the average homeowner is unlikely to install solar panels on a roof that may need to be replaced in the near future, so a solar roof would be the best option.

SolarCity’s existing ‘retro-fit’ panels will not be axed, confirmed Musk, who believes the new business plan will work alongside SolarCity’s existing products. This doesn’t appear to impact Musk’s proposed plan, which was announced following Tesla’s acquisition of SolarCity

Elon Musk’s Turnkey Vision For Energy Independence

In hishis authentic Elon Musk-ian way, the Tesla cofounder and CEO unveiled the roadmap for future of the electic motor company.

Yesterday, Telsa’s blog posted Elon Musk’s Master Plan Part Deux, the highly anticipated sequel to 2006’s master pan. In Musk’s attempt to make sense of Tesla’s recent moves, he explained the decision to acquire SolarCity and the vision to create a (more) sustainable world.

“The point of all this was, and remains, accelerating the advent of sustainable energy, so that we can imagine far into the future and life is still good. That’s what “sustainable” means. It’s not some silly, hippy thing — it matters for everyone.”said Musk in the statement released July 20, “We can’t do this well if Tesla and SolarCity are different companies, which is why we need to combine and break down the barriers inherent to being separate companies.”

Tesla’s absorption of SolarCity is essential to “create a smoothly integrated and beautiful solar-roof-with-battery product that just works.” At this point it is unclear if this relates exclusively to Tesla’s vehicles, or will also apply the Powerwall, Tesla’s built-for-the-home battery.

Regardless, the future of sustainability (as Musk sees it), is do or die: “By definition, we must at some point achieve a sustainable energy economy or we will run out of fossil fuels to burn and civilization will collapse.”

Elon Musk Reveals Tesla Master Plan that Includes Solar Roofs, 10X Safer Self-Driving, and Car-Sharing

Read more about Musk’s Master Plan here.

How Nanotechnologies Will Disrupt the Electrical Grid – And Other ‘Small Wonders’ Using Quantum Dots, Graphene


Power Grid Nano nanotech%20power%20grid

by Christine Hertzog

Is it just me, or is the pace of technology innovation speeding up for you too? Acceleration is certainly evident in nanotechnology R&D. Back in December 2014 I wrote two blogs that updates my 2020 predictions first published in January 2014. Nanotechnology discoveries are now occurring on almost a weekly basis. Universities have been a hotbed of scientific discoveries in material sciences.

Consider the recent news that graphene, a particularly interesting nanomaterial and photons. A photon is a unit of electromagnetic radiation that has energy but not an electrical charge. To the naked human eye, photons are sunshine. Research in Switzerland revealed that graphene can take one photon and make multiple electrons. This is what today’s solar panels do – convert photons into electrons. But graphene has a multiplier effect, with the potential to boost existing best case conversion rates from 32% to 60%.

While this announcement addresses research results, commercialization won’t be far behind, and we’ll soon be reading about new solar panels that leverage graphene materials to increase harvestability of solar potential. Other research advances focused on making solar harvesting materials more flexible.   What do these research announcements mean? Here are three key points.

Solar panels, like microprocessors, will shrink in size and increase in power. Second, areas that have marginal value for solar generation will get a second look as panels improve in their productivity and their flexibility to be adhered to non-traditional surfaces. Third, distributed energy resource (DER) momentum grows as a result as more rooftops, landscapes, and other building surfaces harvest solar energy and proliferate in distribution grids.

Other nano research is concluding that a little stress can be a good thing for silicon crystals known as quantum dots. Around the time of the 1973 energy crisis, the popular saying was “small is beautiful”. In at least some research labs around the world, the new saying could be “small and stressed is beautiful”. One commercial application possibility focuses again on improving the energy harvestability of solar panels made from silicon. However, there’s also interest in how these nanocrystal reactions can increase the charge/discharge cycles of batteries, improve computer displays, and decrease power consumption.3-QD Solar PhotoV improvingane

Are investors paying attention? Graphene has been dubbed the “wonder material”, and big players like IBM and Samsung have been allocating money and resources into it.  China has filed more patents involving graphene than any other country. One of the first commercial applications of graphene research is a light bulb that improves on the energy efficiency of LED bulb technologies. Once these new bulbs are available later this year, investors who have been hanging back will be looking for other commercialization opportunities.

From a Smart Grid perspective, graphene has exciting application potential in energy harvesting, energy storage, and even energy consumption, specifically reductions in waste heat. It’s a rapidly innovating area of materials science research that will be the foundation for disruptive technologies integrated into the electric grid. The dual impacts of these disruptors will be to increase the amount of electricity generated by DER assets and reduce electricity consumption as devices become more energy efficient. The speed at which R&D in graphene and other nanomaterials is advancing to commercialization may blast past my predictions of overall progress by 2020.

Photo Credit: Nanotech and Electrical Infrastructure/shutterstock

By Christine Hertzog

Solar Power, and Somewhere to Store It


MIT sunedisonx519An innovative startup that blends solar energy and battery storage reflects broader interest combining the technologies.

A growing number of companies are now selling large-scale battery storage together with solar installations to lower costs and to address challenges introduced by the intermittent nature of solar power, which is produced only when the sun is shining.

Last week the U.S. solar giant SunEdison announced that it had acquired Solar Grid Storage, a startup that integrates solar installations with battery storage. And SolarCity, the largest solar power installer in the U.S., is almost done installing 430 combined solar and storage systems in a pilot program in the San Francisco Bay area; the company plans to roll out the technology more widely this summer.+

The U.S. Department of Energy, meanwhile, is gathering proposals for $15 million worth of research projects aimed at finding more effective ways to combine photovoltaic and storage technology. One goal is to lower the cost of storing solar power to no more than the projected average U.S. grid price for residential power in 2020: 14 cents per kilowatt-hour. Solar storage currently costs about 20 cents to $1 per kilowatt-hour.+

As more solar power is installed, intermittency will become more of a problem. At the same time, though, the grid storage that could help compensate for this problem is becoming cheaper, and new converter technology can be used for both.+

Tom Leyden, formerly CEO of Solar Grid Storageand now SunEdison’s vice president for energy storage deployment, says his company is using a power converter that links both a photovoltaic array and a battery to the grid. Solar panels and batteries both need converters because they produce direct current (DC) power, whereas power grids carry alternating current (AC)

The company’s four operating projects in Maryland, Pennsylvania, and New Jersey are partnerships. The customer buys solar panels for its site, and Leyden’s operation provides a 10-by-20-foot shipping container holding the dual-use power converter and lithium-ion batteries.+

At the height of a sunny day, for example, the converter is primarily producing AC power from the host’s solar panels. At all other times, however, it feeds spare capacity to the battery to serve the regional utility.+

The solar tax break for the combined system is slated to drop from 30 percent of the equipment cost to 10 percent in 2017, but Leyden says the dual-use converters should also come down in price as more are produced.+

MIT Professor: Power Your House With 5 Liters of Water Per Day – March 2009 – Where Are We Today?


MIT Solar Water Power splash

March 27, 2009 – At the Aspen Environment Forum today, MIT professor Dan Nocera gave a revolutionary picture of the new energy economy with an assertion that our homes will be our power plants and our fuel stations, powered by sunlight and water. And it’s not science fiction.

Nocera stated that even if we put all available acreage into fuel crops, all available acreage in wind power, and build a new nuclear power plant every 1.5 days, and we save 100% of our current energy use (yes, you read that correctly), we will still come up short by 2050. His estimate is that we will need 16 TW of energy production by then, and with our current methods, we won’t get there.

But there is a solution. And we don’t need to invent anything new to get from here to there.

Nocera said that MIT will announce its patent next week of a cheap, efficient, manufacturable electrolyzer made from cobalt and potassium phosphate. This technology, powered by a 6 meter by 5 meter photovoltaic array on the roof, is capable of powering an entire house’s power needs plus a fuel cell good for 500 km of travel, with just 5 liters of water.

The new electrolyzer works at room temperature (“It would work in this water glass right here”) to efficiently produce hydrogen and oxygen gases from water in a simple manner, which will enable a return to using sunlight for our primary energy source.

This technology will decentralize power production and provide true energy independence. The details of implementation still need to be worked out, but Nocera says that fears of hydrogen technology (safety) are unfounded, as companies that work with these gases have the capability to safely store and use them.  “It’s safer than natural gas. You burn that in your house with an open flame. Now that’s dangerous.”

*** Team GNT Writes: In 2009 – Professor Nocera’s announcement was, well … “stunning” to the Renewable Energy community to say the least. So what has become of Professor Nocera’s research?

Where Are We TODAY? – The Artificial Leaf

Prof D. Nocera df12556_79822

“Nocera’s critics—and there are many—want people to know that, in their view, the artificial leaf is virtually a nonstarter in today’s renewable energy landscape: The technology doesn’t plug into the existing power infrastructure (the “grid”), it’s not that cheap or efficient, and hydrogen as a fuel is no safer than other combustible fuels.

Mike Lyons, a chemist at Trinity College Dublin, Ireland, told Chemistry World magazine last year, “Dan’s a great story teller. But that has its inherent dangers.” Other critics point out that Nocera’s own start-up company, Sun Catalytix of Cambridge, Massachusetts, quietly shelved development of the artificial leaf technology a few years ago.

*** From a Special Report: National Geographic “Innovators” Series ***

As usual, Daniel Nocera came in by the back door.

On a rainy night in April, as the trees on the Boston College campus were sending out their first tentative shoots of spring, Nocera arrived (slightly late) as the keynote speaker for a meeting of the American Physical Society, where he was about to discuss a decidedly inorganic variation on a vernal theme: the “artificial leaf,” his invention that uses sunlight to generate an alternative form of energy.

Nocera made his way across a parking lot, went in the “Employees Only” entrance to the banquet hall, asked a bemused janitor for directions, and found himself in an elevator that deposited him right in the middle of the kitchen. “I’m the speaker tonight,” he told an equally bemused maître d’. “Do you know how to get there?”

“You’re in the right place,” the maître d’ announced. “Follow me!” And the man proceeded to lead Nocera out to the dining room.

“Whaddarewe having tonight?” Nocera asked in his rapid, exuberant New York patois, as he passed line cooks preparing roast beef, chicken, and vegetarian lasagna. Because he sees everything through the lens of photosynthesis, the meal becomes material for the talk he was about to give.

To save the planet from the dire consequences of its hydrocarbon addiction, we are going to have to overhaul our entire energy system.

Life on Earth has converted energy from the sun for at least three billion years, and the sun may be the answer to our energy needs in the future, he begins. He tells the audience that even the food they are starting to digest is unleashing energy from chemical bonds originally forged by the sun.

Nocera, 56, is a professor of energy at Harvard University, and a bit of a celebrity innovator in renewable energy circles, but he never forgets (and never lets you forget) that he has always taken the hard way, the less-traveled way, and certainly the less conventional way—from his second-grade excommunication from parochial school, to his defiant rejection of the immigrant values of his Italian American family, to his serial desertions from high school to follow his favorite rock band. It was almost inevitable that his scientific career would also follow a quixotic path.

Saving the Planet From Hydrocarbon Addiction

Nocera rarely passes up an opportunity to explain the artificial leaf. He estimates that he gave a hundred invited talks last year, and almost all the rubber-chicken sermons dwell on sustainability and renewable energy. Of all his provocative assertions, however, perhaps the most radical is not scientific but socioeconomic: To save the planet from the dire consequences of its hydrocarbon addiction, we are going to have to overhaul our entire energy system, and the only way to do that, he says, is to “take care of the poor.” They will be the early adopters of the artificial leaf, he believes, and they will lead the way to an era Nocera echoes Bryan Furnass in calling the “Sustainocene.”

It’s not a particularly popular, or even feasible, message at the moment, and the frequent talks are also a reminder that sometimes the hardest part of innovation comes after you make the discovery.

Daniel Nocera, a professor at Harvard University, is a bit of a celebrity innovator in renewable energy circles. PHOTOGRAPH BY DEANNE FITZMAURICE, NATIONAL GEOGRAPHIC

It takes a special temperament to want to be the kind of messenger that everyone wants to shoot; if not born to the part, Nocera has certainly warmed to the task. Mischievous child, rebellious teenager, long-haired counterculture scientist—they’re all on his resume. And although in photographs he projects an ascetic, almost clerically severe demeanor, he turns out in person to be a gregarious provocateur, charmingly pugnacious and as ebullient as the bubbles in the beaker of his most famous invention.

“Because I Was an American. I Had to Succeed.”

Nocera first became interested in science as a kind of buffer against the almost yearly relocations his family made—Massachusetts, Rhode Island, New York, New Jersey—to accommodate his father’s frequent work transfers (he was a retail buyer for Sears and later J. C. Penney). “The most defining point of my young life was when I was having breakfast one morning and I found out our house had been sold,” he says. “People ask, ‘Why did you become a scientist?’ Because when you’re waking up and you lose your friends every morning because you’re moving again, you start focusing on things you can control. I really turned to science because I could carry it with me.” The things he carried included a microscope and radio he built himself, assembled with the 1960s version of do-it-yourself science kit.

“In and Out” of School

One of his earliest experiments, alas, was throwing a “really chalky” eraser at a nun at his parochial school because he was curious to see what kind of mark it would leave on a black habit; the result was “spectacular,” but he was invited to leave. He embraced the rough-and-tumble of public schooling, even as he rejected his family. “I didn’t like my parents,” he says bluntly. “They always drove me so hard.” To get even, the teenaged Nocera became a member of an Orthodox synagogue in Tenafly, the northern New Jersey town where the family finally settled. “To annoy my Catholic mother,” he says, “I decided to join a temple. I became the best Jew.”

His academic career was spotty, too—he attended Bergenfield High School in northern New Jersey, but only intermittently (“in and out” is how he puts it). “I was the kid with the long hair that all the parents would tell all the other kids, ‘Stay away from him!'” By the time he was in high school, he started disappearing for weeks at a time to follow the Grateful Dead at concerts. “I really went to the Grateful Dead because I needed a family of people,” he says, “and the Grateful Dead is about family.” (The computer in his spare, corner office at Harvard contains 111 gigabytes of Grateful Dead music, to which he listens while writing scientific papers.)

I really turned to science because I could carry it with me.

Given that background, Nocera was not exactly a Westinghouse Science Talent Search kind of kid. He attended Rutgers University and initially planned to pursue biology, until everyone in his family told him he should be a doctor, at which point he switched to chemistry. After graduating in 1979, he entered the Ph.D. program at one of the world’s citadels of hard science: California Institute of Technology.

His adviser at Caltech, Harry Gray, had done pioneering work in photosynthesis, the process by which plants convert sunlight into usable energy. Alternative energy was much in the air because of the Arab oil embargo of the 1970s, and Nocera became captivated by the idea of using sunlight like a leaf does, to split water into hydrogen and oxygen. “I went to graduate school to do that,” he says, and spent the next 30 years trying to get the idea to work. But an innovative idea in energy, he learned, isn’t enough; the idea has to be cheap enough to compete “against the cold, hard facts of a real economic system.”

In 1995, a special issue of the journal Accounts of Chemical Research asked leading chemists to describe “holy grail” projects in the field; one of the essays, by Allen J. Bard and Marye Anne Fox, then at the University of Texas at Austin, described the process of splitting water using sunlight. The sheer simplicity of the process conceals its chemical elegance—it takes energy to break chemical bonds, such as the bonds that hold hydrogen atoms to oxygen in a molecule of water, and plants use the energy of sunlight to break those bonds. The result is hydrogen and oxygen. Plants release oxygen into the air and repurpose the hydrogen to make food, in the form of carbohydrates. But hydrogen on its own, as a gas, is a clean and storable form of energy known as a chemical fuel; it can be stored for later use, and that’s what Nocera was after.

Meet the Artificial Leaf

The idea is simple and elegant, but not easy and especially not easy without considerable cost. (John Turner of the National Renewable Energy Laboratory in Colorado had in fact achieved a version of water-splitting years earlier, but the process used prohibitively expensive materials.) Nocera began working on a cheap and simple approach during his grad school days at Caltech, continued after he took a job as a professor at Michigan State University in 1984, and finally declared success in a splashy 2011 paper in Science as a professor at Massachusetts Institute of Technology, where he moved in 1997.

Nocera’s artificial leaf can split oxygen from hydrogen—mimicking the natural process of plants. PHOTOGRAPH BY DEANNE FITZMAURICE, NATIONAL GEOGRAPHIC

What does an artificial leaf look like?

“We can go in the lab,” Nocera says, rising from his desk. “I’ll just turn on a fake sun, and we can look at it. I mean, right now! Just to prove how easy it is. And you’ll see, like, bubbles coming … smooooosh!” Snapping his fingers, he adds, “It will be that fast.”

In reality, the artificial leaf—at least the demonstration version a graduate student fetched out of a lab drawer—looks more like a sawed-off postage stamp than an appendage on any self-respecting tree. It’s not green; it’s not leaf-shaped; and it doesn’t convert water and carbon dioxide into carbohydrates, as plant leaves do. But after a few minutes of setup, the graduate student placed the “leaf” in a little beaker of water and focused light on it. Within moments, a steady stream of miniscule bubbles scrambled off the leaf, like a rat race of effervescence.

The leaf is actually a thin sandwich of inorganic materials that uses the energy of sunlight to break the chemical bonds holding hydrogen and oxygen atoms together in ordinary H2O. The leaf works because the middle of the sandwich is what’s called a photovoltaic wafer, which converts sunlight into wireless electricity, and that electricity is then channeled to the outer layer of the “leaf,” which is coated with different chemical catalysts on either side. One accelerates the formation of hydrogen gas, the other oxygen.

The artificial leaf mimics the natural process of photosynthesis. PHOTOGRAPH BY DEANNE FITZMAURICE, NATIONAL GEOGRAPHIC

Renewable Energy Celebrity

Armed with this basic invention, Nocera leaped ahead—too far and too fast, according to some of his critics—to a radical vision of how the artificial leaf would revolutionize the world. In a scenario he often shares in talks, he sees artificial leaves on the roof of every house, using sunlight to convert ordinary tap water into hydrogen and oxygen; the photovoltaic cells could provide electricity during daylight hours, and the hydrogen could be stored and later converted in a fuel cell to electricity overnight. Your house would become your personal power plant and your gas station, fueling the hydrogen-powered cars that Nocera says are already on the way. And, as he likes to say, “You can buy all this stuff on Google today.”

In 2011, when Nocera first described the artificial leaf at the annual meeting of the American Chemical Society, the immediate reaction was huge. MIT issued a big press release. Nocera formed a start-up company, Sun Catalytix, to commercialize the invention. There were YouTube videos; Nocera became a renewable energy go-to celebrity, invited to events like the Mountain Film Festival in Telluride, Colorado. And when he decided to move his research group to Harvard in 2012, online chemistry blogs dissected the transfer as if it were a superstar trade in baseball. “Nocera to Harvard!” ChemBark reported.

But not all the attention has been positive, not least because of the term “artificial leaf.” Many scientists thought it was a grandiose, attention-getting name. “Oh, they hate me!” Nocera confirms. “It’s like sport to come after me. But you can see with my retiring personality that it’s very upsetting to me,” he adds with a smile. Indeed, it brings out the combative public school persona in him. “It’s like being outside the boys’ room and getting into fights,” he says. “I did that a lot of times in my life, so I’m pretty good at this.”

“Frugal Innovation”

Despite the criticism, Nocera notes that the artificial leaf incorporates several key innovations. One is the discovery of a special kind of catalyst (created by then-lab member Matthew Kanan in 2008) that basically accelerates the formation of oxygen without depleting itself; in other words, the cobalt-phosphate coating on one side of the leaf acts as a middleman-facilitator to the chemical splitting of water without either using itself up or charging a minimal fee (in terms of energy). Another is that the basic architecture of the leaf is simple, modular, and relatively inexpensive, satisfying Nocera’s desire for what he calls “frugal innovation.”

Nocera wakes up every morning thinking about how to make the artificial leaf technology cheaper, more efficient, and simpler so that it will be impossible to resist the frugality of its innovation.

The company had “really tough discussions” in the fall of 2011, Nocera admits, about whether to proceed with a pilot project to test the artificial leaf idea in a developing country, and decided to “backburner” the technology until it could be done more cheaply. As Nocera puts it, “I did a holy grail of science. Great! That doesn’t mean I did a holy grail of technology. And that’s what scientists and professors don’t get.”

Sun Catalytix has shifted its focus to another technology—one that plugs into the existing infrastructure, but still advances the cause of renewable energy; it’s called a flow battery, and Nocera believes it will provide a cheap, innovative way to store energy on the grid. Meanwhile, Nocera insists, the company “has not given up on the artificial leaf” and still plans to field-test the idea, but only when the technology is less expensive. “So what are we talking about?” he says. “Innovation to reduce cost.”

A fuel cell can turn the split oxygen and hydrogen from the artifical leaf into energy. PHOTOGRAPH BY DEANNE FITZMAURICE, NATIONAL GEOGRAPHIC

Revolution in Renewable Energy

Nocera is a self-confessed workaholic. He says he works up to 14 hours a day, seven days a week, and he wakes up every morning thinking about how to make the artificial leaf technology cheaper, more efficient, and simpler so that it will be impossible to resist the frugality of its innovation.

But he’s also chastened by the challenge ahead. On the one hand, he sees a projected world population of nine billion people by 2050, who will need an estimated 30 terawatts—30 trillion watts—of energy; building 200 new nuclear power plants a year for 40 years, he tells the Boston College audience, wouldn’t satisfy the demand. On the other hand, traditional venture capitalism in the developed world doesn’t have the patience or vision, he says, to invest in the massive changes necessary to create an alternative energy system.

In the developed world, Nocera points out, venture capitalists want a return on their investment in two to five years—”and five is really generous,” he says. Setting up an alternative, photosynthetic-based energy system will never satisfy the appetite for a quick return on investment. “What’s the VC community good at?” he says. “An app that a kid can do in a college dorm—which many have done at Harvard. And it gives them their success stories, and makes them all rich. But these are apps. We’re not talking about high-end [innovation]. With energy, we’re talking about changing a massive infrastructure. There’s nothing a kid in his college room dorm is going to do that’s going to change a massive infrastructure.”

How massive? There’s no firm, agreed-upon figure on America’s historical investment in the current power infrastructure—the power plants, the coal mines, the oil rigs and fracking wells, the refineries, the railroads and ships that transport fuels, the wires that bring electricity to virtually every home. Nocera estimates the number at $150 trillion since the mid-19th century, and it is the $150 trillion gorilla in the energy debate.

“There’s nobody in a Harvard lab or at MIT who’s going to make a discovery—one discovery—that’s going to change an infrastructure that this country built over 150 years,” he says. “You’re at hundreds of trillions of dollars. So what is one person with a bunch of students in a lab going to do?”

That is why he believes the revolution in renewable energy will happen not in the developed world, with its entrenched infrastructure and its impatient venture capitalists, but in places like Africa and India, where there is no existing infrastructure to block the way. And don’t mistake Nocera’s interest in the poor for altruism; it’s pure practicality.

“People say, ‘Oh, it’s so nice that Nocera is doing something for the poor.’ It makes my blood curdle! I’m not helping the poor. I’m a jerk! The poor are helping me. They don’t have an infrastructure, so they’ll walk you to a renewable energy future.”

Given his unconventional past, this future makes perfect sense to Nocera. “I can start looking back over my life, and I can see how my immigrant family and being poor Italians and following the Grateful Dead—it all fits in some way,” he says, face brightening. “The whole energy project. I mean, and then you share it, and it’s distributed! The Grateful Dead!”

3D Printed Lenslets Used to Improve Efficiency and Cut Costs of Rooftop Solar Panels


Concentrated photovoltaics (CPV) are a technology that generates electricity from sunlight. You probably know that already, but now a team of researchers have worked on enabling CPV systems for rooftop use by combining photovoltaic cells and a 3D printed plastic lens array which not only reduces the size and weight, but also cuts the total cost of such systems.

Image 21 - CopyUsing miniaturized photovoltaic cells of gallium arsenide, the 3D printed plastic lens arrays, and a focusing mechanism which moves to track the sun, a traditional solar panel can be placed on the south-facing side of a building’s roof.

The researchers discovered that they could reach 70 percent optical efficiency — and they hope to reach 90 percent efficiency — using their design.

“The main benefit of printed optics for CPV is rapid prototyping and testing of initial concepts. The quality of the printed optics is sufficient for proof of concept,” said Noel Giebink, one of the authors of the research and an assistant professor of electrical engineering at Penn State University.

Image 22According to Geibink, focusing sunlight on the array of cells with the embedded 3D printed plastic ‘lenslet’ arrays means each of them in the top array acts like a tiny magnifying glass. Using their technique, they can intensify sunlight more than 200 times, and as the focal point moves with the sun over the course of a day, the middle solar cell sheet works by moving laterally in the center of the lenslet array.

“We partnered with colleagues at the University of Illinois because they are experts at making small, very efficient multi-junction solar cells,” said Giebink. “These cells are less than 1 square millimeter, made in large, parallel batches and then an array of them is transferred onto a thin sheet of glass or plastic.”

Previous tracking systems only functioned about two hours a day as the focal point moved out of the range of the solar cells. The researchers solved that problem and enabled solar focusing for a complete eight-hour period — and with a total movement of approximately 1 centimeter.

One of the arrays, a refractive surface, collimated the light while another which was coated with a reflective material reflects the collimated light onto the micro-cells.

argonneThe findings, by Jared Price, Xing Sheng, Bram Meulblok, John Rogers, and Giebink, were published in their paper, “Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics,” in the journal Nature Communications.

“Current CPV systems are the size of billboards and have to be pointed very accurately to track the sun throughout the day,” Giebink says. “You can’t put a system like this on your roof, which is where the majority of solar panels throughout the world are installed.”

The research was funded by the US Department of Energy.

Do you know of any other ways 3D printing is being used to move energy production systems forward? Let us know in the 3D Printed Lenslets forum thread on 3DPB.com.

(Watch the Video Below)

(See Simple Diagram Below)

CPV Solar 1 Explanation_acrylic

Solving Solar Power’s Problem


WEF solarpowersavemoney-628x330*From the World Economic Forum on Energy – Francesca McCaffrey*

Several government agencies, academic researchers, and firms have proposed scenarios for the future in which photovoltaic (PV) technologies grow rapidly. To support such growth, PV technologies would need to be developed with resource constraints in mind. For some PV technologies, the production of the required input materials would need to grow at a rate never before seen in the metals industry, according to a new analysis by MIT researchers.

The future availability of critical materials is a widely acknowledged concern within the energy community. Other studies have examined whether projected production growth rates are realistic, but they have approached the question through the lens of constraints such as annual metal production levels and reserves.

MIT graduate student Goksin Kavlak, postdoctoral associate James McNerney, Professor Robert Jaffe of physics, and Professor Jessika Trancik of engineering systems develop a novel method in a paper recently published in Proceedings of the 40th IEEE Photovoltaic Specialists Conference.

“We provide a new perspective by putting the projected PV metal requirements into an historical context,” says Trancik, who is the Atlantic Richfield Career Development Assistant Professor in Energy Studies at MIT and the team lead. “We focus on the changes in metals production over time rather than the absolute amounts.”

This approach allows for an assessment of how quickly metals production would need to be scaled up to meet the rapidly increasing PV deployment levels required by aggressive low-carbon energy scenarios.

To calculate the metals production growth rates required under those scenarios, as lead author Kavlak explained in a recent interview, the researchers first estimated the required production in 2030 for each metal of interest, and then calculated the annual growth rate needed to reach that level. They took into account the projected demand for each metal by both the PV sector and other industrial sectors. In addition, they looked at the effect of potential improvements in PV technology that would reduce the amount of each metal required in production.SA Solar 5 191b940e-6e05-402a-bfbb-3e7be5f8a46f_16x9_600x338

The researchers then compared these projected growth rates to historical metals production growth rates in order to “understand the extent of production growth that happened in the past and whether the projected growth rates have historical precedent,” says Trancik.

The results of this analysis differed from one kind of PV technology to another. For silicon-based PVs, which include first-generation panels using crystalline silicon solar cells, the results presented an optimistic view of the future.

“Silicon-based PVs look promising from a material point of view: The growth-rate of silicon production required to meet high deployment goals does not exceed historical norms,” says Jaffe, the Morningstar Professor of Physics and MacVicar Faculty Fellow at MIT.

The outlook is more complex for newer photovoltaic technologies, especially increasingly attractive thin-film PV technologies. While a handful of thin-film solar panels use silicon in their absorption layers, many make use of other metals, such as cadmium telluride and copper indium gallium diselinide, commonly referred to as CIGS.

Trancik summarized the paper’s findings concerning CIGS and cadmium telluride production: “To meet even relatively small percentages of electricity demand by the year 2030, these technologies would require historically unprecedented [metals production] growth rates.”

The reasoning? In mining, CIGS and cadmium telluride are considered byproduct metals, not mined for their own sake, but only accessible as byproducts of the mining processes for other metals, such as copper. Upping their production, therefore, is a cost-intensive process.

“It is quite possible that the cost and availability of these critical elements will constrain deployment of otherwise game-changing technologies,” said Jaffe.

Published in collaboration with MIT News

*** Team GNT adds: “We are encouraged with regard to an emerging nanotechnology using cadmium-free Quantum Dots for solar energy generation. As such with regards to this article, it is a ‘metal-neutral’ tech with potential for high conversion rates with LOW manufacturing costs.”

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Designing Nanomaterials: Method allows for greater variation in band gap tenability


greatervariationx250If you can’t find the ideal material, then design a new one.

Northwestern Univ.’s James Rondinelli uses quantum mechanical calculations to predict and design the properties of new materials by working at the atom-level. His group’s latest achievement is the discovery of a novel way to control the electronic band gap in complex oxide materials without changing the material’s overall composition.

The finding could potentially lead to better electro-optical devices, such as lasers, and new energy-generation and conversion materials, including more absorbent solar cells and the improved conversion of sunlight into chemical fuels through photoelectrocatalysis.

“There really aren’t any perfect materials to collect the sun’s light,” said Rondinelli, assistant professor of materials science and engineering in the McCormick School of Engineering. “So, as materials scientists, we’re trying to engineer one from the bottom up. We try to understand the structure of a material, the manner in which the atoms are arranged, and how that ‘genome’ supports a material’s properties and functionality.”

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Atomic-scale structure of ‘designer’ layered oxides: Band-gap engineering is enabled by varying the sequence of the well-defined layers, seen as planes of similarly colored (green and purple) atoms, in transition metal oxides without changing the materials overall chemical composition

The electronic band gap is a fundamental material parameter required for controlling light harvesting, conversion, and transport technologies. Via band-gap engineering, scientists can change what portion of the solar spectrum can be absorbed by a solar cell, which requires changing the structure or chemistry of the material.

Current tuning methods in non-oxide semiconductors are only able to change the band gap by approximately one electronvolt, which still requires the material’s chemical composition to become altered. Rondinelli’s method can change the band gap by up to 200% without modifying the material’s chemistry. The naturally occurring layers contained in complex oxide materials inspired his team to investigate how to control the layers. They found that by controlling the interactions between neutral and electrically charged planes of atoms in the oxide, they could achieve much greater variation in electronic band gap tunability.

“You could actually cleave the crystal and, at the nanometer scale, see well-defined layers that comprise the structure,” he said. “The way in which you order the cations on these layers in the structure at the atomic level is what gives you a new control parameter that doesn’t exist normally in traditional semiconductor materials.”

By tuning the arrangement of the cations—ions having a net positive, neutral, or negative charge—on these planes in proximity to each other, Rondinelli’s team demonstrated a band gap variation of more than two electronvolts. “We changed the band gap by a large amount without changing the material’s chemical formula,” he said. “The only difference is the way we sequenced the ‘genes’ of the material.”

Supported by DARPA and the U.S. Dept. of Energy, the research is described in a paper published in Nature Communications.

Arranging oxide layers differently gives rise to different properties. Rondinelli said that having the ability to experimentally control layer-by-layer ordering today could allow researchers to design new materials with specific properties and purposes. The next step is to test his computational findings experimentally.

Rondinelli’s research is aligned with President Barack Obama’s Materials Genome Initiative, which aims to accelerate the discovery of advanced materials to address challenges in energy, healthcare, and transportation.

“Today it’s possible to create digital materials with atomic level precision,” Rondinelli said. “The space for exploration, however, is enormous. If we understand how the material behavior emerges from building blocks, then we make that challenge surmountable and meet one of the greatest challenges today—functionality by design.”

Source: Northwestern Univ.

Hong Kong U of Science & Tech: Researchers Create ‘Nanobowl’ Optical Concentrator for Organic Solar Cell


Nano Bowl researchersaGeometrical light trapping is a simple and promising strategy to largely improve the optical absorption and efficiency of solar cells. Nonetheless, implementation of geometrical light trapping in organic photovoltaic (OPV) is challenging due to the fact that uniform organic active layer can rarely be achieved on textured substrate.

Professor Zhiyong Fan and his group from Hong Kong University of Science and Technology (HKUST) reported novel nanobowl optical concentrator fabricated on low-cost aluminum foil and aiming at tackling this problem. They have successfully fabricated OPV devices based on such optical concentrator and demonstrated over 28 % enhancement in power conversion efficiency over the devices without nanobowl. This work was published in Science Bulletin.

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Electron microscopic image and optical simulation of nanobowl optical concentrator. Credit: ©Science China Press

Solar energy is one of the most promising renewable energy resources and represents a clean and ultimate replacement for fossil fuels in the future. Over the past decades, enormous efforts have been invested in developing efficient and cost effective photovoltaic devices which are competitive to the fossil fuel. Organic photovoltaic (OPV) has been regarded as one of the promising candidates for large-scale, low-cost and efficient solar energy harvesting.

Typical OPV devices are fabricated on glass substrate and using indium-doped tin oxide as electrode. However, such substrate is not flexible and the relatively high resistance of ITO electrode will compromises the OPV device performance. Comparatively, an aluminum foil substrate has the advantages of excellent conductivity, flexibility, cost-effectiveness and roll-to-roll processibility. Meanwhile, light trapping by nano-textured substrate is an appealing strategy to improve solar cell efficiency.

Nonetheless, such application for OPV has yet been successfully demonstrated up to now. This is partly due to the more stringent requirement on active layer thickness uniformity for OPV devices and such uniformity is hard to be guaranteed on nano-texture with the existing coating techniques.

The novel nanobowl optical concentrator developed by Professor Zhiyong Fan can largely enhance the in the active layer of organic solar cell and optical simulation revealed that such improvement was contributed by the superior photon capturing capability of the nanobowl. In addition, they have investigated the effect of geometry of nanobowl on the solar cell performance and three types of nanobowl with pitch of 1000 nm, 1200 nm and 1500 nm were studied.

Solar cells based on nanobowl with pitch of 1000 nm exhibited the best photon absorption in photoactive layer leading to the highest short-circuit current density of ~9.41 mA cm-2 among all nanobowl substrates. With open-circuit voltage of 0.573 V and fill factor of 57.9 %, this nanobowl solar cell achieved a solar energy conversion efficiency of 3.12 %, which is 28 % improvement over the control device without nanobowl. This work not only revealed the in-depth understanding of light trapping by nanobowl optical concentrator, but also demonstrated the feasibility of implementing geometrical light trapping in low-cost, solution processible OPV.

The development of the novel nanobowl optical concentrator and its application on OPV were a collaborative effort involving Professors in Department of Chemistry of HKUST including Professor Shihe Yang and Professor He (Henry) Yan, who are working on cutting-edge researches about organic photovoltaics. The research project was supported by General Research Funds from Hong Kong Research Grants Council and Hong Kong Innovation Technology Commission.

Explore further: Imec demonstrates organic photovoltaics modules showing excellent optical properties, high efficiencies

U of Toronto: “Ghost Busters ~ Nanotechnology ~ Solar Energy” ~ New Inexpensive “Spray-on Solar Cells Turn Any Surface (almost) into a Solar Power Source


Ghost Busters II hk98vnmo0eumdsmjxkfc“Who Ya Gonna Call?”

Researchers at the University of Toronto have unveiled a cheap, fast spray-on solar cell process that could enable the creation of solar arrays using the most modest of manufacturing methods. Even better, with the cells ‘printed’ onto flexible material, they could turn anything from airplane wings to your patio furniture into a solar power plant.

The research was led by University of Toronto researcher Illan Kramer, who calls the system sprayLD. Much as with many previous spray-on solar designs, spray LD utilizes colloidal quantum dots (CQD). CQD are tiny, light-sensitive dots—invisible to the naked eye—that can act as an absorbing photovoltaic material. The technology has long held promise, but the process of incorporating light-sensitive CQD’s onto surfaces has been expensive, slow and laborious.

Kramer spray-ld-1-537x358

What Kramer and his colleagues have done is to invent an entirely new, cheap, efficient technique for creating solar cells using CQD. They based the technique on a newspaper-printing process, and explain “SprayLD blasts a liquid containing CQDs directly onto flexible surfaces, such as film or plastic… by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler.”

Watch the Video:

As for their prototype, the team admits that it may look “more like junkyard wars than high-tech,” but that’s because it was made entirely from affordable, readily available parts; U of T explains “[Kramer] sourced a spray nozzle used in steel mills to cool steel with a fine mist of water, and a few regular air brushes from an art store.”university_of_toronto

Which perhaps makes it all the more surprising that this technique does not appear to cause any major drop offs in efficiency. However, efficiency is still a major consideration with spray-on solar. The sprayLD system converts about 8.1% of sunlight to power, as opposed to 15-20% for standard rooftop solar arrays. But, speaking to Co.Exist, Kramer explained that while he is working on boosting sprayLD’s efficiency “we think of ourselves as operating in a slightly different paradigm, where we don’t have to be quite as efficient because we’re so much less expensive.”

And in the long run, Kramer explains: “My dream is that one day you’ll have two technicians with Ghostbusters backpacks come to your house and spray your roof!”

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