energy (17)

Black Silicon...

12360303470?profile=RESIZE_710x

Fluorine gas etches the surface of silicon into a series of angular peaks that, when viewed with a powerful microscope, look much like the pyramid pattern in the sound-proofing foam shown above. Researchers at PPPL have now modeled how these peaks form in silicon, creating a material that is highly light absorbent. Credit: Pixabay/CC0 Public Domain

Topics: Energy, Environment, Materials Science, Nanomaterials, Solar Power

Researchers at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have developed a new theoretical model explaining one way to make black silicon, an important material used in solar cells, light sensors, antibacterial surfaces, and many other applications.

Black silicon is made when the surface of regular silicon is etched to produce tiny nanoscale pits on the surface. These pits change the color of the silicon from gray to black and, critically, trap more light, an essential feature of efficient solar cells.

While there are many ways to make black silicon, including some that use the charged, fourth state of matter known as plasma, the new model focuses on a process that uses only fluorine gas. PPPL Postdoctoral Research Associate Yuri Barsukov said the choice to focus on fluorine was intentional: The team at PPPL wanted to fill a gap in publicly available research. While some papers have been published about the role of charged particles called ions in the production of black silicon, not much has been published about the role of neutral substances, such as fluorine gas.

"We now know—with great specificity—the mechanisms that cause these pits to form when fluorine gas is used," said Barsukov, one of the authors of a new paper about the work, appearing in the Journal of Vacuum Science & Technology A.

"This kind of information, published publicly and openly available, benefits us all, whether we pursue further knowledge into the basic knowledge that underlines such processes or we seek to improve manufacturing processes," Barsukov added.

How black silicon, a prized material used in solar cells, gets its dark, rough edge, Rachel Kremen, Princeton Plasma Physics Laboratory

Read more…

Cooling Circuitry...

12345221085?profile=RESIZE_710x

Illustration of a UCLA-developed solid-state thermal transistor using an electric field to control heat movement. Credit: H-Lab/UCLA

Topics: Applied Physics, Battery, Chemistry, Electrical Engineering, Energy, Thermodynamics

A new thermal transistor can control heat as precisely as an electrical transistor can control electricity.

From smartphones to supercomputers, electronics have a heat problem. Modern computer chips suffer from microscopic “hotspots” with power density levels that exceed those of rocket nozzles and even approach that of the sun’s surface. Because of this, more than half the total electricity burned at U.S. data centers isn’t used for computing but for cooling. Many promising new technologies—such as 3-D-stacked chips and renewable energy systems—are blocked from reaching their full potential by errant heat that diminishes a device’s performance, reliability, and longevity.

“Heat is very challenging to manage,” says Yongjie Hu, a physicist and mechanical engineer at the University of California, Los Angeles. “Controlling heat flow has long been a dream for physicists and engineers, yet it’s remained elusive.”

But Hu and his colleagues may have found a solution. As reported last November in Science, his team has developed a new type of transistor that can precisely control heat flow by taking advantage of the basic chemistry of atomic bonding at the single-molecule level. These “thermal transistors” will likely be a central component of future circuits and will work in tandem with electrical transistors. The novel device is already affordable, scalable, and compatible with current industrial manufacturing practices, Hu says, and it could soon be incorporated into the production of lithium-ion batteries, combustion engines, semiconductor systems (such as computer chips), and more.

Scientists Finally Invent Heat-Controlling Circuitry That Keeps Electronics Cool, Rachel Newur, Scientific American

Read more…

Fusion's Holy Grail...

12344656301?profile=RESIZE_710x

A view of the assembled experimental JT-60SA Tokamak nuclear fusion facility outside Tokyo, Japan. JT-60SA.ORG

Topics: Applied Physics, Economics, Energy, Heliophysics, Nuclear Fusion, Quantum Mechanics

Japan and the European Union have officially inaugurated testing at the world’s largest experimental nuclear fusion plant. Located roughly 85 miles north of Tokyo, the six-story JT-60SA “tokamak” facility heats plasma to 200 million degrees Celsius (around 360 million Fahrenheit) within its circular, magnetically insulated reactor. Although JT-60SA first powered up during a test run back in October, the partner governments’ December 1 announcement marks the official start of operations at the world’s biggest fusion center, reaffirming a “long-standing cooperation in the field of fusion energy.”

The tokamak—an acronym of the Russian-language designation of “toroidal chamber with magnetic coils”—has led researchers’ push towards achieving the “Holy Grail” of sustainable green energy production for decades. Often described as a large hollow donut, a tokamak is filled with gaseous hydrogen fuel that is then spun at immense high speeds using powerful magnetic coil encasements. When all goes as planned, intense force ionizes atoms to form helium plasma, much like how the sun produces its energy.

[Related: How a US lab created energy with fusion—again.]

Speaking at the inauguration event, EU energy commissioner Kadri Simson referred to the JT-60SA as “the most advanced tokamak in the world,” representing “a milestone for fusion history.”

“Fusion has the potential to become a key component for energy mix in the second half of this century,” she continued.

The world’s largest experimental tokamak nuclear fusion reactor is up and running, Andrew Paul, Popular Science.

Read more…

Everything, Everywhere, All at Once...

12287926495?profile=RESIZE_710x

The Flood by Antonio Marziale Carracci

Topics: Civilization, Climate Change, Energy, Environment, Existentialism, Global Warming

Another week, another catastrophic, record-setting, history-making flood, this time in Kentucky.

Preliminary assessments indicate rainfall in Graves County last week likely set a new record for most precipitation in a 24-hour period, with 11.28 inches of rain. This would make it yet another “1,000-year” flood event, which had, according to historical projections, less than a 0.1 percent chance of occurring in any given year. One of the towns that experienced flash flooding was Mayfield, a community still rebuilding from a 2021 tornado that killed 57 people.

This was just one of the 11 flash flood emergencies in as many days in the United States, according to Weather Channel meteorologist Heather Zons. These events have claimed multiple lives: 2-year-old Mattie Shiels, 9-month-old brother, Conrad, and their mother, Katie Seley drowned after getting swept away by flash flooding in Pennsylvania, during an event that killed at least four others. In New York earlier this month, 43-year-old Pamela Nugent was swept away trying to evacuate a flooded area; 63-year-old Stephen Davoll drowned in his home in Vermont.

Other catastrophic, deadly flooding events have occurred almost simultaneously around the globe. Just this weekend, 10 inches of rain fell on parts of Nova Scotia, Canada, which is about as much as the region experiences over a period of three months. Four people, including two children, are still missing.

Everything, everywhere, all at once: The great floods of 2023, Jessica McKenzie, Bulletin of the Atomic Scientists, July 27, 2023

Read more…

Build Better Batteries...

12202262287?profile=RESIZE_710x

Electric field- and pressure-assisted fast sintering to control graphene alignment in thick composite electrodes for boosting lithium storage performance. Credit: Hongtao Sun, Penn State

Topics: Battery, Energy, Graphene, Green Tech, Lithium, Materials Science, Nanomaterials

The demand for high-performance batteries, especially for use in electric vehicles, is surging as the world shifts its energy consumption to a more electric-powered system, reducing reliance on fossil fuels and prioritizing climate remediation efforts. To improve battery performance and production, Penn State researchers and collaborators have developed a new fabrication approach that could make for more efficient batteries that maintain energy and power levels.

The improved method for fabricating battery electrodes may lead to high-performance batteries that would enable more energy-efficient electric vehicles, as well as such benefits as enhancing power grid storage, according to Hongtao Sun. Sun is an assistant professor of industrial and manufacturing engineering at Penn State and the co-corresponding author of the study, which was published in and featured on the front cover of Carbon.

"With current batteries, we want them to enable us to drive a car for longer distances, and we want to charge the car in maybe five minutes, 10 minutes, comparable to the time it takes to fill up for gas," Sun said. "In our work, we considered how we can achieve this by making the electrodes and battery cells more compact, with a higher percentage of active components and a lower percentage of passive components."

If an electric car maker wants to improve the driving distance of their vehicles, they add more battery cells, numbering in the thousands. The smaller and lighter, the better, according to Sun.

"The solution for longer driving distances for an electric vehicle is just to add compact batteries, but with denser and thicker electrodes," Sun said, explaining that such electrodes could better connect and power the battery's components, making them more active. "Although this approach may slightly reduce battery performance per electrode weight, it significantly enhances the vehicle's overall performance by reducing the battery package's weight and the energy required to move the electric vehicle."

Thicker, denser, better: New electrodes may hold the key to advanced batteries, Jamie Oberdick, Pennsylvania State University, techxplore.

Read more…

Solar...

11148143690?profile=RESIZE_710x

The LRESE parabolic dish: the solar reactor converts solar energy to hydrogen with an efficiency of more than 20%, producing around 0.5 kg of "green" hydrogen per day. (Courtesy: LRESE EPFL)

Topics: Applied Physics, Energy, Environment, Research, Solar Power

A new solar-radiation-concentrating device produces “green” hydrogen at a rate of more than 2 kilowatts while maintaining efficiencies above 20%. The pilot-scale device, which is already operational under real sunlight conditions, also produces usable heat and oxygen, and its developers at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland say it could be commercialized in the near future.

The new system sits on a concrete foundation on the EPFL campus and consists of a parabolic dish seven meters in diameter. This dish collects sunlight over a total area of 38.5 m2, concentrates it by a factor of about 1000, and directs it onto a reactor that comprises both photovoltaic and electrolysis components. Energy from the concentrated sunlight generates electron-hole pairs in the photovoltaic material, which the system then separates and transports to the integrated electrolysis system. Here, the energy is used to “split” water pumped through the system at an optimal rate, producing oxygen and hydrogen.

Putting it together at scale

Each of these processes has, of course, been demonstrated before. Indeed, the new EPFL system, which is described in Nature Energy, builds on previous research from 2019, when the EPFL team demonstrated the same concept at a laboratory scale using a high-flux solar simulator. However, the new reactor’s solar-to-hydrogen efficiency and hydrogen production rate of around 0.5 kg per day is unprecedented in large-scale devices. The reactor also produces usable heat at a temperature of 70°C.

The versatility of the new system forms a big part of its commercial appeal, says Sophia Haussener, who leads the EPFL’s Laboratory of Renewable Energy Science and Engineering (LRESE). “This co-generation system could be used in industrial applications such as metal processing and fertilizer manufacturing,” Haussener tells Physics World. “It could also be used to produce oxygen for use in hospitals and hydrogen for fuels cells in electric vehicles, as well as heat in residential settings for heating water. The hydrogen produced could also be converted to electricity after being stored between days or even inter-seasonally.”

Concentrated solar reactor generates unprecedented amounts of hydrogen, Isabelle Dumé, Physics World.

Read more…

TEG...

11035675488?profile=RESIZE_584x

The new self-powered thermoelectric generator device uses an ultra-broadband solar absorber (UBSA) to capture sunlight, which heats the generator. Simultaneously, another component called a planar radiative cooling emitter (RCE) cools part of the device by releasing heat. Credit: Haoyuan Cai, Jimei University

Topics: Alternate Energy, Battery, Chemistry, Energy, Materials Science, Thermodynamics

Researchers have developed a new thermoelectric generator (TEG) that can continuously generate electricity using heat from the sun and a radiative element that releases heat into the air. Because it works during the day or night and in cloudy conditions, the new self-powered TEG could provide a reliable power source for small electronic devices such as outdoor sensors.

"Traditional power sources like batteries are limited in capacity and require regular replacement or recharging, which can be inconvenient and unsustainable," said research team leader Jing Liu from Jimei University in China. "Our new TEG design could offer a sustainable and continuous energy solution for small devices, addressing the constraints of traditional power sources like batteries."

TEGs are solid-state devices that use temperature differences to generate electricity without moving parts. In the journal Optics Express, Liu and a multi-institutional team of researchers describe and demonstrate a new TEG that can simultaneously generate the heat and cold necessary to create a temperature difference large enough to generate electricity even when the sun isn't out. The passive power source is made of components that can easily be manufactured.

"The unique design of our self-powered thermoelectric generator allows it to work continuously, no matter the weather," said Liu. "With further development, our TEG has the potential to impact a wide range of applications, from remote sensors to wearable electronics, promoting a more sustainable and eco-friendly approach to powering our daily lives."

New passive device continuously generates electricity during the day or night, Optica/Tech Explore

Read more…

Serendipitous Quasicrystals...

10923354081?profile=RESIZE_710x

Cross-section of a fulgurite sample showing fused sand and melted conductor metal from a downed powerline. Credit: Luca Bindi et al.

Topics: Condensed Matter Physics, Energy, Materials Science

A team of researchers from Università di Firenze, the University of South Florida, California Institute of Technology, and Princeton University has found an incidence of a quasicrystal formed during an accidental electrical discharge.

In their paper published in Proceedings of the National Academy of Sciences, the group describes their study of a quasicrystal found in a sand dune in Nebraska.

Quasicrystals, as their name suggests, are crystal-like substances. They possess characteristics not found in ordinary crystals, such as a non-repeating arrangement of atoms. To date, quasicrystals have been found embedded in meteorites and in the debris from nuclear blasts. In this new effort, the researchers found one embedded in a sand dune in Sand Hills, Nebraska.

A study of the quasicrystal showed it had 12-fold, or dodecagonal, symmetry—something rarely seen in quasicrystals. Curious about how it might have formed and ended up in the sand dune, the researchers did some investigating. They discovered that a power line had fallen on the dune, likely due to a lightning strike. They suggest the electrical surge from either the power line or the lightning could have produced the quasicrystal.

The researchers note that the quasicrystal was found inside a tubular piece of fulgurite. They suggest it was also formed during the electrical surge due to the fusing of melted sand and metal from the power line.

Quasicrystal formed during accidental electrical discharge, Bob Yirka, Phys.org

Read more…

Caveat Emptor...

10913832662?profile=RESIZE_710x

National Ignition Facility operators inspect a final optics assembly during a routine maintenance period in August. Photo credit: Lawrence Livermore National Laboratory

Topics: Alternate Energy, Applied Physics, Climate Change, Energy, Global Warming, Lasers, Nuclear Fusion

After the heady, breathtaking coverage of pop science journalism, I dove into the grim world inhabited by the Bulletin of the Atomic Scientists on their take on the first-ever fusion reaction. I can say that I wasn’t surprised. With all this publicity, it will probably get the Nobel Prize nomination (my guess). Cool Trekkie trivia: the National Ignition Facility was the backdrop for the Enterprise's warp core for Into Darkness.

*****

This week’s headlines have been full of reports about a “major breakthrough” in nuclear fusion technology that, many of those reports misleadingly suggested, augurs a future of abundant clean energy produced by fusion nuclear power plants. To be sure, many of those reports lightly hedged their enthusiasm by noting that (as The Guardian put it) “major hurdles” to a fusion-powered world remain.

Indeed, they do.

The fusion achievement that the US Energy Department announced this week is scientifically significant, but the significance does not relate primarily to electricity generation. Researchers at Lawrence Livermore National Laboratory’s National Ignition Facility, or NIF, focused the facility’s 192 lasers on a target containing a small capsule of deuterium–tritium fuel, compressing it and inducing what is known as ignition. In a written press release, the Energy Department described the achievement this way: “On December 5, a team at LLNL’s National Ignition Facility (NIF) conducted the first controlled fusion experiment in history to reach this [fusion ignition] milestone, also known as scientific energy breakeven, meaning it produced more energy from fusion than the laser energy used to drive it. This historic, first-of-its-kind achievement will provide the unprecedented capability to support [the National Nuclear Security Administration’s] Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy, which would be a game-changer for efforts to achieve President Biden’s goal of a net-zero carbon economy.”

Because of how the Energy Department presented the breakthrough in a news conference headlined by Energy Secretary Jennifer Granholm, news coverage has largely glossed over its implications for monitoring the country’s nuclear weapons stockpile. Instead, even many serious news outlets focused on the possibility of carbon-free, fusion-powered electricity generation—even though the NIF achievement has, at best, a distant and tangential connection to power production.

To get a balanced view of what the NIF breakthrough does and does not mean, I (John Mecklin) spoke this week with Bob Rosner, a physicist at the University of Chicago and a former director of the Argonne National Laboratory who has been a longtime member of the Bulletin’s Science and Security Board. The interview has been lightly edited and condensed for readability.

See their chat at the link below.

The Energy Department’s fusion breakthrough: It’s not really about generating electricity, John Mecklin, The Bulletin of the Atomic Scientists, Editor-in-Chief

Read more…

Solar Lilly Pads...

10832249652?profile=RESIZE_710x

A floating artificial leaf – which generates clean fuel from sunlight and water – on the River Cam near King's College Chapel in Cambridge, UK. (Courtesy: Virgil Andrei)

Topics: Climate Change, Energy, Environment, Materials Science, Solar Power

Leaf-like devices that are light enough to float on water could be used to generate fuel from solar farms located on open water sources. This avenue hasn’t been explored before, according to researchers from the University of Cambridge in the UK who developed them. The new devices are made from thin, flexible substrates and perovskite-based light-absorbing layers. Tests showed that they can produce either hydrogen or syngas (a mixture of hydrogen and carbon monoxide) while floating on the River Cam.

Artificial leaves like these are a type of photoelectrochemical cell (PEC) that transforms sunlight into electrical energy or fuel by mimicking some aspects of photosynthesis, such as splitting water into its constituent oxygen and hydrogen. This differs from conventional photovoltaic cells, which convert light directly into electricity.

Because PEC artificial leaves contain both light harvesting and catalysis components in one compact device, they could, in principle, be used to produce fuel from sunlight cheaply and simply. The problem is that current techniques for making them can’t be scaled up. What is more, they are often composed of fragile and heavy bulk materials, which limits their use.

In 2019 a team of researchers led by Erwin Reisner developed an artificial leaf that produced syngas from sunlight, carbon dioxide, and water. This device contained two light absorbers and catalysts, but it also incorporated a thick glass substrate and coatings to protect against moisture, which made it cumbersome.

Floating artificial leaves could produce solar-generated fuel, Isabelle Dumé, Physics World

Read more…

Martian Windmills...

9972036484?profile=RESIZE_710x

Artist's rendition of a future colony on Mars., e71lena via Shutterstock

Topics: Applied Physics, Energy, Mars, Space Exploration

(Inside Science) -- Mars is known for its dust storms, which can cause problems for lander equipment and block out the sun that fuels solar panels. These punishing storms, which can last for weeks, have already caused damage to equipment and even killed NASA’s Opportunity rover. But they could also be dangerous to astronauts on the ground, who would rely on solar power for oxygen, heat, and water cleansing during future missions.

Vera Schorbach, a professor of wind energy at the Hamburg University of Applied Sciences in Germany, was curious to see whether wind turbines could harness the power of these storms, filling in for solar panels on the Red Planet during times of need.

"I asked myself, 'Why don't they have a wind turbine if they have dust storms,'" said Schorbach, the lead author of a study about the potential for wind power on Mars published recently in the journal Acta Astronautica.

Could martian dust storms help astronauts keep the lights on? Joshua Rapp Leam, Astronomy/Inside Science

Read more…

OIPCs and Janus...

9966243098?profile=RESIZE_710x

Topics: Battery, Energy, Green Tech, Research, Solid-State Physics

Janus, in Roman religion, the animistic spirit of doorways (januae) and archways (Jani). Janus and the nymph Camasene were the parents of Tiberinus, whose death in or by the river Albula caused it to be renamed Tiber. Source: Encylopedia Britannica

Over the past decade, lithium-ion batteries have seen stunning improvements in their size, weight, cost, and overall performance. (See Physics Today, December 2019, page 20.) But they haven’t yet reached their full potential. One of the biggest remaining hurdles has to do with the electrolyte, the material that conducts Li+ ions from anode to cathode inside the battery to drive the equal and opposite flow of charge in the external circuit.

Most commercial lithium-ion batteries use organic liquid electrolytes. The liquids are excellent conductors of Li+ ions, but they’re volatile and flammable, and they offer no defense against the whisker-like Li-metal dendrites that can build up between the electrodes and eventually short-circuit the battery. Because safety comes first, battery designers must sacrifice some performance in favor of not having their batteries catch fire.

A solid-state electrolyte could solve those problems. But what kind of solid conducts ions? An ordered crystal won’t do—when every site is filled in a crystalline lattice, Li+ ions have nowhere to move to. A solid electrolyte, therefore, needs to have a disordered, defect-riddled structure. It must also provide a polar environment to welcome the Li+ ions, but with no negative charges so strong that the Li+ ions stick to them and don’t let go.

For several years, Jenny PringleMaria Forsyth, and colleagues at Deakin University in Australia have been exploring a class of materials, called organic ionic plastic crystals (OIPCs), that could fit the bill. As a mix of positive and negative ions, an OIPC offers the necessary polar environment for conducting Li+. And because the constituent ions are organic, the researchers have lots of chemical leeways to design their shapes so they can’t easily fit together into a regular lattice but are forced to adopt a disordered, Li+-permeable structure.

Two-faced ions form a promising battery material, Johanna L. Miller, Physics Today

Read more…

Peat Batteries...

9720195300?profile=RESIZE_710x

An aerial view of peat fields in Elva, Estonia. September 30, 2021. REUTERS/Janis Laizans

Topics: Battery, Biofuels, Chemistry, Energy, Green Tech

TARTU, Estonia, Oct 11 (Reuters) - Peat, plentiful in bogs in northern Europe, could be used to make sodium-ion batteries cheaply for use in electric vehicles, scientists at an Estonian university say.

Sodium-ion batteries, which do not contain relatively costly lithium, cobalt, or nickel, are one of the new technologies that battery makers are looking at as they seek alternatives to the dominant lithium-ion model.

Scientists at Estonia's Tartu University say they have found a way to use peat in sodium-ion batteries, which reduces the overall cost, although the technology is still in its infancy.

"Peat is a very cheap raw material - it doesn't cost anything, really," says Enn Lust, head of the Institute of Chemistry at the university.

Energy from bogs: Estonian scientists use peat to make batteries, Janis Laizans and Andrius Sytas, Reuters Science

Read more…

Nearing Ignition...

9438571460?profile=RESIZE_584x

An artist’s rendering shows how the National Ignition Facility’s 192 beams enter an eraser-size cylinder of gold and heat it from the inside to produce x-rays, which then implode the fuel capsule at its center to create fusion.

LAWRENCE LIVERMORE NATIONAL LABORATORY

Topics: Energy, Environment, Modern Physics, Nuclear Fusion, Nuclear Power

More than a decade ago, the world’s most energetic laser started to unleash its blasts on tiny capsules of hydrogen isotopes, with managers promising it would soon demonstrate a route to limitless fusion energy. Now, the National Ignition Facility (NIF) has taken a major leap toward that goal. Last week, a single laser shot sparked a fusion explosion from a peppercorn-size fuel capsule that produced eight times more energy than the facility had ever achieved: 1.35 megajoules (MJ)—roughly the kinetic energy of a car traveling at 160 kilometers per hour. That was also 70% of the energy of the laser pulse that triggered it, making it tantalizingly close to “ignition”: a fusion shot producing an excess of energy.

 “After many years at 3% of ignition, this is super exciting,” says Mark Herrmann, head of the fusion program at Lawrence Livermore National Laboratory, which operates NIF.

NIF’s latest shot “proves that a small amount of energy, imploding a small amount of mass, can get fusion. It’s a wonderful result for the field,” says physicist Michael Campbell, director of the Laboratory for Laser Energetics (LLE) at the University of Rochester.

“It’s a remarkable achievement,” adds plasma physicist Steven Rose, co-director of the Centre for Inertial Fusion Studies at Imperial College London. “It’s made me feel very cheerful. … It feels like a breakthrough.”

And it is none too soon, as years of slow progress have raised questions about whether laser-powered fusion has a practical future. Now, according to LLE Chief Scientist Riccardo Betti, researchers need to ask: “What is the maximum fusion yield you can get out of NIF? That’s the real question.”

Fusion, which powers stars, forces small atomic nuclei to meld together into larger ones, releasing large amounts of energy. Extremely hard to achieve on Earth because of the heat and pressure required to join nuclei, fusion continues to attract scientific and commercial interest because it promises copious energy, with little environmental impact.

With explosive new result, laser-powered fusion effort nears ‘ignition’, Daniel Clery, Science Magazine

Read more…

Argonne, Assemble...

8819569099?profile=RESIZE_584x

(Image by Shutterstock/muratart.)

Topics: Climate Change, Energy, Environment, Existentialism, Global Warming, Green Tech

Thankfully, we're not. Hat tip to Marvel, and Rotten Tomatoes.

Scientists aren’t superheroes. Or are they? Superheroes defend the defenseless and save humanity from any number of disasters, both natural and unnatural, often using powers of logic and some really hip techno-gadgets.

The Earth is in crisis and while it has its own mechanisms to fight back, it could use a helping hand. Earth could use a superhero.

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are stepping up and applying decades of expertise and research to combat some of Earth’s toughest foes, from waste and pollution to climate change. And they’ve assembled a cache of some of the world’s coolest technology for this crusade.

So, this Earth Day, we take a look at just a few of the ways Argonne’s scientist-superheroes are swooping in to keep Earth healthy and its citizens safe.

Predicting Earth’s future

What better way to save the planet than knowing what the future holds? Argonne and DOE are leaders in modeling Earth’s complex natural systems to help us keep tabs on the planet’s health. The best of these models can simulate how changes in these systems and our own actions might influence climate and ecosystems many years into the future. They give us a better understanding of the roles played by tropical rain forests, ice sheets, permafrost, and oceans in maintaining carbon levels and help us devise strategies for protecting them — ultimately, identifying how much carbon dioxide (CO2) we need to reduce from human activities and remove from the atmosphere to stabilize the planet’s temperature.

8 Things Argonne is Doing to Save the Earth, Argonne National Laboratory

Read more…

Colloidal Quantum Dots...

8621019874?profile=RESIZE_710x

FIG. 1. (a) Schematic of La Mer and Dinegar's model for the synthesis of monodispersed CQDs. (b) Representation of the apparatus employed for CQD synthesis. Reproduced with permission from Murray et al., Annu. Rev. Mater Res. 30(1), 545–610 (2000). Copyright 2000 Annual Reviews.

Topics: Energy, Materials Science, Nanotechnology, Quantum Mechanics, Solar Power

ABSTRACT
Solution-processed colloidal quantum dot (CQD) solar cells are lightweight, flexible, inexpensive, and can be spray-coated on various substrates. However, their power conversion efficiency is still insufficient for commercial applications. To further boost CQD solar cell efficiency, researchers need to better understand and control how charge carriers and excitons transport in CQD thin films, i.e., the CQD solar cell electrical parameters including carrier lifetime, diffusion length, diffusivity, mobility, drift length, trap state density, and doping density. These parameters play key roles in determining CQD thin film thickness and surface passivation ligands in CQD solar cell fabrication processes. To characterize these CQD solar cell parameters, researchers have mostly used transient techniques, such as short-circuit current/open-circuit voltage decay, photoconductance decay, and time-resolved photoluminescence. These transient techniques based on the time-dependent excess carrier density decay generally exhibit an exponential profile, but they differ in the signal collection physics and can only be used in some particular scenarios. Furthermore, photovoltaic characterization techniques are moving from contact to non-contact, from steady-state to dynamic, and from small-spot testing to large-area imaging; what are the challenges, limitations, and prospects? To answer these questions, this Tutorial, in the context of CQD thin film and solar cell characterization, looks at trends in characterization technique development by comparing various conventional techniques in meeting research and/or industrial demands. For a good physical understanding of material properties, the basic physics of CQD materials and devices are reviewed first, followed by a detailed discussion of various characterization techniques and their suitability for CQD photovoltaic devices.

Advanced characterization methods of carrier transport in quantum dot photovoltaic solar cells, Lilei Hu, Andreas Mandelis, Journal of Applied Physics

Read more…

Argonne, and STEM...

8171108500?profile=RESIZE_584x

Students and instructors wave bye to each other after the close of a virtual session of All About Energy. (Image by Argonne National Laboratory.)

Topics: Education, Energy, Research, STEM

Argonne Educational Programs and Outreach transitioned to virtual summer programming, ensuring that Argonne continues to build the next generation of STEM leaders.

At the U.S. Department of Energy’s (DOE) Argonne National Laboratory, scientists and educators have found new ways to balance their work with safety needs as the laboratory’s Educational Programs and Outreach Department successfully transitioned all of its summer programming to a virtual learning environment.

By connecting scientific and research divisions across the laboratory, Argonne was able to create multiple virtual programs, helping young people stay connected and engage with the laboratory’s science, technology, engineering and math (STEM) education opportunities.

“Providing STEM opportunities and a constant presence with our next generation of STEM professions during a time that is unsettling and turbulent for everyone, but especially our school age and university student populations, was our top priority.” — Meridith Bruozas, Educational Programs, and Outreach manager

“Argonne continues to adapt and lead impactful science during the ongoing pandemic, a strategy that includes strengthening the STEM pipeline with unique educational programs for future scientists and engineers,” said Argonne Director Paul Kearns. ​“For years, hundreds of students have pursued summer learning opportunities at Argonne that are not available anywhere else. I’m pleased that in 2020 our lab community came together to maintain these high-quality STEM experiences through a successful virtual program for next-generation researchers.”

Argonne provides STEM opportunities for more than 800 students during pandemic, Nathan Schmidt, Argonne National Laboratory

Read more…