Chemists could make ‘smart glass’ smarter by manipulating it at the nanoscale: Colorado State University

Chemists have devised a potentially major improvement to both the speed and durability of smart glass by providing a better understanding of how the glass works at the nanoscale.

An alternative nanoscale design for eco-friendly smart glass

Source: Colorado State University

“Smart glass,” an energy-efficiency product found in newer windows of cars, buildings and airplanes, slowly changes between transparent and tinted at the flip of a switch.

“Slowly” is the operative word; typical smart glass takes several minutes to reach its darkened state, and many cycles between light and dark tend to degrade the tinting quality over time. Colorado State University chemists have devised a potentially major improvement to both the speed and durability of smart glass by providing a better understanding of how the glass works at the nanoscale.

They offer an alternative nanoscale design for smart glass in new research published June 3 in Proceedings of the National Academy of Sciences. The project started as a grant-writing exercise for graduate student and first author R. Colby Evans, whose idea — and passion for the chemistry of color-changing materials — turned into an experiment involving two types of microscopy and enlisting several collaborators. Evans is advised by Justin Sambur, assistant professor in the Department of Chemistry, who is the paper’s senior author.

The smart glass that Evans and colleagues studied is “electrochromic,” which works by using a voltage to drive lithium ions into and out of thin, clear films of a material called tungsten oxide. “You can think of it as a battery you can see through,” Evans said. Typical tungsten-oxide smart glass panels take 7-12 minutes to transition between clear and tinted.

The researchers specifically studied electrochromic tungsten-oxide nanoparticles, which are 100 times smaller than the width of a human hair. Their experiments revealed that single nanoparticles, by themselves, tint four times faster than films of the same nanoparticles. That’s because interfaces between nanoparticles trap lithium ions, slowing down tinting behavior. Over time, these ion traps also degrade the material’s performance.

To support their claims, the researchers used bright field transmission microscopy to observe how tungsten-oxide nanoparticles absorb and scatter light. Making sample “smart glass,” they varied how much nanoparticle material they placed in their samples and watched how the tinting behaviors changed as more and more nanoparticles came into contact with each other. They then used scanning electron microscopy to obtain higher-resolution images of the length, width and spacing of the nanoparticles, so they could tell, for example, how many particles were clustered together, and how many were spread apart.

Based on their experimental findings, the authors proposed that the performance of smart glass could be improved by making a nanoparticle-based material with optimally spaced particles, to avoid ion-trapping interfaces.

Their imaging technique offers a new method for correlating nanoparticle structure and electrochromic properties; improvement of smart window performance is just one application that could result. Their approach could also guide applied research in batteries, fuel cells, capacitors and sensors.

“Thanks to Colby’s work, we have developed a new way to study chemical reactions in nanoparticles, and I expect that we will leverage this new tool to study underlying processes in a wide range of important energy technologies,” Sambur said.

The paper’s co-authors include Austin Ellingworth, a former Research Experience for Undergraduates student from Winona State University; Christina Cashen, a CSU chemistry graduate student; and Christopher R. Weinberger, a professor in CSU’s Department of Mechanical Engineering

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Story Source:

Materials provided by Colorado State University. Original written by Anne Manning. Note: Content may be edited for style and length.

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Journal Reference:

1. R. Colby Evans, Austin Ellingworth, Christina J. Cashen, Christopher R. Weinberger, Justin B. Sambur. Influence of single-nanoparticle electrochromic dynamics on the durability and speed of smart windows. Proceedings of the National Academy of Sciences, 2019; 201822007 DOI: 10.1073/pnas.1822007116

 

Colorado State University. “Chemists could make ‘smart glass’ smarter by manipulating it at the nanoscale: An alternative nanoscale design for eco-friendly smart glass.” ScienceDaily. ScienceDaily, 4 June 2019. <www.sciencedaily.com/releases/2019/06/190604131210.htm>.

The Future Of Energy Isn’t Fossil Fuels Or Renewables, It’s Nuclear Fusion (Really?)

 

Colorado State University scientists, using a compact but powerful laser to heat arrays of ordered nanowires, have demonstrated micro-scale nuclear fusion in the lab.

Let’s pretend, for a moment, that the climate doesn’t matter. That we’re completely ignoring the connection between carbon dioxide, the Earth’s atmosphere, the greenhouse effect, global temperatures, ocean acidification, and sea-level rise. From a long-term point of view, we’d still need to plan for our energy future. Fossil fuels, which make up by far the majority of world-wide power today, are an abundant but fundamentally limited resource. Renewable sources like wind, solar, and hydroelectric power have different limitations: they’re inconsistent. There is a long-term solution, though, that overcomes all of these problems: nuclear fusion.

Even the most advanced chemical reactions, like combusting thermite, shown here, generate about a million times less energy per unit mass compared to a nuclear reaction.NIKTHESTUNNED OF WIKIPEDIA

It might seem that the fossil fuel problem is obvious: we cannot simply generate more coal, oil, or natural gas when our present supplies run out. We’ve been burning pretty much every drop we can get our hands on for going on three centuries now, and this problem is going to get worse. Even though we have hundreds of years more before we’re all out, the amount isn’t limitless. There are legitimate, non-warming-related environmental concerns, too.

Even if we ignored the CO2-global climate change problem, fossil fuels are limited in the amount Earth contains, and also extracting, transporting, refining and burning them causes large amounts of pollution.GREG GOEBEL

The burning of fossil fuels generates pollution, since these carbon-based fuel sources contain a lot more than just carbon and hydrogen in their chemical makeup, and burning them (to generate energy) also burns all the impurities, releasing them into the air. In addition, the refining and/or extraction process is dirty, dangerous and can pollute the water table and entire bodies of water, like rivers and lakes.

Wind farms, like many other sources of renewable energy, are dependent on the environment in an inconsistent, uncontrollable way.WINCHELL JOSHUA, U.S. FISH AND WILDLIFE SERVICE

On the other hand, renewable energy sources are inconsistent, even at their best. Try powering your grid during dry, overcast (or overnight), and drought-riddled times, and you’re doomed to failure. The sheer magnitude of the battery storage capabilities required to power even a single city during insufficient energy-generation conditions is daunting. Simultaneously, the pollution effects associated with creating solar panels, manufacturing wind or hydroelectric turbines, and (especially) with creating the materials needed to store large amounts of energy are tremendous as well. Even what’s touted as “green energy” isn’t devoid of drawbacks.

Reactor nuclear experimental RA-6 (Republica Argentina 6), en marcha. The blue glow is known as Cherenkov radiation, from the faster-than-light-in-water particles emitted.CENTRO ATOMICO BARILOCHE, VIA PIECK DARÍO

But there is always the nuclear option. That word itself is enough to elicit strong reactions from many people: nuclear. The idea of nuclear bombs, of radioactive fallout, of meltdowns, and of disasters like Chernobyl, Three Mile Island, and Fukushima — not to mention residual fear from the Cold War — make “NIMBY” the default position for a large number of people. And that’s a fear that’s not wholly without foundation, when it comes to nuclear fission. But fission isn’t the only game in town.

Watch the Video: Nuclear Bomb – The First H Bomb Test

 

In 1952, the United States detonated Ivy Mike, the first demonstrated nuclear fusion reaction to occur on Earth. Whereas nuclear fission involves taking heavy, unstable (and already radioactive) elements like Thorium, Uranium or Plutonium, initiating a reaction that causes them to split apart into smaller, also radioactive components that release energy, nothing involved in fusion is radioactive at all. The reactants are light, stable elements like isotopes of hydrogen, helium or lithium; the products are also light and stable, like helium, lithium, beryllium or boron.

 

The proton-proton chain responsible for producing the vast majority of the Sun’s power is an example of nuclear fusion.BORB / WIKIMEDIA COMMONS

So far, fission has taken place in either a runaway or controlled environment, rushing past the breakeven point (where the energy output is greater than the input) with ease, while fusion has never reached the breakeven point in a controlled setting. But four main possibilities have emerged. 

1. Inertial Confinement Fusion. We take a pellet of hydrogen — the fuel for this fusion reaction — and compress it using many lasers that surround the pellet. The compression causes the hydrogen nuclei to fuse into heavier elements like helium, and releases a burst of energy.
2. Magnetic Confinement Fusion. Instead of using mechanical compression, why not let the electromagnetic force do the confining work? Magnetic fields confine a superheated plasma of fusible material, and nuclear fusion reactions occur inside a Tokamak-style reactor.
3. Magnetized Target Fusion. In MTF, a superheated plasma is created and confined magnetically, but pistons surrounding it compress the fuel inside, creating a burst of nuclear fusion in the interior.
4. Subcritical Fusion. Instead of trying to trigger fusion with heat or inertia, subcritical fusion uses a subcritical fission reaction — with zero chance of a meltdown — to power a fusion reaction.

The first two have been researched for decades now, and are the closest to the coveted breakeven point. But the latter two are new, with the last one gaining many new investors and start-ups this decade.

The preamplifiers of the National Ignition Facility are the first step in increasing the energy of laser beams as they make their way toward the target chamber. NIF recently achieved a 500 terawatt shot – 1,000 times more power than the United States uses at any instant in time.DAMIEN JEMISON/LLNL

Even if you reject climate science, the problem of powering the world, and doing so in a sustainable, pollution-free way, is one of the most daunting long-term ones facing humanity. Nuclear fusion as a power source has never been given the necessary funding to develop it to fruition, but it’s the one physically possible solution to our energy needs with no obvious downsides. If we can get the idea that “nuclear” means “potential for disaster” out of our heads, people from all across the political spectrum just might be able to come together and solve our energy and environmental needs in one single blow. If you think the government should be investing in science with national and global payoffs, you can’t do better than the ROI that would come from successful fusion research. The physics works out beautifully; we now just need the investment and the engineering breakthroughs.

Special Contribution to Forbes by: Ethan Siegel Senior Contributor

Creating a Life-Saving, Blood-Repellent Super Material – Revolutionizing Medical Implants: Colorado State University

Briefly

• Biomedical engineers and materials scientists have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water.
• The result is a surface that completely repels any liquid with which it would come in contact – a material that could revolutionize medical implants.

GOODBYE REJECTION

Implanted medical devices like stents, catheters, and titanium rods are essential, life-saving tools for patients around the world. Still, having a foreign object in the human body does pose its own risks – chiefly, having the body reject the object or increasing the risk of dangerous blood clots. A new collaboration between two distinct scientific disciplines is working toward making those risks a concern of the past.

Biomedical engineers and materials scientists from Colorado State University (CSU) have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water. The titanium is essentially studded with nanoscale tubes treated with a non-stick chemical. The result is a surface that completely repels any liquid with which it would come in contact. The team’s findings are published in Advanced Healthcare Materials.

Fluorinated nanotubes provided the best superhemophobic surfaces in the CSU researchers’ experiments. Credit: Kota lab/Colorado State University

AN END TO CLOTTING

In cases where a body does reject a medical implant, the patient’s immune system detects the foreign object and mounts a defense against it, which can lead to serious inflammation and other complications. The real trick to the team’s surface is that the body doesn’t even recognize that it’s there. According to Arun Kota, assistant professor of mechanical engineering and biomedical engineering at CSU, “We are taking a material that blood hates to come in contact with, in order to make it compatible with blood.”

Regarding clotting, patients with medical implants often need to stay on a regimen of blood-thinning drugs to decrease the risk. However, blood thinners are not guaranteed to work, and they also carry the risk of leading to excessive bleeding due to the prevention of even beneficial clotting near wounds. As Ketul Popat, associate professor of mechanical engineering and biomedical engineering at CSU explains, “The reason blood clots is because it finds cells in the blood to go to and attach.” He continues, “if we can design materials where blood barely contacts the surface, there is virtually no chance of clotting.”

This material is only in its earliest stages of development. Should the team’s findings hold up to further scrutinization, these life-saving medical devices could be given an unprecedented boost in safety.

References: Advanced Healthcare Materials. 

Kota Labs Research Group: Colorado State University

NREL’s Keith Emery Awarded Prestigious Cherry Award: Efficiency of Solar Cells

Top PV award goes to researcher who brought credibility to testing of solar cells and modules

June 19, 2013

An engineer from the Energy Department’s National Renewable Energy Laboratory (NREL) whose testing and characterization laboratory brings credibility to the measurement of efficiency of solar cells and modules has been awarded the prestigious William R. Cherry Award by the Institute of Electrical and Electronics Engineers (IEEE).

Keith Emery, a principal scientist at NREL, received the award at the 39th IEEE’s Photovoltaic Specialists Conference in Tampa Bay.

“Accredited measurements from Emery’s laboratories are considered the gold standard by the U.S. and international PV communities,” said NREL colleague Pete Sheldon, Deputy Director of the National Center for Photovoltaics on the NREL campus in Golden, CO. “His leadership in the development of cell and module performance measurement techniques and the development of standards, has set the foundation for the PV community for the last 25 years.”

The award is named in honor of William R. Cherry, a founder of the photovoltaic community. In the 1950s, Cherry was instrumental in establishing solar cells as the ideal power source for space satellites and for recognizing, advocating and nurturing the use of photovoltaic systems for terrestrial applications. The purpose of the award is to recognize an individual engineer or scientist who devoted a part of their professional life to the advancement of the science and technology of photovoltaic energy conversion.

Emery is the third consecutive Cherry Award winner from NREL. In 2011, Jerry Olson, who developed the multi-junction solar cell, won the award. Last year, Sarah Kurtz, who helped Olson develop the multi-junction cell and now is a global leader in solar module reliability, won the award. Three other NREL scientists won the Cherry Award previously – Paul Rappaport (1980), Larry Kazmerski (1993), and Tim Coutts (2005).

Emery says he was floored by the award, considered among the top one or two annual awards globally in the photovoltaic community.

Others aren’t surprised, citing his work to bring iron-clad certainty to the claims made by solar companies about the efficiency of their photovoltaic cells and modules – not to mention the 320 scientific publications he was able to write.

He has spent his career building the capabilities of that testing and characterization lab, making it one of a handful of premier measurement labs in the world – and the only place in the United States that calibrates primary terrestrial standards for solar-cell characterization.

Unbelievable claims of high efficiency would be out in the literature without any independent verification. “We decided that independent verification was critical for credibility,” Emery said.

“We have to thank DOE for this,” Emery said. “They’ve funded it. We’ve been able to offer the service to all terrestrial PV groups in the U.S. from national labs to universities to low-budget startups. They all get the same quality of service.”

The readily available service is so researchers and companies have equal access to the resources needed for independent efficiency measurement, he said. “We provide the same playing field for everyone.”

Emery spent the first 25 years of his life in Lansing, Michigan, attending public schools, then going on to Lansing Community College and Michigan State University where he earned his bachelor’s and master’s degrees. From there he went to Colorado State University to fabricate and test ITO on silicon solar cells, and then was hired at NREL. At NREL, in the 1980s, Emery developed the test equipment and put together the data-acquisition system for characterizing and measuring the efficiency of solar cells.

Emery gives much of the credit to the colleagues who work in his lab and who have on average about 16 years at NREL. “Take my team away and I wouldn’t have gotten this award – it’s that simple.”

Sheldon said Emery’s work “brings scientific credibility to the entire photovoltaic field, ensuring global uniformity in cell and module measurements. His getting the award is certainly well deserved.”

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by the Alliance for Sustainable Energy, LLC.

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