Nanostructures Trap Photons in Ultrathin Solar Cells
In the quest to make sun power more competitive, researchers are designing ultrathin solar cells that cut material costs. At the same time, they’re keeping these thin cells efficient by sculpting their surfaces with photovoltaic nanostructures that behave like a molecular hall of mirrors.
“We want to make sure light spends more quality time inside a solar cell,” says Mark Brongersma, a professor of materials science and engineering at Stanford and co-author of a review article in Nature Materials.
Americans generate nearly 300 million scrap tires every year, according to the EPA. Historically, these worn tires often end up in landfills or, when illegally dumped, become breeding grounds for disease-carrying mosquitoes and rodents. They also pose a potential fire hazard.
In recent years, however, interest has been growing in finding new, beneficial and environmentally friendly uses for discarded tires.
Whether it’s recycling, composting or buying environmentally friendly products, guilt can be a strong motivator — not just on Earth Day.
Now, research from Concordia Univ.’s John Molson School of Business published in the Journal of Business Ethics, proves that even just asking ourselves, or predicting, whether we will engage in sustainable shopping behavior can increase the likelihood of following through — especially when there’s an audience.
You can trace the genetic makeup of most corn grown in the U.S., and in many other places around the world, to Hawaii.
The tiny island state, located 2,500 miles from the nearest continent, is so critical to the nation’s modern corn-growing business that the industry’s leading companies all have farms there, growing new varieties genetically engineered for desirable traits like insect and drought resistance. But these same farms have become a flash point in a spreading debate over genetic engineering in agriculture.
Biofuels made from the leftovers of harvested corn plants are worse than gasoline for global warming in the short term, a study shows, challenging the Obama administration’s conclusions that they are a much cleaner oil alternative and will help combat climate change.
A $500,000 study paid for by the federal government and released this week in Nature Climate Change concludes that biofuels made with corn residue release 7 percent more greenhouse gases in the early years compared with conventional gasoline.
The proportion of land used to cultivate shade grown coffee, relative to the total land area of coffee cultivation, has fallen by nearly 20 percent globally since 1996, according to a new study by scientists from Univ. of Texas at Austin and five other institutions.
The study’s authors say the global shift toward a more intensive style of coffee farming is probably having a negative effect on the environment, communities and individual farmers.
Since the discovery of the Antarctic ozone hole, scientists, policymakers, and the public have wondered whether we might someday see a similarly extreme depletion of ozone over the Arctic.
But a new MIT study finds some cause for optimism: ozone levels in the Arctic haven’t yet sunk to the extreme lows seen in Antarctica, in part because international efforts to limit ozone-depleting chemicals have been successful.
Think of the pressure change you feel when an elevator zips you up multiple floors in a tall building. Imagine how you’d feel if that elevator carried you all the way up to the top of Mt. Everest — in the blink of an eye.
That’s similar to what many fish experience when they travel through the turbulent waters near a dam. For some, the change in pressure is simply too big, too fast and they die or are seriously injured. In an article in Fisheries, ecologists from the Department of Energy’s Pacific Northwest National Laboratory and colleagues from around the world explore ways to protect fish from the phenomenon, known as barotrauma.
Wearable computers or devices have been hailed as the next generation of mobile electronic gadgets, from smart watches, to smart glasses to smart pacemakers. For electronics to be worn by a user, they must be light, flexible and equipped with a power source, which could be a portable, long-lasting battery or no battery at all but a generator. How to supply power in a stable and reliable manner is one of the most critical issues to commercialize wearable devices.
A team of The Korea Advanced Institute of Science and Technology (KAIST) researchers headed by Byung Cho, a professor of electrical engineering, proposed a solution to this problem by developing a glass fabric-based thermoelectric (TE) generator that is extremely light and flexible and produces electricity from the heat of the human body. In fact, it is so flexible that the allowable bending radius of the generator is as low as 20 mm. There are no changes in performance even if the generator bends upward and downward for up to 120 cycles.
Filter Recover 80 Percent of Gold in Cell Phone Scrap
Cell phone scrap can contain precious metals, such as gold and copper. VTT Technical Research Centre of Finland has developed a biological filter made of mushroom mycelium mats enabling recovery of as much as 80 percent of the gold in electronic scrap. Extraction of copper from circuit board waste, on the other hand, can be enhanced significantly by floating the crushed and sieved material.
Although research into the biological methods is active, these are still rarely used in metal recovery chains. In a European “Value from Waste” project, VTT developed both biological and mechanical pre-treatment methods for more efficient recovery of precious metals from electronic waste. Other methods developed by researchers included recovery of gold from dissolved materials by biosorption and extraction, using as few harmful chemicals as possible.
Porous silicon manufactured in a bottom up procedure using solar energy can be used to generate hydrogen from water, according to a team of Penn State mechanical engineers, who also see applications for batteries, biosensors and optical electronics as outlets for this new material.
"The surface area of this porous silicon is high," says Donghai Wang, assistant professor of mechanical engineering. "It is widely used and has a lot of applications."
Process Turns Cellulose into Energy Storage Devices
Based on a fundamental chemical discovery by scientists at Oregon State Univ., it appears that trees may soon play a major role in making high-tech energy storage devices.
OSU chemists have found that cellulose – the most abundant organic polymer on Earth and a key component of trees – can be heated in a furnace in the presence of ammonia, and turned into the building blocks for supercapacitors.
Solar Cells More Efficient When Molecules Face Each Other
New research from North Carolina State Univ. and UNC-Chapel Hill reveals that energy is transferred more efficiently inside of complex, three-dimensional organic solar cells when the donor molecules align face-on, rather than edge-on, relative to the acceptor. This find may aid in the design and manufacture of more efficient and economically viable organic solar cell technology.
Organic solar cell efficiency depends upon the ease with which an exciton – the energy particle created when light is absorbed by the material – can find the interface between the donor and acceptor molecules within the cell. At the interface, the exciton is converted into charges that travel to the electrodes, creating power. While this sounds straightforward enough, the reality is that molecules within the donor and acceptor layers can mix, cluster into domains or both, leading to variances in domain purity and size which can affect the power conversion process. Moreover, the donor and acceptor molecules have different shapes, and the way they are oriented relative to one another matters. This complexity makes it very difficult to measure the important characteristics of their structure.
Okinawa Institute of Science and Technology Graduate Univ.’s Energy Materials and Surface Sciences Unit has made a surprising discovery about the degradation of solar cells that could help pave the way to creating a longer lifetime for these cells. Key factors for creating cost-efficient solar cells to compete with conventional energy sources like fossil fuels include fabrication cost, efficiency and lifetime of the cells. Prof. Yabing Qi and members of his unit have investigated the cause of degradation of a high efficiency solar cell. This discovery, published in The Journal of Physical Chemistry Letters, can help move various forms of solar cell technology forward now that researchers know what is causing degradation and shortening the lifespan.