Posts belonging to Category green power

Carbon NanoTubes Solar Cells Twice More Efficient

Lighter, more flexible, and cheaper than conventional solar-cell materials, carbon nanotubes (CNTs) have long shown promise for photovoltaics. But research stalled when CNTs proved to be inefficient, converting far less sunlight into power than other methods.

Now a research team led by Mark Hersam, professor of materials science and engineering at the McCormick School of Engineering, Northwestern University, has created a new type of CNT solar cell that is twice as efficient as its predecessors. It is also the first CNT solar cell to have its performance certified by the National Renewable Energy Laboratory.

solar cells
The field had been hovering around 1 percent efficiency for about a decade; it had really plateaued,.” Hersam said. “But we’ve been able to increase it to over 3 percent. It’s a significant jump
The problem is that each nanotube chirality only absorbs a narrow range of optical wavelengths,” Hersam said. “If you make a solar cell out of a single chirality carbon nanotube, you basically throw away most of the solar light.”

Hersam’s team made a mixture of polychiral, or multiple chirality, semiconducting nanotubes. This maximized the amount of photocurrent produced by absorbing a broader range of solar-spectrum wavelengths. The cells significantly absorbed near-infrared wavelengths, a range that has been inaccessible to many leading thin-film technologies.
The research is described in the article “Polychiral Semiconducting Carbon Nanotube-Fullerene Solar Cells” in the August 7 issue of Nano Letters.

Liver Cancer: Hope Is Coming From Plants

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-associated death worldwide. Also called malignant hepatoma, HCC is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitis infection (hepatitis B or C) or cirrhosis (alcoholism being the most common cause of hepatic cirrhosis). These regrettably poor prognoses are due to the difficulty in treating this cancer using conventional chemotherapeutic drugs such as doxorubicin, epirubicin, cisplatin, 5-fluorouracil, etoposide or combinations therein. This may be attributed to that the conventional medicines are not able to reach in a sufficient concentration in the liver tumor cells at levels that are not harmful to the rest of the body.

Now a team of scientists, led by Prof. Taeghwan Hyeon at the Institute for Basic Science (IBS)/Seoul National University and Prof. Kam Man Hui at the National Cancer Center Singapore, has screened a library containing hundreds of natural products against a panel of HCC cells to search a better drug candidate. The screen uncovered a compound named triptolide, a traditional Chinese medicine isolated from the thunder god vine (Tripterygium wilfordii (Latin) or lei gong teng (Chinese)) which was found to be far more potent than current therapies. Studies from other researchers corroborate the findings as triptolide has also found to be very effective against several other malignant cancers including; pancreatic, neuroblastoma and cholangiocarcinoma. However this excitement was tempered when the drug was administered to mice as the increased potency was coupled with increased toxicity as well. Prof. Hyeon et al. endeavoured to alleviate the toxic burden by increasing the specific delivery of the drug to the tumor using a nanoformulation. The designed formulation was a pH-sensitive nanogel coated with the nucleotide precursor, folate.

Defect-Free Graphene For Electric Car Batteries

Researchers at from Korea’s KAIST institute developed a new method to fabricate defect-free graphene. Using this graphene, they developed a promising high-performance anode for Li-Ion batteries. Graphene has already been demonstrated to be useful in Li-ion batteries, despite the fact that the graphene used often contains defects. Large-scale fabrication of graphene that is chemically pure, structurally uniform, and size-tunable for battery applications has so far remained elusive. Now in a new study, scientists have developed a method to fabricate defect-free graphene (df-G) without any trace of structural damage. Wrapping a large sheet of negatively charged df-G around a positively charged Co3O4 creates a very promising anode for high-performance Li-ion batteries.
electric car

The research groups of Professor Junk-Ki Park and Professor Hee-Tak Kim from Korea Advanced Institute of Science and Technology (KAIST) and Professor Yong-Min Lee’s research group from Hanbat National University, all in Daejeon, South Korea, have published their paper on the new fabrication method in a recent issue of Nano Letters.


Sunblocks Are Toxic For Aquatic Life

The sweet and salty aroma of sunscreen and seawater signals a relaxing trip to the shore. But scientists from the Université Aix-Marseille, France, are now reporting that the idyllic beach vacation comes with an environmental hitch. When certain sunblock ingredients wash off skin and into the sea, they can become toxic to some of the ocean’s tiniest inhabitants, which are the main course for many other marine animals.

Antonio Tovar-Sanchez and David Sánchez-Quiles (IMERAUniversité Aix Marseille) point out that other than staying indoors, slathering on sunscreen is currently the best way to protect skin from the sun’s harmful rays. But when sunbathers splash into the ocean to cool off, some of their lotions and creams get rinsed into the water. The problem is that titanium dioxide and zinc oxide nanoparticles, which are common ingredients in sunblock, can react with ultraviolet light from the sun and form new compounds, such as hydrogen peroxide, that could be toxic. High amounts of hydrogen peroxide can harm phytoplankton, the microscopic algae that feed everything from small fish to shrimp to whales. The scientists wanted to figure out just how serious of an impact beachgoers could be having on life in coastal waters.

To investigate the matter, they hit the beach. They went to Majorca Island’s Palmira beach on the Mediterranean along with about 10,000 beachgoers, a small portion of the more than 200 million tourists that flock to Mediterranean shores every year. Based on lab tests, seawater sampling and tourism data, the researchers concluded that titanium dioxide from sunblock was largely responsible for a dramatic summertime spike in hydrogen peroxide levels in coastal waters — with potentially dangerous consequences for aquatic life.


Computer: Nano Optical Cables To Replace Copper

Electrical engineers design nano-optical cables that could replace copper wiring on computer chips. The invention of fibre optics revolutionized the way we share information, allowing us to transmit data at volumes and speeds we’d only previously dreamed of. Now, electrical engineering researchers at the University of Alberta are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips. This could result in radical increases in computing speeds and reduced energy use by electronic devices. A new step towards the nanocomputer era.

We’re already transmitting data from continent to continent using fibre optics, but the killer application is using this inside chips for interconnect—that is the Holy Grail,” says Zubin Jacob, an electrical engineering professosr leading the research. “What we’ve done is come up with a fundamentally new way of confining light to the nano scale.
At present, the diameter of fibre optic cables is limited to about one thousandth of a millimetre. Cables designed by graduate student Saman Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on computer chips. (To put that into perspective, a dime is about one millimetre thick.)


Less Than One Percent of Nanotubes Pass The Pulmonary Barrier

Having perfected an isotope labeling method allowing extremely sensitive detection
of carbon nanotubes in living organisms, CEA and CNRS  researchers have looked at what happens to nanotubes after one year inside
an animal.
Studies in mice revealed that a very small  percentage (0.75%of  the  initial  quantity of  nanotubes  inhaled  crossed  the pulmonary epithelial barrier  and translocated to the  liverspleen,  and  bone  marrow.

Although  these  results  cannot  be  extrapolated  to  humans,  this  work
highlights  the importance  of  developing  ultrasensitive  methods  for 
  the  behavior of nanoparticles in animals.


Carbon  nanotubes  are  highly  specific  nanoparticles  with  outstanding mechanical and electronic properties that make them suitable for use in a wide
range of applications, from structural materials to certain electronic components.
Their many present and future uses explain why research teams around the world
are now focusing on their impact on human health and the environment.

The findings  have been published in the journal ACSNano.
CEA and CNRS are located in Paris, France.


Cigarette Butts Better Than Graphene To Store Energy

A group of scientists from South Korea have converted cigarette butts into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles and wind turbines to store energy. Presenting their findings today, 5 August 2014, in IOP Publishing’s journal Nanotechnology, the researchers have demonstrated the material’s superior performance compared to commercially available carbon, graphene and carbon nanotubes. It is hoped the material can be used to coat the electrodes of supercapacitors electrochemical components that can store extremely large amounts of electrical energy – while also offering a solution to the growing environmental problem caused by used cigarette filters. It is estimated that as many as 5.6 trillion cigarette butts (equivalent to 766 571 metric tons), are deposited into the environment worldwide every year.

cigarette buttsOur study has shown that used cigarette filters can be transformed into a high-performing carbon-based material using a simple one-step process, which simultaneously offers a green solution to meeting the energy demands of society“, said co-author of the study Professor Jongheop Yi, from Seoul National University. “Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used cigarette filters that are disposed of into the environment each year; our method is just one way of achieving this.”


How To Turn ANYTHING Into A Solar Panel

A team of scientists at the University of Sheffield  (U.K.) is the first to fabricate perovskite solar cells using a spray-painting process – a discovery that could help cut the cost of solar electricity.  
Efficient organometal halide perovskite based photovoltaics were first demonstrated in 2012. They are now a very promising new material for solar cells as they combine high efficiency with low materials costs. The spray-painting process wastes very little of the perovskite material and can be scaled to high volume manufacturing – similar to applying paint to cars and graphic printing.

perovskite solar panel

Remarkably, this class of material offers the potential to combine the high performance of mature solar cell technologies with the low embedded energy costs of production of organic photovoltaics“, said  lead researcher Professor David Lidzey.” While most solar cells are manufactured using energy intensive materials like silicon, perovskites, by comparison, requires much less energy to make. By spray-painting the perovskite layer in air the team hope the overall energy used to make a solar cell can be reduced further”. “The best certified efficiencies from organic solar cells are around 10 per cent. “Perovskite cells now have efficiencies of up to 19 per cent. This is not so far behind that of silicon at 25 per cent – the material that dominates the world-wide solar market” , he added.


Thousand Miles Range Electric Car

Imagine owning an electric vehicle that can travel 1,000 miles (1610 km) before needing to be recharged. Now imagine that same vehicle being able to be charged to capacity in less than 5 minutes. Or, imagine owning a smart phone that only needs to be charged once a week and that charge taking less than one minute. Now a little start-up company, HyCarb, led by Sigrid Cottrell, is working to allow that imaginary world to come true. Hyper efficient supercapacitors & batteries are designed by utilizing Nanotechnology and nano-super structure technologies in order to power the next generation of consumer electronics, electric vehicles, military equipment and medical devices. They function as both a battery and a supercapacitor. They provide the long, steady power output comparable to a conventional battery, as well as a supercapacitor’s quick burst of high energy.

2014 Renault

HyCarb, Inc. is a Florida-based, for-profit, small business, headquartered at the UCF Business Incubator in Research Park. The team of researchers has already filed 3 patents protecting the system of processes required to generate a Hy-Carb supercapictor battery develops nanostructured materials using high-throughput combinatorial electrochemical methods and other proprietary techniques.

Nano-engineered battery/super capacitor is lightweight, ultra thin, completely flexible, and geared toward meeting the trickiest design and energy requirements of tomorrow’s gadgets, electric vehicles, implantable medical equipment and any number of other applications. aligned carbon nanotubes, which will give the device its black color. The nanotubes act as electrodes and allow the storage devices to conduct electricity.
The creation of this unique nano-composite surface drew from a diverse pool of disciplines, requiring expertise in materials science, energy storage, and chemistry. Along with use in small handheld electronics, the batteries’ lighter weight could make them ideal for use in automobiles, aircraft, and even boats. The Hy-Carb Supercapicitor could also be manufactured into different shapes, such as a car door, which would enable important new engineering innovations. .

Electronics Enter The Nanocomputer Age

An UAlberta research team is developing atom-scale, ultra-low-power computing devices to replace transistor circuits. In the drive to get small, Robert Wolkow and his lab at the University of Alberta are taking giant steps forward. The digital age has resulted in a succession of smaller, cleaner and less power-hungry technologies since the days the personal computer fit atop a desk, replacing mainframe models that once filled entire rooms. Desktop PCs have since given way to smaller and smaller laptops, smartphones and devices that most of us carry around in our pockets. But as Wolkow points out, this technological shrinkage can only go so far when using traditional transistor-based integrated circuits. That’s why he and his research team are aiming to build entirely new technologies at the atomic scale.
Our ultimate goal is to make ultra-low-power electronics because that’s what is most demanded by the world right now,” said Wolkow, the iCORE Chair in Nanoscale Information and Communications Technology in the Faculty of Science. “We are approaching some fundamental limits that will stop the 30-year-long drive to make things faster, cheaper, better and smaller; this will come to an end soon. “An entirely new method of computing will be necessary.”

Wolkow and his team in the U of A’s physics department and the National Institute for Nanotechnology are working to engineer atomically precise technologies that have practical, real-world applications. His lab already made its way into the Guinness Book of World Records for inventing the world’s sharpest object—a microscope tip just one atom wide at its end.