World Record Solar Cell With 44.7% Efficiency

Sep. 23, 2013 — The Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin jointly announced today having achieved a new world record for the conversion of sunlight into electricity using a new solar cell structure with four solar subcells. Surpassing competition after only over three years of research, and entering the roadmap at world class level, a new record efficiency of 44.7% was measured at a concentration of 297 suns. This indicates that 44.7% of the solar spectrum's energy, from ultraviolet through to the infrared, is converted into electrical energy. This is a major step towards reducing further the costs of solar electricity and continues to pave the way to the 50% efficiency roadmap.

World record solar cell with 44.7% efficiency, made up of four solar subcells based on III-V compound semiconductors for use in concentrator photovoltaics. (Credit: © Fraunhofer ISE)

Back in May 2013, the German-French team of Fraunhofer ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin had already announced a solar cell with 43.6% efficiency. Building on this result, further intensive research work and optimization steps led to the present efficiency of 44.7%.
These solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants in sun-rich locations. The terrestrial use of so-called III-V multi-junction solar cells, which originally came from space technology, has prevailed to realize highest efficiencies for the conversion of sunlight to electricity. In this multi-junction solar cell, several cells made out of different III-V semiconductor materials are stacked on top of each other. The single subcells absorb different wavelength ranges of the solar spectrum.
"We are incredibly proud of our team which has been working now for three years on this four-junction solar cell," says Frank Dimroth, Department Head and Project Leader in charge of this development work at Fraunhofer ISE. "This four-junction solar cell contains our collected expertise in this area over many years. Besides improved materials and optimization of the structure, a new procedure called wafer bonding plays a central role. With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells."
"This world record increasing our efficiency level by more than 1 point in less than 4 months demonstrates the extreme potential of our four-junction solar cell design which relies on Soitec bonding techniques and expertise," says André-Jacques Auberton-Hervé, Soitec's Chairman and CEO. "It confirms the acceleration of the roadmap towards higher efficiencies which represents a key contributor to competitiveness of our own CPV systems. We are very proud of this achievement, a demonstration of a very successful collaboration."
"This new record value reinforces the credibility of the direct semiconductor bonding approaches that is developed in the frame of our collaboration with Soitec and Fraunhofer ISE. We are very proud of this new result, confirming the broad path that exists in solar technologies for advanced III-V semiconductor processing," said Leti CEO Laurent Malier. Concentrator modules are produced by Soitec (started in 2005 under the name Concentrix Solar, a spin-off of Fraunhofer ISE). This particularly efficient technology is employed in solar power plants located in sun-rich regions with a high percentage of direct radiation. Presently Soitec has CPV installations in 18 different countries including Italy, France, South Africa and California.

Animated videos introduce stem cell science in one-minute bursts

StemCellShorts – created by young Canadian researchers – are narrated by renowned scientists            

Two Canadian researchers with a passion for animation and the communication of science have created a series of one-minute videos to introduce basic concepts in stem cell research.
The first of three – What is a stem cell? – premieres today on Signals, the official blog of the Stem Cell Network, which helped fund the videos, and the Centre for Commercialization of Regenerative Medicine.

Ben Paylor

Mike Long, PhD

The videos are the brainchild of Ben Paylor , a PhD candidate in Experimental Medicine at the University of British Columbia, and Dr. Mike Long, a post-doctoral fellow at the University of Toronto, who pitched the idea for the video series through a Public Outreach Award offered by the Stem Cell Network. They channeled the $5,000 in seed funding from the award through their Vancouver-based animation studio, InfoShots, engaging award-winning animator David Murawsky and Emmy-nominated composer James Wallace to create the animations and music for the films.
InfoShots, which they founded in 2011, specializes in explaining complex topics in simple terms. Current projects including animations that explain scientific papers, grants and the research of individual labs.

Narrated by the 'father of stem cell research'

Jim Till, PhD

To give the videos credibility and make an impact in the scientific community, they worked with the Stem Cell Network to enlist world-renowned stem cell scientists to narrate the videos. "Animation is an excellent medium for explaining complex topics in a very simple and engaging manner," said Paylor, an 2012-13 Action Canada fellow. "And being able to secure such prestigious narrators … was the icing on the cake."
The first video features the voice of Dr. Jim Till, who, along with Dr. Ernest McCulloch, first identified stem cells from bone marrow in 1961.Their description of stem cell characteristics became the foundation of the field of stem cellresearch. These concepts that are revealed in the first video which is targeted at youth of high-school age and older.
"I felt that it was important to contribute to What is a stem cell? because of the fortuitous involvement of Dr. Ernest McCulloch and myself in what turned out to be the foundation of a new field of experimental stem cell research," said Dr. Till.
He said he hoped the authenticity of the scientists' voices on the videos would help make the films more appealing to young people.

Communicating Science

Elsevier Connect's Communicating Science feature deals with all aspects of science communication, including creative ways researchers are presenting science to reach a broader audience. If you have a project or story you would like to present on Elsevier Connect, please submit your idea to Editor-in-Chief Alison Bert: ECEditor@elsevier.com.

The remaining two videos are "What is an embryonic stem cell?" narrated by Dr. Janet Rossant, Chief of Research at SickKids Hospital of the University of Toronto, and "What is an induced pluripotent stem cell?" narrated by Dr. Mick Bhatia, Director of the McMaster University Stem Cell and Cancer Research Institute in Hamilton, Ontario.
They will be posted on the Signals Blog on October 11 and October 25 respectively.
In addition, the world screening premiere will be held at the 2013 Till & McCulloch Meetings October 24 in Banff, Alberta.
All videos will be hosted on the Stem Cell Network's vimeo channel: vimeo.com/stemcellnetwork.
For Paylor and Long, the work is far from complete. They recently received a second Public Outreach Award and matching funds from the Canadian Stem Cell Foundation to produce five more videos, which will be released in the spring.

The Stem Cell Network and Public Outreach Award

The Stem Cell Network, established in 2001, brings together more than 100 leading cientists, clinicians, engineers and ethicists from universities and hospitals across Canada. The Network supports cutting-edge projects that translate research discoveries into new and better treatments for millions of patients in Canada and around the world.
Hosted by the University of Ottawa, the Stem Cell Network is one of Canada's Networks of Centres of Excellence funded through Industry Canada and its three granting councils.
The Stem Cell Network's Public Outreach Award supports activities that communicate stem cell science, policy or ethics to targeted public audiences in Canada and abroad. The award enables Stem Cell Network members and trainees to gain access to development and production funding for the creation of materials required as part of these activities.

The Author

Lisa Willemse

Lisa Willemse  is Director of Communications for the Stem Cell Network, one of Canada's Networks of Centres of Excellence. In addition to more traditional forms of communications, in which she uses her previous experience as an editor, journalist and photographer, she has a strong interest in new media and online communications. In 2008, she began developing the Signals Blog, the official blog of the Stem Cell Network and the Centre for Commercialization of Regenerative Medicine. The blog is dedicated to sharing findings and commentary related to stem cell research while serving as a training/mentorship platform for young scientists interested in acquiring science communications skills. She serves as the blog's editor and an occasional contributor. 

source:http://www.elsevier.com/connect/animated-videos-introduce-stem-cell-science-in-one-minute-bursts

Future Laptops Could Be Powered By Typing

Charge your laptop by typing on it — sounds like a perfect idea to one who believes in the ideal world. But this could soon become a reality as Researchers from the Royal Melbourne Institute of Technology (RMIT) have successfully measured a piezoelectric thin film’s capacity for turning mechanical pressure into electricity — which is said to be a crucial step towards the development of self-powering portable electronics.

Piezoelectricity, a phenomenon that was used in electric cigarette lighters was discovered in the 19th century. Similar to the way electric cigarette lighters use piezoelectric crystals to produce a high voltage electric current, laptops could also generate electric energy to self-charge themselves when buttons are pressed.
According to Dr. Madhu Bhaskaran:

The power of piezoelectrics could be integrated into running shoes to charge mobile phones, enable laptops to be powered through typing or even used to convert blood pressure into a power source for pacemakers – essentially creating an everlasting battery.
With the drive for alternative energy solutions, we need to find more efficient ways to power microchips, which are the building blocks of everyday technology like the smarter phone or faster computer.
The next key challenge will be amplifying the electrical energy generated by the piezoelectric materials to enable them to be integrated into low-cost, compact structures.

This study has been co-authored by Dr Bhaskaran with Dr Sharath Sriram, who is part of the Microplatforms Research Group, led by Professor Arnan Mitchell. Australian National University’s Dr Simon Ruffell also collaborated on the research. The study was published in Volume 21, Issue 12 of Advanced Functional Materials.
The drawback of this is that the piezelectric film is still not cost-effective to manufacture, but experts believe this dream will come true sooner rather than later.

Solar Tunnel To Power 4,000 Trains Annually

Europe’s first “solar tunnel” is providing power to high-speed trains running between Paris and Amsterdam.
The 3.6-kilometer (2.2-mile) tunnel, built to protect trains from falling trees as they pass through an ancient forest near Antwerp, is covered with solar cells and could generate 3.3 MWh of electricity annually. Enfinity, the company behind the project, says that’s equivalent to the average annual consumption of nearly 1,000 homes. It also claims that the tunnel will decrease CO2 emissions by 2,400 tons per year.

“For train operators, it is the perfect way to cut their carbon footprints because you can use spaces that have no other economic value and the projects can be delivered within a year because they don’t attract the protests that wind power does,” Bart Van Renterghem, the UK head of Enfinity, told the Guardian.
The $22.9 million project uses 16,000 solar panels covering 50,000 square meters (roughly 538,000 square feet), which is about the size of eight football pitches. They will provide enough electricity to power 4,000 trains a year. The first of those trains left Antwerp on Monday, filled with commuters and students. The trains tap into the solar energy as they pass through the tunnel at 186 mph. The electricity also provides power for lighting, signals and other infrastructure.
“By using electricity generated on-site, we eliminate energy losses and transport costs,” Enfinity chief executive Steven De Tollenaere, told AFP.
Enfinity has said there had been plans afoot to introduce similar solar infrastructure in the UK but recent cuts to financial incentives would make the projects “unviable.”
“Apparently the UK Government is more concerned about the Treasury than the mid and long-term carbon reduction objectives that we have,” van Renerghem said. “Personally, I think it is short-sighted.”

Energy minister Greg Barker MP said in response: “We want to create a long-term platform for growth. Now that does mean that, in the short term, large-scale schemes aren’t going to get the sort of funding that we see in Belgium currently. There are a lot of exciting things in solar but we have got to think it through so that we get good value for the bill-payers as well as a great deal for the solar pioneers.”

 

How to Make Ceramics That Bend Without Breaking: Self-Deploying Medical Devices?

Sep. 26, 2013 — Ceramics are not known for their flexibility: they tend to crack under stress. But researchers from MIT and Singapore have just found a way around that problem -- for very tiny objects, at least.

When subjected to a load, the molecular structure of the ceramic material studied by the MIT-Singapore team deforms rather than cracking. When heated, it then returns to its original shape. Though they have the same chemical composition, the two molecular configurations correspond to different natural minerals, called austenite and martensite. (Credit: Graphic: Lai et al)

The team has developed a way of making minuscule ceramic objects that are not only flexible, but also have a "memory" for shape: When bent and then heated, they return to their original shapes. The surprising discovery is reported this week in the journal Science, in a paper by MIT graduate student Alan Lai, professor Christopher Schuh, and two collaborators in Singapore.
Shape-memory materials, which can bend and then snap back to their original configurations in response to a temperature change, have been known since the 1950s, explains Schuh, the Danae and Vasilis Salapatas Professor of Metallurgy and head of MIT's Department of Materials Science and Engineering. "It's been known in metals, and some polymers," he says, "but not in ceramics."
In principle, the molecular structure of ceramics should make shape memory possible, he says -- but the materials' brittleness and propensity for cracking has been a hurdle. "The concept has been there, but it's never been realized," Schuh says. "That's why we were so excited."
The key to shape-memory ceramics, it turns out, was thinking small.
The team accomplished this in two key ways. First, they created tiny ceramic objects, invisible to the naked eye: "When you make things small, they are more resistant to cracking," Schuh says. Then, the researchers concentrated on making the individual crystal grains span the entire small-scale structure, removing the crystal-grain boundaries where cracks are most likely to occur.
Those tactics resulted in tiny samples of ceramic material -- samples with deformability equivalent to about 7 percent of their size. "Most things can only deform about 1 percent," Lai says, adding that normal ceramics can't even bend that much without cracking.
"Usually if you bend a ceramic by 1 percent, it will shatter," Schuh says. But these tiny filaments, with a diameter of just 1 micrometer -- one millionth of a meter -- can be bent by 7 to 8 percent repeatedly without any cracking, he says.
While a micrometer is pretty tiny by most standards, it's actually not so small in the world of nanotechnology. "It's large compared to a lot of what nanotech people work on," Lai says. As such, these materials could be important tools for those developing micro- and nanodevices, such as for biomedical applications. For example, shape-memory ceramics could be used as microactuators to trigger actions within such devices -- such as the release of drugs from tiny implants.
Compared to the materials currently used in microactuators, Schuh says, the strength of the ceramic would allow it to exert a stronger push in a microdevice. "Microactuation is something we think this might be very good for," he says, because the ceramic material has "the ability to push things with a lot of force -- the highest on record" for its size.
The ceramics used in this research were made of zirconia, but the same techniques should apply to other ceramic materials. Zirconia is "one of the most well-studied ceramics," Lai says, and is already widely used in engineering. It is also used in fuel cells, considered a promising means of providing power for cars, homes and even for the electric grid. While there would be no need for elasticity in such applications, the material's flexibility could make it more resistant to damage.
The material combines some of the best attributes of metals and ceramics, the researchers say: Metals have lower strength but are very deformable, while ceramics have much greater strength, but almost no ductility -- the ability to bend or stretch without breaking. The newly developed ceramics, Schuh says, have "ceramiclike strength, but metallike ductility."
In addition to Schuh and Lai, the work was carried out by Zehui Du and Chee Lip Gan of Nanyang Technological University in Singapore.