Mobiles phones, remote controls, and other gadgets are generally convenient--that is, until their batteries go dead. For many consumers, having to routinely recharge or replace batteries remains the weakest link in portable electronics. To solve the problem, a group of European researchers say they've found a way to combine a thin-film organic solar cell with a new type of polymer battery, giving it the capability of recharging itself when exposed to natural or indoor light.
It's not only ultraslim, but also flexible enough to integrate with a wide range of low-wattage electronic devices, including flat but bendable objects like a smart card and, potentially, mobile phones with curves. The results of the research, part of the three-year, five-country European Polymer Solar Battery project, were recently published online in the journal Solar Energy.
"It's the first time that a device combining energy creation and storage shows [such] tremendous properties," says Gilles Dennler, a coauthor of the paper and a researcher at solar startup Konarka Technologies, based in Lowell, MA. Prior to joining Konarka, Dennler was a professor at the Linz Institute for Organic Solar Cells at Johannes Kepler University, in Austria. "The potential for this type of product is large, given [that] there is a growing demand for portable self-rechargeable power supplies."
Prototypes of the solar battery weigh as little as two grams and are less than one millimeter thick. "The device is meant to ensure that the battery is always charged with optimum voltage, independently of the light intensity seen by the solar cell," according to the paper. Dennler says that a single cell delivers about 0.6 volts. By shaping a module with strips connected in series, "one can add on voltages to fit the requirements of the device."
The organic solar cell used in the prototype is the same technology being developed by Konarka. (See "Solar-Cell Rollout.") It's based on a mix of electrically conducting polymers and fullerenes. The cells can be cut or produced in special shapes and can be printed on a roll-to-roll machine at low temperature, offering the potential of low-cost, high-volume production.
To preserve the life of the cells, which are vulnerable to photodegradation after only a few hours of air exposure, the researchers encapsulated them inside a flexible gas barrier. This extended their life for about 3,000 hours. Project coordinator Denis Fichou, head of the Laboratory of Organic Nanostructures and Semiconductors, near Paris, says that the second important achievement of the European project was the incorporation into the device of an extremely thin and highly flexible lithium-polymer battery developed by German company VARTA-Microbattery, a partner in the research consortium. VARTA's batteries can be as thin as 0.1 millimeter and recharged more than 1,000 times, and they have a relatively high energy density. Already on the market, the battery is being used in Apple's new iPod nano.
Dennler says that the maturity of the battery and the imminent commercial release of Konarka-style organic solar cells mean that the kind of solar-battery device designed in the project could be available as early as next year, although achieving higher performance would be an ongoing pursuit.
The paper's coauthor Toby Meyer, cofounder of Swiss-based Solaronix, says that the prototypes worked well enough under low-light conditions, such as indoor window light, to be considered as a power source for some mobile phones. Artificial light, on the other hand, may impose limitations. "Office light is probably too weak to generate enough power for the given solar-cell surface available on the phone," he says.
Watches, toys, RFID tags, smart cards, remote controls, and a variety of sensors are among the more likely applications, although the opportunity in the area of digital cameras, PDAs, and mobile phones will likely continue to drive research. "The feasibility of a polymer solar battery has been proven," the paper concludes.
Rights to the technology are held by Konarka, though the solar company says it has no plans itself to commercial the battery.
2) An Amazing Conference on Energy
David Houle, April 4, 2007, Evolution Shift, http://www.evolutionshift.com/blog/2007/04/04/an-amazing-conference-on-energy/
This past weekend I had the great good fortune to attend a three day energy conference attended by some of the world’s greatest energy experts. Thanks to the good graces of the Foundation for the Future I was invited to attend the conference as an observer. The Foundation invited 15 of the foremost physicists and energy experts in the world to come together for three days of presentations and discussions on the future of energy. An additional 15 or so people were invited to attend as observers.
The name of the conference was “Energy Challenges: The next Thousand Years”. The goal was to “consider all potential sources and technologies for energy production over three time frames: the near term (rest of this century), the medium term (next few centuries), and the longer term (thousand-year future), as well as the challenges facing humans on the planet in developing and implementing self-sufficient strategies for energy”. This framework was shaped by the mission of the Foundation for the Future, which is to continue to look toward the long term future of humanity, under the umbrella “Humanity Three Thousand”.
This structure led to two clear results. First some incredibly interesting discussions of long term energy solutions, some that are available to develop, and some that are almost beyond the minds of even physicists to fully comprehend. I will take a look at some of these solutions in future posts. Second a unanimous position that in spite of the title of the conference, new forms of renewable energy must be developed and fully utilized on a global basis during this century or humanity and much of the biosphere is at risk of possible extinction. When Foundation for the Future Executive Director Bob Citron made his closing remarks, he commented that in the ten year history of Foundation conferences that looked ahead one thousand years, this is the first one where the discussions kept coming back to the next one hundred years, and with great purpose.
The main headline of the conference then was that, simply put, a room full of some of the greatest experts on energy in the world are concerned that if the major issues surrounding energy are not dealt with in the next few decades, cataclysms of various types are almost guaranteed to occur. As far as I am concerned, based on the evidence passionately presented at the conference, the discussion on global warming is over. In fact, several times global warming was described as the “canary in the mine” in the sense that it is the advance warning of much greater underlying problems.
To emphasis this point, some random quotes from the conference, all from distinguished and well respected scientists.
-“If the energy consumption of all the countries in the world rose up to that of the U.S. using current forms and means of energy, the world population would need three planets’ worth of resources to sustain it.”
-“If all the world gets up to US consumption levels, game over!”
-“72% of the planet is covered by water, so we should really call it Planet Ocean rather than Planet Earth, but the oceans are dying. If the increase in acidity of the oceans, which is at the highest it has been in hundreds of millions of years is not reversed, and soon, then by the year 2100 the oceans may no longer be able to sustain life.”
The alarmism was to the point that major actions, across the board must be taken and very soon. It doesn’t have to end badly for us all. There are solutions, there is developing technology, there are possible breakthroughs of historic proportions, there are ways to greatly alter energy creation, storage and usage, but we must start to implement and develop them immediately.
I was greatly honored to observe and participate in the discussion that occurred over these three days. The brilliance of the people in the room was staggering. The ideas presented and discussed could be transformative for humanity. I will try to do my best in the posts ahead to present some of them in an understandable way. The good news is that some of the best minds in the world are working intently on the global energy problems. The bad news is that the work that needs to be done and the changes that need to occur are massive, and we have just begun to address them.
ScienceAlert-Australia/New Zealand, 06 April 2007 http://www.sciencealert.com.au/news/20070604-14870.html
Solar cell technology developed by the Massey University Nanomaterials Research Centre will enable New Zealanders to generate electricity from sunlight at a 10th of the cost of current silicon-based photo-electric solar cells.
Dr Wayne Campbell and researchers in the centre have developed a range of coloured dyes for use in dye-sensitised solar cells.
The synthetic dyes are made from simple organic compounds closely related to those found in nature. The green dye Dr Campbell (pictured) is synthetic chlorophyll derived from the light-harvesting pigment plants use for photosynthesis.
Other dyes being tested in the cells are based on haemoglobin, the compound that give blood its colour.
Dr Campbell says that unlike the silicon-based solar cells currently on the market, the 10x10cm green demonstration cells generate enough electricity to run a small fan in low-light conditions – making them ideal for cloudy climates. The dyes can also be incorporated into tinted windows that trap to generate electricity.
He says the green solar cells are more environmentally friendly than silicon-based cells as they are made from titanium dioxide – a plentiful, renewable and non-toxic white mineral obtained from New Zealand’s black sand. Titanium dioxide is already used in consumer products such as toothpaste, white paints and cosmetics.
“The refining of pure silicon, although a very abundant mineral, is energy-hungry and very expensive. And whereas silicon cells need direct sunlight to operate efficiently, these cells will work efficiently in low diffuse light conditions,” Dr Campbell says.
“The expected cost is one 10th of the price of a silicon-based solar panel, making them more attractive and accessible to home-owners.”
The Centre’s new director, Professor Ashton Partridge, says they now have the most efficient porphyrin dye in the world and aim to optimise and improve the cell construction and performance before developing the cells commercially.
“The next step is to take these dyes and incorporate them into roofing materials or wall panels. We have had many expressions of interest from New Zealand companies,” Professor Partridge says.
He says the ultimate aim of using nanotechnology to develop a better solar cell is to convert as much sunlight to electricity as possible.
“The energy that reaches earth from sunlight in one hour is more than that used by all human activities in one year”.
The solar cells are the product of more than 10 years research funded by the Foundation for Research, Science and Technology.
Editor's Note: Original news release can be found here.
A new type of material could allow solar cells to harvest far more light. Much more efficient solar cells may soon be possible as a result of technology that more efficiently captures and uses light. StarSolar, a startup based in Cambridge, MA, aims to capture and use photons that ordinarily pass through solar cells without generating electricity. The company, which is licensing technology developed at MIT, claims that its designs could make it possible to cut the cost of solar cells in half while maintaining high efficiency. This would make solar power about as cheap as electricity from the electric grid.
The effort uses a type of material called a photonic crystal that makes it possible to "do things with light that have never been done before," says John Joannopoulos, a professor of physics at MIT who heads the lab where the new designs for solar applications were developed. Photonic crystals, which can be engineered to reflect and diffract all the photons in specific wavelengths of light, have long been attractive for optical communications, in which the materials can be used to direct and sort light-borne data. Now new manufacturing processes could make the photonic crystals practical for much-larger-scale applications such as photovoltaics.
StarSolar's approach addresses a long-standing challenge in photovoltaics. Silicon, the active material that is used in most solar cells today, has to do double duty. It both absorbs incoming light and converts it into electricity. Solar cells could be cheaper if they used less silicon. If the silicon is made thinner than it is now, it may still retain its ability to convert the photons it absorbs into electricity. But fewer photons will be absorbed, decreasing the efficiency of the cell.
MIT researchers developed sophisticated computer simulations to understand how thin layers of photonic crystal could be engineered to capture and recycle the photons that slip through thin layers of silicon. Silicon easily absorbs blue light, but not red and infrared light. The researchers found that by creating a specific pattern of microscopic spheres of glass within a precisely designed photonic crystal, and then applying this pattern in a thin layer at the back of a solar cell, they could redirect unabsorbed photons back into the silicon.
Today's solar cells already reflect some of the light that passes through the silicon. But the photonic crystal has distinct advantages. Conventional solar cells are backed with a sheet of aluminum. The photonic crystal reflects more light than the aluminum does, especially once the aluminum oxidizes. And the photonic crystal diffracts the light so that it reenters the silicon at a low angle. The low angle prevents the light from escaping the silicon. Instead, it bounces around inside; this increases the chances of the light being absorbed and converted into electricity.
As a result, the photonic crystal can increase the efficiency of solar cells by up to 37 percent, says Peter Bermel, CTO and a cofounder of StarSolar. This makes it possible to use many times less silicon, he says, cutting costs enough to compete with electricity from the grid in many markets. The savings would be especially large now, since a current shortage in refined silicon is keeping solar-cell prices high and slowing the growth of solar-cell production.
The company plans to work with existing solar-cell makers, applying its photonic crystals with a machine added to the solar-cell makers' assembly lines, Bermel says. But StarSolar needs to choose a large-scale manufacturing technique that will allow it to produce the photon crystals inexpensively. What's needed is a way to cheaply arrange two materials in an orderly three-dimensional pattern. For example, microscopic spheres of glass would be arranged in rows and columns inside silicon. Currently, techniques such as e-beam lithography can be used, but that's too slow for large-scale manufacturing.
Shawn-Yu Lin, professor of physics at Rensselaer Polytechnic Institute, has developed a method for manufacturing eight-inch disks of photonic crystal--a measurement considerably larger than what can be done with conventional techniques. The method, which employs optical lithography similar to that used in the semiconductor industry, works best for a type of solar cell that concentrates light onto a small chunk of expensive semiconductor material. Such a device would require a relatively small amount of photonic crystal compared with conventional solar cells. Lin says the technique could be applied for more-conventional solar panels, although it would be expensive.
Another potentially less-expensive method, called interference lithography, creates orderly patterns in the photonic-crystal materials. The method is fast and uses machines that are far less expensive than those used for conventional optical lithography. It also requires fewer steps than Lin's existing process, so he says it could be far cheaper. Such methods have been developed by Henry Smith, professor of electrical engineering at MIT, who was not involved with the StarSolar-related work. Smith says his interference-lithography method could be used to build templates for imprinting photonic-crystal patterns on large areas.
Another promising technique is self-assembly, in which the chemical and physical properties of material building blocks are engineered so that they arrange themselves in orderly patterns on a surface. For example, Chekesha Liddell, professor of materials science and engineering at Cornell University, has engineered building blocks in the shape of peanuts and the caps of mushrooms that line up in rows because of the way they fit together and the tug of short-range forces between them. She says this could be useful for assembling photonic crystals for solar cells.
With such approaches available, Bermel says that StarSolar hopes to have a prototype solar cell within a year and a pilot manufacturing line operating in 2008.
6) Superconductors Inspire Quantum Test for Dark Energy
Zeeya Merali , 07 April 2007, New Scientist Print Edition,
DARK energy is so befuddling that it's causing some physicists to do their science backwards.
"Usually you propose your theory and then work out an experiment to test it," says Christian Beck of Queen Mary, University of London. A few years ago, however, he and his colleague Michael Mackey of McGill University in Montreal, Canada, proposed a table-top experiment to detect the elusive form of energy, without quite knowing why it might work. Now the pair have come up with the theory behind the experiment. "It is certainly an upside-down way of doing things," Beck admits.
Dark energy is the mysterious force that many physicists think is causing the expansion of the universe to accelerate. In 2004, Beck and Mackey claimed that the quantum fluctuations of empty space could be the source of dark energy and suggested a test for this idea. This involved measuring the varying current induced by quantum fluctuations in a device called a Josephson junction - a very thin insulator sandwiched between two superconducting layers. Beck reasoned that if quantum fluctuations and dark energy are related, the current in the Josephson junction would die off beyond a certain frequency (New Scientist, 10 July 2004, p 11). But they hadn't worked out what exactly caused the cut-off.
Now the duo say they know, and last week Beck presented the theory at a conference on unsolved problems for the standard model of cosmology held at Imperial College London. Quantum mechanics says that the vacuum of space is seething with virtual photons that are popping in and out of existence. Beck and Mackey suggest that when these virtual photons have a frequency below a certain threshold, they are able to interact gravitationally, contributing to dark energy. Their theory is inspired by superconducting materials. "Below a critical temperature, electrons in the material act in a fundamentally different way, and it starts superconducting," says Beck. "So why shouldn't virtual photons also change character below a certain frequency?"
If so, virtual photons should behave differently below a frequency of around 2 terahertz, causing any currents in the Josephson junction to taper off above this frequency. Physicist Paul Warburton at University College London is building such a dark energy detector and could have results next year. Some evidence that dark energy works like this may already have been found. In 2006, Martin Tajmar at the Austrian Research Centers facility in Seibersdorf and his colleagues noticed bizarre behaviour in a spinning niobium ring. At room temperature, niobium does not superconduct, and accelerometers around the ring measured that it was spinning at a constant rate. But once the temperature fell, the niobium started to superconduct, and the accelerometers suddenly picked up a signal (New Scientist, 11 November 2006, p 36).
"We measured an acceleration even though the ring's motion hadn't changed at all," says Clovis de Matos, who works at the European Space Agency in Paris and established the theory behind the experiment. He thinks the results could be explained if gravity got a boost inside the superconductor. "Beck and Mackey's gravitationally activated photon would have that effect," he says. The controversial experiment seemed to fall foul of Einstein's equivalence principle, which states that all objects should accelerate under gravity at the same rate. It implied that "if you have two elevators, one made of normal matter and one made of superconducting matter, and accelerate them by the same amount, objects inside will feel different accelerations", de Matos says. Astronomers may have seen a similar violation of the principle (see "Two-speed gravity").
The odd acceleration detected in the niobium ring also suggests that energy isn't conserved in the superconductor - another major violation of known physics. Dark energy could solve that problem, however. "We did the sums and found out that energy wasn't conserved, but perhaps that was just because we were missing dark energy," de Matos says.
"If Galileo could have dropped a lump of dark matter and a lump of normal matter from the top of the Leaning Tower of Pisa, he might have expected them to fall at the same rate," says Orfeu Bertolami at the Instituto Superior Técnico in Lisbon, Portugal. "But he would have been wrong." Bertolami and his colleagues studied a galaxy cluster known as Abell cluster A586 to see if dark matter and normal matter fall in the same way under gravity. He says this cluster is ideal because it is spherical, suggesting that it has settled down: "The only motion we are seeing now is due to gravity toward the cluster's centre."
The team studied 25 galaxies in the cluster using gravitational lensing - the shift in the apparent position of a light source caused by gravity bending the light. When they analysed the positions of galaxies using conventional models, things just didn't add up. "It only makes sense if the normal matter is falling faster than the dark matter," Bertolami says.
This is the first astronomical observation to suggest that Einstein's principle of equivalence is violated, says Bertolami (www.arxiv.org/astro-ph/0703462
Provided as a courtesy from www.IntegrityResearchInstitute.org where a FREE copy of the Progress in Future Energy DVD featuring Dr. Tom Valone is available upon request (with postal address).