A great deal of the light that falls on solar cell panels does little to generate electricity, with a high percentage bouncing off pointlessly. Princeton researchers have confronted this issue with a layered assembly, otherwise known as a subwavelength plasmonic cavity. Developed by Princeton University researcher Stephen Chou and a team of scientists, the cavity dampens reflections and traps light. According to Princeton’s announcement, “The new technique allowed Chou’s team to create a solar cell that only reflects about 4 percent of light and absorbs as much as 96 percent. It demonstrates 52 percent higher efficiency in converting [direct] light to electrical energy than a conventional solar cell.” Overall, the team was able to increase solar cell efficiency a total of 175 percent with their nanostructured sandwich by capturing not only direct sunlight, but angled rays and diffuse light that occurs on cloudy days. MIT researchers recently reported attempts to gather varying wavelengths of light to effect the same type of …
Power Spraying Takes on a Whole New Meaning
Several news sources, apparently using the same press release from Mitsubishi Chemical Corp., have announced a spray-on solar cell, which can be applied in the same fashion as paint – to “buildings, vehicles and even clothing.” This “means that the places where energy from the sun can be harvested are almost limitless.” Less than one millimeter thick and capable of 10.1-percent efficiency, the new material is said to have a weight one-tenth of traditional silicon cells. Mitsubishi says these are prototype materials, and that they hope to achieve 15-percent efficiency by 2015, with 20 percent as a more distant possibility. Mitsubishi is a bit soft on details, but says, “The new solar cells utilize carbon compounds which, when dried and solidified, act as semiconductors and generate electricity in reaction to being exposed to light. Most existing solar cell technology requires crystalline silicon to be sandwiched between glass sheets and positioned on the roofs of homes and office buildings, or in space-consuming …
Not Your Father’s 172
George Bye, CEO of Bye Energy and head of the Green Flight Project, hopes to test fly the electric Cessna 172 in the spring of 2011. Recent illustrations show the “full-dress” electric craft with Ascent solar cells, a high-tech propeller, streamlined cowling, and vortex collectors at the wing tips’ trailing edges. Each element is intended to extend the range and efficiency of the airplane, a strong selling point, particularly in electrically-powered machines. Ascent Solar’s thin-film cells are thinner than a human hair, and thus will not impede the airflow over the wing’s surface. As the cells’ efficiency grows with development, they will provide greater flexibility of operation. Their resistance to failure, demonstrated in the video, will enhance the reliability of the overall airplane. George Bye has noted an economy of operation that might relight some aviation enthusiasts’ desire to go flying. Standard 172s cost about $35 to $50 per hour in direct operating costs, with those costs climbing as oil …
The Light at the End of the Funnel
In some exciting news that could make several quantum leaps in solar cell performance, Massachusetts Institute of Technology researchers have announced a hundred-fold increase in light gathering capabilities for solar cells. If a cell were able to exploit this increase, an aircraft such as the Solar Impulse could fly on 120 solar cells instead of the 12,000 now spread across its over 200-foot wingspan. We’ve reported on carpet-like light-capturing formats for increasing solar cell output, but the MIT approach funnels light down a multi-carbon nanotube filament, boosting the output of the “tiny” solar cell at the bottom. MIT’s press release explains the outcome. “’Instead of having your whole roof be a photovoltaic cell, you could have little spots that were tiny photovoltaic cells, with antennas that would drive photons into them,’ says Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering and leader of the research team. “Strano and his students describe their new carbon nanotube antenna, …
Solar Impulse Overnighter: 26 Hours Nine Minutes
Andre’ Borschberg, CEO and co-founder of the Solar Impulse project, landed this morning at 9:00 a.m. (local tme) in Payerne, Switzerland, having completed the first-ever night flight on battery energy stored during the previous day through the craft’s solar cells. Taking off at 6:51 a.m. July 7, Borschberg flew the 64-meter span, four-motor airplane in large patterns around the area, gaining altitude to a height of 8,564 meters (27,404 feet) above sea level and charging the batteries – all while running the motors at climb power. As night fell, he glided to preserve the stored power, ran the motors as needed to maintain altitude, and landed with a small reserve. This successful demonstration of being able to run the motors on solar power while still charging the batteries means the project can go on to its next stages, spelled out in this morning’s press release “The success of this first night flight by a solar-powered plane is crucial for the further …
Solar Impulse All-Nighter July 1
Solar Impulse is set to attempt its first night flight on Thursday, July 1, 2010. Weather conditions are “Favourable for attempting the first night flight on solar energy,” according to the Solar Impulse web site. “The situation continues to look good and the likelihood of seeing the HB-SIA take off on July 1st and land back in the early morning 2nd July is increasingly probable.” The Solar Impulse team will confirm the date 24 hours before take-off time. Only accredited journalists will be allowed on-site to witness the event, so don’t head for the Payerne, Switzerland airbase, but follow the flights on the Internet at the project’s special Night Flight web page at www.solarimpulse.com. These flights are crucial to the ongoing aim of flying a solo mission around the world in five hops, followed by the development of a two-seat version of the airplane that will enable a non-stop, around-the world solar flight. This will hinge on the ability of the craft’s over …
Shaping Plastics into Inexpensive Solar Cells
Dr. Yeuh-Lin Loo, an Assistant Professor in Chemical Engineering, has led a team of Princeton, University of Texas – Austin, Pennsylvania State University, University of California – Santa Barbara, and Dupont researchers in developing a conductive plastic that takes the place of expensive indium tin oxide (ITO) used in solar cells, flat-screen TVs, and other electronic devices with display screens. ITO, a byproduct of mining, is rare and expensive, but a necessity in today’s electronics. An inexpensive substitute would be desirable in bringing costs down and removing pressure from the growing demand for ITO. Loo comments on this in the Princeton press release. “The cost of indium tin oxide is skyrocketing. To bring down the costs of plastic solar cells, we need to find a replacement for ITO. Our conducting plastics allow sunlight to pass through them, making them a viable alternative.” ITO has the characteristic of allowing sunlight to pass through its transparent structure, enabling its collection and conversion …
Big Nano
A solar cell manufacturer that boasts of 100 times thinner panels than current silicon solar cells, and production rates 100 times faster than with the methods usually employed in the industry will definitely catch our attention. Nanosolar, of San Jose, California, makes a CIGS-based solar film claimed to be thinner and much less expenive (ultra-low cost, according to Nanosolar) than silicon-based panels. CIGS stands for copper/indium/gallium/selenium, the primary components of the new film. Coated onto a thin aluminum substrate, the CIGS ink is literally printed on, the nanoparticles providing a demonstrated efficiency of up to 16.4-percent, verified by the National Renewable Energy Laboratory (NREL). Initial production runs are producing panels of at least 11-percent efficiency. While currently only half as efficient as the best production silicon solar cells, the high-speed manufacturing process promises to enable low-cost installations and future improvements in efficiency would lead to the light, flexible, powerful panels that could make solar-powered or augmented flight a commonplace. The company’s white paper on their technology should give readers an insight into a promising new development …
And Now For Something Completely Different
Tolstoy, in War and Peace, wrote that, “Among the innumerable subdivisions that can be made in the phenomena of life, one can subdivide them all into those in which content predominates and those in which form predominates.” One group attempting to meld form and function is the Land Art Generator Initiative, a group attempting to “bring together artists, architects, scientists, and engineers in a first of its kind collaboration. The goal of the Land Art Generator Initiative is to design and construct a series of land art installations across the UAE that uniquely combine aesthetic intrigue with clean energy generation. The LAGI viewing platforms will be tourist destinations that draw people from around the world to experience the beauty of the collaborative art creations here in the United Arab Emirates. At the same time, the art itself will continuously distribute clean energy into the electrical grid with each land art sculpture having the potential to provide power to thousands of …