Solar Cells Collect More Light, Display Art

Dean Sigler Electric Powerplants, Sustainable Aviation 0 Comments

Friend and frequent contributor Colin Rush sent this Economist item about Semprius, a concentrating solar cell maker about to go into production with their highly efficient technology. It’s big news that a production solar panel is able to convert 42.5 percent of sunlight falling on it into energy, when the world’s record for any solar cell was set last September by the German Fraunhofer Institute for Solar Energy Systems with an experimental multi-junction solar cell that’s 44.7 percent efficient.  The 42.5 percent for Semprius cells drops to about 35 percent when they are surrounded by the normal mounting flanges and connecting lines – still well above most production panels. These may achieve 50 percent with suitable refinement. Using breakthroughs devised …

5X Batteries? How About 70,000X Solar Cells?

Dean Sigler Electric Powerplants, Sustainable Aviation 2 Comments

Matt Shipman of North Carolina State University News Services reports on a connector that could allow stacking solar cells without losing voltage.  This stacking could allow cells to operate at solar concentrations of “70,000 suns worth of energy without losing much voltage as ‘wasted energy’ or heat.”  This could have tremendous implications improving the overall efficiency of solar energy devices and reducing the cost of solar energy production. Stacked solar cells live up to their name, simply being several cells stacked on one another, with their layering leading to up to 45-percent efficiency in converting solar energy into electricity.  So far, the big drawback has been the junctions between cells, which tend to waste the energy from the connected cells as …

Solar Cells and Artificial Photosynthesis Make Hydrogen Directly

Dean Sigler Electric Powerplants, Sustainable Aviation 0 Comments

Science 2.0.com reports on an exciting potential breakthrough in solar energy and its direct transformation into hydrogen fuel.  Usually, solar cells generate current from photons, making electricity which can run things or be stored in batteries. This new and different approach, using an innovative and inexpensive solar cell and a metal oxide photo anode, can store nearly five percent of solar energy chemically as hydrogen. The metal oxide bismuth vanadate (BiVO4) photo anode includes a small dose of tungsten atoms, was then sprayed onto conducting glass and “coated with an inexpensive cobalt phosphate catalyst,” which helped speed up oxygen formation during water splitting. Science 2.0 reports Professor Dr. Roel van de Krol’s remarks.  He’s head of the Helmholtz Zentrum Berlin …

Thinner than Kleenex®, as Powerful as the Sun

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David L. Chandler of the Massachusetts Institute of Technology (MIT) News Office reports that an MIT research team headed by Jeffrey Grossman has found a way to make sheets that push “towards the ultimate power conversion from a material” for solar power.  His team has managed to fabricate molecule-thick photovoltaic sheets which could pack hundreds of times more power per weight than conventional solar cells. Senior author of a new paper on the team’s study in Nano Letters, Grossman found that despite the interest in two-dimensional materials such as graphene – only an atom thick – few have studied their potential for solar applications.  Grossman says, “They’re not only OK, but it’s amazing how well they do.” Stacking sheets of …

GraphExeter Aims for Power with Transparency

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It doesn’t sound much like dispassionate, objective scholarly reporting, but the University of Exeter in England headlines its report on a University-created breakthrough material, “Revolutionary new device joins world of smart electronics.” Layering graphene and the GraphExeter, a material obviously headed for product marketing, gives a “new flexible, transparent, photosensitive device” that can lead to solar-powered clothing able to charge the wearer’s cell phone, “intelligent” windows that can “harvest light and display images,” and just maybe (in this writer’s dreams) help power electric cars and airplanes. GraphExeter, Exeter claims, is the best known room temperature transparent conductor and with graphene – the thinnest conductive material – the pair make for great potential.   Researchers  developed  GraphExeter by sandwiching molecules of …

Peel-and-Stick Solar Cells Make Debut

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The U. S. Department of Energy’s National Renewable Energy Laboratory (NREL) and Stanford University have teamed up to create what may be the thinnest of thin solar cells – a peel-and-stick decal. One micron thick, the decal-like  peel-and-stick, or water-assisted transfer printing (WTP), technologies were developed by Stanford researchers and have been used for nanowire based electronics.  Meeting at a conference where both made presentations, Stanford’s Xiaolin Zheng talked about her peel-and-stick technology, and NREL principal scientist Qi Wang spoke on his team’s research in thin-film amorphous solar cells. Zheng realized that the NREL had the type of solar cells needed for her peel-and-stick project, according to the NREL announcement. The NREL press release explains, “The university and NREL showed …

Alchemy with Thin Film Structures

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The blog has looked at several recent attempts to pull electricity from solar cells that have the ability to capture a broad range of light wavelengths.  These are based on everything from layers of graphene and zinc nano-wires, to an exotic subwavelength  plasmonic cavity, to straining solar cells to form wide bandgap funnels which capture light’s energy. Joining these efforts along with those of researchers in America and Germany, colleagues at the Vienna University of Technology are testing single atomic layers of oxide heterostructures, a new class of materials, to “create a new kind of extremely efficient ultra-thin solar cells.” Professor Karsten Held from the Institute for Solid State Physics at the University, explains, “Single atomic layers of different oxides …

Princeton Solar Cell is “Black Hole for Light”

Dean Sigler Electric Powerplants, Sustainable Aviation 2 Comments

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 …

Power Spraying Takes on a Whole New Meaning

Dean Sigler Electric Powerplants, Sustainable Aviation 4 Comments

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, …

Not Your Father’s 172

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

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 …