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Scientists are designing a solar cell that captures almost all of the energy of the solar spectrum

The new design, which converts direct sunlight into electricity with an efficiency of 44.5 percent, has the potential to be the most efficient solar cell in the world

A stacked solar cell. Illustration: Matthew Lamb
A stacked solar cell. Illustration: Matthew Lamb

A George Washington University researcher helped design and build a new solar cell prototype that combines multiple cells stacked into a single device that can capture nearly all of the energy in the solar spectrum.
The new design, which converts direct sunlight into electricity with an efficiency of 44.5 percent, has the potential to be the most efficient solar cell in the world.
The approach is different from the solar panels you usually see on roofs or in the fields. The new device uses panels with a photovoltaic concentrator (PV) with lenses that concentrate sun rays on tiny micro-sized solar cells. Because of their small size—less than one square millimeter—solar cells that use more sophisticated materials can be cost-effectively developed.
The study, "Gallium antimony-based solar cells for harvesting the energy of the full solar spectrum", was published in the journal "Advanced Energy Materials".
The stacked cell acts almost like a sieve for sunlight, and the special materials in each layer absorb the energy of a specific set of wavelengths, said Matthew Lamb, the study's lead author and a research scientist in the School of Engineering and Applied Science. As the light passes through the entire stack, just under half of the available energy is converted to electricity. For comparison, the most common solar cell today converts only a quarter of the available energy into electricity.
"Around 99 percent of the energy contained in the direct sunlight that reaches the Earth's surface is between the wavelengths of 250 nm and 2,500 nm, but the usual materials of solar cells with multiple junctions and high efficiency cannot capture this entire spectral range," said Dr. Lamb. "Our new device is able to release the energy stored in long-wavelength photons, which are lost in normal solar cells, and therefore allows a route to realizing the ultimate multi-junction solar cell."
Scientists have been working on developing more efficient solar cells for years, but this approach has two novel aspects. It uses a family of materials based on gallium antimony (GaSb) substrates, commonly found in light detector and infrared laser applications. These GaSb-based solar cells are assembled into a stacked structure together with high-efficiency solar cells grown on conventional substrates that capture solar photons with shorter wavelengths. In addition, the stripping process uses a technique called transfer printing, which enables XNUMXD assembly of these tiny devices with high precision.
This particular solar cell is very expensive, but the researchers believe it was important to show the upper limit of what is possible in terms of efficiency. Despite the current costs of the materials involved, the technique used to create the cells looks promising, the researchers say. In the end it will be possible to bring a similar product to the market which will be made possible by reducing costs due to very high levels of solar concentration and technologies for recycling the expensive growing media.

The research relies on the developments made in the MOSAIC program, a $24 million research project funded by the Advanced Research Projects Agency - Energy that funds 11 separate teams across the United States that are engaged in the development of technologies and ideas that will revolutionize the performance of the PV and reduce costs. The funding of this type of research is essential for the development of viable commercial technologies in the future, the researchers say.

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8 תגובות

  1. The solutions can sit in the gutter for years and the revolution will start only if the economic balance between the old and the new technology changes, that is, the extraction of the processes from the bottom up. this.
    There is a gap here that can theoretically be solved, but practically probably not.
    The only way to promote the right trends and prevent selfishness is almost an oxymoron at the current stage and the exact name is: "miracle" and miracles happen either when we are on our knees or we have given up our uniqueness and become one body and therefore almost an oxymoron,
    In order to soften the reaction of the part of you that doesn't like one reality with another (not imagination) I will ask you a question - since we all know that the technology mentioned above - is possible, then why are tenders that huge corporations won, which on the one hand - apparently there is the carrot - the price of electricity bought at By the cheap franchisors, there is a lot of technology -: "good for the industry"……. Looks good, looks good, but could already be much better.
    You don't need a net meter, vortex pumps, heat pumps or anything that covers the eyes of options such as combining PV technology with battery storage technology and continuing to use it for purposes with other correct combinations.

  2. What are they selling? Spectrolab Ltd. developed solar cells with an efficiency close to 50% a few years ago. The company belongs to Boeing. Open the site and see. These panels are used in satellites because of the high price. They will never be acts for home use. There is another technology with similar performance called spectral conversion in which the light spectrum is moved to the area where the panel is at maximum efficiency. With this method it is possible to reach 85% theoretically, but in practice the result will not exceed 65%. Leave details for the contact and you will receive more information on the matter. If there is an interested investor here, we will be happy to update him.

  3. In my opinion, solar cells of one kind or another are the future and this is what will solve all our problems with Energia with the Fed and global warming....
    All the roofs in the country should have solar cells, this should be included in the law, just as it is required to install a solar heater.
    But the problem is probably a conflict of interests and politics, apparently the electricity company and the state that profit from the fuel are not that interested in it.

  4. The revolution will come from a decrease in production costs. And even more than an improvement in batteries. Green energy is not worth much without an effective means of storing electricity. The big improvement will come thanks to the automotive world that will become electric.
    Its contribution to the development of large battery technologies and, no less important, the development of cheaper production technologies will perhaps be even greater than the direct contribution of reducing pollution. (Of course there is a difference in the requirements of a car battery and a green energy storage battery. The emphasis in a car is on weight, volume, and energy compression. Whereas for energy storage, the volume is less important and the weight is not important at all. To verify this, the price per unit and the amount of wasted energy in charging is more important.

  5. Conan
    Regarding 2: This is true but... what happens if there is a lot of radiation in long waves and less in short waves? In this case, shouldn't you concentrate on the long waves?

  6. This is all well and good, but:
    1. Already several years ago he decided in experiments to use the entire possible range of the sun's spectrum in order to optimize the use of sunlight. I don't remember if it was the same group or a different group of scientists - but since then no progress and status of the research has been published - is it because of scientific difficulties or budgetary difficulties?
    2. Light with a longer wavelength has less energy relative to shorter wavelengths; If so - why not use UV-A and UV-B radiation to increase the energy produced from our solar spectrum, instead of using infrared light?
    3. Finally, during the use of a photovoltaic cell there are two important mechanisms: one is the ability to create a relatively easy charge separation in the atom/molecule in use, and the other is the prevention of recombination, in which the separated charge comes back and connects, so that in fact we did not benefit from the absorption of light. Why is there no reference to these processes?

  7. In the end, it's all a matter of price, they already managed to reach an efficiency of almost 40% with a cell of gallium arsenide (a single node), (and I think that with a structure of several nodes they reached an efficiency of 60%) but still, with the exception of applications that require high efficiency at a point, cells are used in most of the world From silicon (with an efficiency in the order of 10%), because silicon is much cheaper (both as a raw material and in terms of production processes).
    Breakthrough ideas in the field can come from two possible directions:
    1. Creating a structure of several nodes from silicon - although silicon has an indirect gap, but the manufacturing technologies allow precision in creating structures of nanometer size (at a relatively low cost).
    2. Moving to a technology that is not based on semiconductors (and therefore does not depend on the energy gap of the material), for example the use of nano antennas, or non-linear optics (there are many challenges in this field that have not yet been overcome), but to the best of my knowledge theoretically it is possible to achieve very high efficiencies high in these techniques (around 80%)

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