Today, conventional silicon solar cells are 10% to 20% efficient (this means that they generate 100 watts to 200 watts per square metre of cells, respectively). These conventional panels are already in use worldwide, and they do work well; however, more efficient panels would still be very helpful in multiple ways.
There is a theoretical technology that involves using a nano-sized rectenna — or a rectifying antenna — which, as the name implies, can absorb and rectify solar energy into direct current (DC).
It can achieve a theoretical maximum of 70% efficiency, which is stunning by any standard — only hydroelectric power plants can surpass this level of efficiency. The efficiency of almost all the other power plants is below 50%.
Unfortunately, this concept has been limited because scientists do not know how to construct and test it. Researchers at the University of Connecticut may have the answer to this puzzle, however. It is called selective area atomic layer deposition (ALD).
According to Phys.org, ALD is what it would take to finally manufacture a working prototype of this recent type of solar cell.
“In a rectenna device, one of the two interior electrodes must have a sharp tip, similar to the point of a triangle. The secret is getting the tip of that electrode within one or two nanometers of the opposite electrode, something similar to holding the point of a needle to the plane of a wall.”
The integration of solar panels into devices is far cheaper than paying contractors to construct mounting equipment and put the panels on the roof, and integrated panels that are 70% efficient can power laptops and cellphones on a smaller scale as well. A 60-watt panel of this type could be mounted on a 17-inch notebook computer, for example.
More efficient solar panels would also use less space, and hence could be stored, shipped, and installed at a lower cost than conventional ones.
As noted above, these aren’t the first researchers to work on this type of solar technology. We reported 2.5 years ago on solar antenna technology MIT scientists were working on that could supposedly “concentrate solar energy 100 times more than a regular photovoltaic cell.” The clincher, of course, was getting the costs down. Those carbon nanotube solar antennas don’t seem to have made it to market yet. Will these rectifying antennas?
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