Solar Power converts photons to electrons. For as long as solar power has existed, I've considered this to be a one to one relationship. A photon hits some sort of electrically unstable substance, and an electron jumps across some sort of barrier creating a current. I've never questioned that this is as good as we can do. One photon...one electron, that's just the way it is.
Well not anymore it's not. Apparently some exotic (and expensive and toxic) substances can produce multiple electrons per photon. But that has never been achieved with non-toxic, inexpensive materials, like silicon. Until now. Scientists at the National Renewable Energy Laboratory (a place where many many more tax dollars should be going) have proven that certain silicon nano-cyrstals can produce two to three electrons per photon of high energy sunlight.
The discover could lead to increasingly inexpensive and efficient silicon solar cells. Senior research fellow Arthur Nozik notes that current silicon cells are theoretically limited to roughly 30% efficiency on their own, and 40% efficiency with concentrating mirrors. This new kind of cell, however, could be easily be 40% efficient on their own and up to 60% efficient with concentrators!
That kind of efficiency is absolutely unheard of in the solar industry!
The nano-crystals could prove much easier to produce than high efficiency mono-crystalline solar panels, and they will contain no toxic substances, unlike other materials that have shown these 'multi-electron' properties.
However, this is of course still in the development stage. While the electrons are being produced, it's turning out to be somewhat difficult to actually extract the electrons from the nano-crystals. In fact, the extra electrons have yet to be measured as an electrical current, but through more indirect means like spectroscopy. But the researchers are working on several designs for panels that might be able to harvest the electrons. And if they are able, that could be very good news for us all.
Via Technology Review
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