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Avalanche Effect Demonstrated In Solar Cells
esocid writes "Researchers at TU Delft (Netherlands) and the FOM (Foundation for Fundamental Research on Matter) have found irrefutable proof that the so-called avalanche effect by electrons occurs in specific semiconducting crystals of nanometer dimensions. This physical effect could pave the way for cheap, high-output solar cells. Solar cells currently have relatively low output, typically 15%, and high manufacturing costs. One possible improvement could derive from a new type of solar cell made of semiconducting nanocrystals and could theoretically lead to a maximum output of 44%, with the added benefit of reducing manufacturing costs. In conventional solar cells, one photon can release precisely one electron. However, in some semiconducting nanocrystals, one photon can release two or three electrons, hence the term 'avalanche effect.' This effect was first measured by researchers at the Los Alamos National Laboratories in 2004, and since then the scientific world had raised doubts about the value of these measurements. This current research does in fact demonstrate that the avalanche effect can occur."
Manufacturing solar PV cells is usually said to cost quite a lot of energy. But how much exactly (on average)?
How many joules are consumed from raw materials to a deliverable PV cell of a given output wattage? Of the old "about 15%" (really about 20-25% these days), and of these new proposed "avalance" PV material ones?
I want to compare that energy cost to the cells' projected energy contribution over their lifetime, which is about 30+ years for today's PV cells. How long would the new ones last in typical service?
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make install -not war
Avalanche photodiodes of certain semiconductor materials have been around for a while now. I believe the novel part of this research is that they're confirming other researchers' data showing that lead selenide semiconductors can exhibit electron cascade effects.
Whether they're hairy, nanotube, or amorphous, cheap, efficient solar cells are always going to be thirty years away as long as there is 'cheap' oil around.
Sig this!
I frequently try to break the laws of thermaldynamics. Especially ones involving Intropy and the Carnal Cycle.
We seem to cavil about a few million dollars, or even a few hundred million, being spent to jump start emerging energy technology, but we have no problem spending billions on oil industry subsidies.
We need to acknowledge that any new tech investment involves high risk. Success brings high rewards. We accept exactly this reasoning when oil executives tell us that oil exploration is expensive and risky, and therefore requires continuing subsidies even when record profits are rolling in. A few million spent on alt energy research that tanks, however, is usually reported as a "this is what happens when you listen to the tree huggers" story.
An attitude adjustment as 'way overdue, and a rediscovery of our spirit of adventure and innovation. Perhaps putting some money into finding out whether this kind of solar cell works and can be mass produced would be a place to start.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
Man who leaps off cliff jumps to conclusion.
We need to wake up, and start the new Manhattan Project for energy; I don't think we can wait on the Free Market for this one.
Solar cells only work outside though.
You'd have to use a thick black raincoat, a wide brimmed hat and sunglasses to protect yourself from the ultraviolent radiation though. And cover up any exposed spots with SPF 10000 suncream.
Even then I'd scuttle back into the basement once the batteries had recharged.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
There is no such thing as irrefutable in science. In fact, some people attempt to define science as the pursuit of knowledge which can be corroborated and refuted using the "scientific method" (to preempt a lot of comments: I said "attempt to define", because this definition rapidly becomes circular unless you are very careful, and it is not clear that defining the "scientific method" is easier than defining science itself).
OTOH, I rather doubt that the scientists themselves claimed irrefutability here. The journalists are probably to blame.
Imagine for a moment if we geeks hadn't come up with DNS but instead tried to use a small handful of machines to handle domain name resolution. The Internet would collapse rather quickly no?
Funny then that to date our power grid is based on a centralized model. Sadly, as much as 20-30% of all power generated is lost during transmission over the grid.
Now effective solar panels and batteries to go with them would allow us to move to a more decentralized model. Imagine whole neighborhoods creating most - though not all - of their power needs. If the panels can get to around 80% of the needs of the house then the current power plants we have can be the only ones we need for awhile.
Or even better, instead of having massive plants with a huge footprint make use of smaller pup nuclear reactors - about the size used in a naval ship. One of those could be placed where the power substations are now and pick up the slack that the solar panels can't fulfill. They wouldn't present any real contamination danger as once their fuel was spent after 30 years or so you truck out the entire unit and refurbish (i.e. refuel) it under controlled conditions in a remote area - while in service the internals of the thing aren't opened up.
These things also wouldn't have to make as much power as the current power stations because, by virtue of being closer to the customers they serve, they wouldn't lose as much power in the lines.
If you actually read up on solar cells instead of sounding off like an idiot, you would know that the cost per watt is dropping quite fast, durability has doubled in the last 5 years, that Sharp are making cells which are nearly twice as efficient as much of the competition and they are being sold as roof panels, that the recently opened German factory can sell everything it makes for many months ahead.
Nobody has ever pretended that a 1 sq M panel would power anything large. There is only so much sunlight, and nobody has ever pretended the second law of thermodynamics would be broken. No-one has ever pretended that 1 sq M panels would cost $1 apiece; you could not make a structure to withstand wind loading that cheaply. There is a huge difference between actual forecasts of an eventual $1 per peak watt, and $1 per sq M. $1 per watt works out at about $140 per sq M for a 14% efficient panel.
To the people who modded this insightful: if you can't tell an obvious troll from engineering reality, plase hand in your geek cards now and go play with Facebook.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."