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."

Comments

APDs

[Wilson_6500]

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.

Los Alamos

[TubeSteak]

The avalanche effect was first measured by researchers at the Los Alamos National Laboratories in 2004. Since then, the scientific world has raised doubts about the value of these measurements. Does the avalanche effect really exist or not? This is the Los Alamos stuff they're talking about:

http://science.slashdot.org/article.pl?sid=04/05/20/1436213

Solar Cells Get Boost
Posted by michael on Thursday May 20 2004, @02:15PM
from the juiced-up dept.
Science Technology
An anonymous reader writes "Researchers from Los Alamos National Laboratory have tapped the efficiencies of nanotechnology to double solar cells' potential energy production. The key to the method is the use of lead selenium nanocrystals which can produce 2 electrons where 1 was produced before. Other optical applications can also benefit."

Re:Manufacturing Energy Costs?

[Animats]

The head of Applied Materials' solar division said in a 2007 talk at Stanford that their current production process costs about 2 years of output for a solar panel. He thinks they can get that down to 6 months of output; he said some things about improvements to the sputtering process. which is derived from IC manufacturing technology where the wafers are smaller.

They'll probably do it. What Applied Materials does is improve semiconductor process technology. They're the world's largest maker of semiconductor fab equipment. This led them into making LCD displays, and then solar panels.

Re:Isn't price the key?

[dakameleon]

To me, the big issue is not efficiency but cost per watt. Read the bloody summary even!

could theoretically lead to a maximum output of 44%, with the added benefit of reducing manufacturing costs So if the summary is to be believed, you're increasing output nearly threefold, and reducing cost of manufacture. The cost-per-watt ratio moves the right way on both sides.

Re:Penny wise, pound foolish

[LynnwoodRooster]

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.

Maybe because most alternative energy sources are big money losers? Take a look at page 16 of this report for the actual numbers about subsidies...

I predict once you can start to get alternative energy sources like solar and wind down an order of magnitude or so in terms of cost you'll see things turn around. However, for now they're getting somewhere around 100X the subsidy per Megawatt-hour that "Big Oil" gets.

An improvement from 15% to 40% simply isn't enough - natural gas and oil get around $0.25 per MWhr, while solar and wind get 100 times that amount per MWhr. And remember, those nasty "Big Oil" companies also pay over $3 in direct federal taxes for every $1 in profit. Over $200 billion flows into the Federal government every year in terms of direct taxes and fees (that's not including the taxes you're paying on consumption of their products).

Right now, and for the last 20 years, wind and solar have been huge money-losers, and only exists BECAUSE of the massive subsidies. If we subsidized wind or solar at a level to get useful output levels, we'd spend literally trillions more per year.

And then there's that whole baseload thing...