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Research team is looking to make solar panels more efficient and give LEDs color changing capability

A pair of researchers at Arizona State University has announced a new advancement in making nanowires that could one day lead to significantly more efficient solar panels and LED lighting that is color changeable. The engineers who made the advance are Cun-Zheng Ning and Alian Pan.

The pair are working on ways to improve the quaternary alloy semiconductor nanowire raw materials. The nanowires the pair work with are nanometers in diameter and tens of microns in length. They are made from four elements, typically by alloying two or more compound semiconductors.

The researchers say that the band gap is the most important thing that controls how solar panels absorb sunlight and what color light LEDs produce. The more available band gaps for solar panels, the more of the spectrum of light panels will be able to absorb. With LEDs, more band gaps mean more colors of light can be produced. 

The big hurdle for the researchers is that naturally occurring and manmade semiconductors today only have a specific band gap. The only way to widen the band gap available to the semiconductor is to compound two or more semiconductors. The trick to accomplishing the alloy of semiconductors is that they two have to have a lattice with similar inter-atomic spaces to match and be grown together.

Ning said, "This is why we cannot grow alloys of arbitrary compositions to achieve arbitrary band gaps. This lack of available band gaps is one of reasons current solar cell efficiency is low, and why we do not have LED lighting colors that can be adjusted for various situations."

So far, the team has been able to create a zinc sulfide and cadmium selenide alloy to produce a quaternary semiconductor – this is the first time that a quaternary semiconductor has been produced in the form of a nanowire or nanoparticle. The team is now studying the application and use of the quaternary alloy materials for making solar cells and has developed a lateral multi-cell design panel.



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RE: Promises promises
By amirite on 3/22/2010 4:29:26 PM , Rating: 2
"In fact, night time demand is already larger than day, in the winter in many locations"

Peak hours during the winter for my electric company is 7am - 12pm.


RE: Promises promises
By porkpie on 3/22/2010 5:57:53 PM , Rating: 2
Your electric company is in NC. Locations that currently have higher peak energy demand at night are in northern (and thus very cold) locations. Also remember that northerly climes tend to get a much higher percentage of their total energy needs from oil and gas heating, rather than electric heat pumps (which are less efficient as ambient temperature drops).

But that's a side issue. The real point is that any serious usage of solar power would reverse the situation, causing night time demand to be greater than day.

And yes, while that would still reduce coal and oil usage, it can't make a very large dent in it. The only thing that can is nuclear...and if we have to build nuclear plants anyway, its far cheaper and more sensible to run them during the day, as well as the night.

Conclusion? Even if we solve the cost problems, solar is really only viable for a peak-shaving approach, rather than substantially filling our energy needs.


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