Breakthrough Efficient, Paintable Solar Cells

An anonymous reader writes "A new solar cell material has been discovered that converts 30% of the sun's energy to electricity." Here's another solar news story. These new cells can harness infrared light which is why they are so much more efficient.

Comments

Re:How much $$$?

[plover]

Because it was just invented. RTFA, the research was published Sunday.

Who knows if it will be expensive, cheap, emit toxic byproducts, or even be producable in consumer quantites yet? It's just research, not a factory.

Potential != Realized

[Daxton]

If you check the original press release, you'll notice UT says the 30% efficiency might be realized "with further improvements in efficiency". The reporter for CTV missed that little nuance.

Re:How much energy?

[ThosLives]

This is irrelevant for something like a solar cell. A solar cell might take lots of energy to produce, but as long as there is the correct incident radiation and the device works, it will produce energy. For instance, say, it takes 10 MJ to produce one of these capable of produce one watt. The 10 MJ will be made up in 10 million seconds, which is not quite 4 months. (1e7 seconds / 86.4e4 seconds/day = 115 days and some change.) My guess is that's on the right order of magnitude.

Note that this material doesn't "produce" energy at all - it just converts it from the sun (which is the thing sending all the energy our way in the first place). This is different than, say, hydrogen, which is an energy storage medium; you have to put energy into hydrogen to store it, then you get a little less out. With these, you simply build the device, then use (solar) radiation to create a current.

Re:Okay since heat is IR...

[elgatozorbas]

For starters: heat is not the same as IR. ALL bodies (except perfect reflectors) at nonzero temperature radiate ligth. For very hot ones, this is visible, for rather cold ones this is IR (i.e. 'below red'). You can also heat something by shining other than IR light on it.

These devices don't suck the radiation out of stuff, just like a (digital) camera doesn't suck light from the object you photograph. You can therefore not use them to cool anything, afaik. CPU coolers suck heat out of your cpu because they offer it a lower temperature, and heat flows from low to high temperature.

These things are different from a thermalcouple in the sense that they are in a completely different ballpark. A thermocouply supplies you with electricity as long as you can maintain a temperature difference over it, or it will drain heat from its cold side and add it to its hot side (increasing the difference) if you supply electricity to it. The things in the article supply you with electricity when you shine a light on them and are probably destroyed when you supply electricity to them.

Z

Paintable solar cells. Not the first ones...

[Spy der Mann]

2002 CNN article about "paintable solar cells".

The advance in here is that these new cells also use infrared. Also, solar cells are only ONE of the possible applications of this new technology (Nanoapex news article).

Re:POTENTIAL 30%, not actual

[Anonymous Coward]

2 comments...

But first, my background...

I actually read the journal paper.

I work on related projects in graduate school, including polymer solar cells, and prior to that worked for a company developing quantum dots for other applications.

1.) The 30% is the theoretical power conversion maximum for a solar energy conversion with a single layer device; they only got a small fraction of this. You could only get this maximum if you had a material that absorbed every photon in the theoretically correct range, every one of these photons created an electron, and every electron came out of the device -- not an easy task, and 30% is the best you could do. The reason there is a 30% maximum is simple -- the device only puts out a single voltage, corresponding to the point of longest wavelength (lowest energy) that the material absorbs. This voltage is the same for all electrons that are generated from each photon. This means all those blue photons become just like the IR photons -- they give up a bunch of energy.

2.) The materials would be cheap. Quantum dots are not exotic. They're just little chunks of semiconductor. They are called quantum dots because their size is such that they have what are called quantum size effects. They are made from soap and metal salts. Massive production would be cheap. The polymer would be cheap to mass produce, as well. The problem is sandwiching it between electrodes -- you couldn't just paint it on without this.

So, basically, this isn't a huge advance... It's the normal stepwise improvement. They took existing technologies that are available, combined them and hyped them up a lot.

Re:How much energy?

[doinky]

From wikipedia:

"A common myth is that the production of photovoltaic cells requires more energy than these cells produce in their lifespan. Modern cells typically require two to six years to pay back the energy investment made in them, and their lifespan is around 30 years."

Re:Only at the poles, for half the year

[cbiltcliffe]

High inefficiencies? What are you talking about?

http://www.nmsea.org/Curriculum/7_12/electrolysis/ electrolysis.htm

Take a look at the section headed:
"Specific things you can point out:"

"....electrolysis can be (and is) performed at very high efficiencies close to 100%."

It's probably one of the most efficient energy transformation methods we know of. It's not exactly quick in most people's experience, because the usual public school science projects use electrodes that are way too small.
The biggest I've currently used was about 6-7 square inches of stainless steel, and used a total of 12 milliamps at 14 volt.