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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.
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.
John
Wearable solar panels... Resistance is Futile.
IR != heat IR is radiation as a result of heat. Your CPU is primarily cooled by conduction (having a large heat sink absorb the heat, distribute it, then itself radiate the heat. You could surround your CPU with the stuff and get back some of the energy that was radiated through inefficiency (heat), but that wouldn't be too significant.
http://bpsolar.com http://www.shell.com/home/Framework?siteId=shellso lar
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.
Sweeping statements should never be made.
since most photoelectrics work off the same principle (photon moves electron to a higher energy state, and so forth) fluourescents would probably work fine. The difference with IR is that their wavelength is much lower - thus the energy is lower, and absorption is that much more difficult (long, detailed explanation omitted)
all too frequently, people use this misconception. Heat is not equivalent to infrared energy.
You see heat in infrared images because things of the temperatures that are common on the Earth (people, plants, cars, etc. ) have blackbody radiation curves that peak in infrared band.
Don't get me started on people that confuse light amplification with infrared cameras.
30% of nothing. They figure it could in theory get 30% efficiency, just as soon as *INSERT BREAKTHROUGH IN CHEMICAL OR PHYSICAL SCIENCE HERE* happens.
This sounds just like every other moon-man technology of the future. Hydrogen will revolutionize our economy! (Just as soon as we figure out how to collect and store it) A space elevator will mean cheap orbital trips, space tourism, extraplanetary mining, a trip to mars- all we need to do is invent the material we need to build it out of.
Bah.
They put metal in some paint and noticed it releases electrons when exposed to light.
It's called the photoelectric effect and it happens with all metals, and Einstein won a nobel prize for explaining it 100 years ago.
I don't need no instructions to know how to rock!!!!
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.
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
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
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).
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.
"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."
Ok, the environmentalists have really gotten to you, ahven't they? Big Oil is investing in alternative fuels because they know that oil will run out someday. here is one example using shell. Don't believe everything you here. They are also investing in fuel cells as well and looking to change their production over to hydrogen if ti ever makes it big. Oil gets used in lots of things. Not just gasoline. They aren't going to go out of business even if everyone switches to hydrogen. Too many other things use petroleum.
Fly me to the moon Let me sing among those stars Let me see what spring is like On jupiter and mars
You owe me two minutes of my life back
30% has been demonstrated in prototypes.
Gallium is rare and expensive. Huge areas of gallium arsenide cells aren't going to happen.
heat is not the same as IR
No, heat is two things. Molecules vibrating (mechanical heat), and IR radiation. These things are in equillibrium with eachother.
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.
Incident IR radiation can do one of two things. 1) Be absorbed 2) Not be absorbed.
In the second case, it just continues on its way. In the first case it turns into molecular vibrations (heat), eventually it will be re-emitted. When something is holding a constant temperature, you have an equillibrium, the radiation absorbed equals the amount emitted.
Now, in a photocell, the absorbed IR radiation is being turned into electricity, and not molecular vibrations. Removing heat radiation from a closed system is the same as removing heat, given the equillibrium. Basic conservation of energy.
So yes, you are making things colder. But given the scale of the world, and that it's not a closed system either (but you do have a local equillibrium where the temperature is such that the incident sunlight equals the amount radiated off into space) it's not going to make things noticeably colder.
High inefficiencies? What are you talking about?
/ electrolysis.htm
http://www.nmsea.org/Curriculum/7_12/electrolysis
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.
"City hall" in German is "Rathaus" Kinda explains a few things......
Serbia has one large reversible power plant on Drina River. Its efficiency is about 2/3.
Water is pumped during the night (when thermal plants produce more than system consumes - and you cannot stop/start thermal plants every couple of hours), and it generates electricity during so-called "peak hours". Great thing, although a bit too large for our needs - it was designed for larger system (i.e. system of former Yugoslavia).
No sig today.
Betteries are quite expensive and have a relatively short life. (We priced them, as you can't be independant of the power grid without them. UGH! It would have nearly DOUBLED the cost of our solar cell system.)
I have hopes that in a few years the supercapacitors will come down in price and up in power. They aren't a "mature" technology the way batteries are, so they are advancing much more quickly. Right now they're thinking (well, dreaming) about trying to replace batteries on hybrid cars, but if they can do that then I suspect that they'll quickly improve. They I'll get the electrical storage system. Either batteries from companies that are trying despearately to find a new market (unlikely, but possible as the newer cars are going to a higher voltage electrical system, which more power storage) or to the super-capacitors, which reportedly don't wear out when you charge and discharge them.
Then again, possibly fuel cells will mature, and I *WILL* be able to electrolyse water during the day, and recombine it at night. That would work too.
I think we've pushed this "anyone can grow up to be president" thing too far.
According to http://www.electricitystorage.org/tech/technologie s_technologies_flywheels.htm Flywheels are ~90%.
Fly me to the moon Let me sing among those stars Let me see what spring is like On jupiter and mars