Quantum Dots…The Future of Solar?
A recent discovery shatters the notion that one photon can only excite one electron. Researchers from the joint SLAC-Stanford Pulse Institute for Ultrafast Energy Science are on the move to boost solar cell efficiencies by confirming that a single photon can indeed excite more than one electron in a quantum dot. Are we at the cross roads of a new solar age?
- » See also: Altus Air Force Base is Flying High on New Green Award
- » Get CleanTechnica by RSS or sign up by email.
By now we all know that there are inherent benefits to solar energy. Sunlight is free, available throughout the globe and produces no greenhouse gases. Solar power is limited, however, by inefficiencies that make it much more expensive than traditional power sources. This could all change thanks to new research that may one day boost solar efficiencies to a level never thought possible.
The recent PULSE experiments use ‘quantum dots’, tiny spheres composed of a few thousand atoms, to boost electron interactions by concentrating the electrons into a extremely small area. Researchers found that with quantum dots, 1 photon can excite up to 3 electrons depending on the sunlight’s color. These results mean that solar cell processes could be as much as one third more efficient if constructed with quantum dots.
Although there are some difficult scientific and engineering feats to be conquered in the production of a solar cell with quantum dots, such a technology could one day revolutionize solar power. Each day solar cell advances bring the technology closer to matching the price of traditional power sources. Although the PULSE team is still in the early stages of research, I have a strong feeling that the quantum dot technology will be implemented in a new generation of solar cells.
Image Credit: .:sandman at Flickr under a Creative Commons liscense
Wouldn’t that be 3 times the performance rather than 1/3 times? I’m no scientist so help me out. Thanks.
Good question! I should have clarified that.
The researchers reported that in the greatest case scenario, 1 photon was able to excite 3 electrons. Although the quantum dots were able to achieve the degree of excitability, there are still cases where 1 photon excites only 1 electron. There should also be cases (I assume) that quantum dots allow 1 photon to excite 2 electrons. I think the researchers looked at the average ability of photon to excite electrons (through quantum dots) and then estimated that efficiency could be improved by one third.
One third of an improvement is still a pretty big advance in my opinion though.
Hi Michael:
Good article. I remember seeing something about this subject a few months ago, then lost track of it. So I tried googling ‘Quantum Dots’ but that brought up too much that was not directed toward solar power. After a few variations I was overwhelmed by the results. There is a whole lot going on out there in the labs.
Cheers, Chris Johnson
Solterra Renewable technologies Inc is actually scaling up both the high volume production of low cost quantum dots and a printed quantum dot solar cell.