If you want more efficient solar power-better then the 15-20 % efficiency we typically see today, Victor Klimov, a physicist at Los Alamos National Laboratory in New Mexico is the person to see. What's his deal ?
"Give him one photon of sunlight, and he'll give you two electrons' worth of electricity", say New Scentist magazine today.
Not impressed by this claim? Well,you should be.
In all solar cells now in use - in everything from satellites to pocket calculators - each incoming photon contributes at most one energised electron to the electric current it generates.
Now Klimov has broken through this barrier.
"He has shown that by shrinking the elements of a solar cell down to a few nanometres, or millionths of a millimetre, each captured photon can be made to generate not one, but two or even more charge carriers."
Producing this multiplicity of electrons - an achievement that has been replicated by a group at the National Renewable Energy Laboratory (NREL) in Golden, Colorado - is a remarkable piece of physics, hails New Scientist.
If the effect can be harnessed, it could change the whole energy debate by making solar power much more efficient and economical. While there are many ongoing efforts to improve solar efficiency - by concentrating sunlight, for example, or by making it easier for electrons to move around within a cell - the new approach is unique in that it gets to the very root of the process and also complements other methods.
For decades, photovoltaics have been stranded on the effete fringe of energy technologies - ideal for niche applications such as satellites, but not economically competitive here on Earth. Made from semiconducting materials, most often silicon, solar cells convert a dismayingly small fraction of the sun's energy into electricity. Radically improving efficiency could give solar energy a boost at a time when it is sorely needed and funding decisions hang in the balance.
"If this could be translated into a robust system that could generate multiple carriers, it could be revolutionary," says Eric Rohlfing, acting director of the chemical sciences, geosciences and biosciences division in the Office of Basic Energy Sciences at the US Department of Energy.
The latest results trace back to 1982, when materials scientist Alexander Efros at the Naval Research Laboratory in Washington DC showed it was theoretically possible for a photon to generate multiple charge carriers in certain semiconductors.
In his latest series of experiments, Klimov claims to have produced as many as 7 excitons per photon in crystals of lead selenide 4 to 8 nanometres in diameter (Nano Letters, vol 6, p 424). "They're very cheap and only take a few minutes to grow," says Klimov. "It's like making new atoms, to go beyond what nature provides."
Full story in New Scientist today (subscription required)
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