Photovoltaic cell concept could boost voltage and efficiency
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Researchers have created photovoltaic (PV) cells designed like LEDs to emit light as well as absorb it.
The counterintuitive concept actually increases voltage and efficiency, according to the team at University of California, Berkeley, who worked with Alta Devices to produce a prototype.
PV cells produce electricity when photons from the sun hit the semiconductor, knocking electrons loose to flow free.
But this can also generate new photons, in a process called luminescence. The idea behind the new design is that these extra photons — which do not come directly from the sun — should be allowed to escape from the cell as easily as possible.
This has the effect of increasing the voltage that the cell is able to produce, leading to a new prototype with an efficiency of 28.3 per cent, up from the previous record for single-junction cells of 26 per cent.
‘Fundamentally, it’s because there’s a thermodynamic link between absorption and emission,’ said Owen Miller of UC Berkley.
Readers' comments (2)
Kerry Green | 27 Apr 2012 12:43 pm
This is great work, I was amazed to read earlier that most PV panels run at 14% efficiency. Could the efficiency ever get up to 90%? Seems like with PV we are at the same point as the petron engine in 1900.
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Jon Mercer | 2 May 2012 1:29 pm
There's a theoretical maximum to the efficiency of solar panels. It's 29% or thereabouts. But with 1 kW m^-2 available, big wins can be made with transparent cells that can be plastered all over the windows of buildings providing the cost of production can be got low enough.
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