Producing light emitting solar cells might appear counter-intuitive. But this is how Eli Yablonovitch, Professor of Electrical Engineering at Berkeley University, has been able to set a new efficiency record of almost thirty percent. Now he is planning to use the same method to turning heat radiation into electricity.
Today's solar panels have an efficiency of less than twenty percent, but Eli Yablonovitch has managed to increase the efficiency of its solar cells to almost thirty percent. The trick is that the solar cells are actually sending out a little light, but of a longer wavelength than which is coming in. In a solar cell, there will always be a little bit of energy that is not converted into electricity and it is better if it is emitted as light than being converted into heat, says Eli Yablonovitch. In practice this means that the solar cells also function as LED lights.
“A good solar cell must also be a good LED. In the R&D field, this was recognized only a few years ago,” he says. Now he hopes to be able to use this method to convert heat radiation into electricity, he calls it the thermo-photo-voltics.