A new type of solar cell that generates two electrons from every photon absorbed has the potential to increase the maximum efficiency of solar panels by over 25%.
Researchers from the Cavendish Laboratory at the University of Cambridge have developed a hybrid cell that absorbs red light and harnesses the extra energy of blue light to boost the electrical current.
“This is just the first step towards a new generation of solar cells and we are very excited to be part of this effort,” said Dr Akshay Rao, co-author of the paper published in NanoLetters.
Traditional solar cells can only absorb part of the light from the sun; most of what is absorbed, particularly of the blue photons is lost as heat. Current solar cells generate a single electron for each photon captured, but by adding pentacene – an organic semiconductor consisting of polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene rings – the solar cells generate two electrons for every photon absorbed from the blue light spectrum.
“Organic and hybrid solar cells have an advantage over current silicon-based technology because they can be produced in large quantities at low cost by roll-to-roll printing,” said Bruno Ehrler, lead author.
Traditional solar cells are unable to convert any more than 34% of the available sunlight into electrical power, but this new cell could capture up to 44% of the incoming solar energy.
However, Ehrler realises this is not the only improvement necessary to make solar energy more appealing.
“Much of the cost of a solar power plant is in the land, labour, and installation hardware,” he said. “As a result, even if organic solar panels are less expensive, we need to improve their efficiency to make them competitive. Otherwise it’d be like buying a cheap painting, only to find out you need an expensive frame.”