Cambridge researchers make solar cell breakthrough

Solar panels work by absorbing energy from particles of light, called photons, which then generate electrons to create electricity. Traditional solar cells are only capable of capturing part of the light from the sun and much of the energy of the absorbed light, particularly of the blue photons, is lost as heat. This inability to extract the full energy of all of the different colours of light at once means that traditional solar cells are incapable of converting more than 34% of the available sunlight into electrical power. The Cambridge team, led by Professor Neil Greenham and Professor Sir Richard Friend, has developed a hybrid cell which absorbs red light and harnesses the extra energy of blue light to boost the electrical current. Typically, a solar cell generates a single electron for each photon captured. However, by adding pentacene, an organic semiconductor, the researchers found that solar cells can generate two electrons for every photon from the blue light spectrum. This could enable the cells to capture 44% of the incoming solar energy. Researcher Bruno Ehrler said: "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. However, much of the cost of a solar power plant is in the land, labour, and installation hardware. "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." The research was funded by the EPSRC.