Optimum solar cell

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QuantaSol, the UK designer and manufacturer of strain-balanced quantum-well solar cells, has developed what it believes to be the most efficient single-junction solar cell ever manufactured.

QuantaSol, a UK designer and manufacturer of strain-balanced quantum-well solar cells, has developed what it believes to be the most efficient single-junction solar cell ever manufactured.

QuantaSol's single-junction device has been independently tested by Fraunhofer ISE as achieving 28.3 per cent efficiency.

QuantaSol was established in June 2007 as a spin-out of Imperial College London to commercialise the university’s solar cell IP and offer devices to concentrator photovoltaic (PV) systems developers.

'This is the first time that anyone has successfully combined high efficiency with ease of manufacture, historically a bugbear of the solar-cell industry,' said Kevin Arthur, QuantaSol’s chief executive. 'We’re now gearing up to provide multi-junction cells of even higher efficiencies as early as Q1 2010.'

The company, which has a development laboratory in Kingston-upon-Thames, Surrey, completed a £2m second funding round last week. It will now concentrate on cutting the cost of ownership of solar energy by moving to multi-junction devices.

QuantaSol is funded and backed by Low Carbon Accelerator and Imperial Innovations, and its strain-balanced quantum-well solar cell (SB-QWSC) is believed to be the highest performing single-junction concentrator cell in the world.

Solar-cell manufacturers need to find a crystalline semiconductor material that exhibits the optimum light absorption range, is a good absorber of solar radiation (silicon, for instance, is weak), has essentially the same lattice spacing of commercially available substrates such as gallium arsenide or germanium, and can be deposited seamlessly on those substrates to form a unique artificial crystal with no defects or unwanted impurities, using commercially viable crystal-growth technologies. None of the known semiconductor compounds or alloys can meet all these conditions at the same time.

QuantaSol’s approach combines several nanostructures of two or more different alloys to obtain synthetic crystals that overcome the problems associated with current solar-cell designs and also enhances the photovoltaic conversion efficiency.