A new window on solar energy

Innovative solar cell technology based on research at the University of Oxford has created glass that generates electricity.

Many buildings today help meet their energy needs by using large banks of somewhat unsightly opaque solar panels. A new kind of solar cell that can be printed directly onto glass or glazing products, enabling them to generate electricity whilst also transmitting light, looks set to revolutionise the energy capabilities of new buildings whilst also offering much greater aesthetic appeal.

The new technology uses low-cost and abundant organic compounds and metal oxides to produce coloured glass panels that generate electricity through a photovoltaic process similar to photosynthesis. The panels are available in a variety of colours and tints, achieved by using different organic dyes, with green being the most efficient colour for electricity generation (though red and purple also work well).

The new device is a form of thin-film solar technology, a relatively new development in solar energy generation, but whereas other dye-sensitised solar cells use volatile liquid electrolytes, University of Oxford physicists led by Dr Henry Snaith have replaced these liquid electrolytes with a solid organic semiconductor while retaining high efficiency. The resulting material can be applied directly to glass by a simple screen-printing process. Not only does this avoid the complicated and expensive high-vacuum manufacturing processes needed for competing technologies, it also does away with the use of the scarce elements and/or toxic materials they generally require.

Dr Snaith’s research team continues to investigate the complex relationship between different materials employed in these solar cells and energy harvesting properties, and seeks to improve the efficiency of the patented technology, while a spin-out company, Oxford Photovoltaics, is working to scale up the process and develop manufacturing expertise. With manufacturing costs expected to be less than half that of other thin-film solar technologies and an environmentally benign product that looks extremely attractive for the rapidly growing building-integrated photovoltaic market, the future is looking bright.

Funded by: The Engineering and Physical Sciences Research Council, the European Commission, the Oxford Martin School, and the University of Oxford John Fell Research Fund.