Solar cell coating set to outperform PV panels

A thin film solar cell coating for glass could soon achieve over 20% efficiency, enabling it to compete directly with regular silicon-based solar PV panels, its inventor Oxford Photovoltaics has claimed. 

The firm will discuss its developments next week in one of 50 events being held as part of Green Sky Thinking Week in London. The event is being hosted by the architect Allies & Morrison, which has been collaborating with the Oxford University offshoot company for some years.

Its newest development, the thin film is based on developing solar cells formed from the mineral crystal perovskite, a semi-transparent material which when applied in an ultra-thin layer to surfaces like glass is able to generate power from the sun’s rays.

The firm’s scientists are currently able to achieve a 15% power conversion rate using perovskite-based cells, but that looks set to rise to over 20% in the near future, better than the majority of PV used today made from crystalline silicon.

“Nobody knows how efficient perovskite could become [some predict up to 50% efficiency is possible] but we are confident we can get it above 20%, which puts us right in the same field as silicon,” said Kevin Arthur, co-founder and CEO of Oxford Photovoltaics. “This realisation has prompted us to change our marketing model and we are now actively thinking about the technology’s applications for mainstream solar PV, rather than solely as a thin film coating for glass.”

Perovskite solar cells are less than 1 micron thick (a thousandth of a millimetre) compared to silicon-based cells, many of which are over 200 microns thick, so much less material is required for their production. In combination with high efficiency, it could signal a new era of cheap, mass-produced solar panels.

Oxford PV has constructed three laboratories in Begbroke Science Park, Oxfordshire, where scientists are working to scale up the technology in preparation for a commercial launch by 2017. Cells of up to A4 in size have been produced so far.

The firm is also looking to license the technology to the major glass manufacturers to enable them to apply the thin film coating to their single and double-glazed products. “Rather than installing ugly panels, PV can be incorporated into the skin of buildings, we’ve had tremendous interest from manufacturers and expect to have some announcements on that at the end of the year,” said Arthur.

Perovskite materials used in solar cells were first reported in 2009, but they were very inefficient and had to remain in a liquid state. Oxford University carried out polymer chemistry work to develop a more suitable solid state material, which when applied to glass is able to convert light photons into electrons and generate a voltage. This voltage is collected by receptors running around the edge of the pane.

Cells of up to A4 in size have been produced so far

Oxford PV will be discussing the technology at an event being held at Allies & Morrison’s studio in Southwark next Tuesday, 29 April. “We will be showing examples of what buildings integrated with the technology might look like and corresponding data models showing the kind of power they will be able to generate and the associated carbon savings,” said Arthur.

“Oxford PV has been working with Allies & Morrision for several years to help position the product in the building integrated PV sector. We want to make sure the product we introduce is the product people want to buy, rather than just something we can make.

Other events being held during Green Sky Thinking Week include a seminar hosted by St Thomas NHS Trust – Sustainable Buildings Experience at King’s Cross  and Atelier Ten – Cutting the Co2 out of Construction. For more details go to www.greenskythinking.org.uk/