Spray coating method used to make solar cells

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Solar cells made using a process similar to spray painting have been developed by a research collaboration between scientists at Sheffield University.

Experts from Sheffield University’s Department of Physics and Astronomy and Cambridge University have created a method of spray-coating a photovoltaic active layer using an air based process to develop a cheaper technique which can be mass produced.

Sheffield University’s Prof David Lidzey said, ‘Spray coating is currently used to apply paint to cars and in graphic printing. We have shown that it can also be used to make solar cells using specially designed plastic semiconductors. Maybe in the future surfaces on buildings and even car roofs will routinely generate electricity with these materials.

Artist's impression of spray-coating glass with the polymer to create a solar cell
Artist’s impression of spray-coating glass with the polymer to create a solar cell

‘We found that the performance of our spray coated solar cells is the same as cells made with more traditional research methods, but which are impossible to scale in manufacturing. We now do most of our research using spray coating.

‘The goal is to reduce the amount of energy and money required to make a solar cell. This means that we need solar cell materials that have low embodied energy, but we also need manufacturing processes that are efficient, reliable and consume less energy.’

Most solar cells are manufactured using energy intensive tools and materials like silicon, which contain large amounts of embodied energy.

Plastic, by comparison, is said to require much less energy to produce and by spray-coating a plastic layer in air the team hope the overall energy used to make a solar cell can be reduced.

According to the university, a downside to using the plastic as solar cell materials – needed for the spray technique – is that they are not currently as efficient at generating electricity as cells made from silicon.

The vast majority of solar panels found in the UK are made from silicon and are expected to last over 25 years. It is unlikely that plastic cells will ever be this stable, but if the energy cost of plastic cells can be lowered enough they will become more effective than silicon over their life cycle.

‘Increasing the energy conversion efficiency and lifetime of plastic cells are significant issues that many groups are working on,’ Lidzey said in a statement. ‘It should also be noted that the cost of silicon solar panels have reduced significantly over the last few years so plastic solar cells will have to catch up with these improvements.’

A paper detailing the research can be found here.