Project aims to boost lifetime of flexible disposable solar cells

UK researchers are hoping to bring flexible, disposable solar cells closer to commercial reality through a new project to improve their lifetime.

Scientists at Bath University are to lead a four-year, €4m (£3.2m) project funded by the EU to find new ways of making dye-sensitised solar cells, a technology that mimics photosynthesis using an organic dye to generate electricity at low cost.

The researchers, working with companies including Oxford Photovoltaics and Australia-based Dyesol, hope to tackle one of the key problems of these kind of cells: their very short lifetime, which, depending on the particular technology, can be as little as a few weeks.

‘Water can get inside them and affect the performance and the dye is an organic dye and that will degrade with time,’ Prof Alison Walker, who is leading the research for Bath University, told The Engineer.

‘Liquid cells are more efficient but they have a shorter lifetime because the electrolyte leaks out. Solid cells are made with a polymer instead of a liquid but are less efficient and the polymer itself can degrade.’

The titanium oxide film that some cells use as an electrode can also cause problems by acting as a catalyst and encouraging reactions that damage the cell.

In order to increase the cells’ lifetime, the researchers plan to experiment with dyes that can cope better with water ingress, improve the external or integrated barriers that protect the cells and find more robust polymers and electrodes.

Walker hopes to improve the technology enough to make it commercially viable, or at least bring it much closer to that point, although the exact lifetime needed to do this will depend on the application.

But because dye-sensitised solar cells are much cheaper than traditional silicon-based photovoltaic they could be marketed as a renewable alternative to disposable batteries and so would only need to last up to several months.

‘Where these cells come into their own is in portable power,’ said Walker. ‘You’re also talking about power in remote places. Cheap solar power could revolutionise lives in developed countries but it’s got to be portable and one thing silicon isn’t is portable.’

The project is funded through the EU’s Marie Curie Initial Training Networks programme, which aims to give early-stage researchers experience in established teams.