STMicroelectronics is developing dye-sensitised solar cells (DSSCs), aimed at technology for large-scale solar electricity generation.

It has produced demonstration DSSCs as complete series-parallel arrays on glass and is looking to build larger power-generating installations. The firm is looking for companies in the solar installation sector following the DSSC development.

“Right now, to be quite frank, we are looking for a partner,” said Salvatore Coffa, deputy R&D manager at ST’s Sicilian development centre.

Regarding the technology, Coffa said: “We have solved some of the issues people have not solved before.”

Conventional crystalline silicon solar cells are efficient, around 16 per cent, but expensive. Much of this expense is in the raw material. “Sixty per cent of the $4/W is the initial silicon wafer,” said Coffa.

DSSC is a non-silicon technology, using layers of polymers and inorganic compounds on glass. It has the potential to produce cells at $0.40/W, said Coffa, and to hit the magic efficiency threshold of ten per cent where it is thought large-scale solar installations will be worth erecting.

“Our target is at least ten per cent,” he said. “If you are getting good reliability with 12 per cent, you really have a good solar cell.”

So far, demonstration cells are operating at eight per cent efficiency with little deterioration. “In intense sun, the [dye] molecules can deteriorate a bit,” said Coffa. “We have tested them for 1,000 hours in sunlight and the efficiency fell from 8 to 7.4 per cent.”

This contrasts with all-organic solar cells which have the potential for very low-cost production but: “we have very big trouble trying to protect it from sunlight,” said Coffa.

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