PhD student devises low-cost solar cell production technique

It is claimed that this will almost certainly result in a further reduction in the price of the cells, which are made of amorphous silicon.

The cost of electricity generated using solar cells is still costly, partly owing to the characteristics of the most widely used material in solar cells — crystalline silicon.

’An interesting alternative to crystalline silicon is amorphous silicon,’ said Prof Miro Zeman of TU Delft. ’Although this material has a lower energy yield than crystalline silicon, solar cells based on it can be produced far more cheaply. The nature of the material means that much thinner layers can be used — around 250nm thick, compared with the 200μm-thick layers of crystalline silicon.’

Amorphous silicon solar cells are already being produced for this reason. ’But one significant problem for the industry is that the usual technique used to produce the cells — which involves vaporising silane gas to deposit the amorphous silicon on glass — is too slow,’ said Zeman. ’It takes about one second to apply a 0.1nm layer, so to apply a complete 250nm layer requires about 40 minutes.’