Thaindian News

Washington, Mar 18 (ANI): The speed at which inexpensive solar cells are produced can be increased by a factor of ten - and this can be achieved without any detriment to the energy yield of the cells, thanks to a new technique developed by a PhD student at TU Delft.

Michael Wank, who submitted his thesis on this subject, said this would 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 greater, 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 Wank’s PhD supervisor Prof Miro Zeman.

“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 200-micrometre thick layers of crystalline silicon,” he added. Amorphous silicon solar cells are already being produced for this reason.

“One significant problem for the industry is that the usual production technique (vaporising layers of silane gas) is too slow. It takes about one second to apply a 0.1-nm layer, so to apply a complete 250-nm layer requires about 40 minutes,” said Zeman.

To speed up the process, Wank concentrated on a new expanding thermal plasma chemical vapour deposition (ETP-CVD) production technique, which could speed up the production by a factor of 10 - to 1nm per second - while maintaining a yield of around seven percent.

However, a conventional ETP-CVD production technique could not be used owing to the fact that it requires a temperature of around 350 degree Celsius - a temperature that would cause damage to the solar cells and affect their energy yield.

To circumvent this, Wank applied an ion bombardment during the production process, which enabled the production to take place at a much lower temperature of around 200 degree Celsius.

“The results of the research are of great interest to industry, which can use the method to make solar cells quickly and inexpensively,” said Zeman.

“As well as the greater speed, another benefit is that the machines needed for this technology are smaller. All in all, this technique promises to cut the production costs of this type of solar cell considerably,” he added. (ANI)