Solar Cells: thin is 'in'

Being thin is 'in' not only in the world of beauty and fashion, but in technology also. Now it is the turn of solar cells. The quest for alternate/renewable sources of energy and the need for greater energy efficiency is driving scentists and researchers to explore newer possibilities. Norwegian researchers at the University of Oslo have succeeded in producing solar cells that are about 20 times thinner than conventional products. This means a saving of nearly 95% of precious silicon from which solar cells (and most other electronic components) are fabricated, thus making them considerably cheaper.

Currently solar cells measure about 200 micrometers (that is, 0.2 mm) in thickness. The individual cells are 'sawn' from a large block of silicon, and this means a lot of wastage of silicon (nearly 40-50 %) by way of 'saw dust'. Naturally, thin cells would mean that the yield is very high.

A 'side effect' that results from this development is that the cells are so thin that a lot of light, especially the wavelenghts near red, passed straight through without contributing to electricity generation. The University boffins have, however, found a way to trap these rays and increase the efficiency of the 10 micrometer thin cells. They deposited small plastic 'micro beads' on the silicon that scattered the rays, making the apparent thickness of the cell about 250 micrometers.

Hectic work is on to adapt these techniques to large-scale manufacturing, and commercial realization could take a few years.

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