Cadmium Thin Film Solar CellsA new technique for building thin film solar cells has been developed at the University of California in Berkeley. The method, which is still only in the experimental phase, involves growing tiny tubes called nanotubes onto a backing sheet. 
The tubes themselves are made from Cadmium Sulfide resemble little pillars and they are grown on Aluminium foil. The a thin film of Cadmium Telluride is added on top of the pillars, and after that another film of copper and gold to act as the top electrode. The researchers also suggest that the whole cell could be encased in a transparent plastic which would mean it would be flexible.At present the researchers have achieved a 6% efficiency in the laboratory using this technique. While this is well below the efficiency of silicon and other solar cells currently in mass production, it does offer a possible new avenue of research into solar power with the potential for increased efficiency as research continues. These chemical names mean little to most of us, but Cadmium Sulfide is carcinogenic and can have other significant health effects even in very small doses. Cadmium Telluride is also suspected of being a carcinogen. While it may be true that the cells being developed use very little of these materials and so in the long term may be cost effective to produce, there still remains the issue of what happens to the Cadmium in the panels when their useful lives are up. Thin film solar panels generally have a short lifespan compared to crystalline solar panels because their thin layers of materials are more quickly degraded by constant exposure to sunlight. Once their useful lives are up they either end up being recycled or thrown out. In this second case, solar panels built using Cadmium compounds would pose a significant environmental problem to people and wildlife in the area of the dumped materials. The research team is aware of this and is exploring the potential of other less toxic compounds using similar techniques. For more information, click here. Return from Thin Film Solar Cells to Solar Power News or return to the Green Planet home page for more Solar Power Facts.
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