Clean Power

Published on August 5th, 2013 | by James Ayre


More Sustainable Solar Cells From Cobalt

August 5th, 2013 by  

More environmentally friendly and cheaper solar cells could be manufactured using cobalt, new research as found. Researchers from the University of Basel have developed a copper-based, dye-sensitized solar cell where the expensive (and relatively rare) element iodine has been replaced by the much more common element cobalt. The new Cu-Co solar cell — as it’s been dubbed — shows no loss of performance as compared to more conventional iodine-containing, dye-sensitized solar cells.

Some context: Dye-sensitized solar cells (DSCs) are a type of solar cell that works by capturing sunlight via a colored dye, which then, through an electron transfer process, produces electrical current. Electrolytes function as the electron transport agents. In conventional DSCs, iodine and iodide are the typical electrolytes used.

solar cells iodine cobalt iodide

© 2013 Royal Society of Chemistry, via University of Basel

According to the researchers, this new replacement significantly improves the potential sustainability of solar cells: “Iodine is a rare element, only present at a level of 450 parts per billion in the Earth, whereas cobalt is 50 times more abundant,” states Project Officer Dr Biljana Bozic-Weber. “Furthermore, this replacement also removes one of the long-term degradation processes in which copper compounds react with the electrolyte to form copper iodide and thus improves the long-term stability of DSCs.”

While this new research represents a great step towards the goal of stable iodide-free copper solar cells, there are still some issues that need to be worked out before commercialization can begin, in anything other than niche markets that is.

“In changing any one component of these solar cells, it is necessary to optimize all other parts as a consequence,” states Ed Constable, a chemistry professor at the University of Basel. “This is part of a new approach termed ‘Molecular Systems Engineering’ in which all molecular and material components of a system can be integrated and optimized to approach new levels of sophistication in nanoscale machinery.”

The new research was just published in the journal Chemical Communications.

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • Hans

    The cost and availability of Iodine seems to be an add-on argument, i.e. not the real reason to do the research, just something to satisfy funding agencies and the general public:

    Iodine is not so expensive: Googling give prices in the range of 16$ to 83$ per kg.

    Cobalt prices seem to move in the same price range:

    However prices are per kg, and Iodine has twice the atomic weight so per atom as Cobalt, so per atom Iodine is roughly twice as expensive . Nevertheless I suspect the contribution to the total cost of the cell is probably very small. I would love to see some numbers on that.

    Improving the long term stability of the solar cell seems to be the real, and very valid, reason to do the work.

  • Hans, keeping you sharp

    I never heard of solar cells using Iodine. Iodine is also not rare, we use it to disinfect wounds. Last time that I was at the chemists a bottle of Iodine solution was dirt cheap. What is probably meant is Indium which is used in so-called CIS-cells (Copper Indium Sulphide). Panels with CIS cells look like a pin-stripe suit.

    Please do your homework next time, journalism is more than rephrasing press-releases.

    • Hans, eating humble pie

      This time I did not do my homework, and read the article only at a glance. DSC-cells are indeed made with Iodine.

  • JamesWimberley

    Replacing iodine with cobalt is not an obvious environmental win. Iodine is not really rare, and there is plenty associated with natural gas production; extraction from seawater is feasible (dixit Wikipedia) but not worth it. Cobalt is mined in the Congo, the world’s worst governed country along with Somalia. The real gain is probably cutting the degradation of copper.

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