Basel University Researchers have replaced rare iodine with cheaper cobalt in dye-sensitised solar cells in a bid to reduce costs of the technology.
Iodine is an electrolyte that transports electrons inside dye-sensitised solar panels during the process of transforming light to electricity. The Swiss team has managed to substitute iodine with more abundant element cobalt without negatively affecting the panel’s performance. The research results have recently been published in the journal ‘Chemical Communications’.
“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,” said the project officer Biljana Bozic-Weber. The team believes these, so-called Cu-Co cells, would make manufacturing of dye-sensitised cells much more sustainable.
The team has also found that replacing iodine with cobalt has an additional desirable effect on the panels’ durability. Copper compounds tend to react with the iodine-based electrolyte, forming copper iodide, which speeds up the panel’s degradation. With the cobalt-based electrolyte, such problem could be easily avoided.
“In changing any component of these solar cells, it is necessary to optimise all other parts as a consequence,” said Ed Constable, Professor of chemistry at the University of Basel and one of the project leaders.
The team has been working on dye-solar cell improvements for several years. In 2012 the team demonstrated that ruthenium – an extremely scarce element used in dye solar cells, could be replaced by copper derivatives.
The recent report is the first one looking into possible combination of copper-based dye cells and cobalt electrolytes.
Dye-sensitised solar cells are low cost solar cells that consist of a semiconductor that is coated with special dye. This coloured complex absorbs light, which is then turned into electric current through an electron transfer process.