Solar cells using ionic liquids as electrolytes are a step closer, thanks to an efficient organogelator developed by European scientists.

Hans-Werner Schmidt at the University of Bayreuth and colleagues have developed an organogelator which can effectively gel mixtures of ionic liquids without affecting their performance in solar cells. The urea-based organogelator is effective even at a loading of only two per cent, half the amount previously needed, said Schmidt. 

Incorporating the organogelator into ionic liquid mixtures gives an electrolyte which stays fluid at high temperatures, enabling it to be introduced into the cell. The mixture gels at lower temperatures, which is important for mechanical stability, according to Schmidt. Testing of the new cells showed that addition of the organogelator did not affect their efficiency.

Ionic liquids are a promising choice as 'green' electrolytes in solar cells due to their low volatility and toxicity, but they need to be gelled in order to work effectively. Schmidt is optimistic about the future and said that the photovoltaic performance of these cells renders them 'a very attractive concept . for power generation'. 

Niyasi Serdar Sariciftci, Chair of the Linz Institute for Organic Solar Cells, Austria, agreed, commenting that Schmidt's work 'opens up the industrial preparation of this type of solar cell by removing the obstacles of electrolyte stability and confinement'.

David Barden