US boffins go pink for green energy

The future of green solar-powered energy may actually be pink, US boffins reported today.
Ohio State University researchers believe that new pink dye-sensitized solar cells (DSSCs), which get their pink colour from a mixture of red dye and white metal oxide powder, could be used to produce next-generation low-cost solar panels.

The researchers report that, currently, the best of these new pink materials convert light to electricity with only half the efficiency of commercially-available silicon-based solar cells – but they do so at only one quarter of the cost.

Yiying Wu, assistant professor of chemistry at Ohio State, said: "We believe that one day, DSSC efficiency can reach levels comparable to any solar cell.

"The major advantage of DSSCs is that the cost is low. That is why DSSCs are so interesting to us, and so important."

http://www.chemistry.ohio-state.edu/

He explained that pink is a typical colour for DSSCs. Most use dyes containing ruthenium, which has a red colour; the metal oxide powder that turns the mix pink is most often titanium oxide or zinc oxide, which are both whitish in colour. But Wu's materials are novel in that he's using more complex metals and exploring different particle shapes to boost the amount of electricity produced.

The project marks the first time that researchers have made a DSSC from anything other than a simple oxide. Wu and his colleagues chose zinc stannate because it belongs to a class of more complex oxides with tunable properties.

"We asked ourselves, what structure is best for gathering light and also transporting materials –
a tree! The leaves provide a high surface area for capturing light, and the branches transport the nutrients to the roots," Wu said.

"In our DSSC design, the dye-coated particles would provide the surface a rea, and the nano-trees would branch out in between them, to transport the electrons."