Transparent electronics

Researchers in Germany have developed advanced physics models to help find transparent materials that could be used as solar cells.

The team from Fraunhofer Institute for Mechanics of Materials (IWM) is looking for transparent base materials that could be doped with atoms to attain conducting coatings.

The transparent base would need one coating to conduct the electricity via electrons  the n-conductors  and one in which electron holes enable the electricity to flow  the p-conductors.

While n-conducting transparent materials are not hard to find, p-conducting materials are problematic. Their conductivity is too low and often their transparency is poor. So manufacturers have found it difficult to find a transparent base material that is amenable to both n and p doping.

Wolfgang Körner, research scientist at the IWM, said: ‘If transparent p-conductors with adequate conductivity could be produced, it would be possible to realise completely transparent electronics.’

Using electron microscope images, the researchers will initially determine the grain boundaries, which are irregularities in the material’s ordered crystal structure. These defect structures are modelled atom by atom.

The Fraunhofer researchers have developed special simulation methods to calculate how the electrons are distributed in the structures and thus in the solid body. From the data the researchers will extract how conductive and transparent the material is.

Körner said results are promising so far.

‘We have found, for example, that phosphorus is suitable for p-doping zinc oxide, but that nitrogen is more promising,’ he said.