Apart from geothermal power and tidal energy, the other major energy sources available to humanity in the long term are based either directly or indirectly on the sun’s radiation. The sun radiates so much energy that, based on the efficiency of the photovoltaic cells currently available on the market, an area of around 800 x 800 km2 in the Sahara would be sufficient to supply the entire global population with the average amount of energy consumed by an average central European.
However, although silicon-based solar cells are very advanced technologically, the cost of generating energy using this technology is far too high. Photovoltaic systems based on organic semiconductors could provide an interesting alternative. These may prove more cost-effective in the future, as the raw material costs involved would be lower and they could be used relatively simply in different forms. There are numerous ways of producing such organic semiconductors at molecular level. Extended conjugated aromatic systems, which are being developed based on benzene and related molecules at the MPI for Polymer Research, are an interesting class of materials. The associated research findings, which resulted primarily from basic research aimed at synthesising large molecules from simple basic molecules, have now reached a stage where they are of relevance to practical application. However, it is not yet possible to predict which class of substance will ultimately prove to be most promising and suitable for integration into polymer photovoltaic cells. The role of research in this field is to make the widest possible range of potential systems accessible and thereby lay a solid foundation for targeted technological development