We all know that the power of the sun solves our heating, lighting and energy needs. But German research institute Fraunhofer-Gesellschaft uses the sun in a new way – as a cleansing agent.

Fraunhofer researchers have developed a photocatalytic coating that destroys bacteria, algae and fungi. Their coating incorporates titanium dioxide molecules which are "activated" by the ultraviolet light of the sun's rays.

The "activated" coating triggers a chemical reaction which produces free radicals that destroy the cell walls of the offending microorganisms and penetrate the cytoplasm, damaging their DNA and destroying them.

The subject was originally tested by researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart on garden furniture.

Garden furniture left in the shade too long often develops a nasty film of algae, moss and other microorganisms. The researchers compared what happened to garden furniture made of ordinary material to those with their photocatalytic coating.

They applied up to 30 different kinds of fungal, bacterial and algal cultures to the furniture and found that those using the coating stayed almost completely clean.

The next step for the researchers would be to develop similar material that could react to artificial light, but other researchers in the Institute are also working on using the coating for more than just keeping garden furniture clean.

Researchers from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA are now working on incorporating titanium dioxide particles in paint for self-cleaning building facades. Still, others are working on applying a similar coating to glass surfaces.