Nanoparticle solar cells make light work

Nature : An alternative solar cell design could lead to cheap, printable solar cells that would massively increase the worldwide use of solar power. In 1991, electrochemist Michael Grätzel of the Swiss Federal Institute of Technology in Lausanne devised the dye-sensitized nanocrystal cell (DSC); it uses organic dye molecules to absorb sunlight, the energy of which kicks electrons onto nanoparticles of ceramic titanium dioxide on which the dye sits. The electrons are then collected by electrodes to generate an electrical current. Grätzel and his colleagues have now developed methods to print DSC arrays onto glass panels and metal foils—a much less expensive material than the silicon in conventional photovoltaic cells. If DSC efficiency can be increased from 12.3% to about 15%, they may become cost-effective competitors to silicon photovoltaics.