The method employed by Karl Leo and his prize-winning former colleagues involves depositing microscopically thin layers of the organic material on a substrate. These coatings have a thickness of no more than one fifth of a micrometer one thousand times thinner than in conventional solar cells. Only about a gram of semiconductor material is needed to coat a surface area of one square meter in a process that takes place at room temperature, not at the 1,000 or so degrees Celsius required to produce inorganic cells.
This not only saves energy but also allows PET films to be used as the substrate, instead of the heat-resistant glass that was previously the only option. PET is the same plastic used to make bottles for soft drinks. It is cheap, light and flexible. The prize-winners have developed a continuous process based on roll-to-roll technology that enables the solar cells to be manufactured cheaply in large numbers. The resulting lightweight modules can be installed on roofs too weak to support the weight of standard photovoltaic panels.
Before making its final choice, the jury had shortlisted three projects as potential winners of the Deutscher Zukunftspreis. A second project rooted in Fraunhofer research was among this year's finalists, competing alongside the organic electronics team. These researchers have developed an advanced photovoltaic technology, known as "concentrated photovoltaics (CPV)", which consists of very-high-efficiency solar cells and sun-tracking concentrator modules. The nominated team comprised Andreas W. Bett, deputy director of the Fraunhofer Institute for Solar Energy Systems ISE, Hansjrg Lerchenm
|Contact: Dr. Karl Leo|