. Researchers from Chemnitz University of Technology and Julius-Maximilians-University of Würzburg, in Germany, have presented solar panels that are printed on standard paper. The technology, known as 3PV (3PV stands for printed paper photovoltaics) uses conventional printing methods and standard substrates, like those used for magazines, posters or packaging. Special inks with electrical properties form the necessary structures on paper, which ensure that electricity is generated when being exposed to light. The polymer/fullerene solar cells are printed on paper using a combination of gravure and flexographic printing techniques, and the cells are free from expensive electrodes made with indium–tin oxide, silver, or gold. Since conventional printing methods (i.e. gravure, flexo and offset printing) are very cost-efficient, the printed solar panels shall generate much cheaper electricity in comparison to conventional solar cells. Prof. Dr. Arved Hübler from the Institute for Print and Media Technology at Chemnitz University of Technology, who is working together with his research team on the 3PV technology for more than three years now, speaks of a paradigm shift in solar technology. His vision for the future is that common printing houses around the world could produce and market 3PV solar panels. The cells that were printed in Chemnitz achieve an energy conversion efficiency of 1.3 percent. The researchers use a new material approach. In a special printing process, naturally oxidized zinc is applied as base electrode. The transparent counter electrode is printed with PEDOT , a conductive polymer. “The materials are constantly optimised and we are confident that the 3PV parameters can be further improved,” says Tino Zillger, researcher and leader of the project. Even the team of Hübler is a bit surprised that it is already possible to produce very stable 3PV modules with a web printing press in the laboratory. “Our long experience in the field of printed electronics pays well here,” says the head of the chair Print Media Technology. Hübler assumes that all in all paper solar cells could have the edge over the current technological state of the art due to the efficient production and lower material costs. The aim of further research is to increase the efficiency to more than five percent in order to ensure that a 3PV module is economically attractive despite a life time of less than one year. “In nature we find a model for this strategy: even green leaves only have a moderate energy conversion efficiency of four to seven percent and a life time of less than one year. Nevertheless, this approach is obviously successful,” explains Hübler. The vision of being able to contribute to the overall energy supply with the help of paper solar panels is only one field of application. Researchers have already shown that it is also possible to drive small electrical devices with these paper solar cells. This opens up the possibility to supply mobile devices with “paper power” in a simple and self-sustaining way. Intelligent packaging, for instance, could include many additional features, ranging from displays to sensors. Handling of the paper solar cells can be very simple. The paper strips can be connected with the help of commercial snap fasteners. Immediately, an electrical current flows. According to the researchers, the paper modules can be recycled like any other waste paper after use. According to Hübler it is, thus, not only possible to generate renewable energy, but also the solar cell itself is made from renewable resources and is consequently renewable. Read More Paper