Biografía del autor Peter Wurfel studied physics at the University of Karlsruhe where he later became Professor. His research activities started with ferroelectric thin films, mostly for pyroelectric infrared detectors. He has a keen interest in the physics of photovoltaics and has more than 25 years research and teaching experience in this field. Uli Wurfel studied physics at the Universities of Freiburg and Heidelberg. He received a PhD from the University of Freiburg in 2006. Since 2009 he is head of the group "dye and organic solar cells" at the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg. Besides an ambition to realize low-cost organic solar cells, he is also highly interested in selective contacts and modelling solar cells.