DESY Research into flexible solar cell films

However, prototypes have so far lacked the necessary efficiency and durability. One sticking point is the metallic contacts that conduct electricity out of the solar cells. The better these are, the more energy that can be “harvested”. Using X-ray radiation from the PETRA III facility, a team led by DESY researcher Dr. Stephan Roth is currently investigating how metal and plastic bond. The solar cell prototypes are supplied by the Munich University of Technology and are coated at the DESY using a special technique known as sputtering. In this particular case, fast inert gas ions collide with a gold film and shoot out individual atoms that then collide with the organic solar cell. Some of these atoms are etched into the plastic while others remain on the surface and congregate to form nanometre-sized islands – the “germ cells” of the contacts. “The intensive and extremely fine X-ray beams generated by PETRA III enable us to monitor the entire process in detail,” explains Roth. “No other method would allow us to do so.” As if watching a slide show, the experts observe how the nano-islands form, which helps them to understand how the production process can be optimised. This work has also revealed that gold atoms can penetrate into the plastic solar cells, a discovery that may help to increase the efficiency of these cells in the future. As Roth explains, “This is an effect observed for the first time at DESY in this type of in-situ experiment. It has been confirmed using X-ray reflectometry. It should help us to increase the efficiency of organic solar cells in the future.”

DESY/red.