Development and characterization of ITO-free organic solar cells and modules at Fraunhofer ISE

The efficiency of solution-processed organic photovoltaic (OPV) devices could be improved considerably in the last years. This renders their stability as the limiting factor for successful applications. Under indoor conditions, OPV is already now one of the smartest choices to power the dynamically increasing number of electronic devices of the so-called internet of things. Another promising approach is to make use of the unique absorption properties of organic semiconductors to realize efficient solar modules with high visual transparency.
I will present results of Indium Tin Oxide (ITO)-free cells developed at Fraunhofer ISE for the different applications. Further, our effort to up-scale these specific device stacks will be discussed.
In the second part, I will shortly present our new approach to detect luminescence. It allows to derive the internal quasi Fermi level separation and it will be shown how this relates to the voltage that is measured between the terminals of the solar cell.