1. Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstr. 6, DE-38678 Clausthal-Zellerfeld, Germany
2. Fiber Optical Sensor Systems, Fraunhofer Heinrich Hertz Institute, HHI, Am Stollen 19 H, DE-38640 Goslar, Germany
3. EST Research Centre Energy Storage Technologies, Clausthal University of Technology, Am Stollen 19 A, DE-38640 Goslar, Germany
4. Institute of Energy Research and Physical Technologies, Clausthal University of Technology, Am Stollen 19 B, DE-38640 Goslar, Germany