Marcus Bär is a renowned researcher in advanced materials characterization, photoelectron spectroscopy, and synchrotron-based analytics for sustainable energy technologies. His work connects interdisciplinary research activities at HI ERN and Friedrich-Alexander-Universität Erlangen-Nürnberg, with a focus on photovoltaics, catalysis related materials research, electrochemical energy conversion, and operando investigations of functional materials. He contributes to the development and application of cutting-edge X-ray and electron spectroscopy methods, particularly at EMIL @ BESSY II, to improve the efficiency, stability, and understanding of energy-related materials and devices.