Uli Würfel
Project Coordinator & Head of Department
Uli Würfel is the Head of Department Organic and Perovskite Photovoltaics at Fraunhofer ISE. He studied Physics at the Universities of Freiburg and Heidelberg and received his PhD from the University of Freiburg in 2006 with the topic “Electron transport in the nanoporous TiO2 layer of dye solar cells”, which was carried out in close collaboration with the Fraunhofer ISE.
His main research interests are characterization and modelling of organic, perovskite and other types of solar cells and the upscaling of organic solar cells.
Email: uli.wuerfel@ise.fraunhofer.de
Uli Würfel
Project Coordinator & Head of Department
Uli Würfel is the Head of Department Organic and Perovskite Photovoltaics at Fraunhofer ISE. He studied Physics at the Universities of Freiburg and Heidelberg and received his PhD from the University of Freiburg in 2006 with the topic “Electron transport in the nanoporous TiO2 layer of dye solar cells”, which was carried out in close collaboration with the Fraunhofer ISE.
His main research interests are characterization and modelling of organic, perovskite and other types of solar cells and the upscaling of organic solar cells.
Email: uli.wuerfel@ise.fraunhofer.de
Markus Kohlstädt
Team Leader & Project Manager
Markus Kohlstädt is a project manager and senior scientist at Fraunhofer Institute for Solar Energy (ISE) and the Freiburg Materials Research Center (FMF) of University of Freiburg. He studied Chemistry and was awarded a PhD by University of Freiburg in 2009. By now, he has more than 12 years experience in in the fabrication and characterization of Organic and Perovskite solar cells and modules, with focus on cell stack development and upscaling. In 2022, he was appointed leader of the team “Thin-Film Perovskite Photovoltaics” at Fraunhofer ISE.
Markus Kohlstädt
Team Leader & Project Manager
Markus Kohlstädt is a project manager and senior scientist at Fraunhofer Institute for Solar Energy (ISE) and the Freiburg Materials Research Center (FMF) of University of Freiburg. He studied Chemistry and was awarded a PhD by University of Freiburg in 2009. By now, he has more than 12 years experience in in the fabrication and characterization of Organic and Perovskite solar cells and modules, with focus on cell stack development and upscaling. In 2022, he was appointed leader of the team “Thin-Film Perovskite Photovoltaics” at Fraunhofer ISE.
Clemens Baretzky
Doctoral Researcher
Clemens Baretzky is a passionate Doctoral researcher at Fraunhofer ISE, specializing in the characterisation and simulation of Metal-organic Perovskites. With a keen interest in steady-state and transient photoluminescence spectroscopy. He obtained a Master of Physics at the Karlsruher Institut of Technology, where his thesis focused on Scanning tunnelling spectroscopy on magnetic atoms and molecules. Following his master’s, Clemens enhanced his practical experience at Greengineers GmbH.
Clemens Baretzky
Senior Scientist
Clemens Baretzky is a passionate Doctoral researcher at Fraunhofer ISE, specializing in the characterisation and simulation of Metal-organic Perovskites. With a keen interest in steady-state and transient photoluminescence spectroscopy. He obtained a Master of Physics at the Karlsruher Institut of Technology, where his thesis focused on Scanning tunnelling spectroscopy on magnetic atoms and molecules. Following his master’s, Clemens enhanced his practical experience at Greengineers GmbH.
Berit Brauer
Project Management & Coordination
Berit Brauer is a passionate project manager at Fraunhofer ISE who attaches great importance to team skills such as trust, conflict resolution and goal orientation.
As an experienced networker, she brings a wealth of professional experience from a Start-up, Universities and the private sector.
In addition to her professional career, Berit enjoys travelling and dancing and teaches the art of swimming, drawing on her knowledge as a former competitive swimmer.
Email: berit.brauer@ise.fraunhofer.de
Berit Brauer
Project Management & Coordination
Berit Brauer is a passionate project manager at Fraunhofer ISE who attaches great importance to team skills such as trust, conflict resolution and goal orientation.
As an experienced networker, she brings a wealth of professional experience from a Start-up, Universities and the private sector.
In addition to her professional career, Berit enjoys travelling and dancing and teaches the art of swimming, drawing on her knowledge as a former competitive swimmer.

