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ROSI Group Members

Dr. Felix Lang

Head of ROSI Group


Capus Golm
Universität Potsdam
Institut für Physik und Astronomie
Physik weicher Materie
Karl-Liebknecht-Str. 24/25
Haus 28. Raum 2.032

Dr. Felix Lang leads the (Radiation-) Tolerant Electronics with Soft Semiconductors (ROSI) Group within the Soft Matter Physics Group at the University of Potsdam. He studied Physics at the Technische Universität München and the Freie Universität Berlin. He received his Ph.D. in physics from the Technical University Berlin, studying the stability and degradation of perovskite solar cells, which he conducted at the Helmholtz-Zentrum Berlin. He was then awarded a Feodor-Lynen Fellowship, which brought him to the group of Prof. S. Stranks from the Cavendish Laboratory at the University of Cambridge, UK, where he tested and developed next-generation perovskite tandem photovoltaics for space photovoltaics. A return Fellowship from the Alexander von Humboldt Foundation brought him to the University of Potsdam, where he focused on a deeper understanding of the degradation-, working- and loss mechanisms of perovskite-based tandem photovoltaics. Recently he was awarded a Freigeist-Fellowship of the Volkswagen Stiftung, and currently, he is setting up the Tolerant Electronics with Soft Semiconductors Group at the University of Potsdam.

Sema Sarisözen

PhD Student


Campus Golm
Haus 28 Raum 2.031

Sema Sarisözen is a Ph.D. student in the (Radiation-) Tolerant Electronics with Soft Semiconductors (ROSI) Group within the Soft Matter Physics Group at the University of Potsdam.  She earned both her bachelor's and master’s degrees in Chemistry at İzmir Institute of Technology. During her masters her research was focused on the design, synthesis, and characterization of colloidal carbon quantum dots and their applications. In addition, her research activities involved the synthesis and characterization of different shapes of colloidal plexcitonic nanocrystals with tunable optical properties in the visible region of the electromagnetic spectrum by using metal nanocrystals and different exciton sources. Currently, Sema is developing and investigating Perovskite Single Crystal (PSC) based Radiation Detectors.

Biruk Alebachew Seid

Ph.D. Student


Campus Golm
Haus 28 Raum 2032

Biruk is originally from Ethiopia and completed hisBachelor and Master degrees at Adama Science and Technology University (ASTU) in Materials Science and Engineering. His masters thesis was on the efficiency improvements of P3HT:PCBM-based OSC through the optimization of the ZnO ETL by Tin(Sn) doping . Alongside this work he conducted worked on Hydrothermal growth of Cs2SnCl6 for Photovoltaic and LED applications, Sol-gel synthesis of metal-doped ZnO for photocatalysis application and metal corrosion. For the next 3 years, his research interest is  focused on  single-junction and tandem perovskite solar cells and optimization of their efficiency and resistance to harsh environment for future aerospace applications.

Julian Cuervo

M.Sc. Student


Campus Golm
Haus 28 Raum 2032

Julian Cuervo works as a research student in the Radiation-) Tolerant Electronics with Soft Semiconductors (ROSI) Group within the Soft Matter Physics Group at the University of Potsdam. He is currently coursing the master of Renewable Energy Systems at the TU Berlin and made his bachelor of mechanical engineering at the Pontificia Universidad Catolica Madre Maestra (PUCMM) in Dominican Republic. He worked at the Universidad ISA in Dominican Republic as the Head of the Renewable Energies Laboratory, where he got multiple Research Grants from FONDOCyT (Research funds for Higher education institutions from Dominican Republic) in the Area of Waste to Energy and Solar Integration to Production Chains. The research activities of Julian include development of new construction methods of Perovskite based photovoltaic devices for space applications.

Sercan Özen

Ph.d. Student


Campus Golm
Haus 28 Raum 2032

I am always fascinated by the light-matter interaction and physical phenomena behind it. I have studied on understanding and tune the structural, electronic, and optical properties of perovskites using both experimental methods and ab-initio simulations. Also, I studied graphene-based flexible photodetectors. Now, as a Ph.D. student, I am excited to move one step further and work on perovskite solar cells within the ROSI Group and contribute to the development of renewable energy.