Quantum mechanics in new solar cells: Research prize for physicist in Bayreuth
University of Bayreuth, Press Release No. 151/2017, 12 December 2017
Dr. Linn Leppert (31), physicist in Bayreuth, has received a research prize from the DFG research training group "Photophysics of Synthetic and Biological Multichromophoric Systems" for her research on new solar cell materials. The materials in question are hybrid halide perovskites with which a surprisingly high level of efficiency can be achieved when converting light to electricity. In order to precisely calculate the electronic structure and dynamics of these highly complex solid state materials, Dr. Leppert uses quantum mechanical methods of density functional theory and many body perturbation theory.
Following the award ceremony at the University of Bayreuth (left to right): Prof. Dr. Stephan Kümmel (Theoretical Physics); Dr. Linn Leppert, Prof. Dr. Christian Laforsch (Vice President of the University of Bayreuth), and Prof. Dr. Jürgen Köhler (Experimental Physics, Chairman of the DFG research training group "Photophysics of Synthetic and Biological Multichromophoric Systems"). Photo: Christian Wißler.
From Berkeley back to Bayreuth
In his speech, the University of Bayreuth's Vice President for Research & Junior Scholars Prof. Dr. Christian Laforsch emphasized that the prizewinner "applied highly demanding theoretical methods to address issues with direct applications and in close proximity to the experiment." She carried out much of her research as a postdoc at the Lawrence Berkeley National Laboratory in the US. For this, the Alexander von Humboldt Foundation awarded her a Feodor Lynen research grant.
Since her return to the University of Bayreuth, she has been leading a project in Collaborative Research Centre 840 "From particulate nanosystems to mesotechnology". "We are trying to understand the electronic structure of familiar solar cell materials in order to derive principles for the design of new, energy-efficient materials. Many body perturbation theory is also indispensable for interdisciplinary research in this field at the intersection of physics and chemistry," Dr. Leppert explained.
Diagram of two light-absorbing pigments (bacteriochlorophylls) in purple bacteria. A charge separation that kick-starts the complex process of photosynthesis occurs at the reaction centre of the bacteria. Illustration: Linn Leppert.
Learning from biological systems
Starting in January 2018, the University of Bayreuth will be leading a junior research group in the scope of the Elite Network of Bavaria (ENB). At the forefront are biological systems that use photosynthesis to get chemical energy from sunlight. Purple bacteria are of particular interest. "We already know a lot about how these bacteria manage to absorb light energy via pigment molecules and transfer it to reaction centres where photosynthesis begins. However, most calculations in the past have been based on models that do not always do justice to the complexity of the physical processes. Quantum mechanical methods with which excitation energies can be calculated even in large pigment molecules are going to enable findings to be considerably more precise," said the award-winning physicist. She added, "On Bayreuth's campus, a very high-performance IT infrastructure is available for this substantial computation power."
Dr. Leppert is confident that the desired results concerning the absorption and utilization of light energy in nature – whether in bacteria or plants – can speed up the development of highly efficient solar cell materials: "These materials may display properties which are lacking in the silicon solar cells that are currently still in use. Learning from natural systems in order to develop artificial systems for collecting and utilizing renewable energy is an exciting vision."
Dr. Linn Leppert at her desk in Bayreuth. Her monitor displays a portion of a hybrid perovskite. Photo: Christian Wißler.
Dr. Linn Leppert
Department of Physics
University of Bayreuth
Phone: +49 (0)921 / 55-4461
University of Bayreuth
Universitätsstr. 30 / ZUV
Phone: +49 (0)921 / 55-5356