SENECA Talk: Inorganic artificial leafs for efficient solar fuel production: Physicochemical boundary conditions and material science challenges
SENECA Talks is a monthly seminar series on solar energy conversion and storage, organized by EnergyVille/imec/UHasselt (imo-imomec).
The upcoming SENECA Talk will be given by Professor Wolfram Jaegermann, Professor of Surface Science (retired), Surface Science Laboratory, Department of Materials Science, TU Darmstadt, Germany.
Abstract
For the conversion of solar energy to a chemical fuel a lot of different materials as well as device structures have been suggested but only very few provide technological competitive conversion efficiencies. Limitations and loss processes can be deduced from a detailed consideration of the involved photovoltaic and electrochemical elementary steps. Optimized performance can only be reached when the photovoltaic and electrolytic boundary conditions of integrated systems are comparable to those of separated devices with no extra loss due to the coupling process.
Based on experiments combining thin film synthesis, photo electrochemistry and surface science the following conclusions can be drawn:
1) The semiconductors must provide a wide splitting of quasi Fermi levels which will be provided by multi-junctions.
2) The interaction of H 2 O and the redox intermediates directly to the light energy converting semiconductor junction must be avoided because of possibly formed detrimental surface states. As consequence a buried junction is needed.
3) The interfaces between the semiconductor absorber material and the electro catalyst must be prepared free of interfacial barriers which may lead to an additional loss of the photo potential across internal double layers.
Efficient photo electrochemical devices are realized for Si and III-V multi-junctions using the input of different approaches ranging from solid state physics, surface science, and electrochemistry finally deducing a materials science related design approach. Based on an improved understanding of the correlation of material’s properties with the involved elementary steps, promising advanced technological solutions seem possible also for novel materials combinations.
Biography
Dr. Jaegermann completed his doctorate in inorganic chemistry on the spectroscopic characterization of inorganic coordination compounds at the University of Bielefeld in 1981. After this he was working as scientist at the Hahn-Meitner-Institute in Berlin on photo electrochemistry, surface science, and thin film solar cells at the end as department head before being appointed in 1997 as founding chair (professor) of the Surface Science Lab at the Materials Science Department of the TU Darmstadt. His research is oriented on thin film materials and interface properties of energy converting materials and devices ranging from solar cells, (photo)electrochemical fuel production, and batteries which lead to technologically competitive device structures. Dr. Jaegermann established energy science and engineering as central research topic at the TU Darmstadt by a number of large scale collaborative research funds as e. g. the Germany excellency graduate school of energy science and engineering. Since 2019 he is formally retired from his position as professor of the TU Darmstadt.
Contact
Sudhanshu.Shukla@imec.be
