FOR 5499:  Molecular Solar Energy Management - Chemistry of MOST Systems

• Subject Area: Chemistry
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 496207555

Today’s technologies are capable of converting solar energy to electricity directly (photovoltaics) or indirectly (wind energy or hydropower) at a large scale and at a cost efficiency which is steadily improving. However, the availability of solar energy varies drastically in space and time. Therefore, energy storage is the primary challenge in our transition to a renewable energy system. Here, new molecular materials may pave the road to a phenomenal variety of new and surprising solutions. In the Research Unit FOR MOST, we propose to explore the potential of such a powerful molecular strategy: The conversion, storage and release of solar energy, all combined in just one single molecule so-called Molecular Solar Thermal (MOST) systems. The working principle is as follows: A switchable molecule absorbs light and is converted from a low-energy state to a metastable high-energy state. To release the stored energy, an external trigger (heat, catalyst, light, electric or magnetic field), is applied and the molecule returns to its low-energy state converting the chemical energy to heat. The concept possesses the big advantage that energy capture, storage and release can be accomplished in a very simple medium consisting of the photochromic molecules only. The key components in MOST systems are tailor-made photoswitches, which must be designed to fulfill specific criteria in the best possible way: • High energy storage density with a long half-life of the metastable high-energy state • Efficient photoconversion (high quantum efficiency, good match to the solar spectrum) • High reversibility and good stability (i.e. high selectivity of the conversion and back conversion reaction with minimal degradation) The design of MOST systems poses great challenges to synthetic chemistry. Hence, it is clear that a multidisciplinary approach is indispensable which combines the expertise (i) to develop new MOST switches (synthesis), (ii) to explore their functionality (spectroscopy), (iii) to model their properties (theory) and (iv) to test them in demonstrating devices. In the proposed Research Unit FOR MOST, we will bring together the required expertise to form a spear-heading research team in Germany, which along with leading international researchers, will push the emerging field of MOST to the next level. However, the knowledge obtained goes far beyond the MOST concept and will make valuable contributions in the general field of organic photochemistry.

• DFG Programme: Research Units
• International Connection: Spain

Projects

• A-Azo: Tuning storage in MOST systems using intra- and intermol- ecular interactions with Azobenzenes (Applicant Wegner, Hermann A. )
• A-Nor: New Concepts for the Norbornadiene/Quadricyclane (NBD/QC) Interconversion (Applicant Hirsch, Andreas )
• B-Cat: Catalytic processes for the efficient energy release from MOST compounds (Applicant Fleischer, Ivana )
• B-SURF: Triggering the energy release from MOST compounds at interfaces – Fundamental mechanisms, kinetics, reversibility (Applicant Libuda, Jörg )
• Boron-Nitrogen containing heterocycles for MOST applications (Applicant Bettinger, Holger )
• C-Photo: Computational photochemistry and in silico design of MOST systems (Applicant Dreuw, Andreas )
• Computational modelling of catalytic processes and screening of MOST compounds (Applicant Mollenhauer, Doreen )
• Coordination Funds (Applicant Wegner, Hermann A. )
• D-Dev: Exploring MOST Systems for/in Devices (Applicant Hölzel, Helen )
• Molecular mechanisms of energy storage and release in MOST systems (Applicant Wachtveitl, Josef )

• Spokesperson: Professor Dr. Hermann A. Wegner