The development of bioinspired constructs for solar energy conversion may hold the key to solve the looming energy and climate crises that face our advanced societies. Biological systems have evolved energy transduction mechanisms that operate at high efficiency using Earth-abundant elements. Key features of the biological photochemistry and catalysis can be incorporated into artificial systems to increase the efficiency of solar fuel production. The poor performance of present-day solar fuel devices is not understood at all because of lacking mechanistic, kinetic and thermodynamic information on their action. To reach the primary goal of large-scale bio-inspired solar energy conversion, it is mandatory to determine and control pathways and mechanisms of energy and charge transfer processes, and identify the physical-chemical nature of the loss processes that hamper the performance of present-day solar fuel devices.
Left: A water splitting dye-sensitized solar cell and Right: a bio-inspired water-splitting reaction center – catalyst by Moore, Moore, Gust, Mallouk of Arizona and Pennsylvania State Universities.
The Artificial Photosynthesis research program aims at functional assessment of artificial photosynthetic modules at varying degrees of functional integration. We will address the issues at hand through the application of advanced time-resolved spectroscopic methods. Unique features of the experimental approach include (i) access to the entire time span between photon absorption and catalytic turnover, i.e., from femtoseconds to milliseconds, (ii) detection methods that provide molecular specificity and information on local structure and reactivity and (iii) multi-pulse capability to manipulate the physical-chemical dynamics of catalytic redox intermediates with preservation of time resolution. Detailed knowledge about the pathways and (loss) mechanisms of energy and charge transfer allows for a design steering feedback loop with organic chemistry and supramolecular catalysis groups to optimize the performance of artificial photosynthetic modules and their joint action in integrated devices.
To understand the relationship between the composition and organization of the nanofabricated solar fuel cell and its function, we will image the device with a stimulated emission depletion (STED) fluorescence microscope at very high resolution (~20 nm). The microscope will be combined with advanced spectroscopy to image energy migration patterns and possible heterogeneities in the solar fuel device. This approach will yield vital information on overall performance that is required for modelling and a full understanding of the solar fuel device.
We will employ long-standing collaborations with internationally renowned groups for model systems design and fabrication. In addition, the research plan will be conducted in the context of the national Towards BioSolar Cells (TBSC) programme.
R. Berera, C. Herrero, I.H.M. van Stokkum, M. Vengris, G. Kodis, R.E. Palacios, H. van Amerongen, R. van Grondelle, D. Gust, T.A. Moore, A.L. Moore, J.T.M. Kennis
A simple artificial light-harvesting dyad as a model for excess energy dissipation in oxygenic photosynthesis
Proc. Natl. Acad. Sci. USA, 2006, 103, p. 5343-5348
Energy transfer, excited-state deactivation and exciplex formation in artificial caroteno-phthalocyanine light harvesting dyads
J. Phys. Chem. B 111, 2007, p. 6868-6877
G. Kodis, C. Herrero, R. Palacios, E. Mariño-Ochoa, S. Gould, L. de la Garza, R. van Grondelle, D. Gust, T.A. Moore, A.L. Moore, J.T.M. Kennis
Light harvesting and photoprotective functions of carotenoids in compact artificial photosynthetic antenna designs
J. Phys. Chem. B 108, 2004, p. 414-425