Inorganic Chemistry Journal has chosen an article featuring results
obtained on the CLF’s advanced laser spectroscopy facility, ULTRA
, for the front cover of one of its latest issues. The work describes how ULTRA has been used to study molecules that capture the energy of light which have the potential to be used as components in molecular devices that accomplish artificial photosynthesis.
Many reactions in natural and artificial systems are powered by light. New approaches and synthetic systems are currently being developed for use in devices that convert light into chemical or electrical energy. Julia Weinstein (Sheffield University) and her collaborators study molecules which capture the energy of light and have potential as components in molecular devices that accomplish artificial photosynthesis and photocatalysis.
The key to such developments are molecules which efficiently absorb light and can form a "charge separated state" – where a positive and a negative charge are spatially separated and can potentially drive independent useful chemistry. Recently, Dave Garner, Stephen Davies and their colleagues at the University of Nottingham have synthesised a new molecule that, upon excitation with light, produces such “separated charges” efficiently. The novel behaviour involves an organic moiety (a naphthalene-diimide group) acting as a light-absorber and electron acceptor and a molybdenum-dithiolene centre acting as the electron donor. The resultant electron-hole pair has an appreciable lifetime of 15 ns, as required for device applications.
The time-resolved infrared capability of the ULTRA facility was used to understand the initial response of these molecules to light and to investigate the dynamics of energy propagation. Together with electronic transient absorption spectroscopy, performed in Sheffield and Minsk over the broad time-span from femto to nanoseconds, these data provide a detailed description of the fundamental light-induced reactions in this novel photoactive molecule - information that will be used in future work in which the molecules are tuned for applications.