Charge transfer dynamics at model metal-organic solar cell surfaces

• The "core-hole clock" implementation of resonant photoemission has been used to investigate the charge-transfer dynamics of bi-isonicotinic acid molecules (4,4'-dicarboxy-2,2'-bipyridine) adsorbed on a rutile TiO2(110) surface containing varying densities of gold islands. In the presence of, nominally, a few monolayers of gold there exists a strong coupling between the adsorbed molecules and the surface. This is derived from the measurement of a <3 fs charge-transfer time for the injection of a core-excited electron into the substrate. This ultrafast charge-transfer time is quenched for a fraction of the molecules upon the addition of only a few further monolayers of gold. There is evidence to suggest that this effect derives from a change in the bonding configuration of bi-isonicotinic acid molecules. However, results also support the occurrence of ultrafast back-transfer from Au states to core-excited unoccupied molecular states.

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NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

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