Ultrafast Electron Transfer Between Dye and Catalyst on a Mesoporous NiO Surface.
The combination of molecular dyes and catalysts with semiconductors into dye-sensitized solar fuel devices (DSSFDs) requires control of efficient interfacial and surface charge transfer between the components. The present study reports on the light-induced electron transfer processes of p-type NiO films cosensitized with coumarin C343 and a bioinspired proton reduction catalyst, [FeFe](mcbdt)(CO)6 (mcbdt = 3-carboxybenzene-1,2-dithiolate). By transient optical spectroscopy we find that ultrafast interfacial electron transfer (τ ≈ 200 fs) from NiO to the excited C343 ("hole injection") is followed by rapid (t1/2 ≈ 10 ps) and efficient surface electron transfer from C343(-) to the coadsorbed [FeFe](mcbdt)(CO)6. The reduced catalyst has a clear spectroscopic signature that persists for several tens of microseconds, before charge recombination with NiO holes occurs. The demonstration of rapid surface electron transfer from dye to catalyst on NiO, and the relatively long lifetime of the resulting charge separated state, suggests the possibility to use these systems for photocathodes on DSSFDs.
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Allison M
AM
Brown
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Liisa J
LJ
Antila
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Mohammad
M
Mirmohades
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Sonja
S
Pullen
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Sascha
S
Ott
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Leif
L
Hammarström