Imperial College London
Alternate

DrPiersBarnes

Faculty of Natural Sciences, Department of Physics

Lecturer in Experimental Solid State Physics
 
 
 
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Contact

 

+44 (0)20 7594 7609piers.barnes

 
 
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Location

 

1003Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Moia:2020:10.1021/acs.jpcc.9b11860,
author = {Moia, D and Abe, M and Wagner, P and Saguchi, H and Koumura, N and Nelson, J and Barnes, PRF and Mori, S},
doi = {10.1021/acs.jpcc.9b11860},
journal = {The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter},
pages = {6979--6992},
title = {The effect of the dielectric environment on electron transfer reactions at the interfaces of molecular sensitized semiconductors in electrolytes},
url = {http://dx.doi.org/10.1021/acs.jpcc.9b11860},
volume = {124},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Electron transfer theories predict that rates of charge transfer vary with the dielectric properties of the environment where the reaction occurs. An appropriate description of this relation for molecular sensitized semiconductors in electrolytes must account for the restricted geometry of these systems compared to “free” molecules in solution. Here, we explore the extent to which dielectric properties of the surrounding medium can explain the rates of charge transfer processes, measured using transient absorption spectroscopy, involving photo-oxidized thiophene–carbazole-based molecules on oxide semiconductors in inert or redox-active electrolytes. We observe no clear correlation between the activation energy of hole hopping between molecules on oxide surfaces or the recombination rate between photogenerated electrons in the oxide and holes on the adsorbed molecules and the dielectric properties of the surrounding solvent. The activation energy of hole hopping tends to increase with time following initial photogeneration of the holes, which we attribute to energetic disorder in the molecular monolayer. The recombination rate in different solvents scales with the hole hopping rate. It can also be varied by adding inert salts in the electrolyte and by controlling the access of cations in solution to the oxide surface. Finally, we show that fast electron transfer from cobalt complexes to photo-oxidized molecules in solvents with low polarity is verified, but the kinetics are limited by the ionic dissociation. Our study highlights the importance of electronic coupling between the redox-active components and their solvation, besides the reorganization energy and the driving force, in the determination of electron transfer rates at molecular sensitized interfaces in electrolytes.
AU  - Moia,D
AU  - Abe,M
AU  - Wagner,P
AU  - Saguchi,H
AU  - Koumura,N
AU  - Nelson,J
AU  - Barnes,PRF
AU  - Mori,S
DO  - 10.1021/acs.jpcc.9b11860
EP  - 6992
PY  - 2020///
SN  - 1932-7447
SP  - 6979
TI  - The effect of the dielectric environment on electron transfer reactions at the interfaces of molecular sensitized semiconductors in electrolytes
T2  - The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter
UR  - http://dx.doi.org/10.1021/acs.jpcc.9b11860
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000526328500004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/82021
VL  - 124
ER  -
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