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The effect of the dielectric environment on electron transfer reactions at the interfaces of molecular sensitized semiconductors in electrolytes
File | Description | Size | Format | |
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![]() | Accepted version | 1.2 MB | Adobe PDF | View/Open |
![]() | Supporting information | 1.89 MB | Adobe PDF | View/Open |
Title: | The effect of the dielectric environment on electron transfer reactions at the interfaces of molecular sensitized semiconductors in electrolytes |
Authors: | Moia, D Abe, M Wagner, P Saguchi, H Koumura, N Nelson, J Barnes, PRF Mori, S |
Item Type: | Journal Article |
Abstract: | 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. |
Issue Date: | 2-Apr-2020 |
Date of Acceptance: | 6-Mar-2020 |
URI: | http://hdl.handle.net/10044/1/82021 |
DOI: | 10.1021/acs.jpcc.9b11860 |
ISSN: | 1932-7447 |
Publisher: | American Chemical Society |
Start Page: | 6979 |
End Page: | 6992 |
Journal / Book Title: | The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter |
Volume: | 124 |
Issue: | 13 |
Copyright Statement: | © 2020 American Chemical Society. |
Keywords: | Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science NANOCRYSTALLINE TIO2 FILMS DYE REGENERATION KINETICS LATERAL SELF-EXCHANGE SOLAR-CELLS REORGANIZATION ENERGY CHARGE RECOMBINATION SOLID-STATE HOLE TRANSPORT ORGANIC-DYES DEPENDENCE Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science NANOCRYSTALLINE TIO2 FILMS DYE REGENERATION KINETICS LATERAL SELF-EXCHANGE SOLAR-CELLS REORGANIZATION ENERGY CHARGE RECOMBINATION SOLID-STATE HOLE TRANSPORT ORGANIC-DYES DEPENDENCE 03 Chemical Sciences 09 Engineering 10 Technology Physical Chemistry |
Publication Status: | Published |
Online Publication Date: | 2020-03-19 |
Appears in Collections: | Physics Experimental Solid State Grantham Institute for Climate Change Faculty of Natural Sciences |