Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon
Functionalizing Si with self-assembled monolayers (SAMs) paves the way for integrating the semiconducting properties of Si with the diverse properties of organic molecules. Highly packed SAMs such as those formed from alkyl chains protect Si from reoxidation in an ambient environment. Such monolayer...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Language: | English |
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AMER CHEMICAL SOC
2021
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| Online Access: | http://purl.org/au-research/grants/arc/DP190100735 http://hdl.handle.net/20.500.11937/93926 |
| _version_ | 1848765812477788160 |
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| author | Li, Tiexin Dief, Essam Lyu, Xin Rahpeima, Soraya Ciampi, Simone Darwish, Nadim |
| author_facet | Li, Tiexin Dief, Essam Lyu, Xin Rahpeima, Soraya Ciampi, Simone Darwish, Nadim |
| author_sort | Li, Tiexin |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Functionalizing Si with self-assembled monolayers (SAMs) paves the way for integrating the semiconducting properties of Si with the diverse properties of organic molecules. Highly packed SAMs such as those formed from alkyl chains protect Si from reoxidation in an ambient environment. Such monolayers have been largely considered oxide-free, but the effect of nanoscale reoxidation on the electrochemical kinetics of Si-based SAMs remains unknown. Here, we systematically study the effect of the oxide growth on the electrochemical charge-transfer kinetics of ferrocene-terminated SAMs on Si by exposing the surfaces to ambient conditions for controlled periods of time. X-ray photoelectron spectroscopy and atomic force microscopy revealed a gradual growth of silicon oxide (SiOx) on the surfaces over time. The oxide growth is accompanied by a decrease in the ferrocene surface coverage and a concomitant decrease in the electron transfer rate constant (ket) measured by electrochemical impedance spectroscopy. The drop in ket is attributed to a greater spacing between the ferrocene moieties induced by the surface oxide, which in turn blocks lateral electron transfer between neighboring ferrocene moieties. These findings explain the highly scattered literature data on electron transfer kinetics for monolayers on Si and have implications for the proper design of Si-based molecular electronic devices. |
| first_indexed | 2025-11-14T11:41:12Z |
| format | Journal Article |
| id | curtin-20.500.11937-93926 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:41:12Z |
| publishDate | 2021 |
| publisher | AMER CHEMICAL SOC |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-939262024-01-18T06:02:50Z Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon Li, Tiexin Dief, Essam Lyu, Xin Rahpeima, Soraya Ciampi, Simone Darwish, Nadim Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science SELF-ASSEMBLED MONOLAYERS LONG-TERM STABILITY ALKYL MONOLAYERS ORGANOMETALLIC CHEMISTRY TERMINATED MONOLAYERS ORGANIC MONOLAYERS MONO LAYERS FUNCTIONALIZATION 1-ALKENES OXIDATION Functionalizing Si with self-assembled monolayers (SAMs) paves the way for integrating the semiconducting properties of Si with the diverse properties of organic molecules. Highly packed SAMs such as those formed from alkyl chains protect Si from reoxidation in an ambient environment. Such monolayers have been largely considered oxide-free, but the effect of nanoscale reoxidation on the electrochemical kinetics of Si-based SAMs remains unknown. Here, we systematically study the effect of the oxide growth on the electrochemical charge-transfer kinetics of ferrocene-terminated SAMs on Si by exposing the surfaces to ambient conditions for controlled periods of time. X-ray photoelectron spectroscopy and atomic force microscopy revealed a gradual growth of silicon oxide (SiOx) on the surfaces over time. The oxide growth is accompanied by a decrease in the ferrocene surface coverage and a concomitant decrease in the electron transfer rate constant (ket) measured by electrochemical impedance spectroscopy. The drop in ket is attributed to a greater spacing between the ferrocene moieties induced by the surface oxide, which in turn blocks lateral electron transfer between neighboring ferrocene moieties. These findings explain the highly scattered literature data on electron transfer kinetics for monolayers on Si and have implications for the proper design of Si-based molecular electronic devices. 2021 Journal Article http://hdl.handle.net/20.500.11937/93926 10.1021/acs.jpcc.1c07788 English http://purl.org/au-research/grants/arc/DP190100735 AMER CHEMICAL SOC fulltext |
| spellingShingle | Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science SELF-ASSEMBLED MONOLAYERS LONG-TERM STABILITY ALKYL MONOLAYERS ORGANOMETALLIC CHEMISTRY TERMINATED MONOLAYERS ORGANIC MONOLAYERS MONO LAYERS FUNCTIONALIZATION 1-ALKENES OXIDATION Li, Tiexin Dief, Essam Lyu, Xin Rahpeima, Soraya Ciampi, Simone Darwish, Nadim Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title | Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title_full | Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title_fullStr | Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title_full_unstemmed | Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title_short | Nanoscale Silicon Oxide Reduces Electron Transfer Kinetics of Surface-Bound Ferrocene Monolayers on Silicon |
| title_sort | nanoscale silicon oxide reduces electron transfer kinetics of surface-bound ferrocene monolayers on silicon |
| topic | Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science SELF-ASSEMBLED MONOLAYERS LONG-TERM STABILITY ALKYL MONOLAYERS ORGANOMETALLIC CHEMISTRY TERMINATED MONOLAYERS ORGANIC MONOLAYERS MONO LAYERS FUNCTIONALIZATION 1-ALKENES OXIDATION |
| url | http://purl.org/au-research/grants/arc/DP190100735 http://hdl.handle.net/20.500.11937/93926 |