Schäfer, Céline (2020)
Interface Investigations of the Si | Cu and Si | Ag Contact with Respect to the Photoelectrochemical Performance.
Technische Universität Darmstadt
doi: 10.25534/tuprints-00011934
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
Due to the worldwide growth of industry nations, the need of energy has drastically increased within the last decades. In order to save our environment and decrease global warming, the development of new renewable energy systems is essential. Here, natural photosynthesis acts as the role model for the successful conversion and storage of the sun’s energy. One emerging technology to achieve a solar to fuel conversion is a photoelectric catalytic cell, which is able to convert CO2 directly into fuels. The first essential part of such a device is the photoabsorber, which has to drive the electrochemical reaction. In this work Si single- and multijunctions serve as photoabsorber material. Different surface terminations were prepared: hydrogen capped as well as native and thermally grown SiO2 as passivating interlayers. The second important part of the direct photoelectrochemical device is an appropriate catalyst, which allows high current densities at low overpotentials when being in contact with a suitable electrolyte. As metallic Cu is known to be able to reduce CO2 to CH4, C2H4 and alcohols in aqueous electrolytes, electron beam deposited metallic Cu is used as catalyst in the different model systems. For understanding the electrochemical performance of such a direct photoelectrochemical device, it is necessary to analyze the electronic structure of the interface between its two main components- the Si junction acting as the photoabsorber and the Cu thin film as catalyst. Therefore, the interface was investigated by X-ray photoelectron spectroscopy (XPS) analysis after the stepwise deposition of Cu onto the Si surface with different surface terminations. Furthermore, cyclic voltammetry (CV) was used to determine the electrochemical (EC) performance in an aqueous 0.3 M KHCO3 electrolyte solution. As an alternative model system the Si | Ag interface was investigated with respect to the photoelectrochemical performance. The aim of this work is to achieve a basic understanding on how the different band alignments due to the different surface terminations impact the CO2 reduction reaction.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2020 | ||||
| Autor(en): | Schäfer, Céline | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Interface Investigations of the Si | Cu and Si | Ag Contact with Respect to the Photoelectrochemical Performance | ||||
| Sprache: | Englisch | ||||
| Referenten: | Jaegermann, Prof. Dr. Wolfram ; Kramm, Prof. Dr. Ulrike | ||||
| Publikationsjahr: | 2020 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 8 Juni 2020 | ||||
| DOI: | 10.25534/tuprints-00011934 | ||||
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/11934 | ||||
| Kurzbeschreibung (Abstract): | Due to the worldwide growth of industry nations, the need of energy has drastically increased within the last decades. In order to save our environment and decrease global warming, the development of new renewable energy systems is essential. Here, natural photosynthesis acts as the role model for the successful conversion and storage of the sun’s energy. One emerging technology to achieve a solar to fuel conversion is a photoelectric catalytic cell, which is able to convert CO2 directly into fuels. The first essential part of such a device is the photoabsorber, which has to drive the electrochemical reaction. In this work Si single- and multijunctions serve as photoabsorber material. Different surface terminations were prepared: hydrogen capped as well as native and thermally grown SiO2 as passivating interlayers. The second important part of the direct photoelectrochemical device is an appropriate catalyst, which allows high current densities at low overpotentials when being in contact with a suitable electrolyte. As metallic Cu is known to be able to reduce CO2 to CH4, C2H4 and alcohols in aqueous electrolytes, electron beam deposited metallic Cu is used as catalyst in the different model systems. For understanding the electrochemical performance of such a direct photoelectrochemical device, it is necessary to analyze the electronic structure of the interface between its two main components- the Si junction acting as the photoabsorber and the Cu thin film as catalyst. Therefore, the interface was investigated by X-ray photoelectron spectroscopy (XPS) analysis after the stepwise deposition of Cu onto the Si surface with different surface terminations. Furthermore, cyclic voltammetry (CV) was used to determine the electrochemical (EC) performance in an aqueous 0.3 M KHCO3 electrolyte solution. As an alternative model system the Si | Ag interface was investigated with respect to the photoelectrochemical performance. The aim of this work is to achieve a basic understanding on how the different band alignments due to the different surface terminations impact the CO2 reduction reaction. |
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| URN: | urn:nbn:de:tuda-tuprints-119344 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
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| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung |
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| Hinterlegungsdatum: | 15 Jul 2020 13:45 | ||||
| Letzte Änderung: | 21 Jul 2020 05:18 | ||||
| PPN: | |||||
| Referenten: | Jaegermann, Prof. Dr. Wolfram ; Kramm, Prof. Dr. Ulrike | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 8 Juni 2020 | ||||
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