uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Direct Spectroscopic Observation of Hole Trapping in Dye-Sensitized NiO films by Transient mid-IR Absorption Spectroscopy
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. (Hammarström)ORCID iD: 0000-0002-7964-8090
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-343483OAI: oai:DiVA.org:uu-343483DiVA, id: diva2:1190201
Available from: 2018-03-14 Created: 2018-03-14 Last updated: 2018-03-14
In thesis
1. Shining Light on Molecules: Electron Transfer Processes in Model Systems for Solar Energy Conversion Investigated by Transient Absorption Spectroscopy
Open this publication in new window or tab >>Shining Light on Molecules: Electron Transfer Processes in Model Systems for Solar Energy Conversion Investigated by Transient Absorption Spectroscopy
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In the recent years, solar energy conversion has attracted a huge research interest due to the potential application for limiting the greenhouse effect. In many solar cells and solar fuel cells, understanding of charge transfer (CT) and recombination is important for future improvement of the overall efficiency. One important tool for that is transient absorption spectroscopy (TAS).

Mesoporous nickel oxide films were investigated due to their potential application in p-type dye-sensitized solar cells (DSSCs), tandem DSSCs and dye sensitized solar fuel cells (DSSFC:s). Firstly, it was found that the hole generated by band gap excitation is trapped on an ultrafast time scale by Ni3+ states. It was possible to observe a direct signal from the holes by transient mid-IR absorption spectroscopy allowing for direct detection of hole injection and trapping. On a ns time scale, the trapped holes relaxed to much less reactive holes which favored long lived NiO-dye charge separation (CS).

A series of perylene monoimide (PMI) dyes with different anchoring groups was studied. Differences in binding affinity and stability were found. Nevertheless, all PMIs showed ultrafast charge separation and similar recombination kinetics. Furthermore, the effect of MLCT localization of ruthenium polypyridyl complexes was investigated. All those dyes showed slow or no hole injection. At the same time, a self-quenching process was found for all compounds that limited the photoconversion efficiency.

Furthermore, a new core-shell structure of p-type DSSCs was proposed and investigated. Here, the liquid electrolyte was replaced by a layer of TiO2. That system was found to undergo both injection and regeneration of the dye on an ultrafast time scale (below 1 ps). Furthermore, the CS state did not show any decay within 2 ns making this structure interesting for application in DSSCs.

A pentad consisting of a known Ru-based (electro)chemical water oxidation catalyst (WOC) linked to two zinc-porphyrin-fullerene dyads (ZnP-C60) was investigated. The charge transfer processes leading to the first oxidation of the WOC were understood. Low levels of water oxidation were detected in presence of a sacrificial electron acceptor.

The gained understanding of the CT dynamics and recombination processes thus allows new strategies to improve the efficiency in molecular systems for solar energy conversion.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 74
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1645
Keywords
photophysics, photoinduced electron transfer, transient absorption spectroscopy, laser spectroscopy, solar energy conversion, p-type DSSCs, Charge separation, recombination, mesoporous NiO
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-343443 (URN)978-91-513-0273-7 (ISBN)
Public defence
2018-05-04, Siegbahnsalen, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2018-04-13 Created: 2018-03-14 Last updated: 2018-04-24

Open Access in DiVA

No full text in DiVA

Search in DiVA

By author/editor
Föhlinger, Jens
By organisation
Physical ChemistryMolecular Biomimetics
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 15 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf