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
Conductivity studies of nanostructured TiO2 films permeated with electrolyte
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
2004 (English)In: Journal of Physical Chemistry B, Vol. 108, no 33, 12388-12396 p.Article in journal (Refereed) Published
Abstract [en]

Charge transport in nanostructured TiO2 films permeated with an electrolyte was studied, using temperature-dependent conductivity and electron accumulation measurements. Two regions for charge transport were distinguished from the relationship between conductivity and electron concentration. In the first region (1−20 electrons per TiO2 particle), the effective electron mobility is dependent on the electron concentration and values between 7 × 10-4 and 78 × 10-4 cm2 V-1 s-1 were determined. The activation energy of the mobility was 0.3 eV. The charge transport can be described with a trapping/detrapping model that involves localized band-gap states. In the second region (> 20 electrons per TiO2 particle), the effective electron mobility is independent of electron concentration and values of 150 × 10-4 cm2 V-1 s-1 are calculated. The activation energy of mobility is in the range of 0−0.15 eV, depending on the electrolyte. Transport of electrons in the conduction band seems to be the most applicable model.

Place, publisher, year, edition, pages
2004. Vol. 108, no 33, 12388-12396 p.
Identifiers
URN: urn:nbn:se:uu:diva-91023DOI: 10.1021/jp037119pOAI: oai:DiVA.org:uu-91023DiVA: diva2:163591
Available from: 2003-11-07 Created: 2003-11-07 Last updated: 2011-04-19
In thesis
1. Interactions in Dye-sensitized Solar Cells
Open this publication in new window or tab >>Interactions in Dye-sensitized Solar Cells
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The interactions between the molecular constituents in dye-sensitized solar cells were studied with UV-VIS and IR spectroscopy, Raman scattering, conductivity and electron accumulation measurements.

From stability studies of the dye, bis(tetrabutylammonium)cis-bis(thiocyanato) bis(2,2’-bipyridine-4-carboxylic acid, 4’-carboxylate) ruthenium(II), in the complete solar cell, the thiocyanate ion ligand was found to be lost from the dye. A method was developed to study mechanisms in a sealed dye-sensitized solar cell using resonance Raman scattering (RRS). RRS studies of a complete dye-sensitized solar cell including iodine and lithium iodide in the electrolyte indicate that triiodide exchange the SCN- ligand of the dye. It was proposed that an ion pair Li+…I3- formation occurred, which, by a reduced electrostatic repulsion between I3- and SCN- facilitated the exchange of these anions at Ru(II) of the dye. The additive 1-methylbenzimidazole suppressed the SCN-/I3- ligand exchange by forming a complex with Li+.

In order to study charge transport in nanostructured TiO2 films permeated with electrolyte, a technique was developed for determining activation energies of conduction, electron accumulation and effective mobility. Two regions were distinguished from the relation between conductivity and electron concentration. In the first region (~1-20 electrons per TiO2 particle), which resembles best the region where the nanostructured dye-sensitized solar cell operates, the results can be fitted to some extent with a trapping/detrapping or a hopping model for charge transport, but not with a conduction band model. For the second region (> 20 electrons per TiO2 particle), charge transport by electrons in the conduction band seems to be the most applicable model.

Through this work many effects from the interplay between the solar cell components were observed. These observations emphasize the importance of well-balanced interactions in dye-sensitized solar cells.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2003. 59 p.
Series
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 901
Keyword
Physical chemistry, solar cells, photovoltaics, dye-sensitized, mesoporous, nanostructured, Raman scattering, Fysikalisk kemi
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-3752 (URN)91-554-5786-X (ISBN)
Public defence
2003-11-28, B42, B4, Uppsala, 10:15
Opponent
Supervisors
Available from: 2003-11-07 Created: 2003-11-07Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Boschloo, GerritHagfeldt, Anders

Search in DiVA

By author/editor
Boschloo, GerritHagfeldt, Anders
By organisation
Department of Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 1001 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