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
Developing Environmentally Friendly Dye-sensitized Solar Cells
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. (Boschloo)
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Due to climate change and its effects, alternative renewable energy sources are needed in the future human society. In the work of this thesis, the Dye-sensitized Solar Cell (DSC) has been investigated and characterized.

DSCs are appealing as energy conversion devices, since they have high potential to provide low cost solar light to electricity conversion. The DSC is built up by a working electrode consisting of a conductive glass substrate with a dye-sensitized mesoporous TiO2 film, a counter electrode with a catalyst and, in between, the electrolyte which performs the charge transport by means of a redox mediator. The aim of this thesis was to develop and evaluate cheap and environmentally friendly materials for the DSC.

An alternative polymer-based counter electrode catalyst was fabricated and evaluated, showing that the PEDOT catalyst counter electrode outperformed the platinum catalyst counter electrode. Different organic dyes were evaluated and it was found that the dye architecture affected the performance of the assembled DSCs. A partly hydrophilic organic triphenylamine dye was developed and applied in water-based electrolyte DSCs. The partly hydrophilic dye outperformed the reference hydrophobic dye. Small changes in dye architecture were evaluated for two similar dyes, both by spectroscopic and electrochemical techniques. A change in the length of the dialkoxyphenyl units on a triphenylamine dye, affected the recombination and the regeneration electron transfer kinetics in the DSC system. Finally, three water soluble cobalt redox couples were developed and applied in water-based electrolyte DSCs. An average efficiency of 5.5% (record efficiency of 5.7%) for a 100% water-based electrolyte DSC was achieved with the polymer-based catalyst counter electrode and an organic dye with short dimethoxyphenyl units, improving the wetting and the regeneration process.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. , 82 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1351
Keyword [en]
dye-sensitized solar cells, dye, cobalt, triphenylamine, titanium dioxide, aqueous, PEDOT
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Physical Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-280291ISBN: 978-91-554-9506-0 (print)OAI: oai:DiVA.org:uu-280291DiVA: diva2:910504
Public defence
2016-04-29, Polhemsalen; Ång/10134, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2016-04-06 Created: 2016-03-09 Last updated: 2016-05-24
List of papers
1. PEDOT counter electrodes for dye-sensitized solar cells prepared by aqueous micellar electrodeposition
Open this publication in new window or tab >>PEDOT counter electrodes for dye-sensitized solar cells prepared by aqueous micellar electrodeposition
Show others...
2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 107, 45-51 p.Article in journal (Refereed) Published
Abstract [en]

Electropolymerization of 3,4-ethylenedioxythiophene (EDOT) was performed in an aqueous micellar solution onto conducting glass and conducting flexible plastic substrates using a simple, scalable process. The background electrolyte in the process consisted merely of a micellar aqueous sodium dodecyl sulfate (SDS) solution. Electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) was conducted at constant current, resulting in homogeneous films, even on large sized conducting glass and plastic substrates (9 cm x 9 cm). The use of water as electrolyte, application on large substrates and applicability on flexible plastic substrates demonstrates the feasibility of this method for upscaling and use in industrial fabrication of DSCs. DSCs were assembled using three different PEDOT thicknesses on conducting glass as counter electrodes and a comparison was made with thermally platinized conducting glass counter electrodes. In cobalt tris(bipyridine)-based electrolyte, the catalytic performance of the PEDOT counter electrodes was significantly higher than that of platinized counter electrodes. DSCs with PEDOT counter electrodes gave higher efficiencies due to higher fill factors and a lower charge transfer resistance. The low charge transfer resistance and good catalytic performance of the PEDOT counter electrodes can be related to its mesoporous morphology resembling crumpled sheets of paper. 

Keyword
Dye-sensitized solar cell, Electrocatalyst, Cobalt tris(bipyridine), Charge-transfer resistance, Nanostructured electrode
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-212422 (URN)10.1016/j.electacta.2013.06.005 (DOI)000326661200005 ()
Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-12-06Bibliographically approved
2. Linker Unit Modification of Triphenylamine-based Organic Dyes for Efficient Cobalt Mediated Dye-Sensitized Solar Cells
Open this publication in new window or tab >>Linker Unit Modification of Triphenylamine-based Organic Dyes for Efficient Cobalt Mediated Dye-Sensitized Solar Cells
Show others...
2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 41, 21029-21036 p.Article in journal (Refereed) Published
Abstract [en]

Linker unit modification of donor-linker-acceptor-based organic dyes was investigated with respect to the spectral and physicochemical properties of the dyes. The spectral response for a series of triphenylamine (TPA)-based organic dyes, called LEG1-4, was shifted into the red wavelength region, and the extinction coefficient of the dyes was increased by introducing different substituted dithiophene units on the pi-conjugated linker. The photovoltaic performance of dye-sensitized solar cells (DSCs) incorporating the different dyes in combination with cobalt-based electrolytes was found to be dependent on dye binding. The binding morphology of the dyes on the TiO2 was studied using photoelectron spectroscopy, which demonstrated that the introduction of alkyl chains and different substituents on the dithiophene linker unit resulted in a larger tilt angle of the dyes with respect to the normal of the TiO2-surface, and thereby a lower surface coverage. The good photovoltaic performance for cobalt electrolyte-based DSCs found here and by other groups using TPA-based organic dyes with a cyclopentadithiophene linker unit substituted with alkyl chains was mainly attributed to the extended spectral response of the dye, whereas the larger tilt angle of the dye with respect to the TiO2-surface resulted in less efficient packing of the dye molecules and enhanced recombination between electrons in TiO2 and Co(III) species in the electrolyte.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-192688 (URN)10.1021/jp403619c (DOI)000326125800001 ()
Available from: 2013-01-24 Created: 2013-01-24 Last updated: 2017-12-06Bibliographically approved
3. An organic hydrophilic dye for water-based dye-sensitized solar cells
Open this publication in new window or tab >>An organic hydrophilic dye for water-based dye-sensitized solar cells
Show others...
2014 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 37, 19964-19971 p.Article in journal (Refereed) Published
Abstract [en]

In this study we report the first organic hydrophilic dye employed for 100% water-based electrolyte DSSCs. We show that the replacement of alkyl by glycolic chains in the dye structure is able to provide excellent wettability, resulting in an efficient system with remarkably reduced desorption problems that allowed us to perform tests over a wide pH range. By changing the electrolyte composition, employing chenodeoxycholic acid as a co-adsorbent and using PEDOT counter-electrodes, 3% power conversion efficiency under 1-sun illumination was obtained. We show that chenodeoxycholic acid does not significantly increase the wettability, and we provide new insights into the higher performance resulting from its co-adsorption.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2014
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-229941 (URN)10.1039/c4cp02774d (DOI)000341359700022 ()
Available from: 2014-08-18 Created: 2014-08-18 Last updated: 2017-12-05Bibliographically approved
4. Influence of Dye Architecture of Triphenylamine Based Organic Dyes on the Kinetics in Dye-Sensitized Solar Cells
Open this publication in new window or tab >>Influence of Dye Architecture of Triphenylamine Based Organic Dyes on the Kinetics in Dye-Sensitized Solar Cells
Show others...
2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 38, 21775-21783 p.Article in journal (Refereed) Published
Abstract [en]

The impact of the dye architecture on the kinetics in the dyesensitized solar cell (DSC) was investigated for two structurally similar organic dyes, adsorbed adsorbed to a mesoporous TiO2 film. Differences in the HOMO and LUMO levels of the triphenylamine dyes D35 and D45 were negligible, indicating that the changes in kinetics of the electron transfer processes in the solar cells can be attributed to structural differences of the organic dyes. The electron transfer kinetics of various processes was investigated by scanning electrochemical microscopy (SECM), transient absorption spectroscopy (TAS), and impedance spectroscopy (IS). SECM was used for the first time to determine the rate constants of the regeneration (reduction) of a photooiddized organic dye by a oneelectron cobalt mediator. Both TAS and IS measurements showed differences in recombination of electrons in TiO2, with oxidized D35 and D45. D45 with its shorter dimethoxyphenyl units yielded faster recombination and regeneration than D35, as measured by SECM and TAS. The results of this study show that small details in the dye structure significantly affect the kinetics of organic triphenylamine dye based dye-sensitized solar cells.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-265912 (URN)10.1021/acs.jpcc.5b04436 (DOI)000361921600003 ()
Funder
Swedish Energy AgencyKnut and Alice Wallenberg FoundationSwedish Research CouncilStandUp
Available from: 2015-11-04 Created: 2015-11-04 Last updated: 2017-12-01Bibliographically approved
5. Development of high efficiency 100% aqueous cobalt electrolyte dye-sensitised solar cells
Open this publication in new window or tab >>Development of high efficiency 100% aqueous cobalt electrolyte dye-sensitised solar cells
Show others...
2016 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 12, 8419-8427 p.Article in journal (Refereed) Published
Abstract [en]

In this study we report the application of three cobalt redox shuttles in 100% aqueous electrolyte dye-sensitised solar cells (DSCs). By using chloride as a counter-ion for cobalt bipyridine, cobalt phenanthroline and cobalt bipyridine pyrazole, the redox shuttles were made water soluble; no surfactant or further treatment was necessary. A simple system of merely the redox shuttles and 1-methylbenzimidazole (MBI) in water as an electrolyte in combination with an organic dye and a mesoporous PEDOT counter electrode was optimised. The optimisation resulted in an average efficiency of 5.5% (record efficiency of 5.7%) at 1 sun. The results of this study present promising routes for further improvements of aqueous cobalt electrolyte DSCs.

Keyword
Dye, solar cell, water, electrolyte, titanium dioxide
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-280289 (URN)10.1039/C6CP00264A (DOI)000372249100012 ()26931779 (PubMedID)
Available from: 2016-03-09 Created: 2016-03-09 Last updated: 2017-11-30Bibliographically approved

Open Access in DiVA

fulltext(25376 kB)369 downloads
File information
File name FULLTEXT01.pdfFile size 25376 kBChecksum SHA-512
05b07fa42fd1745448c51381642b8553adce64ece1ca4c0750b198c410f7987433a5d045c636c839aef8595fe3a607b56cfe9931facdbe47c1ef5983a3363227
Type fulltextMimetype application/pdf
errata(96 kB)13 downloads
File information
File name ERRATA01.pdfFile size 96 kBChecksum SHA-512
0430ab60f8e79c5deb5130ac8481c2b021d587f91eb76c8826a9eed196f7bf69ef539d6bea3e11e9c7a17fc301a5235f706f72d8424291a1fcc4ba8a3909362c
Type errataMimetype application/pdf
Buy this publication >>

Authority records BETA

Ellis, Hanna

Search in DiVA

By author/editor
Ellis, Hanna
By organisation
Physical Chemistry
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 369 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 2454 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