Photo-oxidation Kinetics of Poly-3-hexylthiophene Thin Films

DSpace Repository

Show simple item record

dc.contributor.advisor Chassé, Thomas (Prof. Dr.) de_DE
dc.contributor.author Hintz, Holger de_DE
dc.date.accessioned 2012-04-13 de_DE
dc.date.accessioned 2014-03-18T10:24:22Z
dc.date.available 2012-04-13 de_DE
dc.date.available 2014-03-18T10:24:22Z
dc.date.issued 2011 de_DE
dc.identifier.other 363789502 de_DE
dc.identifier.uri http://nbn-resolving.de/urn:nbn:de:bsz:21-opus-61408 de_DE
dc.identifier.uri http://hdl.handle.net/10900/49656
dc.description.abstract Poly-3-hexylthiophene (P3HT) is a widely employed, organic semiconductor used in the field of organic solar cells. However there is still a lack of understanding about the basic degradation mechanisms which leads to the decomposition of the material limiting the lifetime. Quantitative information about competing reaction pathways under ambient conditions is hardly available. In the present work the influence of environmental factors on the degradation process of P3HT film has been investigated quantitatively. The decay kinetics of the polymer absorption during variation of intensity and spectral distribution of the incident light, oxygen concentration, ozone concentration, humidity level as well as temperature are monitored using infrared, UV/VIS and photoelectron spectroscopy. Additionally the oxygen diffusion into the polymer film has been investigated using fluorescence spectroscopy under the same experimental conditions. The degradation process is light initiated with a strong increase of the effectiveness towards the ultraviolet region of the spectrum. The observed photo oxidation is not oxygen diffusion limited although an activation energy of 26 kJmol-1 was observed for both degradation and oxygen diffusion. The observed kinetics, especially its dependence on wavelength of the incident light, point to a radical- based degradation process in the solid state rather than a singlet oxygen based mechanism as it is observed in the liquid phase. Furthermore the presence of humidity strongly affects the degradation process although water itself does not decompose the polymer. Changing the structure of the polymer from regio-regular to regio-random significantly accelerates the degradation, probably due to the higher triplet yield of the regio-random polymer. Ozone degradation is negligible at ambient ozone levels. en
dc.description.abstract Poly-3-hexylthiophene (P3HT) is a widely employed, organic semiconductor used in the field of organic solar cells. However there is still a lack of understanding about the basic degradation mechanisms which leads to the decomposition of the material limiting the lifetime. Quantitative information about competing reaction pathways under ambient conditions is hardly available. In the present work the influence of environmental factors on the degradation process of P3HT film has been investigated quantitatively. The decay kinetics of the polymer absorption during variation of intensity and spectral distribution of the incident light, oxygen concentration, ozone concentration, humidity level as well as temperature are monitored using infrared, UV/VIS and photoelectron spectroscopy. Additionally the oxygen diffusion into the polymer film has been investigated using fluorescence spectroscopy under the same experimental conditions. The degradation process is light initiated with a strong increase of the effectiveness towards the ultraviolet region of the spectrum. The observed photo oxidation is not oxygen diffusion limited although an activation energy of 26 kJmol-1 was observed for both degradation and oxygen diffusion. The observed kinetics, especially its dependence on wavelength of the incident light, point to a radical- based degradation process in the solid state rather than a singlet oxygen based mechanism as it is observed in the liquid phase. Furthermore the presence of humidity strongly affects the degradation process although water itself does not decompose the polymer. Changing the structure of the polymer from regio-regular to regio-random significantly accelerates the degradation, probably due to the higher triplet yield of the regio-random polymer. Ozone degradation is negligible at ambient ozone levels. en
dc.language.iso en de_DE
dc.publisher Universität Tübingen de_DE
dc.rights ubt-podok de_DE
dc.rights.uri http://tobias-lib.uni-tuebingen.de/doku/lic_mit_pod.php?la=de de_DE
dc.rights.uri http://tobias-lib.uni-tuebingen.de/doku/lic_mit_pod.php?la=en en
dc.subject.classification Reaktionskinetik , Photooxidation de_DE
dc.subject.ddc 540 de_DE
dc.subject.other Poly-3-hexylthiophen , P3HT, Photooxidation de_DE
dc.subject.other Photo-oxidation , Poly-3-hexylthiophene en
dc.title Photo-oxidation Kinetics of Poly-3-hexylthiophene Thin Films en
dc.title Kinetik der Photooxidation von Poly-3-hexylthiophen in Dünnen Schichten de_DE
dc.type Dissertation de_DE
dcterms.dateAccepted 2012-02-23 de_DE
utue.publikation.fachbereich Chemie de_DE
utue.publikation.fakultaet 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE
dcterms.DCMIType Text de_DE
utue.publikation.typ doctoralThesis de_DE
utue.opus.id 6140 de_DE
thesis.grantor 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE

Dateien:

This item appears in the following Collection(s)

Show simple item record