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Anselmo, Ana Sofia
Publications (10 of 18) Show all publications
Anselmo, A. S., Dzwilewski, A., Svensson, K. & Moons, E. (2016). Photodegradation of the electronic structure of PCBM and C60 films in air. Chemical Physics Letters, 652, 220-224
Open this publication in new window or tab >>Photodegradation of the electronic structure of PCBM and C60 films in air
2016 (English)In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 652, p. 220-224Article in journal (Refereed) Published
Abstract [en]

Fullerenes are common electron acceptors in organic solar cells. Here the photostability in air of the electronic structures of spin-coated PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and evaporated C60 films are studied using ultraviolet photoelectron spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. After exposing these materials in air to simulated sunlight, the filled and empty molecular orbitals are strongly altered, indicating that the conjugated π-system of the C60-cage has degraded. Even a few minutes in normal lab light induces changes. These results stress the importance of protecting fullerene-based films from light and air during processing, operation, and storage.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Degradation; Fullerene; Photostability; Photovoltaics; NEXAFS
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-16111 (URN)10.1016/j.cplett.2016.04.003 (DOI)000377204100042 ()
Note

The article was still in manuscript form in anna Anselmos thesis. It had then the title: Light-induced modification of the electronic structure of PCBM and C60 films

Available from: 2012-12-07 Created: 2012-12-07 Last updated: 2019-05-20Bibliographically approved
Hörmann, U., Lorch, C., Hinderhofer, A., Gerlach, A., Gruber, M., Kraus, J., . . . Brütting, W. (2014). Voc from a Morphology Point of View: the Influence of Molecular Orientation on the Open Circuit Voltage of Organic Planar Heterojunction Solar Cells. Journal of physical chemistry C, 118(46), 26462-26470
Open this publication in new window or tab >>Voc from a Morphology Point of View: the Influence of Molecular Orientation on the Open Circuit Voltage of Organic Planar Heterojunction Solar Cells
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2014 (English)In: Journal of physical chemistry C, ISSN 1932-7455, Vol. 118, no 46, p. 26462-26470Article in journal (Refereed) Published
Abstract [en]

The film morphology and device performance of planar heterojunction

solar cells based on the molecular donor material α-sexithiophene (6T) are investigated.

Planar heterojunctions of 6T with two different acceptor molecules, the C60 fullerene and

diindenoperylene (DIP), have been prepared. The growth temperature of the 6T bottom

layer has been varied between room temperature and 100 °C for each acceptor. By means

of X-ray diffraction and X-ray absorption, we show that the crystallinity and the molecular

orientation of 6T is influenced by the preparation conditions and that the 6T film

templates the growth of the subsequent acceptor layer. These structural changes are

accompanied by changes in the characteristic parameters of the corresponding

photovoltaic cells. This is most prominently observed as a shift of the open circuit

voltage (Voc): In the case of 6T/C60 heterojunctions, Voc decreases from 0.4 to 0.3 V,

approximately, if the growth temperature of 6T is increased from room temperature to 100

°C. By contrast, Voc increases from about 1.2 V to almost 1.4 V in the case of 6T/DIP solar

cells under the same conditions. We attribute these changes upon substrate heating to

increased recombination in the C60 case while an orientation dependent intermolecular coupling seems to change the origin of the photovoltaic gap in the DIP case.

National Category
Condensed Matter Physics
Research subject
Physics; Materials Science
Identifiers
urn:nbn:se:kau:diva-35420 (URN)10.1021/jp506180k (DOI)000345474000005 ()
Funder
German Research Foundation (DFG), SPP 1355Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Note

publication date: October 27, 2014

Available from: 2015-03-22 Created: 2015-03-22 Last updated: 2018-06-20Bibliographically approved
Anselmo, A. S. (2013). Materials aspects in spin-coated films for polymer photovoltaics. (Doctoral dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Materials aspects in spin-coated films for polymer photovoltaics
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Polymer-based photovoltaics have the potential to contribute to boosting photovoltaic energy conversion overall. Besides allowing large-area inexpensive processing, polymeric materials have the added benefit of opening new market applications for photovoltaics due to their low-weight and interesting mechanical properties. The energy conversion efficiency values of polymer photovoltaics have reached new record values over the past years. It is however crucial that stability issues are addressed together with efficiency optimization. Understanding fundamental materials aspects is key in both areas.

In the work presented in this thesis, the morphology of polymer:fullerene films and its influence on device performance was studied, as well as the effect of light exposure on the surface of fullerene films. Several polyfluorene copolymers were used for the morphology studies, where the effects of changing spin-coating solvent and of side chain engineering were investigated with dynamic secondary ion mass spectrometry (dSIMS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Polymer-enriched surfaces were found in all blend films, even in the cases with homogeneous distributions in the bulk. Side chain engineering of the polymer led to gradual changes in the compositional variations perpendicular to the surface, and to slight variations in the photocurrent. The electronic structure of the fullerene derivative PCBM was studied in detail and the spectroscopic fingerprint of the materials was analysed by comparison with theoretically simulated spectra. Photo-stability studies done in air showed that the surface of fullerene films underwent severe damages at the molecular level, which is evident from changes in the valence band and X-ray absorption spectra. These changes were explained by transitions from sp2-type to sp3 hybridization of the carbon atoms in the cage that resulted in the destruction of the fullerene cage.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2013. p. 88
Series
Karlstad University Studies, ISSN 1403-8099 ; 2013:3
Keywords
materials science, photovoltaics, conjugated polymer, polymer solar cell, bulk heterojunction, coating, morphology, fullerene, photostability, degradation, X-ray absorption spectroscopy, synchroton-based techniques
National Category
Physical Sciences
Research subject
Materialvetenskap
Identifiers
urn:nbn:se:kau:diva-16107 (URN)978-91-7063-475-8 (ISBN)
Public defence
2013-01-25, 21A342, Karlstad University, SE-651 88, Karlstad, 13:15 (English)
Opponent
Supervisors
Available from: 2013-01-07 Created: 2012-12-07 Last updated: 2013-01-07Bibliographically approved
Anselmo, A. S., Dzwilewski, A., Svensson, K. & Moons, E. (2013). Molecular Orientation and Composition at the Surface of Spin-Coated Polyfluorene:Fullerene Blend Films. Journal of Polymer Science Part B: Polymer Physics, 51(3), 176-182
Open this publication in new window or tab >>Molecular Orientation and Composition at the Surface of Spin-Coated Polyfluorene:Fullerene Blend Films
2013 (English)In: Journal of Polymer Science Part B: Polymer Physics, ISSN 0887-6266, E-ISSN 1099-0488, Vol. 51, no 3, p. 176-182Article in journal (Refereed) Published
Abstract [en]

The surface composition in spin-coated films of polyfluorene:fullerene blends was determined quantitatively by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. By comparing partial and total electron yield spectra, we found vertical compositional differences in the surface region. Furthermore, the orientation of the polymer chains was investigated by variable-angle NEXAFS. Blend films of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole] with [6,6]-phenyl-C61-butyric acid methyl ester in two different blend ratios were studied. Results showed polymer enrichment of the surfaces for films with a polymer:fullerene weight ratio of 20:80 and of 50:50, spin-coated from both chlorobenzene and chloroform solutions. The angular dependence of the NEXAFS spectra of the pure polymer films showed a preferential plane-on orientation, which was slightly stronger in the subsurface region than at the surface. In blend films, this orientational preference was less pronounced and the difference between surface and subsurface vanished

Place, publisher, year, edition, pages
Hoboken, New Jersey: John Wiley & Sons, 2013
Keywords
polymer solar cell, bulk heterojunction, phase separation, morphology, miscibility, near-edge X-ray absorption fine structure
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-16005 (URN)10.1002/polb.23198 (DOI)000312728600002 ()
Available from: 2012-11-30 Created: 2012-11-30 Last updated: 2019-05-20Bibliographically approved
Brumboiu, I., Anselmo, A. S., Brena, B., Dzwilewski, A., Svensson, K. & Moons, E. (2013). Near-edge X-ray Absorption Fine Structure Study of the C60-derivative PCBM. Chemical Physics Letters, 568-569, 130-134
Open this publication in new window or tab >>Near-edge X-ray Absorption Fine Structure Study of the C60-derivative PCBM
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2013 (English)In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 568-569, p. 130-134Article in journal (Refereed) Published
Abstract [en]

The fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester plays a key role for electron transport in polymer solar cells. We have studied the unoccupied molecular orbitals of PCBM by near edge X-ray absorption fine structure spectroscopy and were able to assign the main resonances to molecular moieties by comparison with calculated sum spectra of individual carbons. We analyzed specifically the origin of the high-energy shoulder to the first π-resonance and identified contributions from the lowest-energy transition of a specific carbon in the phenyl and from transitions to higher unoccupied orbitals of the unmodified carbons in the C60-cage.

Place, publisher, year, edition, pages
Amsterdam: , 2013
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-16110 (URN)10.1016/j.cplett.2013.03.031 (DOI)000318320300025 ()
Note

(included in PhD thesis: Material aspects in spin-coated films for polymer photovoltaics, Ana Sofia Anselmo)

Available from: 2012-12-07 Created: 2012-12-07 Last updated: 2019-05-20Bibliographically approved
Dzwilewski, A., Anselmo, A. S., Svensson, K. & Moons, E. (2012). Light induced effects in PCBM:P3HT blend films. In: Anders Hagfeldt (Ed.), Hybrid and Organics Photovoltaics Conference: Uppsala, Sweden, 2012. Paper presented at 4th international Conference on Hybrid and Organic Photovoltaics, HOPV12, Uppsala, 6-9 May 2012 (pp. 155-155). SEFIN, Castelló (Spain)
Open this publication in new window or tab >>Light induced effects in PCBM:P3HT blend films
2012 (English)In: Hybrid and Organics Photovoltaics Conference: Uppsala, Sweden, 2012 / [ed] Anders Hagfeldt, SEFIN, Castelló (Spain), 2012, p. 155-155Conference paper, Poster (with or without abstract) (Refereed)
Place, publisher, year, edition, pages
SEFIN, Castelló (Spain): , 2012
Series
Nanoenergy Series ; Vol. 9
Keywords
fullerene, photovoltaics, molecular, photostability
National Category
Condensed Matter Physics Materials Chemistry
Research subject
Materials Science; Physics; Chemistry
Identifiers
urn:nbn:se:kau:diva-29029 (URN)978-84-940189-0-9 (ISBN)
Conference
4th international Conference on Hybrid and Organic Photovoltaics, HOPV12, Uppsala, 6-9 May 2012
Funder
Swedish Research Council, 2010-4155
Available from: 2013-09-13 Created: 2013-09-13 Last updated: 2019-05-20Bibliographically approved
Anselmo, A. S., Dzwilewski, A., Wang, E., Andersson, M. R., van Stam, J., Svensson, K. & Moons, E. (2012). Molecular orientation and composition at the surface of APFO3:PCBM blend films. In: Anders Hagfeldt (Ed.), Hybrid and Organics Photovoltaics Conference: Uppsala, Sweden, 2012. Paper presented at 4th international Conference on Hybrid and Organic Photovoltaics, HOPV12, Uppsala, 6-9 May 2012 (pp. 278). SEFIN, Castelló (Spain)
Open this publication in new window or tab >>Molecular orientation and composition at the surface of APFO3:PCBM blend films
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2012 (English)In: Hybrid and Organics Photovoltaics Conference: Uppsala, Sweden, 2012 / [ed] Anders Hagfeldt, SEFIN, Castelló (Spain), 2012, p. 278-Conference paper, Poster (with or without abstract) (Refereed)
Place, publisher, year, edition, pages
SEFIN, Castelló (Spain): , 2012
Series
Nanoenergy Series ; Vol. 9
Keywords
polymer, solar cell, photovoltaics
National Category
Materials Chemistry Condensed Matter Physics
Research subject
Materials Science; Physics; Chemistry
Identifiers
urn:nbn:se:kau:diva-29032 (URN)978-84-940189-0-9 (ISBN)
Conference
4th international Conference on Hybrid and Organic Photovoltaics, HOPV12, Uppsala, 6-9 May 2012
Funder
Swedish Research Council, 2010-4155
Available from: 2013-09-13 Created: 2013-09-13 Last updated: 2019-05-20Bibliographically approved
Anselmo, A. S., Lindgren, L., Svensson, K., Hörmann, U., Brütting, W., van Stam, J., . . . Moons, E. (2012). Polyfluorene copolymers with functionalized side chains: Opto-electronic properties and solar cell performance.
Open this publication in new window or tab >>Polyfluorene copolymers with functionalized side chains: Opto-electronic properties and solar cell performance
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2012 (English)Manuscript (preprint) (Other academic)
Keywords
conjugated polymers, photovoltaics, bulk heterojunction, acceptor-donor interaction, HOMO/LUMO levels, I-V characteristics
National Category
Physical Sciences
Identifiers
urn:nbn:se:kau:diva-16108 (URN)
Available from: 2012-12-07 Created: 2012-12-07 Last updated: 2017-12-06Bibliographically approved
Anselmo, A. S., Dzwilewski, A., Rysz, J., Budkowski, A., Svensson, K., van Stam, J. & Moons, E. (2012). Polymer solar cells: Visualizing vertical phase separation in solution-processed films of polymer fullerene blends. In: Hans-Klaus Roth, Klaus Heinemann (Ed.), Proceedings of the 5th International Symposium Technologies for Polymer Electronics - TPE 12: . Paper presented at 5th International Symposium Technologies for Polymer Electronics - TPE 12 - May 24-26, 2012, Rudolstadt, Germany (pp. 125-128). Ilmenau, Germany: Universitätsverlag Ilmenau
Open this publication in new window or tab >>Polymer solar cells: Visualizing vertical phase separation in solution-processed films of polymer fullerene blends
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2012 (English)In: Proceedings of the 5th International Symposium Technologies for Polymer Electronics - TPE 12 / [ed] Hans-Klaus Roth, Klaus Heinemann, Ilmenau, Germany: Universitätsverlag Ilmenau , 2012, p. 125-128Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Ilmenau, Germany: Universitätsverlag Ilmenau, 2012
National Category
Condensed Matter Physics Textile, Rubber and Polymeric Materials
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-15767 (URN)978-3-86360-022-8 (ISBN)
Conference
5th International Symposium Technologies for Polymer Electronics - TPE 12 - May 24-26, 2012, Rudolstadt, Germany
Available from: 2012-11-23 Created: 2012-11-23 Last updated: 2019-05-20Bibliographically approved
Moons, E., Anselmo, A. S., Dzwilewski, A., Svensson, K. & van Stam, J. (2012). Vertical Phase Separation in Polymer:Fullerene Films for Photovoltaics. In: Anders Hagfeldt (Ed.), Hybrid and Organics Photovoltaics Conference 2012: Uppsala, Sweden, 6th to 9th May 2012. Paper presented at 4th international Conference on Hybrid and Organic Photovoltaics, HOPV12 (pp. 53-53). Castelló, Spain: Society for Nanomolecular Photovoltaics (SEFIN)
Open this publication in new window or tab >>Vertical Phase Separation in Polymer:Fullerene Films for Photovoltaics
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2012 (English)In: Hybrid and Organics Photovoltaics Conference 2012: Uppsala, Sweden, 6th to 9th May 2012 / [ed] Anders Hagfeldt, Castelló, Spain: Society for Nanomolecular Photovoltaics (SEFIN) , 2012, p. 53-53Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Castelló, Spain: Society for Nanomolecular Photovoltaics (SEFIN), 2012
Series
Nanoenergy Symposia ; 9
Keywords
energy, nano, photovoltaics, molecular
National Category
Materials Chemistry Physical Chemistry Condensed Matter Physics
Research subject
Materials Science; Physics; Chemistry
Identifiers
urn:nbn:se:kau:diva-29024 (URN)978-84-940189-0-9 (ISBN)
Conference
4th international Conference on Hybrid and Organic Photovoltaics, HOPV12
Funder
Swedish Research Council, 2010-4155
Available from: 2013-09-13 Created: 2013-09-13 Last updated: 2019-05-20Bibliographically approved
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