Change search
Link to record
Permanent link

Direct link
BETA
Publications (9 of 9) Show all publications
Züfle, S., Hansson, R., Katz, E. A. & Moons, E. (2019). Initial photo-degradation of PCDTBT:PC 70 BM solar cells studied under various illumination conditions: Role of the hole transport layer. Solar Energy, 183(1), 234-239
Open this publication in new window or tab >>Initial photo-degradation of PCDTBT:PC 70 BM solar cells studied under various illumination conditions: Role of the hole transport layer
2019 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 183, no 1, p. 234-239Article in journal (Refereed) Published
Abstract [en]

ncapsulated organic solar cells often show a burn-in behaviour under illumination. This burn-in manifests itself as a rapid performance loss followed by a much slower progression of the degradation. Here we investigate the burn-in for PCDTBT:PC 70 BM solar cells under a wide range of illumination intensities. We find that increasing the sunlight concentration from 1 Sun to up to 100 Suns does not change the degradation behaviour, i.e. the dependence of all principal photovoltaic parameters on the dose of solar exposure (in Sun hours). This suggests that the degradation mechanisms under solar concentration (≤100 Suns) are the same as those observed under 1 Sun. This result makes it possible to use concentrated sunlight for accelerated stability assessment of these devices. We also find that devices with PEDOT:PSS as hole transport material show a rapid drop in open-circuit voltage of around 100 mV during the first Sun hour of light exposure. By replacing PEDOT:PSS with MoO 3 this initial process can be prevented and only the much slower part of the photo-degradation takes place.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-47260 (URN)10.1016/j.solener.2019.03.020 (DOI)
Funder
Swedish Energy Agency, 38327-1Swedish Research Council, 2015-03778Göran Gustafsson Foundation for Research in Natural Sciences and Medicine, MP1307,STSM-MP1307-090216-070777
Note

Publicerad i Hanssons doktorsavhandling Materials and Device Engineering for Efficient and Stable Polymer Solar Cells som manuskript med titeln: "The role of the hole transport layer in the initial photo-degradation of PCDTBTPC70BM solar cells"

Available from: 2016-11-23 Created: 2016-11-23 Last updated: 2019-04-05Bibliographically approved
Ciammaruchi, L., Hansson, R., Moons, E. & Galagan, Y. (2018). Stability of organic solar cells with PCDTBT donor polymer: An interlaboratory study. Journal of Materials Research, 33(13), 1909-1924
Open this publication in new window or tab >>Stability of organic solar cells with PCDTBT donor polymer: An interlaboratory study
2018 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 33, no 13, p. 1909-1924Article in journal (Refereed) Published
Abstract [en]

This work is part of the interlaboratory collaboration to study the stability of organic solar cells containing PCDTBT polymer as a donor material. The varieties of the OPV devices with different device architectures, electrode materials, encapsulation, and device dimensions were prepared by seven research laboratories. Sets of identical devices were aged according to four different protocols: shelf lifetime, laboratory weathering under simulated illumination at ambient temperature, laboratory weathering under simulated illumination, and elevated temperature (65 degrees C) and daylight outdoor weathering under sunlight. The results generated in this study allow us to outline several general conclusions related to PCDTBT-based bulk heterojunction (BHJ) solar cells. The results herein reported can be considered as practical guidance for the realization of stabilization approaches in BHJ solar cells containing PCDTBT.

Place, publisher, year, edition, pages
New York: Cambridge University Press, 2018
Keywords
energetic material, nanoscale, organic
National Category
Physical Sciences Materials Chemistry
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-68746 (URN)10.1557/jmr.2018.163 (DOI)000438739300009 ()
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-10-18Bibliographically approved
Opitz, A., Wilke, A., Amsalem, P., Oehzelt, M., Blum, R.-P., Rabe, J. P., . . . Koch, N. (2016). Organic heterojunctions: Contact-induced molecular reorientation, interface states, and charge redistribution. Scientific Reports, 6, Article ID 21291.
Open this publication in new window or tab >>Organic heterojunctions: Contact-induced molecular reorientation, interface states, and charge redistribution
Show others...
2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 21291Article in journal (Refereed) Published
Abstract [en]

We reveal the rather complex interplay of contact-induced re-orientation and interfacial electronic structure-in the presence of Fermi-level pinning-at prototypical molecular heterojunctions comprising copper phthalocyanine (H16CuPc) and its perfluorinated analogue (F16CuPc), by employing ultraviolet photoelectron and X-ray absorption spectroscopy. For both layer sequences, we find that Fermi-level (E-F) pinning of the first layer on the conductive polymer substrate modifies the work function encountered by the second layer such that it also becomes E-F-pinned, however, at the interface towards the first molecular layer. This results in a charge transfer accompanied by a sheet charge density at the organic/organic interface. While molecules in the bulk of the films exhibit upright orientation, contact formation at the heterojunction results in an interfacial bilayer with lying and co-facial orientation. This interfacial layer is not EF-pinned, but provides for an additional density of states at the interface that is not present in the bulk. With reliable knowledge of the organic heterojunction's electronic structure we can explain the poor performance of these in photovoltaic cells as well as their valuable function as charge generation layer in electronic devices.

National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-41201 (URN)10.1038/srep21291 (DOI)000370370200001 ()26887445 (PubMedID)
Available from: 2016-04-01 Created: 2016-04-01 Last updated: 2018-06-20Bibliographically approved
Hansson, R., Lindqvist, C., Ericsson, L., Opitz, A., Wang, E. & Moons, E. (2016). Photodegradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell. Physical Chemistry, Chemical Physics - PCCP, 18(16), 11132-11138
Open this publication in new window or tab >>Photodegradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell
Show others...
2016 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 16, p. 11132-11138Article in journal (Refereed) Published
Abstract [en]

We have studied the photo-degradation in air of a blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and how the photo-degradation affects the solar cell performance. Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, changes to the electronic structure of TQ1 and PCBM caused by illumination in ambient air are investigated and compared between the pristine materials and the blend. The NEXAFS spectra show that the unoccupied molecular orbitals of TQ1 are not significantly changed by the exposure of pristine TQ1 to light in air, whereas those of PCBM are severely affected as a result of photo-induced degradation of PCBM. Furthermore, the photo-degradation of PCBM is accelerated by blending it with TQ1. While the NEXAFS spectrum of TQ1 remains unchanged upon illumination in air, its valence band spectrum shows that the occupied molecular orbitals are weakly affected. Yet, UV-Vis absorption spectra demonstrate photo-bleaching of TQ1, which is attenuated in the presence of PCBM in blend films. Illumination of the active layer of TQ1: PCBM solar cells prior to cathode deposition causes severe losses in electrical performance.

Keywords
polymer solar cells, photodegradation, fullerene, near-edge X-ray absorption fine structure
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-37835 (URN)10.1039/c5cp07752d (DOI)000374786300053 ()
Available from: 2015-09-04 Created: 2015-09-03 Last updated: 2018-06-20Bibliographically approved
van Stam, J., Lindqvist, C., Hansson, R., Ericsson, L. & Moons, E. (2015). Fluorescence and UV/VIS absorption spectroscopy studies on polymer blend films for photovoltaics. In: Hayes, SC; Bittner, ER (Ed.), Proceedings of SPIE: Physical Chemistry of Interfaces and Nanomaterials XIV. Paper presented at 2015 Optics + Photonics conference, 9-13 August 2015, San Diego, California, (pp. 95490L1-95490L9). SPIE - International Society for Optical Engineering, 9549
Open this publication in new window or tab >>Fluorescence and UV/VIS absorption spectroscopy studies on polymer blend films for photovoltaics
Show others...
2015 (English)In: Proceedings of SPIE: Physical Chemistry of Interfaces and Nanomaterials XIV / [ed] Hayes, SC; Bittner, ER, SPIE - International Society for Optical Engineering, 2015, Vol. 9549, p. 95490L1-95490L9Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2015
National Category
Physical Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-38102 (URN)10.1117/12.2188618 (DOI)000365189200005 ()
Conference
2015 Optics + Photonics conference, 9-13 August 2015, San Diego, California,
Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2018-06-20Bibliographically approved
Hansson, R. (2015). Morphology and material stability in polymer solar cells. (Licentiate dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Morphology and material stability in polymer solar cells
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Polymer solar cells are promising in that they are inexpensive to produce, and due to their mechanical flexibility have the potential for use in applications not possible for more traditional types of solar cells. The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime of polymer solar cells has become at least as important as improving the efficiency.

 

In this thesis, the relation between morphology and solar cell performance is studied, and the material stability for blend films of the thiophene-quinoxaline copolymer TQ1 and the fullerene derivatives PCBM and PC70BM. Atomic force microscopy (AFM) and scanning transmission X-ray microscopy (STXM) are used to investigate the lateral morphology, secondary ion mass spectrometry (SIMS) to measure the vertical morphology and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to determine the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed TQ1 surface enrichment does not affect the performance. Changes to the unoccupied molecular orbitals as a result of illumination in ambient air are observed by NEXAFS spectroscopy for PCBM, but not for TQ1. The NEXAFS spectrum of PCBM in a blend with TQ1 changes more than that of pristine PCBM. Solar cells in which the active layer has been illuminated in air prior to the deposition of the top electrode exhibit greatly reduced electrical performance. The valence band and absorption spectrum of TQ1 is affected by illumination in air, but the effects are not large enough to account for losses in solar cell performance, which are mainly attributed to PCBM degradation at the active layer surface.

Abstract [en]

The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime has become at least as important as improving the efficiency for polymer solar cells to become a viable technology.

 

In this work, the relation between morphology and solar cell performance is studied as well as the material stability for polymer:fullerene blend films. A combination of microscopic and spectroscopic methods is used to investigate the lateral and vertical morphology as well as the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed surface enrichment of polymer does not affect the performance. Changes to the unoccupied molecular states as a result of illumination in ambient air are observed for the fullerene, but not for the polymer, and fullerenes in a blend change more than pristine fullerenes. Solar cells in which the active layer has been illuminated exhibit greatly reduced electrical performance, mainly attributed to fullerene degradation at the active layer surface.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2015. p. 51
Series
Karlstad University Studies, ISSN 1403-8099 ; 2015:44
Keywords
polymer solar cell, photovoltaics, morphology, photo-degradation, conjugated polymer, fullerene, synchroton-based techniques
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-37843 (URN)978-91-7063-662-2 (ISBN)
Presentation
2015-10-16, Eva Erikssonsalen, 21A 342, Karlstad universitet, 10:15 (English)
Opponent
Supervisors
Note

Paper 2 ingick som manuskript i avhandlingen. Nu publicerad. 

Available from: 2015-09-25 Created: 2015-09-04 Last updated: 2018-06-20Bibliographically approved
Brumboiu, I. E., Ericsson, L. K. .., Hansson, R., Moons, E., Eriksson, O. & Brena, B. (2015). The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM. Journal of Chemical Physics, 142, 054306
Open this publication in new window or tab >>The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM
Show others...
2015 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 142, p. 054306-Article in journal (Refereed) Published
Place, publisher, year, edition, pages
AIP Publishing: , 2015
Keywords
Adsorption, X-ray photoelectron spectroscopy, X-ray absorption near edge structure, Atomic spectra, Fullerenes
National Category
Condensed Matter Physics
Research subject
Physics; Materials Science
Identifiers
urn:nbn:se:kau:diva-35419 (URN)10.1063/1.4907012 (DOI)000349614200019 ()
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationGöran Gustafsson Foundation for Research in Natural Sciences and MedicineSwedish National Infrastructure for Computing (SNIC)
Available from: 2015-03-22 Created: 2015-03-22 Last updated: 2018-06-20Bibliographically approved
Hansson, R., Ericsson, L. K. .., Holmes, N. P., Rysz, J., Opitz, A., Campoy-Quiles, M., . . . Moons, E. (2015). Vertical and lateral morphology effects on solar cell performance for a thiophene–quinoxaline copolymer:PC70BM blend. Journal of Materials Chemistry A, 3, 6970-6979
Open this publication in new window or tab >>Vertical and lateral morphology effects on solar cell performance for a thiophene–quinoxaline copolymer:PC70BM blend
Show others...
2015 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, p. 6970-6979Article in journal (Refereed) Published
Keywords
NEXAFS, SIMS, solar cell, organic photovoltaics, solvent additives
National Category
Condensed Matter Physics
Research subject
Physics; Materials Science
Identifiers
urn:nbn:se:kau:diva-35418 (URN)10.1039/c5ta00683j (DOI)000351552300034 ()
Funder
Swedish Research Council, 2010-4155Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Available from: 2015-03-22 Created: 2015-03-22 Last updated: 2018-06-20Bibliographically 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
Show others...
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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4745-1074

Search in DiVA

Show all publications