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Ericsson, Leif
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Publications (10 of 19) Show all publications
van Stam, J., Ericsson, L., Deribew, D. & Moons, E. (2018). Morphology in Dip-Coated Blend Films for Photovoltaics Studied by UV/VIS Absorption and Fluorescence Spectroscopy. In: S. Reineke, K. Vandewal (Ed.), Organic Electronics and Photonics: Fundamentals and Devices. Paper presented at Conference on Organic Electronics and Photonics - Fundamentals and Devices, APR 24-26, 2018, Strasbourg, FRANCE. SPIE-INT SOC OPTICAL ENGINEERING, Article ID UNSP 106870A.
Open this publication in new window or tab >>Morphology in Dip-Coated Blend Films for Photovoltaics Studied by UV/VIS Absorption and Fluorescence Spectroscopy
2018 (English)In: Organic Electronics and Photonics: Fundamentals and Devices / [ed] S. Reineke, K. Vandewal, SPIE-INT SOC OPTICAL ENGINEERING , 2018, article id UNSP 106870AConference paper, Published paper (Refereed)
Abstract [en]

Blend thin films, prepared by dip-coating, of polyfluorene (F8 or PFO), acting as an electron donor, and [6,6]-phenyl-C-61-butyric acid methyl ester (PC60BM), acting as the electron acceptor, have been characterized by UV/VIS absorption spectroscopy, static and dynamic fluorescence, and atomic force microscopy. Four different solvents were used for the film preparation; the monohalogenated fluorobenzene and chlorobenzene and their dihalogenated counterparts o-difluorobenzene and o-dichlorobenzene, respectively. Fluid mechanics calculations were used to determine the withdrawal speed for each solvent, in order to prepare wet films of comparable thicknesses. The resulting dry films were also of similar thicknesses. It was found that the choice of solvent influences the ability for F8 to form its beta-phase.

Place, publisher, year, edition, pages
SPIE-INT SOC OPTICAL ENGINEERING, 2018
Series
Proceedings of SPIE, ISSN 0277-786X ; 10687
National Category
Physical Sciences Materials Engineering Chemical Sciences
Research subject
Physics; Chemistry
Identifiers
urn:nbn:se:kau:diva-70966 (URN)10.1117/12.2306857 (DOI)000453618300001 ()978-1-5106-1901-2 (ISBN)
Conference
Conference on Organic Electronics and Photonics - Fundamentals and Devices, APR 24-26, 2018, Strasbourg, FRANCE
Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-06-14Bibliographically approved
Blazinic, V., Ericsson, L., Muntean, S. A. & Moons, E. (2018). Photo-degradation in air of spin-coated PC60BM and PC70BM films. Synthetic metals, 241, 26-30
Open this publication in new window or tab >>Photo-degradation in air of spin-coated PC60BM and PC70BM films
2018 (English)In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 241, p. 26-30Article in journal (Refereed) Published
Abstract [en]

The fullerene derivatives PC60BM and PC70BM are widely used as electron accepting components in the active layer of polymer solar cells. Here we compare their photochemical stability by exposing thin films of PC60BM and PC70BM to simulated sunlight in ambient air for up to 47 h, and study changes in their UV–vis and FT-IR spectra. We quantify the photo-degradation by tracking the development of oxidation products in the transmission FT-IR spectra. Results indicate that PC60BM photodegrades faster than PC70BM. The rate of photo-oxidation of the thin films is dependent on the rate of oxygen diffusion in to the film and on the photo-oxidation rate of a single molecule. Both factors are dependent on the nature of the fullerene cage. The faster photo-oxidation of PC60BM than of PC70BM is in agreement with its slightly lower density and its higher reactivity. The use of PC70BM in solar cells is advantageous not only because of its absorption spectrum, but also because of its higher stability.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Fullerene derivatives, Photo-oxidation, UV-vis spectroscopy, IR spectroscopy
National Category
Condensed Matter Physics
Research subject
Materials Science
Identifiers
urn:nbn:se:kau:diva-66953 (URN)10.1016/j.synthmet.2018.03.021 (DOI)
Available from: 2018-04-09 Created: 2018-04-09 Last updated: 2019-07-12Bibliographically approved
Hansson, R., Ericsson, L., Holmes, N. P., Blazinic, V., Dastoor, P. & Moons, E. (2017). Opportunities and challenges in probing local composition of organic material blends for photovoltaics. Journal of Materials Research, 32(10), 1982-1992
Open this publication in new window or tab >>Opportunities and challenges in probing local composition of organic material blends for photovoltaics
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2017 (English)In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 32, no 10, p. 1982-1992Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Materials Research Society, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kau:diva-47259 (URN)10.1557/jmr.2017.7 (DOI)000402284600014 ()
Funder
Swedish Energy Agency, 38327-1Swedish Research Council, 2015-03778Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Available from: 2016-11-23 Created: 2016-11-23 Last updated: 2018-01-05Bibliographically 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
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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
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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
van Stam, J., Hansson, R., Lindqvist, C., Ericsson, L. & Moons, E. (2015). Fluorescence spectroscopy studies on polymer blend solutions and films for photovoltaics. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 483, 292-296
Open this publication in new window or tab >>Fluorescence spectroscopy studies on polymer blend solutions and films for photovoltaics
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2015 (English)In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 483, p. 292-296Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2015
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kau:diva-38100 (URN)10.1016/j.colsurfa.2015.04.003 (DOI)000362146200039 ()
Available from: 2015-10-05 Created: 2015-10-05 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
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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
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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
Ericsson, L. K. (2013). Growth and Characterization of ZnO Nanocrystals. (Doctoral dissertation). Karlstad: Karlstads universitet
Open this publication in new window or tab >>Growth and Characterization of ZnO Nanocrystals
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The understanding of surfaces of materials is of crucial importance to all of us. Considering nanocrystals (NCs), that have a large surface to bulk ratio, the surfaces become even more important. Therefore, it is important to understand the fundamental surface properties in order to use NCs efficiently in applications. In the work reported in this thesis ZnO NCs were studied.

At MAX-lab in Lund, synchrotron radiation based Spectroscopic Photoemission and Low Energy Electron Microscopy (SPELEEM) and X-ray Photoelectron Spectroscopy (XPS) were used. At Karlstad University characterization was done using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Scanning Tunnelling Microscopy (STM), Auger Electron Spectroscopy (AES), and XPS.

The fundamental properties of ZnO surfaces were studied using distributions of ZnO NCs on SiO2/Si surfaces. The conditions for distribution of ZnO NCs were determined to be beneficial when using ethanol as the solvent for ultrasonically treated dispersions. Annealing at 650 °C in UHV cleaned the surfaces of the ZnO NCs enough for sharp LEEM imaging and chemical characterization while no sign of de-composition was found. A flat energy band structure for the ZnO/SiO2/Si system was proposed after 650 °C. Increasing the annealing temperature to 700 °C causes a de-composition of the ZnO that induce a downward band bending on the surfaces of ZnO NCs.

Flat ZnO NCs with predominantly polar surfaces were grown using a rapid microwave assisted process. Tuning the chemistry in the growth solution the growth was restricted to only plate-shaped crystals, i.e. a very uniform growth. The surfaces of the NCs were characterized using AFM, revealing a triangular reconstruction of the ZnO(0001) surface not seen without surface treatment at ambient conditions before. Following cycles of sputtering and annealing in UHV, we observe by STM a surface reconstruction interpreted as 2x2 with 1/4 missing Zn atoms.

Abstract [en]

Baksidestext

The understanding of the surfaces of materials is of crucial importance to all of us. Considering nanocrystals (NCs), that have a large surface to bulk ratio, the surfaces become even more important. In the work in this thesis ZnO NCs were studied.

The fundamental properties of ZnO surfaces were studied using distributions of ZnO NCs on SiO2/Si surfaces. Annealing at 650 °C in UHV cleaned the surfaces of the ZnO NCs enough for sharp LEEM imaging and chemical characterization while no sign of de-composition was found. A flat energy band structure for the ZnO/SiO2/Si system was proposed after 650 °C. Increasing the annealing temperature to 700 °C causes a de-composition of the ZnO that induce a downward band bending on the surfaces of ZnO NCs.

Flat ZnO NCs with predominantly polar surfaces were grown using a microwave assisted process. Tuning the chemistry in the growth solution the growth was restricted to only plate-shaped crystals, i.e. a very uniform growth. The surfaces of the NCs were characterized using AFM, revealing a triangular reconstruction of the ZnO(0001) surface not seen without surface treatment at ambient conditions before. Following cycles of sputtering and annealing in UHV, we observe by STM a surface reconstruction interpreted as 2x2 with 1/4 missing Zn atoms.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2013. p. 56
Series
Karlstad University Studies, ISSN 1403-8099 ; 2013:26
Keywords
ZnO, Nanocrystals, Surface physics, XPS, SEM, AES, AFM, STM
National Category
Nano Technology Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-27156 (URN)978-91-7063-503-8 (ISBN)
Public defence
2013-06-14, 21A 342, Karlstad University, Karlstad, 13:15 (English)
Opponent
Supervisors
Available from: 2013-05-23 Created: 2013-05-02 Last updated: 2013-05-23Bibliographically approved
Ericsson, L. & Magnusson, K. (2013). Microwave assisted rapid growth of flat ZnO(0001) platelets.
Open this publication in new window or tab >>Microwave assisted rapid growth of flat ZnO(0001) platelets
2013 (English)Manuscript (preprint) (Other academic)
Keywords
ZnO, Nanostructures, Microwave assisted growth
National Category
Condensed Matter Physics Nano Technology
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-27153 (URN)
Projects
Bio2Mat
Funder
Vinnova
Available from: 2013-05-02 Created: 2013-05-02 Last updated: 2014-02-10Bibliographically approved
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