Ellen Moons

 
Professor of Physics

Research

I am interested in the self-organisation of molecules and new materials in thin films for applications in organic optoelectronics, such as solar cells and light-emitting diodes (LEDs). 

Key words

  • molecular materials
  • thin film coating from solution
  • scanning probe microscopy
  • X-ray spectroscopy
  • Polymer solar cells
  • Perovskite solar cells
  • Molecular opto-electronics. 

Research Focus

My present prime research focus is on novel materials for photovoltaic applications, including organic and polymer-based solar cells and solution-processed perovskite solar cells. We are interested in the morphology formation and degradation processes of such materials, and their relations to device performance and stability. 

The main activities of the research group are in the experimental studies of the formation of  phase-separated domain structures in thin films containing conjugated polymers and molecules, such as fullerene derivatives, as they are coated from solution. This work is supported by molecular and thermodynamic modelling. Microscopy and spectroscopy studies carried out in the research group have resulted in contributions  to the understanding of how the morphology of such thin films is formed and how that impacts on the solar cell performance.

For halide perovskite and organic solar cell materials, we also study the alignment of energy levels at the interfaces between the photoactive material and the interfacial layers and investigate alternative interfacial layers and transparent electrode materials for the solar cells. 

The stability of photovoltaic devices forms another part of our research activities, where we focus especially on the photodegradation of the active layer materials in ambient conditions. 

Other topics of interest include blends of conjugated polymers with non-conjugated polymers, self-organisation of monolayers of thiolated conjugated molecular rods on gold surfaces.

History

The research activities in polymer-based solar cells at Karlstad University started in 2002 with a first project funded by the Swedish Research Council (Vetenskapsrådet) and PhD students supported by the National Graduate School for Materials Science. Over the years the research activities have continued with funding from the Swedish Energy Agency (Energimyndigheten) (2007-2010, 2014-2018 and 2020 -present), Vetenskapsrådet (2011-2013, 2016-2019, and 2022-present), and the Göran Gustafsson Foundation for Natural Sciences and Medicine (2012 - 2015). The group participated in the COST Action  StableNextSol (MP1307) with over 60 partners from 26 countries. During 2016-2022 Ellen Moons coordinated a project funded by the the K.A. Wallenberg foundation, with partners at Chalmers University, Linköping university and Lund University, on the topic "Mastering Morphology for solution-borne electronics"

Methods and Collaborations

Atomic force microscopy has been one of the main tools the group has used to characterise the nanosized structures formed in spin-coated thin films of polymer blends. The capabilities of AFM-IR to chemically identify the components in the blend by their infrared vibrational fingerprints, and study their distribution in the thin film with nano-scale resolution, has added an important dimension to the morphology studies of these intermixed molecular layers. 

The research activities stretch over the disciplinary borders of materials physics and physical chemistry. The research facilities contain instrumentation for the fabrication and electrical characterization of solar cell devices, as well as equipment for structural and chemical characterization of thin polymer blend films, such as Atomic Force Microscopy (AFM) and FT-IR spectroscopy.

In collaboration with the Jagiellonian University in Krakow, we study compositional depth profiles of the polymer blend thin films by dynamic SIMS.

We are also users of synchrotron facilities, such as the national facility MAX IV in Lund and the SOLARIS synchrotron in Krakow. We use soft X-ray spectroscopy, such as Near-edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy and high-resolution X-ray Photoelectron Spectroscopy (XPS) to study the photo-induced degradation of molecular semiconductor thin films. We have also used Scanning Transmission X-ray Microscopy (STXM) at the Swiss Light Source (SLS) and the Advanced Light Source in Berkeley in California, USA, to image the composition variations in molecular thin films.

Teaching

  • FYGA25 Experimental problem solving and data analysis, 7.5 ECTS. (2014 - 2021)
  • CBAD81 Functional Materials, 7.5 ECTS. 
  • Diploma work in physics and engineering physics.

Collaboration

My research group collaborates with many researchers, nationally and internationally, and participates in networks and graduate schools. Some examples are:

- Wallenberg Initiative Materials Science for Sustainability (WISE) 2023-present. 

- PhD Research and Innovation in Synchrotron Methods and Applications in Sweden (PRISMAS). 2023- present. 

- Research project SOLution-borne materials for organic electronic Applications (SOLA), (2016-2022) funded by the Knut and Alice Wallenberg Foundation. SOLA is a collaboration between Karlstad University (materials physics och Physical chemistry), Chalmers, Linköping University and Lund University (chemical physics and theoretical chemistry). https://www.kau.se/sola 

- COST Action MP1307, StableNextSol, Unraveling Degradation Mechanisms of Organic and Perovskite Solar Cells by Complementary Characterization Techniques, is a European multidisciplinary network of academic och industrial researchers. 

Bio

Since 2011 professor in Materials Physics at Karlstad University, Sweden.

Previously employed as Research Scientist at Cambridge Display Technology in Cambridge, UK, and as Research Assistant at University of Cambridge.

Post-doc research related to dye-sensitized solar cells at EPFL Lausanne in Switzerland and TU Delft in The Netherlands.

PhD. from the Weizmann Institute of Science in Rehovot, Israel.

Selected publications

  • Hansson, R., Ericsson, L. K.E., Blazinic, V., Holmes, N.P., Dastoor, P., Moons, E., Opportunities and challenges in probing local composition of organic material blends for photovoltaics Journal of Materials Science, Focus Issue: Microstructural Characterization for Emerging Photovoltaic Materials 32, 10 (2017) 1982-1992.

  • Sudam Chavhan, Hansson, R., Ericsson, L.K.E., Beyer P., Opitz A., Moons, E., Low temperature processed NiO hole transport layers for efficient polymer solar cells, Organic Electronics, Organic Electronics 44 (2017) 59-66.

  • Ana Sofia Anselmo, Dzwilewski, A., Svensson, K., Moons, E. Light-induced Degradation of the Electronic Structure of PCBM and C60 Thin Films, Chem. Phys. Lett., 652 (2016) 220-224. 

  • Rickard Hansson, Lindqvist, C., Ericsson, L. K. E., Opitz, A., Wang, E., Moons, E., Photodegradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell, Phys. Chem. Chem. Phys., 18 (2016) 11132-11138.

  • Andreas Opitz, Andreas Wilke, Patrick Amsalem, Martin Oehzelt, Ralf-Peter Blum, Jürgen Rabe, Toshiko Mizokuro, Ulrich Hoermann, Rickard Hansson, Ellen Moons, and Norbert Koch, Organic heterojunctions: Contact-induced molecular reorientation, interface states, and charge re-distribution, Scientific Reports, 6 (2016) 21291

  • Rickard Hansson, Ericsson, L.K.E., Holmes, N.P., Rysz, J., Opitz, A., Campoy-Quiles M., Wang, E., Barr, M.G., Kilcoyne, A.L.D., Zhou, X., Dastoor, P., Moons, E., Vertical and lateral morphology effects on solar cell performance for a thiophene-quinoxaline copolymer:PC70BM blend, J. Mater. Chem. A 3 (2015), 6970-6979. 

  • Jasper Michels, Moons, E., Simulation of Surface-Directed Phase Separation in a Solution-Processed Polymer/PCBM Blend, Macromolecules 46, 12 (2013) p. 8693-8701. 

  • Iulia Brumboiu, Anselmo, A.S., Brena, B., Dzwilewski, A., Svensson, K., Moons, E., Near-edge X-ray Absorption Fine Structure Study of the C60-derivative PCBM, Chemical Physics letters 568–569 (2013) p. 130–134.

  • Cecilia M. Björström Svanström, Rysz, J., Bernasik, A., Budkowski, A., Zhang, F., Benson-Smith, J. J., Inganäs, O., Andersson, M. R., Magnusson, K. O., Nelson, J., Moons, E., Device performance of APFO-3/PCBM solar cells with controlled morphology, Adv. Mater. 21, 43 (2009), p.4398-4403.

  • Somsakul Watcharinyanon, Puglia, C., Göthelid, E., Jan-E. Bäckvall, J.-E., Moons, E., and Johansson, L. S. O., Molecular orientation of thiol-derivatized tetraphenylporphyrin on gold studied by XPS and NEXAFS, Surface Science 603, 7 (2009), p.1026-33.

  • Nilsson, S., Bernasik, A., Budkowski, A., Moons, E., Morphology and phase segregation of spin-casted films of polyfluorene/PCBM blends, Macromolecules 40, 23 (2007), p. 8291-8301

  • Zhang, F., Jespersen, K.G., Björström, C., Svensson, M., Andersson, M.R., Sundström, V., Magnusson, K.O., Moons E., Yartsev, A., and Inganäs, O., Influence of solvent mixing on the morphology and performance of solar cells based on polyfluorene copolymer/fullerene blends, Adv. Funct. Mater., 16, 5, (2006) p. 667-674

  • Cecilia M. Björström, Bernasik, A., Rysz, J., Budkowski, A., Nilsson, S., Svensson, M., Andersson, M.R., Magnusson, K.O., and Moons, E., Multilayer formation in spin-coated thin films of low-bandgap polyfluorene:PCBM blends, J. Phys.: Condens. Matter, 17 (2005), L529–L534.

  • Morteani, A.C., Dhoot, A.S., Kim, J.-S., Silva, C., Greenham, N.C., Friend, R.H., Murphy, C., Moons, E., Ciná, S., Burroughes, J., Barrier-Free Electron-Hole Capture in Polymer Blend Heterojunction Light-Emitting Diodes, Adv. Mater. 15, 20 (2003) p. 1708-1712

  • Ellen Moons, Conjugated Polymer Blends: Linking Film Morphology to Performance of Light Emitting Diodes and Photodiodes, J. Phys.: Condens. Matter 14, 47 (2002) p. 12235-12260.

  • Lukas Schmidt-Mende, Fechtenkötter, A., Müllen, K., Moons, E., Friend, R.H., MacKenzie, J.D., Self-organised Discotic Liquid Crystals for High Efficiency Organic Photovoltaics, Science 293 (2001) p. 1119-1122.

Publications