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  • 1. Alarcón, H.
    et al.
    Hedlund, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Hagfeldt, Anders
    KTH, Fysikalisk kemi / Physical Chemistry.
    Boschloo, Gerrit K.
    KTH, Fysikalisk kemi / Physical Chemistry.
    Modification of nanostructured TiO2 electrodes by electrochemical Al3+ insertion: Effects on dye-sensitized solar cell performance2007In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 35, p. 13267-13274Article in journal (Refereed)
    Abstract [en]

    Nanostructured TiO2 films were modified by insertion with aluminum ions using an electrochemical process. After heat treatment these films were found suitable as electrodes in dye-sensitized solar cells. By means of a catechol adsorption test, as well as photoelectron spectroscopy (PES), it was demonstrated that the density of Ti atoms at the metal oxide/electrolyte interface is reduced after Al modification. There is, however, not a complete coverage of aluminum oxide onto the TiO2, but the results rather suggest either the formation of a mixed Al−Ti oxide surface layer or formation of a partial aluminum oxide coating. No new phase could, however, be detected. In solar cells incorporating Al-modified TiO2 electrodes, both electron lifetimes and electron transport times were increased. At high concentrations of inserted aluminum ions, the quantum efficiency for electron injection was significantly decreased. Results are discussed at the hand of different models:  A multiple trapping model, which can explain slower kinetics by the creation of additional traps during Al insertion, and a surface layer model, which can explain the reduced recombination rate, as well as the reduced injection efficiency, by the formation of a blocking layer.

  • 2.
    Augustsson, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II. Physics I.
    Henningsson, A
    Butorin, S
    Department of Physics and Materials Science, Physics II. Physics I.
    Siegbahn, H
    Department of Physics and Materials Science, Physics II. Physics I.
    Nordgren, J
    Department of Physics and Materials Science, Physics II. Physics I.
    Guo, J H
    Lithium ion insertion in nanoporous anatase Ti02 studied with RIXS2003In: Journal of Chemical Physics, Vol. 119, no 7, p. 3983-3987Article in journal (Refereed)
  • 3.
    Berner, Simon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Lidbaum, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ledung, G.
    Åhlund, John
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Nilson, Katharina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Schiessling, Joachim
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Gelius, Ulrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Bäckwall, J. E.
    Puglia, Carla
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Oscarsson, Sven
    Electronic and structural studies of immobilized thiol-derivatized cobalt porphyrins on gold surfaces2007In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 253, no 18, p. 7540-7548Article in journal (Refereed)
    Abstract [en]

    The immobilisation of thiol-derivatized cobalt porphyrins on gold surfaces has been studied in detail by means of combined scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). S-thioacetyl has been used as a protective group for the thiol. Different routes for deprotection of the acetyl groups were performed in acidic and in basic conditions. The results show the formation of monolayer films for the different preparation schemes. The immobilisation of the molecules on the gold surface takes place through the thiol-linkers by the formation of multiple thiolate bonds. In the case of layers formed with protected porphyrins approximately 60% of the linkers are bonded to the gold surface whereas for deprotected layers the amount of bonded linkers is increased up to about 80%. STM measurements revealed that the molecules arrange in a disordered overlayer and do not exhibit mobility on the gold surface. Annealing experiments have been performed in order to test the stability of the porphyrin layers. Disordered patterns have been observed in the STM images after annealing at T = 400 °C. XPS revealed that the sulphur content disappeared completely after annealing at T = 180 °C and that the molecules did undergo significant modifications.

  • 4. Beutler, A
    et al.
    Strisland, F
    Sandell, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Jaworowski, A
    Nyholm, R
    Wiklund, M
    Andersen, J N
    Adsorption properties of a mixed surface: CO/0.5 ML Pd/Rh(111)1998In: Surface Science, Vol. 411, p. 111-Article in journal (Refereed)
  • 5. Bexell, U
    et al.
    Grehk, M
    Olsson, M
    Gelius, Ulrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    XPS and AES characterization of hydrolysed gamma-mercaptopropyltrimethoxysilane deposited on Al, Zn and Al-43.4Zn-1.6Si alloy-coated steel2004In: Surface and Interface Analysis, Vol. 36, p. 624-631Article in journal (Refereed)
  • 6. Chularis, A A
    et al.
    Kolpacheva, O V
    Kolpachev, A B
    Gelius, Ulrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Nikiforov, I Y
    The XPS spectra and the electron energy structure of tetragonal titanium cuprides and TiCuxNi1-x alloys2004In: Journal of Electron Spectroscopy and Related Phenomena, Vol. 137-40, no SIArticle in journal (Refereed)
  • 7. Fullham, S
    et al.
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Noncovalent Self-Assembly of Silver and Gold Nanocrystal Aggregates in Solution2002In: Chemistry of Materials, Vol. 14, no 3643Article in journal (Other (popular scientific, debate etc.))
  • 8.
    Gelius, Ulrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics V.
    Svensson, Svante
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics V.
    Pireaux, J J
    ICESS-9 - Proceedings of the Ninth International Conference on Electronic Spectroscopy and Structure - Uppsala, Sweden, June 30-July 4, 2003 - Foreword2004In: Journal of Electron Spectroscopy and Related Phenomena, Vol. 137-40, no SIArticle in journal (Other (popular scientific, debate etc.))
  • 9. Gorgoi, M
    et al.
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Schaefers, F
    Öhrwall, G
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Mertin, M
    Bressler, P
    Karis, O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Siegbahn, H
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sandell, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Doherty, W
    Jung, C
    Braun, W
    Eberhardt, W
    The high kinetic energy photoelectron spectroscopy facility at BESSY progress and first results2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 601, no 1-2, p. 48-53Article in journal (Refereed)
    Abstract [en]

    Photoelectron spectroscopy at high kinetic energy is a research field that receives an increasing interest due to the possibility of studying bulk properties of materials and deeply buried interfaces. Recently the high kinetic energy electron (HIKE) spectroscopy facility at BESSY in Berlin has become operative at the bending magnet beamline KMC-1. The first results show very good performance. Electron spectra have been recorded using X-ray energies from 2 keV up to 12 keV. Using back-scattering conditions in the crystal monochromator, very high-resolution has been achieved for photon energies around 2, 6 and 8 keV. In the latter case, spectra with a resolving power from the monochromator of >= 80 000 have been achieved and it has been possible to perform electron spectroscopy with resolving power of >= 60 000, yielding a total instrument resolution of about 150 meV as determined directly from spectra. This paper describes the facility and reports some of the first results. (C) 2009 Elsevier B.V. All rights reserved.

  • 10.
    Guo, J H
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Luo, Yi
    Augustsson, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rubensson, J E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Såthe, C
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Ågren, H
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Nordgren, J
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    X-ray emission spectroscopy of hydrogen bonding and electronic structure of liquid water2005In: Physical Review Letters, Vol. 89, no 13Article in journal (Refereed)
  • 11.
    Hedlund, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik1.
    Johansson, Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Effects of water in the Surface Adsorption of Dye molecules at Nanostructured TiO22006In: 16th International Conference on Photochemical Conversion and Storage of Solar Energy (IPS-16), 2006Conference paper (Other scientific)
    Abstract [en]

    The dye-sensitized solar cell is a promising new alternative to conventional solar cells. However these molecular solar cells may suffer from long term stability problems. Some of these problems are believed to be linked to the presence of water. Recently, dyes possessing long hydrophobic chains have been introduced, as an effort to come to terms with problems related to water [1]. In this study the Ru-dyes N3, N719 and 520DN (an analog containing hydrophobic chains) bound to TiO2, have after being exposed to water, been investigated by photoelectron spectroscopy (PES). PES was used to understand on a molecular level, how the introduction of water influences the molecular and electronic structure of these dye sensitized surfaces.

    In general, the surface sensitized with 520DN does not give signs of any major changes after being subjected to water. The investigation therefore found that the hydrophobic chains in the dye surface with 520DN effectively protect the molecular structure of the surface. However the surfaces of N3 and N719 do show large changes after exposing the surface to water. More specifically, it has been found that the outermost molecular orbitals (HOMO), which are vital for the function of the solar cell, are affected by water by shifting towards higher binding energies.

    Also, changes in the thiocyanate group can be found in the N3 and N719 dyes after being exposed to water. Specifically, the sulphur S2p energy levels have a substantially larger amount of a second spin-orbit split peak after being exposed to water. The nitrogen N1s peak relating to the thiocyanate group also changes shape. Moreover, in the case of N719, the counter ion TBA+ is not present on the dye sensitized surface after being subjected to water.

    Finally, the amount of dye on the TiO2 surfaces is also important for the efficiency of the solar cell. It was found that the coverage of N3 and N719 dye decreases when exposed to water, but the coverage of the 520DN dye remains the same.

  • 12.
    Henningsson, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik I.
    Andersson, M P
    Uvdal, P
    Siegbahn, H
    Sandell, A
    Li insertion in thin film anatase TiO2: Identification of a two-phase regime with photoelectron spectroscopy2002In: Chemical Physics Letters, Vol. 360, p. 85-Article in journal (Refereed)
  • 13.
    Henningsson, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Physics, Department of Physics and Materials Science, Physics I. Department of Physical and Analytical Chemistry, Physical Chemistry.
    Rensmo, H
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Department of Physical and Analytical Chemistry, Physical Chemistry.
    Sandell, A
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Department of Physical and Analytical Chemistry, Physical Chemistry.
    Siegbahn, H
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Department of Physical and Analytical Chemistry, Physical Chemistry.
    Södergren, S
    Lindström, H
    Hagfeld, A
    Physics, Department of Physics and Materials Science, Physics I. Department of Physical and Analytical Chemistry, Physical Chemistry.
    Electronic structure of electrochemically Li-inserted TiO2 studied with synchrotron radiation electron spectroscopies2003In: Journal of Chemical Physics, Vol. 118, no 12, p. 5607-5612Article in journal (Refereed)
  • 14.
    Henningsson, Anders
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Sandell, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Södergren, Sven
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Insertion of H+, Li+, Na+ and K+ into thin films prepared from silicotungstic acid - a photoelectron spectroscopy study2004In: Thin Solid Films, Vol. 461, no 2, p. 237-242Article in journal (Refereed)
  • 15.
    Henningsson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Stashans, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sandell, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Södergren, Sven
    Lindström, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Vayssieres, L.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Lunell, Sten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry. Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Proton insertion in polycrystalline WO3 studied with electron spectroscopy and semi-empirical calculations2004In: Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815, Vol. 47, p. 23-36Article in journal (Refereed)
  • 16.
    Herstedt, Marie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Andersson, A.M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Rensmo, Håkan
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Siegbahn, Hans
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Characterisation of the SEI formed on natural graphite in PC-based electrolytes2004In: Electrochimica Acta, no 49, p. 4939-4947Article in journal (Refereed)
    Abstract [en]

    The origin of the different Li+ intercalation behavior of raw and jet-milled natural graphite has been investigated. Jet-milled graphite is found to cycle reversibly in equal solvent mixture of propylene carbonate (PC) and etylene carbonate (EC), whereas raw graphite does not. Using both Al Ka and synchrotron radiation (SR) Photoelectron Spectroscopy, new insight is obtained inti the formation of the solid electrolyte interphase (SEI) on the two different graphite materials during electrochemical cycling in 1 M LiPF6 in either PC:EC (1:1) or in PC with 5% vinylene carbonate (VC) as additive. Solvent reduction products are found at the surface of both raw and jat-milled graphite cycled in PC:EC (1:1), but differed in composition. The addition of VC reduces primarily the quantities of salt reaction products (LiF and LixPFy compounds) and produces a mainly organic SEI layer. Electron diffraction from the edges for raw and jet-milled graphite particles shows a physical barrier hindering PC co-intercalation and faciltating the formation of a stable SEI layer.

  • 17.
    Herstedt, Marie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Rensmo, Håkan
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Siegbahn, Hans
    Department of Physics. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Physics, Department of Physics and Materials Science, Physics I. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. strukturkemi.
    Electrolyte additives for enhanced thermal stability of the graphite anode interface in a Li-ion battery2004In: Electrochimica Acta, no 49, p. 2351-2359Article in journal (Refereed)
    Abstract [en]

    The influence of electrolyte additives on the thermal stability of graphite anodes in a Li-ion battery has been investigated. The selected additives are: ethyltriacetoxysilane, 1,3 benzoldioxole, tetra (ethylene glycol) dimethylether and vinylene carbonate. These compounds were added in 4% to an electrolyte consisting of 1 M LiBF4 ethylene carbonate (EC/diethyl carbonate (DEC) solvent mixture. Differential scanning calorimetry (DSC) was used to investigated the thermal stability. The electrochemical performance was investigated by galvanostatic cycling and the formed solid electrolyte interphase (SEI) was characterised by photoelectron spectroscopy (PES) using Al Ka and synchrotron radiation /SR). The onset temperature for the thermally activated reactions was found to increas for all electrodes cycled with additives compared to electordes cycled without additives. The onset temperature in creased in the order: no additive < tetra (ethylene glycole) dimethyl ether < 1,3-benzoldioxole < ethyl-triacetoxysilane < vinylene carbonate. Feature in the PES spectra found to be associated with high onset temeratures for thermally activated reactions are: (i) no discernible graphite peak, (ii) small amount of salt species of the type LiF and LixBFyOz and (iii) larger amounts of organic compounds preferably with a high oxygen content.

  • 18.
    Herstedt, Marie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Stjerndahl, Mårten
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Nytén, Anton
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Gustafsson, Torbjörn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Rensmo, Håkan
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I.
    Siegbahn, Hans
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I.
    Ravet, N
    Armand, M
    Thomas, John Oswald
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Edström, Kristina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Structural Chemistry. Physics, Department of Physics and Materials Science, Physics I. strukturkemi.
    Surface Chemistry of Carbon-Treated LiFePO4 Particles for Li-Ion Battery Cathodes Studied by PES2003In: Electrochemical and Solid-State Letters, Vol. 6, no 9, p. A202-A206Article in journal (Refereed)
  • 19. Holland, D M P
    et al.
    Karlsson, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II. Fysik II.
    Siegbahn, K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II. Fysik I.
    A reinvestigation of the vibrational structure and the orbital assignments in the photoelectron bands of cyclopropane2002In: Journal of Electron Spectroscopy and Related Phenomena, Vol. 125, no 1, p. 57-68Article in journal (Refereed)
  • 20. Jaworowski, A J
    et al.
    Asmundson, R
    Uvdal, P
    Sandell, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik I.
    Determination of NO adsorption sites on Pd(100) using core level photoemission and low energy electron diffraction2002In: Surface Science, Vol. 501, no 1-2, p. 74-82Article in journal (Refereed)
  • 21. Jaworowski, A J
    et al.
    Uvdal, P
    Gray, S M
    Sandell, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik I.
    Mn-induced NO dissociation on Pd(100)2002In: Surface Science, Vol. 501, no 1-2, p. 83-92Article in journal (Refereed)
  • 22.
    Johansson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Interfaces in Dye-Sensitized Oxide / Hole-Conductor Heterojunctions for Solar Cell Applications2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanoporous dye-sensitized solar cells (DSSC) are promising devices for solar to electric energy conversion. In this thesis photoelectron spectroscopy (PES), x-ray absorption spectroscopy (XAS) and photovoltaic measurements are used for studies of the key interfaces in the DSSC.

    Photovoltaic properties of new combinations of TiO2/dye/hole-conductor heterojunctions were demonstrated and their interfacial structures were studied. Three different types of hole-conductor materials were investigated: Triarylamine derivatives, a conducting polymer and CuI. The difference in photocurrent and photovoltage properties of the heterojunction due to small changes in the hole-conductor material was followed. Also a series of dye molecules were used to measure the influence of the dye on the photovoltaic properties. Differences in both the energy-level matching and the geometric structure of the interfaces in the different heterojunctions were studied by PES. This combination of photovoltaic and PES measurements shows the possibility to link the interfacial electronic and molecular structure to the functional properties of the device.

    Three effective dyes used in the DSSC, Ru(dcbpy)2(NCS)2, Ru(tcterpy)(NCS)3 and an organic dye were studied in detail using PES and XAS and resonant core hole decay spectroscopy. The results gave information of the frontier electronic structure of the dyes and how the dyes are bonded to the TiO2 surface.

    Finally, the hole-conductor mechanism in a conducting polymer was investigated theoretically using semi-empirical and ab-initio methods.

    List of papers
    1. Electronic and Molecular Surface Structure of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2 Adsorbed from Solution onto Nanostructured TiO2: A Photoelectron Spectroscopy Study
    Open this publication in new window or tab >>Electronic and Molecular Surface Structure of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2 Adsorbed from Solution onto Nanostructured TiO2: A Photoelectron Spectroscopy Study
    2005 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 47, p. 22256-22263Article in journal (Refereed) Published
    Abstract [en]

    The element specificity of photoelectron spectroscopy (PES) has been used to compare the electronic and molecular structure of the dyes Ru(tcterpy)(NCS)3 (BD) and Ru(dcbpy)2(NCS)2adsorbed from solution onto nanostructured TiO2. Ru(dcbpy)2(NCS)2 was investigated in its acid (N3) and in its 2-fold deprotonated form (N719) having tetrabutylammonium (TBA+) as counterions. A comparison of the O1s spectra for the dyes indicates that the interactions through the carboxylate groups with the TiO2 surface are very similar for the dyes. However, we observe that some of the dye molecules also interact through the NCS groups when adsorbed at the TiO2 surface. Comparing the N719 and the N3 molecule, the fraction of NCS groups interacting through the sulfur atoms is smaller for N719 than for N3. We also note that the counterion TBA+ is coadsorbed with the N719 and BD molecules although the amount was smaller than expected from the molecular formulas. Comparing the valence levels for the dyes adsorbed on TiO2, the position of the highest occupied electronic energy level is similar for N3 and N719, while that for BD is lower by 0.25 eV relative to that of the other complexes.

    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94528 (URN)10.1021/jp0525282 (DOI)
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    2. Frontier electronic structures of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2: A photoelectron spectroscopy study
    Open this publication in new window or tab >>Frontier electronic structures of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2: A photoelectron spectroscopy study
    Show others...
    2007 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 126, no 24, p. 244303-Article in journal (Refereed) Published
    Abstract [en]

    The frontier electronic structures of Ru(tcterpy)(NCS)(3) [black dye (BD)] and Ru(dcbpy)(2)(NCS)(2) (N719) have been investigated by photoelectron spectroscopy (PES), X-ray absorption spectroscopy (XAS) and resonant photoelectron spectroscopy (RPES). N1s XAS has been used to probe the nitrogen contribution in the unoccupied density of states, and PES, together with RPES over the N1s edge, has been used to delineate the character of the occupied density of states. The experimental findings of the frontier electron structure are compared to calculations of the partial density of states for the nitrogens in the different ligands (NCS and terpyridine/bipyridine) and for Ru4d. The result indicates large similarities between the two complexes. Specifically, the valence level spectra show two well separated structures at low binding energy. The experimental results indicate that the outermost structure in the valence region largely has a Ru4d character but with a substantial character also from the NCS ligand. Interestingly, the second lowest structure also has a significant Ru4d character mixed into the structure otherwise dominated by NCS. Comparing the two complexes the BD valence structures lowest in binding energy contains a large contribution from the NCS ligands but almost no contribution from the terpyridine ligands, while for N719 also some contribution from the bipyridine ligands is mixed into the energy levels.

    Keywords
    dyes, electronic density of states, photoelectron spectra, X-ray absorption spectra, valence bands, binding energy
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94529 (URN)10.1063/1.2738066 (DOI)000247625800021 ()
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    3. Electronic and Molecular Surface Structure of a Polyene-diphenylaniline Dye Adsorbed from Solution onto Nanoporous TiO2
    Open this publication in new window or tab >>Electronic and Molecular Surface Structure of a Polyene-diphenylaniline Dye Adsorbed from Solution onto Nanoporous TiO2
    Show others...
    2007 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 24, p. 8580-8586Article in journal (Refereed) Published
    Abstract [en]

    The surface electronic and molecular structure of a new organic chromophore useful for dye-sensitized nanostructured solar cells has been investigated by means of electron spectroscopy. Initially the use of a simple molecular system containing the polyene-diphenylaniline chromophore in a solar cell device was verified. The electronic and molecular surface structure of the functional dye-sensitized interface was then investigated in detail by a combination of core level spectroscopy, valence level spectroscopy, X-ray absorption spectroscopy, and resonant photoemission spectroscopy. The results indicate a dominating orientation of the molecule at the surface, having the diphenylaniline moiety pointing out from the surface. Valence level spectroscopy, X-ray absorption spectroscopy, and resonant photoemission spectroscopy were used to experimentally delineate the frontier electronic structure of the molecule, and the experimental spectra were analyzed against theoretical spectra, based on density functional theory. Together the investigation gives insight into energy matching of the molecular electronic states with respect to the TiO2 substrate as well as the localization of the frontier electronic states and the direction of the charge-transfer absorption process with regards to the TiO2 surface.

    National Category
    Chemical Sciences
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94530 (URN)10.1021/jp068771y (DOI)000247215200028 ()
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    4. Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-sensitized Dense TiO2 and Triarylamine derivatives
    Open this publication in new window or tab >>Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-sensitized Dense TiO2 and Triarylamine derivatives
    Show others...
    2007 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 8, p. 2071-2078Article in journal (Refereed) Published
    Abstract [en]

    A series of solid-state heterojunctions comprising a dense TiO2 film electrode as an electron conductor, a ruthenium polypyridine complex (Ru(dcbpy)2(NCS)2) as a light-absorbing dye, and different triarylamine derivatives as hole conductors were prepared, and their photovoltaic properties as well as the molecular and electronic interfacial structures were investigated. The photovoltaic properties were compared to systems containing the hole conductors dissolved in an organic solvent as well as to a system containing a liquid electrolyte containing the iodide/tri-iodide redox couple. Two of the solid-state heterojunctions showed conversion efficiencies close to those of the system containing the iodide/tri-iodide redox couple, while one system was clearly less efficient. To explain the differences in photovoltaic properties the electronic and molecular interfacial structures of the solid-state heterojunctions were investigated by photoelectron spectroscopy (PES). By valence level PES the electronic energy levels highest in energy for the dye and the hole conductors were mapped, and the differences in energy matching partly explain the trends in photovoltaic properties. Differences in the molecular surface structure of the heterojunctions were also observed from the N Is core level measurements. Specifically it was found that the smaller hole conductor, showing low photocurrent yield, is inserted into the dye layer.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94531 (URN)10.1021/cm062498v (DOI)000245549500028 ()
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    5. Interfacial Properties of Photovoltaic TiO2/dye/PEDOT-PSS Heterojunctions
    Open this publication in new window or tab >>Interfacial Properties of Photovoltaic TiO2/dye/PEDOT-PSS Heterojunctions
    Show others...
    2005 (English)In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 149, no 2-3, p. 157-167Article in journal (Refereed) Published
    Abstract [en]

    Systems comprising a dense TiO2 film electrode, a ruthenium polypyridine dye and a PEDOT–PSS(poly(3,4-ethylenedioxythiophene)–poly(4-styrenesulphonate)) film were prepared. The heterojunctions were shown to have photovoltaicproperties, with the dye absorbing the light, the TiO2 acting as an electron conducting material and PEDOT–PSS acting as a hole transport material. A series of dyes was used to investigate their influence on the photocurrent and the photovoltage characteristics of the heterojunction. These results were compared to a photoelectrochemical system in which the PEDOT–PSS was replaced by a liquid electrolyte containing triiodide/iodide redox-couple.

    Photoelectron spectroscopy (PES) was used to monitor the interfacialproperties of the heterojunction and the investigation points out effects of importance when assembling the materials together to a functional unit. Specifically, it was concluded that the interaction with the dye clearly affects the structure ofPEDOT–PSS, both with respect to the surface composition of PSS relative to PEDOT and with respect to the chemical state of the sulphur in the polymers. Moreover, a comparison of the Ru3d and the valence band spectra of the two different interfaces (dye/TiO2 and dye/PEDOT–PSS) indicates that the energy level structure of the dyes compared to the substrate is different for the two surfaces. Thus, in the combined energy level picture under dark conditions, the energy levels in TiO2 relative to the energy levels inPEDOT–PSS depend on the dye.

    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94532 (URN)10.1016/j.synthmet.2004.12.004 (DOI)
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    6. Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO2/RuL2(NCS)2/CuI
    Open this publication in new window or tab >>Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO2/RuL2(NCS)2/CuI
    Show others...
    2004 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, no 23, p. 11224-11232Article in journal (Refereed) Published
    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94533 (URN)10.1063/1.1739399 (DOI)
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
    7. Electronic structure and mechanism for conductivity in thiophene oligomers and regioregular polymer
    Open this publication in new window or tab >>Electronic structure and mechanism for conductivity in thiophene oligomers and regioregular polymer
    2004 (English)In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 144, no 2, p. 183-191Article in journal (Refereed) Published
    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94534 (URN)10.1016/j.synthmet.2004.03.005 (DOI)
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
  • 23.
    Johansson, Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    TiO2/Ru-dye/Conducting Polymer Heterojunctions Electron Spectroscopic, Quantum Chemical and Photovoltaic Studies2004Licentiate thesis, monograph (Other scientific)
  • 24.
    Johansson, Erik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Hedlund, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Electronic and molecular surface structure of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2 adsorbed from solution onto nanostructured TiO2 – A Photoelectron spectroscopy study2005In: Journal of Physical Chemistry B, Vol. 149, no 47, p. 22256-22263Article in journal (Refereed)
  • 25.
    Johansson, Erik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Karlsson, Patrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik1.
    Hedlund, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Ryan, Declan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    PHOTOVOLTAIC AND INTERFACIAL PROPERTIES OF HETEROJUNCTIONS COMPRISING DYE-SENSITIZED DENSE TiO2 AND TRIARYLAMINE DERIVATIVES IN SOLID AND LIQUID STATE.1996Conference paper (Other scientific)
    Abstract [en]

    Different triarylamine derivatives have successfully been used as solid hole-conductor materials in dye-sensitized solar cells with efficiencies up to 4% [1-3]. In the present work TiO2/dye/ hole-conductor heterojunctions is assembled to form model systems for solid state DSSC and the interfacial structure at the molecular level. A series of triarylamine molecules is used to investigate the influence of small differences in the hole-conductor material structure on the photovoltaic and molecular surface properties. Both solid state and liquid state junctions with the triarylamine molecules were investigated. In the solid state heterojunctions the hole-conductor molecules were evaporated on the substrate and in the liquid state heterojunctions the hole-conductor molecules were solvated in an organic solvent. The photovoltaic properties of the heterojunction largely depend on the electron transfer rates at the interfaces between the different materials (semiconductor, dye and hole-conductor). Photoelectron Spectroscopy (PES) measurements was used to investigate the molecular and electronic interface structure. In the figure below the valence electronic structure of interfaces with the different hole-conductors are shown.

    From the valence PES the interaction and the energy level matching between the dyes and the hole-conductors is studied. The results show large differences in the energy matching of the different holconducting materials with respect to the dye molecules partly explaining the differences in efficiency. The valence structure also shows that when combining different materials their individual properties adjust slightly to their new environment. From the core level PES we observe differences molecular surface structure. Specifically it was found that the smaller holecondctors are able to penetrate the dye layer and contact the TiO2 surface.

  • 26.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Hedlund, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Electronic and Molecular Surface Structure of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2 Adsorbed from Solution onto Nanostructured TiO2: A Photoelectron Spectroscopy Study2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 47, p. 22256-22263Article in journal (Refereed)
    Abstract [en]

    The element specificity of photoelectron spectroscopy (PES) has been used to compare the electronic and molecular structure of the dyes Ru(tcterpy)(NCS)3 (BD) and Ru(dcbpy)2(NCS)2adsorbed from solution onto nanostructured TiO2. Ru(dcbpy)2(NCS)2 was investigated in its acid (N3) and in its 2-fold deprotonated form (N719) having tetrabutylammonium (TBA+) as counterions. A comparison of the O1s spectra for the dyes indicates that the interactions through the carboxylate groups with the TiO2 surface are very similar for the dyes. However, we observe that some of the dye molecules also interact through the NCS groups when adsorbed at the TiO2 surface. Comparing the N719 and the N3 molecule, the fraction of NCS groups interacting through the sulfur atoms is smaller for N719 than for N3. We also note that the counterion TBA+ is coadsorbed with the N719 and BD molecules although the amount was smaller than expected from the molecular formulas. Comparing the valence levels for the dyes adsorbed on TiO2, the position of the highest occupied electronic energy level is similar for N3 and N719, while that for BD is lower by 0.25 eV relative to that of the other complexes.

  • 27.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Hedlund, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Odelius, M.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Frontier electronic structures of Ru(tcterpy)(NCS)3 and Ru(dcbpy)2(NCS)2: A photoelectron spectroscopy study2007In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 126, no 24, p. 244303-Article in journal (Refereed)
    Abstract [en]

    The frontier electronic structures of Ru(tcterpy)(NCS)(3) [black dye (BD)] and Ru(dcbpy)(2)(NCS)(2) (N719) have been investigated by photoelectron spectroscopy (PES), X-ray absorption spectroscopy (XAS) and resonant photoelectron spectroscopy (RPES). N1s XAS has been used to probe the nitrogen contribution in the unoccupied density of states, and PES, together with RPES over the N1s edge, has been used to delineate the character of the occupied density of states. The experimental findings of the frontier electron structure are compared to calculations of the partial density of states for the nitrogens in the different ligands (NCS and terpyridine/bipyridine) and for Ru4d. The result indicates large similarities between the two complexes. Specifically, the valence level spectra show two well separated structures at low binding energy. The experimental results indicate that the outermost structure in the valence region largely has a Ru4d character but with a substantial character also from the NCS ligand. Interestingly, the second lowest structure also has a significant Ru4d character mixed into the structure otherwise dominated by NCS. Comparing the two complexes the BD valence structures lowest in binding energy contains a large contribution from the NCS ligands but almost no contribution from the terpyridine ligands, while for N719 also some contribution from the bipyridine ligands is mixed into the energy levels.

  • 28.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Karlsson, Patrik G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Hedlund, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Ryan, Declan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-sensitized Dense TiO2 and Triarylamine derivatives2007In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 8, p. 2071-2078Article in journal (Refereed)
    Abstract [en]

    A series of solid-state heterojunctions comprising a dense TiO2 film electrode as an electron conductor, a ruthenium polypyridine complex (Ru(dcbpy)2(NCS)2) as a light-absorbing dye, and different triarylamine derivatives as hole conductors were prepared, and their photovoltaic properties as well as the molecular and electronic interfacial structures were investigated. The photovoltaic properties were compared to systems containing the hole conductors dissolved in an organic solvent as well as to a system containing a liquid electrolyte containing the iodide/tri-iodide redox couple. Two of the solid-state heterojunctions showed conversion efficiencies close to those of the system containing the iodide/tri-iodide redox couple, while one system was clearly less efficient. To explain the differences in photovoltaic properties the electronic and molecular interfacial structures of the solid-state heterojunctions were investigated by photoelectron spectroscopy (PES). By valence level PES the electronic energy levels highest in energy for the dye and the hole conductors were mapped, and the differences in energy matching partly explain the trends in photovoltaic properties. Differences in the molecular surface structure of the heterojunctions were also observed from the N Is core level measurements. Specifically it was found that the smaller hole conductor, showing low photocurrent yield, is inserted into the dye layer.

  • 29.
    Johansson, Erik M .J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sandell, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Mahrov, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Figgemeier, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Jönsson, S.K.M.
    Fahlman, Mats
    Interfacial Properties of Photovoltaic TiO2/dye/PEDOT-PSS Heterojunctions2005In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 149, no 2-3, p. 157-167Article in journal (Refereed)
    Abstract [en]

    Systems comprising a dense TiO2 film electrode, a ruthenium polypyridine dye and a PEDOT–PSS(poly(3,4-ethylenedioxythiophene)–poly(4-styrenesulphonate)) film were prepared. The heterojunctions were shown to have photovoltaicproperties, with the dye absorbing the light, the TiO2 acting as an electron conducting material and PEDOT–PSS acting as a hole transport material. A series of dyes was used to investigate their influence on the photocurrent and the photovoltage characteristics of the heterojunction. These results were compared to a photoelectrochemical system in which the PEDOT–PSS was replaced by a liquid electrolyte containing triiodide/iodide redox-couple.

    Photoelectron spectroscopy (PES) was used to monitor the interfacialproperties of the heterojunction and the investigation points out effects of importance when assembling the materials together to a functional unit. Specifically, it was concluded that the interaction with the dye clearly affects the structure ofPEDOT–PSS, both with respect to the surface composition of PSS relative to PEDOT and with respect to the chemical state of the sulphur in the polymers. Moreover, a comparison of the Ru3d and the valence band spectra of the two different interfaces (dye/TiO2 and dye/PEDOT–PSS) indicates that the energy level structure of the dyes compared to the substrate is different for the two surfaces. Thus, in the combined energy level picture under dark conditions, the energy levels in TiO2 relative to the energy levels inPEDOT–PSS depend on the dye.

  • 30.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Yartsev, Arkady
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sundstrom, Villy
    Photocurrent Spectra and Fast Kinetic Studies of P3HT/PCBM Mixed with a Dye for Photoconversion in the Near-IR Region2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 7, p. 3014-3020Article in journal (Refereed)
    Abstract [en]

    Photoconversion properties are demonstrated for a device based on a small dye molecule, absorbing light in the near-IR region, mixed with two organic charge transport materials and together forming a dye-sensitized organic bulk heterojunction. The organic dye molecule, phthalocyanine (1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine), mixed with a blend of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C-61 (PCBM), shows a photoconversion spectrum extended more than 150 nm toward longer wavelengths, as compared to a device without such dye sensitization. In the dye-sensitized region of the photoconversion spectrum the maximum infernal quantum efficiency was estimated to 40%. With higher dye concentrations the internal quantum efficiency decreases. Transient laser spectroscopy measurements show that after excitation of the dye there is an electron transfer from the dye to PCBM and a subsequent hole transfer from the dye to P3HT, which results in a long-lived (P3HT(+)/dye/PCBM-) charge-separated state.

  • 31.
    Johansson, Erik M.J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Odelius, M.
    Hagberg, Daniel P.
    KTH, Organisk kemi / Organic chemistry.
    Sun, Licheng
    KTH, Organisk kemi / Organic chemistry.
    Hagfeldt, Anders
    KTH, Fysikalisk kemi / Physical Chemistry.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Electronic and Molecular Surface Structure of a Polyene-diphenylaniline Dye Adsorbed from Solution onto Nanoporous TiO22007In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 24, p. 8580-8586Article in journal (Refereed)
    Abstract [en]

    The surface electronic and molecular structure of a new organic chromophore useful for dye-sensitized nanostructured solar cells has been investigated by means of electron spectroscopy. Initially the use of a simple molecular system containing the polyene-diphenylaniline chromophore in a solar cell device was verified. The electronic and molecular surface structure of the functional dye-sensitized interface was then investigated in detail by a combination of core level spectroscopy, valence level spectroscopy, X-ray absorption spectroscopy, and resonant photoemission spectroscopy. The results indicate a dominating orientation of the molecule at the surface, having the diphenylaniline moiety pointing out from the surface. Valence level spectroscopy, X-ray absorption spectroscopy, and resonant photoemission spectroscopy were used to experimentally delineate the frontier electronic structure of the molecule, and the experimental spectra were analyzed against theoretical spectra, based on density functional theory. Together the investigation gives insight into energy matching of the molecular electronic states with respect to the TiO2 substrate as well as the localization of the frontier electronic states and the direction of the charge-transfer absorption process with regards to the TiO2 surface.

  • 32.
    Johansson m fl, E M J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik I.
    Electronic and molecular surface structure of Ru(tcterpy)(NCS)(3) and Ru(dcbpy)(2)(NCS)(2) adsorbed from solution onto nanostructured TiO2: A photoelectron spectroscopy study2005In: Journal of Physical Chemistry B, Vol. 109, no 47, p. 22256-22263Article in journal (Refereed)
  • 33.
    Johansson m fl, R J M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik I.
    Interfacial properties of photovoltaic TiO2/dye/PEDOT-PSS heterojunctions2005In: Synthetic Metals, Vol. 149, no 2-3, p. 157-167Article in journal (Refereed)
  • 34.
    Karlsson, P. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Bolik, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Richter, J. H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Mahrov, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Johansson, E. M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Blomquist, J.
    Uvdal, P.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sandell, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Interfacial Properties of the Nanostructured Dye-Sensitized Solid Heterojunction TiO2/RuL2(NCS)2/CuI2004In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, no 23, p. 11224-11232Article in journal (Refereed)
    Abstract [en]

    The interfaces of the nanostructured dye-sensitized solid heterojunction TiO2/Ru–dye/CuIhave been studied using photoelectron spectroscopy of core and valence levels, x-ray absorption spectroscopy and atomic force microscopy. A nanostructured anatase TiO2 film sensitized with RuL2(NCS)2 [cis-bis(4,4-dicarboxy-2,2-bipyridine)-bis(isothio-cyanato)-ruthenium(II)] was prepared in a controlled way using a novel combined in-situ and ex-situ(Ar atmosphere) method. Onto this film CuI was deposited in-situ. The formation of the dye–CuI interface and the changes brought upon the dye–TiO2 interface could be monitored in a stepwise fashion. A direct interaction between the dye NCS groups and the CuI is evident in the core level photoelectron spectra. Concerning the energy matching of the valence electronic levels, the photoelectron spectra indicate that the dye HOMO overlaps in energy with the Cu 3d–I 5p hydrid states. The CuI grow in the form of particles, which at the initial stages displace the dye molecules causing dye–TiO2 bond breaking. Consequently, the very efficient charge injection channel provided by the dye–TiO2carboxylic bonding is directly affected for a substantial part of the dye molecules. This may be of importance for the functional properties of such a heterojunction

  • 35.
    Karlsson, P. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Bolik, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Richter, J. H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Mahrov, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Johansson, E. M .J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Blomquist, J.
    Uvdal, P.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Sandell, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO2/RuL2(NCS)2/CuI2004In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, no 23, p. 11224-11232Article in journal (Refereed)
  • 36.
    Karlsson, P. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Göthelid, E.
    Richter, J. H.
    Sandell, A.
    Initial stages of ZrO2 chemical vapour deposition on Si(100)-(2x1) from zirconium tetra-tert-butoxideManuscript (Other academic)
  • 37.
    Karlsson, P. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Richter, J. H.
    Andersson, M. P.
    Blomquist, J.
    Johansson, M. K.-J
    Siegbahn, H.
    Uvdal, P.
    Sandell, A.
    CVD of TiO2 on Si(111), SiOx/Si(111) and TiO2: Substrate and temperature dependenceManuscript (Other academic)
  • 38.
    Karlsson, P. G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Richter, J. H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Andersson, M. P.
    Blomquist, J.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Uvdal, P.
    Sandell, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    UHV-MOCVD growth of TiO2 on SiOx/Si(111): Interfacial properties reflected in the Si 2p photoemission spectra2005In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 580, no 1-3, p. 207-217Article in journal (Refereed)
    Abstract [en]

    Metal–organic chemical vapour deposition growth of titanium oxide on moderately pre-oxidised Si(1 1 1) using the titanium(IV) isopropoxide precursor has been studied for two different growth modes, reaction-limited growth at 300 °C and flux-limited growth at 500 °C. The interfacialproperties have been characterized by monitoring synchrotron radiation excited Si2pphotoemissionspectra. The cross-linking from oxidised Si to bulk Si after TTIP exposure has been found to be very similar to that of SiOx/Si(1 1 1). However, the results show that the additional oxidation of Si most probably causes a corrugation of the SiOx/Si interface. Those conclusions are valid for both growth modes. A model is introduced in which the amorphous interface region is described as (TiO2)x(SiO2)y where x and y changes linearly and continuously over the interface. The model quantifies how (TiO2)x(SiO2)y mixing changes the relative intensities of the signals from silicon oxide and silicon. The method can be generalised and used for the analyses of other metal-oxides on silicon.

  • 39.
    Karlsson, P G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Richter, J H
    Andersson, M P
    Johansson, M K-J
    Blomquist, J
    Siegbahn, H
    Uvdal, P
    Sandell, A
    Metal-organic chemical vapor deposition of TiO2 on silicon substrates using titanium (IV)isopropoxide: Surface chemistry and interfacial properties2005In: ICTF 13/ACSIN 8, 2005Conference paper (Other (popular scientific, debate etc.))
  • 40.
    Karlsson, Patrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Electron spectroscopy studies of silicon-metal oxide and dye-solid interfaces2005Licentiate thesis, monograph (Other scientific)
  • 41.
    Karlsson, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Surface Science Studies of Metal Oxides Formed by Chemical Vapour Deposition on Silicon2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For an electronic device well-designed interfaces are critical for the performance. Studies of interfaces down to an atomic level are thus highly motivated both from a fundamental and technological point of view. In this thesis, a surface science approach has been employed to study the formation of interfaces in systems relevant for transistor and solar cell applications. Surface science methodology entails ultra high vacuum environment, single crystalline surfaces, submonolayer control of deposited material, surface sensitive spectroscopy and atomic resolution microscopy.

    The primary experimental method for characterization is electron spectroscopy. This is a family of very powerful experimental techniques capable of giving information on the atomic level. Additionally, studies have been performed using scanning tunnelling microscopy. Combined these two methods can provide an atomic level characterisation of the geometric and electronic properties of the surface.

    The emphasis of this work is placed on ultra thin TiO2 and ZrO2 films grown on silicon substrates by means of ultra-high vacuum metal-organic chemical vapour deposition. ZrO2 has also been grown on SiC and FeCrAl. Deposition has been performed with different process parameters. The interface region of each film has been characterised. The band alignment, a most important issue with regard to the development of new transistor devices, for the ZrO2/Si(100) system has been explored. Decomposition pathways of the metal organic precursors have been studied in detail. Changing process parameters is shown to alter both the precursor decomposition pathway and the nature of the interface region, thus opening the possibility to tailor the material function.

    The titanium dioxide films grown in situ have shown to be excellent models of nanostructured electrode materials. In this spirit, interfaces of model systems for the solid-state dye-sensitized solar cell have been studied. Links between device performance and interface structure have been elucidated.

    List of papers
    1. Metalorganic chemical vapor deposition of anatase titanium dioxide on Si: Modifying the interface by pre-oxidation
    Open this publication in new window or tab >>Metalorganic chemical vapor deposition of anatase titanium dioxide on Si: Modifying the interface by pre-oxidation
    Show others...
    2003 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 530, no 1-2, p. 63-70Article in journal (Refereed) Published
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94705 (URN)10.1016/S0039-6028(03)00386-8 (DOI)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    2. UHV-MOCVD growth of TiO2 on SiOx/Si(111): Interfacial properties reflected in the Si 2p photoemission spectra
    Open this publication in new window or tab >>UHV-MOCVD growth of TiO2 on SiOx/Si(111): Interfacial properties reflected in the Si 2p photoemission spectra
    Show others...
    2005 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 580, no 1-3, p. 207-217Article in journal (Refereed) Published
    Abstract [en]

    Metal–organic chemical vapour deposition growth of titanium oxide on moderately pre-oxidised Si(1 1 1) using the titanium(IV) isopropoxide precursor has been studied for two different growth modes, reaction-limited growth at 300 °C and flux-limited growth at 500 °C. The interfacialproperties have been characterized by monitoring synchrotron radiation excited Si2pphotoemissionspectra. The cross-linking from oxidised Si to bulk Si after TTIP exposure has been found to be very similar to that of SiOx/Si(1 1 1). However, the results show that the additional oxidation of Si most probably causes a corrugation of the SiOx/Si interface. Those conclusions are valid for both growth modes. A model is introduced in which the amorphous interface region is described as (TiO2)x(SiO2)y where x and y changes linearly and continuously over the interface. The model quantifies how (TiO2)x(SiO2)y mixing changes the relative intensities of the signals from silicon oxide and silicon. The method can be generalised and used for the analyses of other metal-oxides on silicon.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94706 (URN)10.1016/j.susc.2005.02.016 (DOI)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    3. CVD of TiO2 on Si(111), SiOx/Si(111) and TiO2: Substrate and temperature dependence
    Open this publication in new window or tab >>CVD of TiO2 on Si(111), SiOx/Si(111) and TiO2: Substrate and temperature dependence
    Show others...
    (English)Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-94707 (URN)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2012-10-09Bibliographically approved
    4. Metal organic chemical vapor deposition of ultrathin ZrO2 films on Si(100) and Si(111) studied by electron spectroscopy
    Open this publication in new window or tab >>Metal organic chemical vapor deposition of ultrathin ZrO2 films on Si(100) and Si(111) studied by electron spectroscopy
    Show others...
    2007 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 601, no 4, p. 1008-1018Article in journal (Refereed) Published
    Abstract [en]

    The growth of ultrathin ZrO2 films on Si(1 0 0)-(2 × 1) and Si(1 1 1)-(7 × 7) has been studied with core level photoelectron spectroscopy and X-ray absorption spectroscopy. The films were deposited sequentially by chemical vapor deposition in ultra-high vacuum using zirconium tetra-tert-butoxide as precursor. Deposition of a > 50 Å thick film leads in both cases to tetragonal ZrO2 (t-ZrO2), whereas significant differences are found for thinner films. On Si(1 1 1)-(7 × 7) the local structure of t-ZrO2 is not observed until a film thickness of 51 Å is reached. On Si(1 0 0)-(2 × 1) the local geometric structure of t-ZrO2 is formed already at a film thickness of 11 Å. The higher tendency for the formation of t-ZrO2 on Si(1 0 0) is discussed in terms of Zr–O valence electron matching to the number of dangling bonds per surface Si atom. The Zr–O hybridization within the ZrO2 unit depends furthermore on the chemical composition of the surrounding. The precursor t-butoxy ligands undergo efficient C–O scission on Si(1 0 0), leaving carbonaceous fragments embedded in the interfacial layer. In contrast, after small deposits on Si(1 1 1) stable t-butoxy groups are found. These are consumed upon further deposition. Stable methyl and, possibly, also hydroxyl groups are found on both surfaces within a wide film thickness range.

    Keywords
    High dielectrics, Zirconium dioxide, Silicon, Chemical vapor deposition, Semiconductor–insulator interfaces, Synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94946 (URN)10.1016/j.susc.2006.11.038 (DOI)000245155800020 ()
    Available from: 2006-10-13 Created: 2006-10-13 Last updated: 2017-12-14Bibliographically approved
    5. Initial stages of ZrO2 chemical vapour deposition on Si(100)-(2x1) from zirconium tetra-tert-butoxide
    Open this publication in new window or tab >>Initial stages of ZrO2 chemical vapour deposition on Si(100)-(2x1) from zirconium tetra-tert-butoxide
    (English)Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-94709 (URN)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2012-10-09Bibliographically approved
    6. Growth of ultrathin ZrO2 films on Si(100): Film-thickness dependent band alignment
    Open this publication in new window or tab >>Growth of ultrathin ZrO2 films on Si(100): Film-thickness dependent band alignment
    Show others...
    2006 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 88, no 13, p. 132905-Article in journal (Refereed) Published
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94710 (URN)10.1063/1.2190073 (DOI)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    7. Ultrathin ZrO2 films on Si-rich SiC(0 0 0 1)-(3 × 3): Growth and thermal stability
    Open this publication in new window or tab >>Ultrathin ZrO2 films on Si-rich SiC(0 0 0 1)-(3 × 3): Growth and thermal stability
    Show others...
    2007 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 601, no 11, p. 2390-2400Article in journal (Refereed) Published
    Abstract [en]

    The growth and thermal stability of ultrathin ZrO2 films on the Si-rich Si(0001)-(3 x 3) surface have been explored using photoelectron spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The films were grown in situ by chemical vapor deposition using the zirconium tetra tert-butoxide (ZTB) precursor. The O 1s XAS results show that growth at 400 degrees C yields tetragonal ZrO2. An interface is formed between the ZrO2 film and the SiC substrate. The interface contains Si in several chemically different states. This gives evidence for an interface that is much more complex than that formed upon oxidation with O-2. Si in a 4+ oxidation state is detected in the near surface region. This shows that intermixing of SiO2 and ZrO2 occurs, possibly under the formation of silicate. The alignment of the ZrO2 and SiC band edges is discussed based on core level and valence PES spectra. Subsequent annealing of a deposited film was performed in order to study the thermal stability of the system. Annealing to 800 degrees C does not lead to decomposition of the tetragonal ZrO2 (t-ZrO2) but changes are observed within the interface region. After annealing to 1000 degrees C a laterally heterogeneous layer has formed. The decomposition of the film leads to regions with t-ZrO2 remnants, metallic Zr silicide and Si aggregates.

    Keywords
    zirconium dioxide; silicon carbide; chemical vapor deposition; semiconductor-insulator interfaces; synchrotron radiation photoelectron; spectroscopy; X-ray absorption spectroscopy
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94711 (URN)10.1016/j.susc.2007.04.026 (DOI)000247408600016 ()
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    8. Initial stages of metal-organic chemical-vapor deposition of ZrO2 on a FeCrAl alloy
    Open this publication in new window or tab >>Initial stages of metal-organic chemical-vapor deposition of ZrO2 on a FeCrAl alloy
    Show others...
    2008 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 516, no 6, p. 875-879Article in journal (Refereed) Published
    Abstract [en]

    The initial stages of metal-organic chemical-vapor deposition of ZrO2 on a model FeCrAl alloy was investigated using synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy, scanning Auger microprobe, and time of flight secondary mass spectrometry. The coatings were grown in ultra-high vacuum at 400 degrees C and 800 degrees C using the single source precursor zirconium tetra-tert-butoxide. At 400 degrees C the coatings mainly consist of tetragonal ZrO2 and at 800 degrees C a mixed ZrO2/Al2O3 layer is formed. The Al metal diffuses from the FeCrAl bulk to the metal/coating interface at 400 degrees C and to the surface of the coating at 800 degrees C. The result indicates that the reaction mechanism of the growth process is different at the two investigated temperatures.

    Keywords
    metal-organic chemical-vapor deposition (MOCVD), zirconium tetra-tert-butoxide (ZTB), zirconium oxide, FeCrAl-alloy, time of flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS)
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94712 (URN)10.1016/j.tsf.2007.04.048 (DOI)000252980400001 ()
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    9. Surface chemistry of HfI4 on Si(100)-(2x1) studied by core level photoelectron spectroscopy
    Open this publication in new window or tab >>Surface chemistry of HfI4 on Si(100)-(2x1) studied by core level photoelectron spectroscopy
    Show others...
    2007 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 601, no 4, p. 917-923Article in journal (Refereed) Published
    Abstract [en]

    The chemistry of HfI4 adsorbed on the Si(100)-(2 x 1) surface has been studied by core level photoelectron spectroscopy in ultra-high vacuum. Two stable surface intermediates are identified: HfI3 and HfI2, both of which remain upon heating to 690 K. The dissociation of HfI4 is accompanied by the formation of SiI. In addition, HfI4 is observed up to 300 K. Complete desorption of iodine occurs in the temperature regime 690-780 K. Deposition of HfI4 at 870 K results in a layer consisting of metallic Hf, whereas deposition at 1120 K results in the formation of Hf silicide. The results indicate that the metallic Hf formed at 870 K is in the form of particles. Oxidation of this film by O2 at low pressure does not result in complete Hf oxidation. This suggests that complete oxidation of Hf is a critical step when using HfI4 as precursor in atomic layer deposition.

    Keywords
    Atomic layer deposition, Chemisorption, Hafnium iodide, Hafnium oxide, Low index single crystal surfaces, Silicon, Synchrotron radiation photoelectron spectroscopy
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94713 (URN)10.1016/j.susc.2006.11.026 (DOI)000245155800008 ()
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14
    10. Adsorption and Charge-Transfer Study of Bi-isonicotinic Acid on In Situ-Grown Anatase TiO2 Nanoparticles
    Open this publication in new window or tab >>Adsorption and Charge-Transfer Study of Bi-isonicotinic Acid on In Situ-Grown Anatase TiO2 Nanoparticles
    Show others...
    2004 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 108, no 10, p. 3114-3122Article in journal (Refereed) Published
    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94714 (URN)10.1021/jp0344491 (DOI)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    11. Interfacial Properties of the Nanostructured Dye-Sensitized Solid Heterojunction TiO2/RuL2(NCS)2/CuI
    Open this publication in new window or tab >>Interfacial Properties of the Nanostructured Dye-Sensitized Solid Heterojunction TiO2/RuL2(NCS)2/CuI
    Show others...
    2004 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, no 23, p. 11224-11232Article in journal (Refereed) Published
    Abstract [en]

    The interfaces of the nanostructured dye-sensitized solid heterojunction TiO2/Ru–dye/CuIhave been studied using photoelectron spectroscopy of core and valence levels, x-ray absorption spectroscopy and atomic force microscopy. A nanostructured anatase TiO2 film sensitized with RuL2(NCS)2 [cis-bis(4,4-dicarboxy-2,2-bipyridine)-bis(isothio-cyanato)-ruthenium(II)] was prepared in a controlled way using a novel combined in-situ and ex-situ(Ar atmosphere) method. Onto this film CuI was deposited in-situ. The formation of the dye–CuI interface and the changes brought upon the dye–TiO2 interface could be monitored in a stepwise fashion. A direct interaction between the dye NCS groups and the CuI is evident in the core level photoelectron spectra. Concerning the energy matching of the valence electronic levels, the photoelectron spectra indicate that the dye HOMO overlaps in energy with the Cu 3d–I 5p hydrid states. The CuI grow in the form of particles, which at the initial stages displace the dye molecules causing dye–TiO2 bond breaking. Consequently, the very efficient charge injection channel provided by the dye–TiO2carboxylic bonding is directly affected for a substantial part of the dye molecules. This may be of importance for the functional properties of such a heterojunction

    National Category
    Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-94715 (URN)10.1063/1.1739399 (DOI)
    Available from: 2006-09-04 Created: 2006-09-04 Last updated: 2017-12-14Bibliographically approved
    12. Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-sensitized Dense TiO2 and Triarylamine derivatives
    Open this publication in new window or tab >>Photovoltaic and Interfacial Properties of Heterojunctions Containing Dye-sensitized Dense TiO2 and Triarylamine derivatives
    Show others...
    2007 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 8, p. 2071-2078Article in journal (Refereed) Published
    Abstract [en]

    A series of solid-state heterojunctions comprising a dense TiO2 film electrode as an electron conductor, a ruthenium polypyridine complex (Ru(dcbpy)2(NCS)2) as a light-absorbing dye, and different triarylamine derivatives as hole conductors were prepared, and their photovoltaic properties as well as the molecular and electronic interfacial structures were investigated. The photovoltaic properties were compared to systems containing the hole conductors dissolved in an organic solvent as well as to a system containing a liquid electrolyte containing the iodide/tri-iodide redox couple. Two of the solid-state heterojunctions showed conversion efficiencies close to those of the system containing the iodide/tri-iodide redox couple, while one system was clearly less efficient. To explain the differences in photovoltaic properties the electronic and molecular interfacial structures of the solid-state heterojunctions were investigated by photoelectron spectroscopy (PES). By valence level PES the electronic energy levels highest in energy for the dye and the hole conductors were mapped, and the differences in energy matching partly explain the trends in photovoltaic properties. Differences in the molecular surface structure of the heterojunctions were also observed from the N Is core level measurements. Specifically it was found that the smaller hole conductor, showing low photocurrent yield, is inserted into the dye layer.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94531 (URN)10.1021/cm062498v (DOI)000245549500028 ()
    Available from: 2006-05-08 Created: 2006-05-08 Last updated: 2017-12-14Bibliographically approved
  • 42.
    Karlsson, Patrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Bolik, Sara
    Richter, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Mahrov, Boriss
    Department of Physical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Johansson, E M J
    Blomquist, J
    Uvdal, P
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Sandell, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Interfacial properties of the nanostructured dye-sensitized solid heterojunction TiO2/RuL2(NCS)(2)/CuI2004In: Journal of Chemical Physics, Vol. 120, no 23, p. 11224-11232Article in journal (Refereed)
  • 43.
    Karlsson, Patrik G.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I.
    Johansson, L. I.
    Richter, Jan Hinnerk
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Virojanadara, C.
    Blomquist, J.
    Uvdal, P.
    Sandell, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Ultrathin ZrO2 films on Si-rich SiC(0 0 0 1)-(3 × 3): Growth and thermal stability2007In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 601, no 11, p. 2390-2400Article in journal (Refereed)
    Abstract [en]

    The growth and thermal stability of ultrathin ZrO2 films on the Si-rich Si(0001)-(3 x 3) surface have been explored using photoelectron spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The films were grown in situ by chemical vapor deposition using the zirconium tetra tert-butoxide (ZTB) precursor. The O 1s XAS results show that growth at 400 degrees C yields tetragonal ZrO2. An interface is formed between the ZrO2 film and the SiC substrate. The interface contains Si in several chemically different states. This gives evidence for an interface that is much more complex than that formed upon oxidation with O-2. Si in a 4+ oxidation state is detected in the near surface region. This shows that intermixing of SiO2 and ZrO2 occurs, possibly under the formation of silicate. The alignment of the ZrO2 and SiC band edges is discussed based on core level and valence PES spectra. Subsequent annealing of a deposited film was performed in order to study the thermal stability of the system. Annealing to 800 degrees C does not lead to decomposition of the tetragonal ZrO2 (t-ZrO2) but changes are observed within the interface region. After annealing to 1000 degrees C a laterally heterogeneous layer has formed. The decomposition of the film leads to regions with t-ZrO2 remnants, metallic Zr silicide and Si aggregates.

  • 44.
    Karlsson, Patrik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Fysik 1.
    Richter, Jan Hinnerk
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Andersson, M P
    Blomquist, J
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Uvdal, P
    Sandell, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    UHV-MOCVD growth of TiO2 on SiOx/Si(111): Interfacial properties reflected in the Si 2p photoemission spectra2005In: Surface Science, Vol. 580, no 1-3, p. 207-217Article in journal (Refereed)
  • 45. Kashtanov, S
    et al.
    Augustsson, Andreas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II.
    Luo, Yi
    Guo, J H
    Såthe, Conny
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II.
    Rubensson, Jan-Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II.
    Nordgren, Joseph
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I. Physics II.
    Ågren, Hans
    Local structures of liquid water studied by x-ray emission spectroscopy2004In: Physical Review B, Vol. 69, no 2Article in journal (Refereed)
  • 46.
    Khodorkovskii, M. A.
    et al.
    Russian Sci Ctr Appl Chem, St Petersburg 197198, Russia.
    Belyaeva, A. A.
    Russian Sci Ctr Appl Chem, St Petersburg 197198, Russia.
    Rakcheeva, L. P.
    Russian Sci Ctr Appl Chem, St Petersburg 197198, Russia.
    Artamonova, T. O.
    Russian Sci Ctr Appl Chem, St Petersburg 197198, Russia.
    Serdobintsev, P. Y.
    St Petersburg State Univ, St Petersburg 198904, Russia.
    Pastor, A. A.
    St Petersburg State Univ, St Petersburg 198904, Russia.
    Kozlov, A. S.
    St Petersburg State Univ, St Petersburg 198904, Russia.
    Murashov, S. V.
    St Petersburg State Univ, St Petersburg 198904, Russia.
    Devdariani, A. Z.
    St Petersburg State Univ, St Petersburg 198904, Russia.
    Hallin, Reinhold
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II.
    Siegbahn, Kai
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics I. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II.
    Multiphoton mass spectra of Xe-2 molecules in the range of excited Xe*(6p, 5d) atoms2006In: Optics and Spectroscopy, Vol. 100, no 4, p. 497-509Article in journal (Refereed)
    Abstract [en]

    The (2 + 1) photoionization mass spectra of Xe-2 molecules are studied in a supersonic jet upon excitation by laser radiation in the energy range 80321.3-77821 cm(-1), corresponding to the dissociation of the Xe-2 molecule into atoms Xe(S-1(0)) + Xe*(6p, 5d). Several vibrational progressions are observed, which are attributed to two-photon transitions of Xe-2 from the ground state to the excited states of the 0(g)(+), 1(g), and 2(g) symmetries. Based on the analysis of these progressions, the molecular constants of a number of excited states of Xe? are estimated.

  • 47.
    Kristensen, E
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Rensmo, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Larsson, R
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology. Department of Physics and Materials Science, Physics I.
    Siegbahn, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Characterization of heparin surfaces using photoelectron spectroscopy and quartz crystal microbalance2003In: Biomaterials, Vol. 24, p. 4153-4159Article in journal (Refereed)
  • 48.
    Kristensen, Emma
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Studies of Biosurfaces using Spectroscopic and Microscopic Techniques2005Licentiate thesis, monograph (Other scientific)
  • 49.
    Kristensen, Emma
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I.
    Nederberg, Fredrik
    Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I. polymerkemi.
    Rensmo, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I.
    Bowden, Tim
    Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I. polymerkemi.
    Hilborn, Jöns
    Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I. polymerkemi.
    Siegbahn, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Materials Chemistry, Polymer Chemistry. Department of Physics and Materials Science, Physics I.
    Photoelectron Spectroscopy Studies of the Functionalization of a Silicon Surface with a Phosphorylcholine-Terminated Polymer Grafted onto (3-Aminopropyl)trimethoxysilane2006In: Langmuir, Vol. 22, no 23, p. 9651-9657Article in journal (Refereed)
    Abstract [en]

    The structure of a biomimetic phosphorylcholine (PC)-functionalized poly(trimethylene carbonate) (PC-PTMC-PC), linked to a silicon substrate through an aminolysis reaction at 120 C with (3-aminopropyl)trimethoxysilane (APTMS), was studied using photoelectron spectroscopy. Two chemical states were found for the unreacted APTMS amine, a neutral state and a protonated state, where the protonated amine on average was situated closer to the silicon substrate than the neutral amine. The experiments also indicated the presence of a third chemical state, where amines interact with unreacted silanol groups. The PTMC chains of the grafted films were found to consist of only 2-3 repeat units, with the grafted chains enriched in the zwitterionic end group, suggesting that these groups are attracted to the surface. This was further supported by the experiments showing that the PC groups were situated deeper within the film.

  • 50. Nilsson, B
    et al.
    Adler, J O
    Andersson, B E
    Annand, J R M
    Akkurt, I
    Boland, M J
    Crawford, G I
    Fissum, K G
    Hansen, K
    Harty, P D
    Ireland, D G
    Isaksson, L
    Karlsson, M
    Lundin, M
    McGeorge, J C
    Miller, G J
    Ruijter, H
    Sandell, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics I.
    Schroder, B
    Sims, D A
    Watts, D
    Near-threshold measurement of the He-4(gamma,n) reaction2005In: Physics Letters B, Vol. 626, p. 65-71Article in journal (Refereed)
12 1 - 50 of 87
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