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  • 201.
    Hammarstrom, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Barigelletti, F
    Flamigni, L
    Armaroli, N
    Sour, A
    Collin, JP
    Sauvage, JP
    Temperature independent Ru->Os electronic energy transfer in a rodlike dinuclear complex with a 2.4 nm intermetal separation1996In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, ISSN 0002-7863, Vol. 118, no 47, p. 11972-11973Article in journal (Other scientific)
  • 202.
    Hammarstrom, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Barigelletti, F
    Flamigni, L
    Indelli, MT
    Armaroli, N
    Calogero, G
    Guardigli, M
    Sour, A
    Collin, JP
    Sauvage, JP
    A study on delocalization of MLCT excited states by rigid bridging ligands in homometallic dinuclear complexes of ruthenium(II)1997In: JOURNAL OF PHYSICAL CHEMISTRY A, Vol. 101, no 48, p. 9061-9069Article in journal (Refereed)
    Abstract [en]

    For the structurally rigid homometallic dinuclear complexes (ttp)Ru(tpy-tpy)Ru(ttp)(4+) and (ttp)Ru(tpy-ph-tpy)Ru(ttp)(4+), we have obtained ground-state absorption spectra and transient-absorption difference spectra at room temperature and luminescence s

  • 203.
    Hammarstrom, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Sun, L
    Magnusson, A
    Frapart, Y
    Berglund-Baudin, H
    Akermark, B
    Styring, S
    Mimicking photosystem II reactions in artificial photosynthesis1999In: ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS, ISSN 0942-9352, Vol. 213, p. 157-163Article in journal (Refereed)
    Abstract [en]

    The paper describes a project aiming at the construction of functional mimics of the oxygen evolving complex of Photosystem II, coupled to photoinduced charge separation. Biomimetic electron donors - manganese complexes and tyrosine - have been linked to

  • 204.
    Hammarstrom, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Sun, LC
    Akermark, B
    Styring, S
    A biomimetic approach to artificial photosynthesis: Ru(II)-polypyridine photo-sensitisers linked to tyrosine and manganese electron donors2001In: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, Vol. 57, no 11, p. 2145-2160Article, book review (Other scientific)
    Abstract [en]

    The paper describes recent advances towards the construction of functional rr mics of the oxygen evolving complex in photosystem II (PSII) that are coupled to photoinduced charge separation. Some key principles of PSII and artificial systems for light-ind

  • 205.
    Hammarstrom, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Sun, LC
    Akermark, B
    Styring, S
    Mimicking photosystem II reactions in artificial photosynthesis: Ru(II)-polypyridine photosensitisers linked to tyrosine and manganese electron donors2000In: CATALYSIS TODAY, ISSN 0920-5861, Vol. 58, no 2-3, p. 57-69Article in journal (Refereed)
    Abstract [en]

    The paper describes a project aiming at constructing functional mimics of the oxygen evolving complex in photosystem II, coupled to photoinduced charge separation. Biomimetic electron donors, manganese complexes and tyrosine, have been linked to a Ru(II)-

  • 206.
    HAMMARSTROM, Leif
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    ALMGREN, M
    LIND, J
    MERENYI, G
    NORRBY, T
    AKERMARK, B
    MECHANISMS OF TRANSMEMBRANE ELECTRON-TRANSFER - DIFFUSION OF UNCHARGED REDOX FORMS OF VIOLOGEN, 4,4'-BIPYRIDINE, AND NICOTINAMIDE WITH LONG ALKYL CHAINS1993In: JOURNAL OF PHYSICAL CHEMISTRY, ISSN 0022-3654, Vol. 97, no 39, p. 10083-10091Article in journal (Refereed)
    Abstract [en]

    Transmembrane electron transfer in lecithin (phosphatidylcholine) vesicles was studied by pulse radiolysis. Upon reduction, cetylmethylviologen (N-hexadecyl-N'-methyl-4,4'-bipyridinium CMV), cetylbipyridine (4-(N-hexadecylpyridinium-4-yl)pyridine, CB), and cetylnicotinamide (N-hexadecyl-3-(aminocarbonyl)pyridinium, CNA) transferred electrons from the bulk water phase to Fe(CN)63- in the internal water phase of the vesicles. The transmembrane electron transfer was found in all cases to proceed through diffusion of uncharged forms of the redox mediators (CMV0, CB0, and CNA0, respectively) but the kinetic behavior varied considerably. The mechanisms for CB and CNA were simple, the reaction following first-order kinetics, and the transmembrane diffusion was rate limiting (k = (1.5 +/- 0.3) x 10(3) S-1 for CB and k = 3.2 +/- 0.5 s-1 for CNA). The mechanism for CMV was more complicated, and the reaction followed second-order kinetics. The rate-determining step was proposed to be the disproportionation of two viologen radicals formed by the radiation pulse (2CMV+ double-line arrow pointing left and right CMV0 + CMV2+), followed by rapid transmembrane diffusion of CMVO and its subsequent reoxidation by Fe(CN)63-. In pulse radiolysis, and in phosphorescence quenching experiments with Pt2(P2O5)4H84-, CB0 and CB+ were used as models in order to obtain the rates of transmembrane diffusion of CMV0 and CMV+, respectively. Our results exclude the possibility of electron tunneling between viologens on opposite sides of the membrane, and they provide strong arguments against transmembrane diffusion of viologen radical (CMV+).

  • 207.
    HAMMARSTROM, Leif
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    ALMGREN, Mats
    ELECTRON-TRANSFER THROUGH VESICLE MEMBRANES - EFFECTS OF REACTANT COMPARTMENTALIZATION AND INTERVESICLE MIGRATION ON THE REACTION-KINETICS1995In: JOURNAL OF PHYSICAL CHEMISTRY, ISSN 0022-3654, Vol. 99, no 31, p. 11959-11966Article in journal (Refereed)
    Abstract [en]

    The kinetics of electron transfer through vesicle membranes mediated by viologen was considered in detail. In previous studies, the rate-determining step of the reaction has been found to be the disproportionation of two viologen radicals: 2C(n)V(+) doubl

  • 208.
    Hammarstrom, Leif
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Norrby, Tomas
    Stenhagen, Gunnar
    Martensson, J
    Akermark, Björn
    Almgren, M
    Two-dimensional emission quenching and charge separation using a Ru(II)-photosensitizer assembled with membrane-bound acceptors1997In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 101, no 38, p. 7494-7504Article in journal (Refereed)
    Abstract [en]

    Novel syntheses of the bipyridine ligand 1, dcHb (dcHb = 4,4'-dicarboxy-2,2'-bipyridine), by anionic oxidation of 4,4'-dimethyl-2',2-bipyridine (dmb) using molecular oxygen (4 atm), and of the sensitizer precursor 4, tris(4,4'-diethoxycarbonyl-2,2'-bipyri

  • 209.
    Hammarström, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Alsins, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Borje, A
    Norrby, T
    Zhang, LA
    Akermark, B
    Structure and photophysical properties of novel ruthenium(II) complexes containing 6-substituted bipyridines1997In: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, ISSN 1010-6030, Vol. 102, no 2-3, p. 139-150Article in journal (Other scientific)
    Abstract [en]

    A series of novel tris(bpy) ruthenium(II)-type complexes (where bpy = 2,2'-bipyridine) Ru(bpy)(2)(6-carboxylato-2,2'-bpy) hexafluorophosphate, Ru(bpy)(2)((2,2'-bpy-6-yl)-acetic acid) dihexafluorophosphate, Ru(bpy)(2)(6-methoxycarbonyl-2,2'-bpy) dihexafluo

  • 210.
    Hammarström, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Jakten på fotosyntesens hemligheter1999In: Aktuell Forskning och Utveckling, Vol. 3, p. 30-33Article in journal (Other (popular scientific, debate etc.))
  • 211.
    Hammarström, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Towards artificial photosynthesis: ruthenium-manganese chemistry mimicking photosystem II reactions2003In: Current Opinion in Chemical Biology, Vol. 7, p. 666-673Article in journal (Refereed)
  • 212.
    Hammarström, Leif
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Sun, Licheng
    Åkermark, Björn
    Styring, Stenbjörn
    Artificial Photosynthesis: Towards Functional Mimics of Photosystem II?1998In: Biochimia et Biophysica Acta, Vol. 1365, p. 193-199Article in journal (Refereed)
  • 213.
    Hammarström, Leif
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Velikian, Irena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Karlsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Cryo-TEM Evidence: Sonication of Dihexadecyl Phosphate Does Not Produce Closed Bilayers with Smooth Curvature1995In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 11, no 2, p. 408-410Article in journal (Other academic)
    Abstract [en]

    Dihexadecyl phosphate (DHP) is commonly used for formation of model membranes. In this report cryo-transmission electron microscopy (cryo-TEM) pictures are presented. They clearly show that after cooling to room temperature, dispersions of DHP sonicated at 80 degrees C are dominated by open and folded bilayer fragments, rather than by vesicles with smooth curvature. Quantitative results of an earlier kinetic investigation of viologen reduction in DHP were reproduced using these dispersions.

  • 214.
    Hansson, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    A fluorescence study of divalent and monovalent cationic surfactants interacting with anionic polyelectrolytes2001In: LANGMUIR, ISSN 0743-7463, Vol. 17, no 14, p. 4161-4166Article in journal (Refereed)
    Abstract [en]

    Self-assemblies of the divalent surfactant dodecyl-1,3-propylenepentamethylbis(ammonium chloride) (DoPPDAC) and the monovalent dodecyltrimethylammonium bromide (DoTAB) were investigated in dilute solutions of anionic polyelectrolytes. Pyrene probing showe

  • 215.
    Hansson, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Self-assembly of ionic surfactants in polyelectrolyte solutions: A model for mixtures of opposite charge2001In: LANGMUIR, ISSN 0743-7463, Vol. 17, no 14, p. 4167-4180Article in journal (Refereed)
    Abstract [en]

    A thermodynamic model of polyelectrolyte/surfactant interactions is derived. The model considers the binding of polyion chains to the surface of oppositely charged surfactant micelles. The electrostatic interactions are treated within the Poisson-Boltzman

  • 216.
    Hansson, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Almgren, M
    Reliable aggregation numbers are obtained for polyelectrolyte bound cationic micelles using fluorescence quenching with a cationic surfactant quencher2000In: JOURNAL OF PHYSICAL CHEMISTRY B, Vol. 104, no 5, p. 1137-1140Other (Other scientific)
  • 217.
    Hansson, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Jonsson, B
    Strom, C
    Soderman, O
    Determination of micellar aggregation numbers in dilute surfactant systems with the fluorescence quenching method.2000In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 104, no 15, p. 3496-3506Article in journal (Refereed)
    Abstract [en]

    This work addresses the problem of determining micellar aggregation numbers for dilute ionic surfactant systems by means of the time-resolved fluorescence quenching method. We argue that the use of quenchers that are themselves surfactants gives us two ad

  • 218.
    Hansson, P.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Schneider, S.
    Lindman, B.
    Macroscopic phase separation in a polyelectrolyte gel interacting with oppositely charged surfactant: correlation between anomalous deswlling and microstructure2000In: Progress in Colloid and Polymer Science, Trends in Colloid and Interface Science, 2000, p. 342-346Chapter in book (Other scientific)
  • 219.
    Hansson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Almgren, Mats
    Interaction of C(n)TAB with sodium (carboxymethyl)cellulose: Effect of polyion linear charge density on binding isotherms and surfactant aggregation number1996In: JOURNAL OF PHYSICAL CHEMISTRY, Vol. 100, no 21, p. 9038-9046Article in journal (Refereed)
    Abstract [en]

    The interaction of alkyltrimethylammonium bromide (C(n)TAB) with sodium (carboxymethyl)cellulose (NaCMC) in dilute aqueous solutions is investigated. The effect of stilt on the binding to NaCMC of high linear charge density (xi = 3.0) is investigated usin

  • 220.
    HANSSON, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    ALMGREN, Mats
    LARGE C(12)TAB MICELLES FORMED IN COMPLEXES WITH POLYVINYLSULFATE AND DEXTRAN SULFATE1995In: JOURNAL OF PHYSICAL CHEMISTRY, ISSN 0022-3654, Vol. 99, no 45, p. 16694-16703Article in journal (Refereed)
    Abstract [en]

    The aggregation of alkyltrimethylammonium bromide (C(n)TAB) surfactants in very dilute aqueous solutions of sodium polyvinylsulfate (NaPVS) and sodium dextransulfate (NaDxS) has been investigated. The aggregation number, N-s, for the surfactant in complex

  • 221.
    HANSSON, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    ALMGREN, Mats
    POLYELECTROLYTE-INDUCED MICELLE FORMATION OF IONIC SURFACTANTS AND BINARY SURFACTANT MIXTURES STUDIED BY TIME-RESOLVED FLUORESCENCE QUENCHING1995In: JOURNAL OF PHYSICAL CHEMISTRY, ISSN 0022-3654, Vol. 99, no 45, p. 16684-16693Article in journal (Refereed)
    Abstract [en]

    A semiempirical model for the distribution of two cationic surfactants between subphases in solutions containing a polyelectrolyte of opposite charge is presented. The model, based on ideal mixing in the surfactant aggregates, is tested in fluorescence qu

  • 222.
    He, Jianjun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Benkö, Gábor
    Korodi, Ferenc
    Polívka, Tomás
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Åkermark, Björn
    Sun, Licheng
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sundström, Villy
    Modified Phtalocyanines for Efficient Near-IR Sensitization of Nanostructured TiO2 Electrode2002In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Journal of American Chemical Society, Vol. 124, p. 4922-4932Article in journal (Refereed)
  • 223.
    He, JJ
    et al.
    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.
    Lindquist, Sten-Eric
    Grennberg, Helena
    Korodi, F
    Sun, Licheng
    Akermark, B
    Phthalocyanine-sensitized nanostructured TiO2 electrodes prepared by a novel anchoring method2001In: LANGMUIR, ISSN 0743-7463, Vol. 17, no 9, p. 2743-2747Article in journal (Refereed)
    Abstract [en]

    A novel method for anchoring phthalocyanines substituted with ester groups onto nanostructured TiO2 films is described. Such phthalocyanines did not adsorb on nanostructured TiO2 film by the ordinary methods. In our new method, the TiO2 film is pretreated

  • 224.
    He, JJ
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Lindström, H
    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.
    Lindquist, Sten-Eric
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Dye-sensitized nanostructured p-type nickel oxide film as a photocathode for a solar cell1999In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 103, no 42, p. 8940-8943Article in journal (Refereed)
    Abstract [en]

    Nanostructured NiO film was prepared by depositing nickel hydroxide slurry on conducting glass and sintering at 500 degrees C to a thickness of about 1 mu m. The photocurrent-voltage (IV) characteristics of the plain nanostructured NiO electrode recorded

  • 225.
    He, JJ
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Lindström, H
    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.
    Lindquist, Sten-Eric
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Dye-sensitized nanostructured tandem cell-first demonstrated cell with a dye-sensitized photocathode2000In: SOLAR ENERGY MATERIALS AND SOLAR CELLS, ISSN 0927-0248, Vol. 62, no 3, p. 265-273Article in journal (Refereed)
  • 226.
    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)
  • 227.
    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)
  • 228.
    Hjelm, Johan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Conducting Polymers Containing In-Chain Metal Centres: Electropolymerisation and Charge Transport2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Conjugated polymers that exhibit high electronic conductivities play key roles in the emerging field of molecular electronics. In particular, linking metal centres with useful electrochemical, photophysical, or catalytic properties to the backbone, or within the polymer chain itself, is a topic which has attracted a significant amount of interest lately. Structurally rigid monomers that can be electropolymerised to form highly conducting molecular wires may provide new insights into conduction mechanisms, e.g., exploiting resonant superexchange (electron-hopping) by tuning the energies of redox centre and bridge states. The focus of this thesis lies on the electrochemical investigation of preparation, growth dynamics, and charge transport dynamics of oligothiophene/transition metal hybrid materials. The incorporation of ruthenium(II) and osmium(II) terpyridine complexes into such polymeric assemblies was accomplished by an electropolymerisation procedure, to produce rod-like oligothienyl-bridged metallopolymers. The properties of the monomers used were characterised by optical spectroscopy and electrochemical techniques. Charge transport was studied in detail for some of the materials created, and it was found that the electron transport rate and dc conductivity was enhanced by up to two orders of magnitude compared to relevant non-conjugated polymers, demonstrating the usefulness of this approach for optimization of charge transport in metallopolymers. The charge transport diffusion coefficent was determined to (2.6 ± 0.5) x 10-6 cm2 s-1 for a quaterthienyl-bridged {Os(tpy)2} polymer by use of an electrochemical steady-state method carried out using a transistor-like experimental geometry. It was found that charge transport in these materials is concentration-gradient driven. The rate limiting step of the charge transport process was investigated using electrochemical impedance spectroscopy. The electropolymerisation dynamics of one of the monomers was studied using microelectrodes, and the results obtained shows that electropolymerisation is highly efficient, and indicate that mass transport controls this process. Through a combination of controlled potential deposition and SEM imaging it was demonstrated that it is possible to exploit the edge effect of microelectrodes to promote film growth in a direction co-planar with the electrode surface.

    List of papers
    1. Electropolymerisable bipyridine ruthenium(II) complexes. Synthesis and electrochemical characterisation of 4-(3-methoxystyryl)- and 4,4'-di(3-methoxystyryl)-2,2'-bipyridine ruthenium complexes
    Open this publication in new window or tab >>Electropolymerisable bipyridine ruthenium(II) complexes. Synthesis and electrochemical characterisation of 4-(3-methoxystyryl)- and 4,4'-di(3-methoxystyryl)-2,2'-bipyridine ruthenium complexes
    2001 In: Journal of the Chemical Society - Dalton Transactions, ISSN 1472-7773, no 8, p. 1319-1325Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-91106 (URN)
    Available from: 2003-11-13 Created: 2003-11-13 Last updated: 2011-04-06
    2. A rod-like polymer containing {Ru(terpy)2} units prepared by electrochemical coupling of pendant thienyl moieties
    Open this publication in new window or tab >>A rod-like polymer containing {Ru(terpy)2} units prepared by electrochemical coupling of pendant thienyl moieties
    Show others...
    2002 (English)In: Chemical Communications, ISSN 1359-7345, no 3, p. 284-285Article in journal (Refereed) Published
    Abstract [en]

    A new rod-like coordination polymer consisting of (Ru-(terpy)2) motifs bridged by bithiophene units has been prepared by electrochemical polymerisation in acidic organic medium. 

    Identifiers
    urn:nbn:se:uu:diva-91107 (URN)
    Available from: 2003-11-13 Created: 2003-11-13 Last updated: 2011-04-19
    3. Conducting polymers containing in-chain metal centers: Homogeneous charge transport through a quaterthienyl-bridged {Os(tpy)2} polymer
    Open this publication in new window or tab >>Conducting polymers containing in-chain metal centers: Homogeneous charge transport through a quaterthienyl-bridged {Os(tpy)2} polymer
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    2003 In: Journal of Physical Chemistry B, ISSN 1520-6106, Vol. 107, no 38, p. 10431-10439Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-91108 (URN)
    Available from: 2003-11-13 Created: 2003-11-13 Last updated: 2011-04-06
    4. Electropolymerisation dynamics of a highly conducting metallopolymer: Poly-[Os(4'-(5-(2,2'-bithienyl))-2,2':6',2''-terpyridine)2]2+
    Open this publication in new window or tab >>Electropolymerisation dynamics of a highly conducting metallopolymer: Poly-[Os(4'-(5-(2,2'-bithienyl))-2,2':6',2''-terpyridine)2]2+
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    In: Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-91109 (URN)
    Available from: 2003-11-13 Created: 2003-11-13 Last updated: 2011-04-06
    5. Conducting polymers containing in-chain metal centers: Electropolymerization of oligothienyl-substituted {M(tpy)2} complexes and in-situ conductivity studies, M = Os(II), Ru(II)
    Open this publication in new window or tab >>Conducting polymers containing in-chain metal centers: Electropolymerization of oligothienyl-substituted {M(tpy)2} complexes and in-situ conductivity studies, M = Os(II), Ru(II)
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    2005 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, no 4, p. 1073-1081Article in journal (Refereed) Published
    Abstract [en]

    The electropolymerization of a series of Ru and Os bis-terpyridine complexes that form rodlike polymers with bithienyl, quaterthienyl, or hexathienyl bridges has been studied. Absorption spectroscopy, scanning electron microscopy, and cyclic voltammetry have been used to characterize the monomers and resulting polymer films. The absolute dc conductivity of the quaterthienyl-bridged {Ru(tpy)2} and {Os(tpy)2} polymers is unusually large and independent of the identity of the metal center at 1.6 × 10-3 S cm-1. The maximum conductivity occurs at the formal potential of each redox process, which typically is observed for systems where redox conduction is the dominant charge transport mechanism. Significantly, the dc conductivity of the metal-based redox couple observed in these polymers is 2 orders of magnitude higher than that of a comparable nonconjugated system.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-91110 (URN)DOI: 10.1021/ic049221m (DOI)
    Available from: 2003-11-13 Created: 2003-11-13 Last updated: 2017-12-14
  • 229.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Constable, E C
    Figgemeier, E
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, R
    Housecroft, C E
    Mukhtar, Emad
    Schofield, E
    A rod-like polymer containing (Ru(terpy)2) units prepared by electrochemical coupling of pendant thienyl moieties2002In: Chemical Communications, p. 284-285Article in journal (Refereed)
  • 230.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Constable, Edwin C.
    Figgemeier, Egbert
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn
    Housecroft, Catherine E.
    Mukhtar, Emad
    Schofield, Emma
    A rod-like polymer containing {Ru(terpy)2} units prepared by electrochemical coupling of pendant thienyl moieties2002In: Chemical Communications, ISSN 1359-7345, no 3, p. 284-285Article in journal (Refereed)
    Abstract [en]

    A new rod-like coordination polymer consisting of (Ru-(terpy)2) motifs bridged by bithiophene units has been prepared by electrochemical polymerisation in acidic organic medium. 

  • 231. Hjelm, Johan
    et al.
    Handel, Robyn W
    Hagfeldt, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Constable, Edwin C
    Housecroft, Catherine E
    Forster, Robert J
    Conducting polymers containing in-chain metal centers: electropolymerization2005In: Inorg Chem, ISSN 0020-1669, Vol. 44, no 4, p. 1073-81Article in journal (Refereed)
  • 232.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn W.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Constable, Edwin C.
    Housecroft, Catherine E.
    Forster, Robert J.
    Conducting polymers containing in-chain metal centers: Electropolymerization of oligothienyl-substituted {M(tpy)2} complexes and in-situ conductivity studies, M = Os(II), Ru(II)2005In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, no 4, p. 1073-1081Article in journal (Refereed)
    Abstract [en]

    The electropolymerization of a series of Ru and Os bis-terpyridine complexes that form rodlike polymers with bithienyl, quaterthienyl, or hexathienyl bridges has been studied. Absorption spectroscopy, scanning electron microscopy, and cyclic voltammetry have been used to characterize the monomers and resulting polymer films. The absolute dc conductivity of the quaterthienyl-bridged {Ru(tpy)2} and {Os(tpy)2} polymers is unusually large and independent of the identity of the metal center at 1.6 × 10-3 S cm-1. The maximum conductivity occurs at the formal potential of each redox process, which typically is observed for systems where redox conduction is the dominant charge transport mechanism. Significantly, the dc conductivity of the metal-based redox couple observed in these polymers is 2 orders of magnitude higher than that of a comparable nonconjugated system.

  • 233.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn W.
    Hagfeldt, Anders
    Constable, Edwin C.
    Housecroft, Catherine E.
    Forster, Robert J.
    Conducting polymers containing in-chain metal centers: Homogeneous charge transport through a quaterthienyl-bridged {Os(tpy)2} polymer2003In: Journal of Physical Chemistry B, ISSN 1520-6106, Vol. 107, no 38, p. 10431-10439Article in journal (Refereed)
  • 234.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn W.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Constable, Edwin C.
    Housecroft, Catherine E.
    Forster, Robert J.
    Conducting Polymers Containing In-Chain Metal Centers: Homogeneous Charge Transport through a Quaterthienyl-Bridged {Os(tpy)2} Polymer2003In: Journal of Physical Chemistry B, Vol. 107, p. 10431-10439Article in journal (Refereed)
  • 235.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn W.
    Hagfeldt, Anders
    Constable, Edwin C.
    Housecroft, Catherine E.
    Forster, Robert J.
    Electropolymerisation dynamics of a highly conducting metallopolymer: Poly-[Os(4'-(5-(2,2'-bithienyl))-2,2':6',2''-terpyridine)2]2+In: Article in journal (Refereed)
  • 236.
    Hjelm, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Handel, Robyn W.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Constable, Edwin C.
    Housecroft, Catherine E.
    Forster, Robert J.
    Electropolymerisation dynamics of a highly conducting metallopolymer: poly-[Os(4-(5-(2,2-bithienyl))-2,2:6,2-terpyridine)2]2+2004In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 6, no 2, p. 193-200Article in journal (Other academic)
    Abstract [en]

    The potential, time, and concentration dependence of the potentiostatic electropolymerisation of the thienyl-substituted transition metal complex [Os(bttpy)22+] onto platinum disk microelectrodes is reported, bttpy is 4-(5-(2,2-bithienyl))-2,2:6,2-terpyridine. Oxidative electropolymerisation of the thienyl bridges is highly efficient with an electropolymerisation efficiency of 36 ± 3% being observed across a wide range of potentials and monomer concentrations. The osmium centres are oxidised when polymerisation proceeds and the deposited polymer is highly conducting allowing high surface coverage films, up to 6 × 10−7 mol cm−2, to be deposited within 60 s. SEM imaging reveals that smooth films can be produced using moderate overpotentials for electrodeposition. Significantly, diffusional mass transport controls the rate of film deposition allowing the radial diffusion field found at microelectrodes to be exploited to favour film growth co-planar with the electrode surface. The electropolymerisation rate increases approximately linearly with increasing monomer concentration from approximately 8 to 400 μM and this first-order dependence likely arises from mass transport limitations. The rate of homogeneous charge transport through potentiostatically deposited films, characterised by D1/2C, where D is the apparent charge transport diffusion coefficient and C is the concentration of osmium centres, is 3.5 ± 0.5 × 10−7 mol cm−2 s−1/2 and is largely insensitive to the deposition potential, and is very similar to that previously observed for potentiodynamically deposited films. This charge transport parameter is approximately two orders of magnitude larger than those found for non-conjugated bridges and is interpreted in terms of resonant superexchange across the quaterthienyl bridge.

  • 237.
    Holm, Ann-Kathrin, 1974-
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Femtosecond Investigations of Spiropyran Photochromism in Solution2003Licentiate thesis, monograph (Other scientific)
  • 238.
    Holm, Ann-Kathrin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Mohammed, Omar F
    Rini, Matteo
    Mukhtar, Emad
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Nibbering, Erik T J
    Fidder, Henk
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Sequential merocyanine product isomerization following femtosecond UV excitation2005In: J Phys Chem A Mol Spectrosc Kinet Environ Gen Theory, ISSN 1089-5639, Vol. 109, no 40, p. 8962-8Article in journal (Refereed)
  • 239.
    Holm, Ann-Kathrin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Rini, Matteo
    Nibbering, Erik T.J.
    Fidder, Henk
    Femtosecond UV/mid-IR study of photochronism of the spiropyran 1’,3’-dihydro-1’,3’,3’-trimethyl-6-nitrospiro-[2H-1-benzopyran-2,2’-(2H)-indole] in solution2003In: Chemical Physics Letters, Vol. 376, p. 214-219Article in journal (Refereed)
  • 240.
    Holmgren, Sverker
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Peterson, Christer
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Karlsson, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry, Quantum Chemistry.
    Time-marching methods for the time-dependent Schrödinger equation2004In: Proc. Int. Conference on Computational and Mathematical Methods in Science and Engineering: CMMSE-2004, Uppsala, Sweden: Uppsala University , 2004, p. 53-56Conference paper (Other academic)
  • 241.
    Huang, P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Magnusson, A.
    Lomoth, R.
    Abrahamsson, M.
    Tamm, M.
    Sun, L.
    van Rotterdam, B.
    Park, J.
    Hammarström, L.
    Åkermark, B.
    Styring, S.
    Photo-induced oxidation of a dinuclear Mn2II,II complex to the Mn2III, IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine2002In: Journal of Inorganic Biochemistry, ISSN 0162-0134, E-ISSN 1873-3344, Vol. 91, p. 159-172Article in journal (Refereed)
  • 242.
    Hällstig, Emil
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry, Quantum Chemistry.
    Nematic Liquid Crystal Spatial Light Modulators for Laser Beam Steering2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Laser beam control is important in many applications. Phase modulating spatial light modulators (SLMs) can be used to electronically alter the phase distribution of an optical wave-front and thus change the direction and shape of a laser beam. Physical constraints set limitations to the SLM and an ideal phase distribution can usually not be realised. In order to understand how such components can be used for non-mechanical beam control three nematic liquid crystal (NLC) SLMs have been thoroughly characterised and modelled.

    The pixel structure and phase quantisation give a discrepancy between ideal and realised phase distributions. The impact on beam steering capability was examined by measurements and simulations of the intensity distribution in the far-field.

    In two of the studied SLMs the pixel period was shorter than the thickness of the LC layer giving the optical phase shift. This results in a so-called “fringing field”, which was shown to degrade the phase modulation and couple light between polarisation modes. The deformation of the LC was simulated and a finite-difference time-domain (FDTD) algorithm was used to calculate how polarised light propagates through the optically anisotropic SLM.

    Non-mechanical beam steering and tracking in an optical free-space communication link were demonstrated. Continual optimisation of the steering angle was achieved by feedback from a video camera.

    The optical properties of the SLM in the time period right after a voltage update were studied. It was shown how light is redistributed between orders during the switching from one blazed grating to another. By appropriate choice of the blazed gratings the effects on the diffraction efficiency can be minimised.

    The detailed knowledge of the SLM structure and its response to electronic control makes it possible to predict and optimise the device performance in future systems.

    List of papers
    1. Intensity variations using a quantized spatial light modulator for non-mechanical beam steering
    Open this publication in new window or tab >>Intensity variations using a quantized spatial light modulator for non-mechanical beam steering
    2003 In: Optical Engineering, ISSN 0091-3286, Vol. 42, no 3, p. 613-619Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92439 (URN)
    Available from: 2004-11-24 Created: 2004-11-24Bibliographically approved
    2. Fringing fields in a nematic liquid crystal spatial light modulator for beam steering
    Open this publication in new window or tab >>Fringing fields in a nematic liquid crystal spatial light modulator for beam steering
    Show others...
    2004 In: Journal of Modern Optics, ISSN 00950-0340, Vol. 51, no 8, p. 613-619Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92440 (URN)
    Available from: 2004-11-24 Created: 2004-11-24Bibliographically approved
    3. Polarization properties of a nematic liquid-crystal spatial light modulator for phase modulation
    Open this publication in new window or tab >>Polarization properties of a nematic liquid-crystal spatial light modulator for phase modulation
    2005 (English)In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 22, no 1, p. 177-184Article in journal (Refereed) Published
    Abstract [en]

    The polarization properties of a nematic zero-twist liquid-crystal (NLC) spatial light modulator (SLM) were studied. A large ratio between the liquid-crystal (LC) layer thickness and the pixel pitch combined with spatial variations in the applied electric field causes fringing fields between pixels. Depending on the LC alignment, the electric field components within the LC layer can result in a twist deformation. The produced inhomogeneous optical anisotropy affects the polarization of light propagating through the device. We experimentally examined polarization effects in different diffraction orders for both binary and blazed phase gratings. Simulations of the LC deformation together with finite-difference time-domain simulations for the optical propagation were used to calculate the corresponding far-field intensities. It was demonstrated how rigorous simulations of the NLC SLM properties can be used to understand the polarization features of different diffraction orders.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-92441 (URN)10.1364/JOSAA.22.000177 (DOI)15669628 (PubMedID)
    Available from: 2004-11-24 Created: 2004-11-24 Last updated: 2017-12-14Bibliographically approved
    4. Retrocommunication utilizing electroabsorption modulators and non-mechanical beam steering
    Open this publication in new window or tab >>Retrocommunication utilizing electroabsorption modulators and non-mechanical beam steering
    Show others...
    2005 (English)In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 44, no 4, p. 045001-Article in journal (Refereed) Published
    Abstract [en]

    A novel retrocommunication link utilizing reflective multiplequantum well (MQW) optical modulators and nonmechanical beamsteering and tracking is demonstrated. Large aperture reflective MQWmodulators using AlGaAs/GaAs are optimized and manufactured. Themodulators exhibit a contrast ratio larger than 4:1 and a modulationbandwidth of 10 MHz. Nonmechanical beam steering and tracking arestudied using nematic liquid crystal (NLC) spatial light modulators(SLMs). The communication link is comprised of a retromodulating arraywith four MQW modulators and a transceiver using a NLC SLM for beamsteering and tracking. Transfer of audio, real-time image data and pseudorandombit sequences over 100-m range while tracking the movingretromodulator is shown. The link is capable of transferring data at approximately8 Mbps.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-92442 (URN)10.1117/1.1883063 (DOI)
    Available from: 2004-11-24 Created: 2004-11-24 Last updated: 2017-12-14Bibliographically approved