Advanced Materials

Cover image for Advanced Materials

January 1995

Volume 7, Issue 1

Pages fmi–fmi, 7–98

  1. Masthead

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. Masthead (page fmi)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070101

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. The new materials research program of the german federal ministry for research and technology (pages 7–9)

      Dr. Jürgen Roemer-Mähler and Dr. Franz-Josef Bremer

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070102

      The German Federal Ministry for Research and Technology (BMFT) has put together a new program of materials research and development support covering the period 1994–;1999. The program, known as Ma Tech, sets priorities in, for example, information, energy, transport, and production technology, medical engineering, and new fields, providing over DM 800m as a follow up to the successful Matfo program. The details and philosophy of the new program are presented.

  3. Articles

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. Raman Scattering in Zeolites and molecular sieves (pages 10–25)

      Dr. Claude Brémard and Dr. Daniel Bougeard

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070103

      The diffusion and location of guests in zeolite frameworks can be studied in-situ using Raman spectroscopy. For example, the location and orientation of crown ethers (e.g. Na⊕ 18C6, see figure) used as templates in the synthesis of faujasite polymorphs can be studied in the framework they have helped to form, and the subsequent calcination process leading to the final zeolite can also be followed using the technique.

    2. Electron microscopy studies of amphiphilic self-assemblies on vitreous ice (pages 26–35)

      Dr. Jaroslaw Majewski, Dr. Lev Margulis, Dr. Isabelle Weissbuch, Dr. Ronit Popovitz-Biro, Dr. Talmon Arad, Prof. Yeshayahu Talmon, Prof. Meir Lahav and Prof. Leslie Leiserowitz

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070104

      The epitaxial growth of nanocrystals(for example of PbS) under monolayers of long-chain carboxylic acids is suggested as an interesting extension to the study of crystalline self-assembled organic thin films on the vitrified water subphase. Low-temperature transmission electron microscopy (cryo-TEM) can provide information on the coherence and mosaicity of the 2-D crystallites as well as on their unit cell dimensions, symmetry, and morphology, and it can be shown that the twinning of the crystallites correlates with the chain length of the amphiphiles. The cryo-TEM technique and its applications are discussed.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. Chlorine precursor route (CPR) chemistry to poly(p-phenylene vinylene)-based light emitting diodes (pages 36–38)

      Dr. Bing R. Hsieh, Dr. Homer Antoniadis, Dr. Douglas C. Bland and Dr. William A. Feld

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070105

      Thin film organic electrolumiscent devices based on poly 2,3-diphenyl-1,4-phenylenevinylene (DP-PPV, see Fig.) have been fabricated using the chlorine-precursor route. Devices with the configuration Mg/DP/-PPV/ITO are shown to have an external quantum efficiency for green electroluminescence of 0.1%, a value comparable to the efficiency of CA/PPV devices.

    2. Lateral deposition of polypyrrole lines by means of the scanning electrochemical microscope (pages 38–40)

      Christine Kranz, Markus Ludwig, Prof. Herrmann E. Gaub and Dr. Wolfgang Schuhmann

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070106

      Laterally deposited polypyrrole structures have been fabricated using a scanning electrochemical microscope on conducting substrates from aqueous solution. The dimensions of the polymer lines obtained are primarily determined by the size of the electrode, opening a number of opportunities in the design of organic electronic devices and selective sensors.

    3. The radical cation iodide of the new electron donor tetraiodotetrathiafulvalene: Magnetic properties and crystal structure (pages 41–43)

      Prof. Rudolf Gompper, Joachim Hock, Dr. Kurt Polborn, Prof. Elmar Dormann and Dr. Hubert Winter

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070107

      Tetrathiafulvalene and its derivatives can be chemically or electrochemically oxidized to yield stable radical cation salts which display unusual electrical properties. In order to increase the dimensionality of the system by extending the π-conjugation and thus stabilizing the metallic state, while at the same time keeping the system small, the tetraiodo-derivative (see Fig.) has been synthesized and characterized.

    4. Polarized electroluminescence from an oriented substituted polythiophene in a light emitting diode (pages 43–45)

      Dr. Peter Dyreklev, Dr. Magnus Berggren, Dr. Olle Inganäs, Dr. Mats R. Andersson, Dr. Olof Wennerström and Dr. Thomas Hjertberg

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070108

      Polarized light sources based on stretch-oriented conjugated polymers are reported. The devices, based on poly 3(4-octylphenyl)-2,2′-bithiophene, show an external quantum efficiency of 0.1% and are produced using a very simple method which may be easily extended to other polymers. The fabrication of the devices is described and factors such as the emission and spectral differences parallel and prependicular to the stretching direction discussed.

    5. Junction electroluminescence from microscopic diode structures in CuInSe2, prepared by electric field-assisted doping (pages 45–48)

      Leonid Chernyak, Dr. Abram Jakubowicz and Prof. David Cahen

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070109

      Light emitting diodes where the efficiency of the junction electroluminescence has been improved over devices fabricated using thermal in-diffusion methods, is demonstrated for structures such as that shown in the figure, which is an electric-field-induced device. As E-field produced transistors are already available, combined monolithic LED/transistor structures produced using E-field-Induced doping of semiconductors could be possible.

    6. Conductivity in redox modified conducting polymers. In-situ conductivity of poly(cyclopentadithiophenes) bearing p-nitrophenyl and 4-N-methylpyridinium groups (pages 48–52)

      Dr. Gianni Zotti, Dr. Anna Berlin, Prof. Giorgio Pagani, Dr. Gilberto Schiavon and Dr. Sandro Zecchin

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070110

      Redox-modified polythiophenes exhibiting the highest mixed-valence conductivities of any polymer containing a pendant redox group are reported. The ordering of the polymer, in which the backbone has been oxidized to a bipolaron conducting state and the redox sites have been reduced to a mixed-valence conducting state, encourages inter-site hopping and results in the high conductivities. Electron interactions are shown not have an influence on the conduction.

    7. Ultrathin membranes of molecularly reinforced liquids on porous substrates (pages 52–55)

      Michael Seufert, Christo Fakirov and Prof. Gerhard Wegner

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070111

      Hairy-rod-like macro-molecules are reported to useful materials in the fabrication of membranes. Cellulose alkylethers, cross-linked through cinnamyl side groups (see Figure), are transferred onto a Celgard 2400 substrate using the Langmuir–Blodgett technique. The preparation and the characteristics of the membranes are presented.

    8. Superconductor thin films: Topotactic corrosion mechanism of YBa2Cu3O7 with Water Vapor (pages 55–58)

      Ralph Börner, Dr. Werner Paulus, Prof. Robert Schöllhorn, Dr. Bernd Kabius and Dr. Jürgen Schubert

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070112

      Corrosion in high-Tc supercnductors (HTSC) caused by water vapor is examined. Htsc thin films prepared usig the laser ablation technique are shown to lose their superconducting properties due to the topotactic formation of a new hydroxylated phase which is a result of the corrosion. The mechanism of the corrosion process, which could be important in future applications of HTSC, is discussed.

    9. Bimetallic Fe/Ga thin films from single sources; molecular control of the thin film stoichiometry (pages 58–61)

      Dr. Roland A. Fischer, Alexander Miehr and Markus M. Schulte

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070113

      Single source CVD precursors for FeGa thin films (e.g. see Fig.) are reported. The precursors are volatile, give clean deposits, and allow the use of unprecedented mild deposition conditions, at temperatures well below the decomposition temperature of the GaAs substrate. It is also shown that single-source precursors for binary materials should be designed with the strongest bond joining the atoms which make up the final material.

    10. Incorporation of methylene blue in NaY zeolite at crystallographically defined positions (pages 61–64)

      Dr. Rainer Hoppe, Prof. Günter Schulz-Ekloff, Prof. Dieter Wöhrle, Dr. Christine Kirschhock, Prof. Hartmut Fuess, Dr. Lieve Uytterhoeven and Prof. Robert Schoonheydt

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070114

      Nanoporous structures containing dye molecules have been found to have interesting nonlinear optical properties. The various methods used for the incorporation of the guests in the host lattice result in very different positioning of the guests relative to the host structure. Here, these methods are compared for the incorporation of Methylene Blue at crystallographically, non-random, positions. The processes are examined using X-ray diffraction and Rietveld analysis.

    11. Imaging the surfaces of nanoporous semiconductors by atomic force microscopy (pages 64–68)

      Dr. Patricia Enzel, Dr. Grant S. Henderson, Prof. Geoffrey A. Ozin and Robert L. Bedard

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070115

      Open framework semiconductors tin(IV) sulfides and tin(IV) selenides) exhibiting bulk crystalline nanoporosity have been studied using atomic force microscopy (AFM). The bulk porosity is reflected in the surface structures of these materials (see Fig.), and little reconstruction can be detected, important points in the assessment of the electrical transport characteristics of this new class of nanoporous materials.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. Polymer ligands that can regulate reaction temperature in “smart” catalysts (pages 69–71)

      Prof. David E. Bergbreiter, Dr. Vimala M. Mariagnanam and Dr. L. Zhang

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070116

      “Smart” homogeneous water-soluble catalysts whose activity is inversely dependent on the temperature is presented. The behavior of the catalysts is based on the inverse temperature dependence o the solubility of some polymers which results in high activity at low temperatures and lower activity at elevated temperatures wher the catalyst is phase separated from the continuous phase containing the substrate. The synthesis and applications of the catalysts are presented.

    2. Nanostructures: New forms of luminescent silicon (pages 72–78)

      Dr. Ömer Dag, Dr. Alex Kuperman and Prof. Geoffrey A. Ozin

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070117

      The cover picture represents a 60-atom silicon nanocluster with a diamond-like structure, within the supercage of zeolite Y. In this article, recent developments in the chemical synthesis of novel and well-defined nanoscale forms of luminescent silicon are reviewed and the methods used to “trick” silicon (an indirect bandgap semiconductor with electric dipole forbidden luminescence) into emitting light discussed.

    3. New nonlinear optical crystals for UV and VUV harmonic generation (pages 79–81)

      Younan Xia, Prof. Chuangtian Chen, Prof. Dingyuan Tang and Prof. Baichang Wu

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070118

      Among the nonlinear optical (NLO) materials, second harmonic generators are important because of their applications in extending the limited frequencies available from lasers. A theory is presented that makes it possible to design and synthesize new NLO materials according to need, based on an understanding of the structure–property relationships. Four inorganic NLO crystals serve as an illustration of the success of this method.

    4. III–V based diluted magnetic semi conductors: Carrier–induced magnetism (pages 82–85)

      Dr. Hiro Munekata

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070119

      Magnetism in III–V semiconductors is a comparatively new area of study: the first III–V based diluted magnetic semiconductors were produced in epitaxial films of (In, Mn)As grown on GaAs(100) substrates in 1989. An account is given of the magnetic behavior of these novel semi-magnetic alloys at various carrier concentrations. Finally, magneto-optical devices are presented in which the control of the carrier concentration by an electric field results in the manipulation of magnetic properties.

    5. Molecular assemblies of functionalized polydiacetylenes (pages 85–89)

      Dr. Wayne Spevak, Dr. Jon O. Nagy and Dr. Deborah H. Charych

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070120

      Thin films and liposomes composed of polydiacetylenes with biologically active head groups have potential applications in cell adhesion, therapeutics, and biological sensing due to the specific interactions between the functionalized head groups and, for example, virus particles. The synthesis and the applications of these assemblies are discussed.

  6. Book Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
  7. Conference Calendar

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    8. Conference Calendar
    1. Conference Calendar (pages 97–98)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070130

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