Advanced Materials

Cover image for Advanced Materials

October 1994

Volume 6, Issue 10

Pages fmi–fmi, 715–808

  1. Masthead

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

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061001

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Correction
    7. Research News
    8. Book Reviews
    1. Materials research support in the UK—The role of the EPSRC (pages 715–718)

      Stuart D. Ward

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061002

      The Engineering and Physical Sciences Research Council has recently taken responsibility in Britain for coordinating the Government funding of materials science (among other fields). The new organization is presented, and its role and objectives, the current program, the mode of proposal assessment, the support of Interdisciplinary Research Centres (IRCs) and national laboratories, and the priorities for future programs are discussed.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Correction
    7. Research News
    8. Book Reviews
    1. MOCVD Routes to Thin Metal Oxide Films for superconducting electronics (pages 719–730)

      Dr. Douglas L. Schulz and Prof. Tobin J. Marks

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061003

      Superconducting, semiconducting and insulating oxide thin films are of interest for applications as active and passive components in microelectronic device technologies. Metal organic chemical vapor deposition (MOCVD) is an important method of thin film production and its use in developing device structures such as that in the figure is discussed.

    2. Raman Scattering in C60 fullerenes and fullerides (pages 731–745)

      Prof. Hans Kuzmany, Dr. Michael Matus, Bernhard Burger and Johannes Winter

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061004

      Buckminsterfullerene and related systems possess a strong chromophoric character resulting from the sp2 hybridization of their valence electrons. As a result, Raman scattering can be used to reveal details of the physical properties and doping dynamics, also allowing the study of the effects of chemical modifications of these systems. Due to the high symmetry of the molecules the spectra at first appear rather simple. However, crystal field effects and general symmetry breaking conditions can also be studied.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Correction
    7. Research News
    8. Book Reviews
    1. Aerosol-assisted chemical vapor deposition (AACVD) of silver, palladium and metal alloy (Ag1−xPdx, Ag1−xCux and Pd1−xCux) Films (pages 746–748)

      Dr. Chongying Xu, Prof. Mark J. Hampden-Smith and Prof. Toivo T. Kodas

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061005

      Thermally labile, low-volatility molecules are usually unsuitable as precursors for the chemical vapor deposition of high-quality metal films. Here, a new method, aerosol-assisted CVD (see Fig.), is reported, and used to produce crystalline silver, palladium, and binary metal alloy thin films from just such precursors.

    2. A high efficiency blue-light-emitting diode based on novel ladder poly(p-phenylene)s (pages 748–752)

      Dr. Johannes Grüner, Dr. Peter J. Hamer, Dr. Richard H. Friend, Dr. Hans-Joachim Huber, Dr. Ullrich Scherf and Dr. Andrew B. Holmes

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061006

      Low energy losses due to non-radiative decay are an important step towards high-efficiency organic LEDs. The rigid, regioregular structure of the novel ladder poly(p-phenylene)s reported here lead to a reduction in such losses and to potentially interesting internal LED efficiencies of 1%. The effect on the efficiency of varying the length of the spacers in the structure is examined.

    3. Two-layer light-emitting diodes based on sexithiophene and derivatives (pages 752–755)

      Dr. Gilles Horowitz, Dr. Philippe Delannoy, Dr. Habib Bouchriha, Dr. Françoise Deloffre, Dr. Jean-Louis Fave, Dr. Francis Garnier, Dr. Riadh Hajlaoui, Dr. Michel Heyman, Dr. Fayçal Kouki, Dr. Pierre Valat, Dr. VÉRonique Wintgens and Dr. Abderrahim Yassar

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061007

      The performance of oligothiophene-based organic LEDs can be dramatically improved (by up to four orders of magnitude) by using a two-layer device made of unsubstituted sexithiophene (6T) and a substituted 6T (see Fig.), although the substituted 6T materials do not produce electroluminescence in single-layer devices. Yellow emission with a quantum yield of 0.15% has been achieved.

    4. A “proton-pump” electrode based on poly(3-carboxymethylpyrrole) (pages 755–758)

      Dr. Hafsa Korri Youssoufi, Dr. Francis Garnier, Dr. Abderrahim Yassar, Dr. Selima Baïteche and Dr. Pratima Srivastava

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061008

      Electroactive pH-controlled membranes are a potential application of materials presented here. The functionalization of conjugated pyrroles with pendant carboxylic groups has been used to produce polymer electrodes exhibiting the electrochemically-controlled release of protons. The synthesis and the electrochemical characterization at varying pH are reported.

    5. Charge transfer complexes of (TTFTe)2: Preparation, structure, and electrical conductivity (pages 758–761)

      Prof. James Y. Becker, Prof. Joel Bernstein, Moshe Dayan, Dr. Arkady Ellern and Leah Shahal

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061009

      Organic metals based on organo-tellurium units are of particular interest because of the increased orbital overlap in these systems which leads to favorable conditions for conductivity. The figure shows the crystal structure of (TTFTe)2 · TCNQ, which is semiconducting, while the (TTFTe)2 · (TCNQ)2 complex has a conductivity of 8.2 S/cm at room temperature.

    6. (TMTTF)2Br: The First Organic Superconductor in the (TMTTF)2X family (pages 762–765)

      Luis Balicas, Dr. Kamran Behnia, Dr. Woun Kang, Dr. Pascale Auban-Senzier, Dr. Enric Canadell, Dr. Denis Jérome, Dr. Michel Ribault and Dr. Jean-Marc Fabre

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061010

      Superconductivity in quasi-1-dimensional organic conductors is shown not to be confined to the selenium-containing (TMTSF)2X series (TMTSF = tetramethyltetraselenafulvalene). The title compound is shown to exhibit superconductivity in the 1 K range provided the spin density wave ground state is suppressed by the application of pressure, leading to conclusions about the origin of pairing strength in organic conductors.

    7. The First sulfur-containing twin-DCNQI-type acceptor (pages 765–768)

      Mar González, Dr. Pilar De Miguel, Dr. Nazario Martin, Dr. Jose Luis Segura, Prof. Carlos Seoane, Dr. Enrique Orti, Dr. Rafael Viruela and Dr. Pedro M. Viruela

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061011

      The search for new electron acceptors and electron donors can facilitated by the use of semiempirical calculations. Here, in a combined experimental and theoretical study the first twin-DCNQI-type acceptor is synthesized (see Fig.) and characterized and calculations are used to assess the structural features which should lead to the desired properties.

    8. Synthesis, X-ray structure and application of bis[allylamine(dimethyl)gallium(III)] as a precursor for the growth of GaP layers by MOVPE (pages 768–772)

      Prof. Herbert Schumann, Dr. Oliver Just, Dr. Siegbert Nickel, Dr. Roman Weimann, Dr. Volker Gottschalch, Dr. Bernd P. Keller and Dr. Reinhard Schwabe

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061012

      Gallium precursors for the growth of gallium-based materials from the vapor phase still need to be improved in terms of their safety and handling properties, especially with respect to their pyrophoricity, air and moisture sensitivity, and toxicity. A new gallium precursor is reported, the first diorganogalliumamine, which exhibits a more favorable safety profile, and its use in the preparation of N-doped GaP is discussed.

    9. Fabrication of PbS nanoparticles embedded in a polymer Film by a gas-aerosol reactive electrostatic deposition technique (pages 772–775)

      Dr. Oleg V. Salata, Dr. Peter J. Dobson, Dr. Peter J. Hull and Dr. John L. Hutchison

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061013

      Semiconductor nanoparticles embedded in an inert matrix can be seen as a type of quantum-dot composite, materials which have great potential in optoelectronic applications such as lasers. Room-temperature electrostatic spraying is used to produce composites based on PbS nanoparticles in a polyvinyl alcohol matrix (e.g. see Fig.) and their potential for application is discussed.

    10. Static SIMS investigation of immobilized molecules on polymer surfaces (pages 775–780)

      Dr. Angelika Leute, Derk Rading, Prof. Alfred Benninghoven, Dr. Kathrin Schroeder and Dr. Doris Klee

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061014

      The covalent immobilization of molecules on polymer surfaces is interesting for example in the development of vascular prostheses, where the immobilization of biological molecules is used to improve the biocompatibility of synthetic materials. Here, TOF-SIMS is used to investigate the immobilization of amino acids on such surfaces, and the results compared with those from XPS and other methods.

    11. Solid-state routes to tantalum nitrides (TaN, Ta3N5) (pages 780–782)

      Dr. Ivan P. Parkin and Dr. Adrian T. Rowley

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061015

      Metal nitrides are hard, durable refractory materials with a number of applications, including wear resistance, reflective coatings, and catalysts. Low-energy approaches to the synthesis of these materials are a topic of current research. A new method for the preparation of tantalum nitride is presented which is a solid-state reaction, a hybrid between the molecular precursor approach and a metathesis reaction.

    12. Effects of pressure on the thermodynamic properties of C60 studied by 13C NMR (pages 782–786)

      Dr. Rachid Kerkoud, Dr. Pascale Auban-Senzier, Dr. Jean Godard, Prof. Denis Jérome, Dr. Jean-Marc Lambert and Dr. Patrick Bernier

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061016

      In fullerenes, the dynamics, molecular motion, and order-disorder transition temperature Tc are strongly affected by the applied pressure. In this study, single-crystal 13C NMR spectroscopy is used to study fullerenes under hydrostatic pressure as a function of temperature (200–343 K). Information is obtained on the thermodynamic properties of these materials, their phase behavior and their molecular dynamics.

    13. Polytriacetylenes: Conjugated polymers with a novel all-carbon backbone (pages 786–790)

      Martin Schreiber, John Anthony, Prof. François Diederich, Michael E. Spahr, Prof. Reinhard Nesper, Dr. Michael Hubrich, Frank Bommeli, Dr. Leonardo Degiorgi, Prof. Peter Wachter, Phil Kaatz, Dr. Christian Bosshard, Prof. Peter Günter, Martin Colussi, Prof. Ulrich W. Suter, Dr. Corinne Boudon, Dr. Jean-Paul Gisselbrecht and Prof. Maurice Gross

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061017

      New, synthetically accessible, soluble, stable all-carbon-backbone polymers are reported. The polytriacetylenes (see Fig.) represent an intermediate step between polydiacetlylenes and carbyne and as such are of interest as alternatives for known conjugated polymers. The synthesis, film casting, and interesting properties are discussed.

  5. Correction

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Correction
    7. Research News
    8. Book Reviews
    1. You have free access to this content
      Correction (page 790)

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061018

  6. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Correction
    7. Research News
    8. Book Reviews
    1. Time-frequency domain optical storage in rare-earth-doped materials (pages 791–793)

      Dr. Ravinder Kachru, Dr. Yu Sheng Bai and Dr. Xiao-An Shen

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061019

      The storage of information in the time domain through the use of spectral hole burning rare-earth-doped crystals is described. The technique, which is also known as stimulated echo, makes serial read/write data rates of 100 MHz possible. Applications include high-speed memory, signal processing, high-speed optical switching, optical interconnects, image processing, and logic operations.

    2. Multi-property materials: Magnetism and NLO properties (pages 794–797)

      Prof. René Cléement, Dr. Pascal G. Lacroix, Dr. Dermot O'Hare and Dr. John Evans

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061020

      Transparent magnets are just one of the novel types of materials which can be imagined when the properties of several materials are combined cooperatively. Intercalation can provide an alternative to other methods such as sol-gel techniques for the synthesis of hybrid organic-inorganic composites and also offers the advantage of better crystallinity. Recent progress in the combination of magnetic and nonlinear optical properties in layered materials is traced.

    3. Molecular conductors from neutral heterocyclic π-radicals (pages 798–802)

      Dr. A. Wallace Cordes, Dr. Robert C. Haddon and Prof. Richard T. Oakley

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940061021

      Stable radical species (e.g. see Fig.) can form an alternative source of organic conducting materials. Suppressing the Peierls distortion and stabilizing the metallic state can be achieved by applying pressure or by developing materials with enhanced two and three-dimensional interactions. Recent progress in the synthesis, and stabilization, for example through doping, is discussed.

  7. Book Reviews

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

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