Advanced Materials

Cover image for Advanced Materials

March 1995

Volume 7, Issue 3

Pages fmi–fmi, 259–330

  1. Masthead

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

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070301

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Reorganizing a major materials research institute in fast Germany—IFW dresden (pages 259–262)

      Prof. Hans Warlimont

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070302

      Scientific institutes in East Germany underwent huge changes in their organization, funding, and research priorities as a result of the reunification of Germany. The Director of one of the most important institutes. “The Institute of Solid State and Materials Research” in Dresden (IFW), traces the development of the political and scientific environment for materials research in the former East Germany and describes the challenges still to be met, in terms of personnel development, the quest for competitiveness, and the organization of funding

  3. Articles

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Conjugated polymers and oligomers: Designing novel materials using a quantum-chemical approach (pages 263–274)

      Prof. Jean-Luc Brédas

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070303

      Quantum chemical calculations can provide reliable information on the geometric and electronic structures of a variety of advanced materials wich can be used to design or predict their electrical or optical properties. The success of the approach does not always depend on the use of the most sophisticated calculational methods, but rather on the infomed selection of the types of calculation applied to a particular problem. The power and potential, and the potential pitfalls, of these methods are reviewed especially as applied to conjugated polymers and oligomers.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Opening and purification of carbon nanotubes in high yields (pages 275–276)

      Dr. Hidefumi Hiura, Dr. Thomas W. Ebbesen and Dr. Katsumi Tanigaki

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070304

      Gram-quantities of pure carbon nanotubes (see Figure) can be produced using a new method reported here. The nanotubes, which can be thought of as cylindrical graphitic microcrystals, are opened and purified by treating them with a mixtue of sulfuric acid and potassium permanganate. The opening of the nanotubes on a large scale is also of interest in terms of filling the tubes with interesting guest molecules.

    2. Photoconductivity in the columnar phases of a glassy discotic twin (pages 276–280)

      Dieter Adam, Peter Schuhmacher, Jürgen Simmerer, Dr. Lukas Häußling, Dr. Wolfgang Paulus, Dr. Karl Siemensmeyer, Dr. Karl-Heinz Etzbach, Prof. Helmut Ringsdorf and Prof. Dietrich Haarer

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070305

      Processible organic materials exhibiting high charge carrier mobilities are a step closer with the development of liquid crystalline photoconducting materials. The mobilities have been measured in various phase regions over the temperature range from – 100 to 165°C and the influence of different annealing conditions assessed, indicating that these materials could soon compete with amorphous semiconductors in electronics applications.

    3. Lyotropic polymorphism in oxovanadium complexes (pages 280–283)

      S. Sherry Zhu and Prof. Timothy M. Swager

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070306

      Ionic transition metal compounds which exhibit mesomorphism in aqueous systems are reported. These oxovanadium-based surfactants display binary (surfactant/H2O) and ternary (surfactant/H2O/decanol) mesomorphism and represent a step towards the development of lyotropic materials with large magnetic anisotropies.

    4. Charge transport and molecular dynamics in columnar stacks of liquid crystalline phthalocyanine derivatives (pages 283–286)

      Herbert Groothues, Prof. Friedrich Kremer, Pieter G. Schouten and Dr. John M. Warman

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070307

      Broadband dielectric spectroscopy has been employed to study the electric charge transport and molecular dynamics in columnar stacks of liquid crystalline phthalocyanine derivatives, materials which are of interest as one-dimensional semiconductors or as photoconductors. Three relaxation processes and a conductivity contribution have been identified and it is concluded that the solid-to-liquid crystalline phase transition has no influence on the temperature dependence of the conductivity.

    5. Nested interfacial growth of carbon nanotubes catalyzed by hafnium (pages 286–289)

      Dr. Masafumi Ata, Dr. Kiyoshi Yamaura and Dr. Andrew J. Hudson

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070308

      Carbon nanotubes containing HfC crystals (see Figure) have been synthesized during the dc arc discharge of a Hf-composite graphite electrode. Clear evidence is presented of the Hf-catalyzed growth of the nanotubes based on transmission electron microscope images, and the growth mechanism, which is thought to be completely different to that active in the production of vapor-grown carbon fibers or metal catalyzed nanotubes, is discussed.

    6. Novel access to polyboro- and polyalumosilazanes suitable as precursors for ternary nitride ceramics (pages 289–292)

      Josua Löffelholz and Prof. Martin Jansen

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070309

      Polymeric precursors for high-performance niride ceramics have been attracting increasing attention as they offer access to fine-grained materials with excellent homogeneity. A new method for the synthesis of polymeric precursors to Si/B/N and Si/Al/N ceramics which starts from easily available compounds and avoids the need for oligomeric intermediates is reported. The compositions of the ceramic powders as well as the properties of the polymers can be tailored on a molecular scale.

    7. On the conjugation length in poly(para-phenylene)-type polymers (pages 292–295)

      Julian Grimme, Martin Kreyenschmidt, Frank Uckert, Prof. Klaus Müllen and Dr. Ullrich Scherf

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070310

      The study of well-defined, monodisperse model PPP oligomers (e.g. see Figure) has revealed that, contrary to expectations, the planarization of the π system in these oligomers leads to a decrease in the effective conjugation length. This result has profound influence on the design of conducting organic materials.

    8. Nature of the optical transitions in charged oligothiophenes (pages 295–297)

      Jérôme Cornil and Prof. Jean-Luc Brédas

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070311

      The charge transport and storage mechanisms in π-doped oligothiophenes can be better understood through a more profound knowledge of their optical excitations. These materials have been investigated using a quantum-chemical approach, results which can also be applied to the interpretation of the experimental data reported for other conjugated oligomers based on the pyrrole, phenylene and phenylenevinylene systems.

    9. Promising new precursors for the CVD of gold (pages 297–300)

      Frank Jansen and Prof. Thomas Kruck

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070312

      High deposition rates for the CVD of gold at low temperatures are reported. The synthesis and use of methyl(alkyldimethoxyphosphine)gold(I) compounds in the chemical vapor deposition of gold (see Figure) is described, and the precursors are found to be easily handled in air, and to result in comparable deposition rates and higher yields compared to currently used materials.

    10. Anisotropic network stabilized ferroelectric gels (pages 300–304)

      Dr. Rifat A. M. Hikmet and Marion Michielsen

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070313

      Displays based on ferroelectric gels offer the possibility to, for example, suppress helical rotation and to improve the shock resistance of thin cells, two important disadvantages of bulk ferroelectric materials. Anisotropic gels of ferroelectric molecules have been produced by in-situ polymerization of reactive LCs in the presence of non-reactive ferroelectric LCs. Their synthesis, characterization, and use in displays is discussed.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Excited-state complexes of conjugated polymers (pages 309–311)

      Prof. Samson A. Jenekhe

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070314

      Excited-state charge-transfer complexes (exciplexes) of conducting polymers can be formed by the absorption of light by the polymers (e.g. see Figure), and their generation is not restricted by the free-energy requirements of their ground-sate analos. This makes them of particular interest for applications ranging from xerographic photoconductors to nonlinear optics and LEDs.

    2. Transition metal oxide films (pages 312–315)

      Dr. Naofumi Uekawa and Prof. Katsumi Kaneko

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070315

      The sol-gel method can be used to produce multicomponent oxide materials which have a homogeneous composition even at the atomic level. Thin transition metal oxide films are shown to exhibit different properties from those of the bulk materials and both the crystal structure and the valence state of the materials can be sensitively controlled by doping. Recent progress in the field is reviewed, including the production of highly oriented films, valence-controlled oxides, the control of instable phase formation and atmosphere-sensitive structural transformations.

    3. Microengineered conducting composites from nanochannel templates (pages 316–318)

      Dr. Carmen Huber, Dr. Mostafa Sadoqi, Prof. Tito Huber and Daborah Chacko

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070316

      Novel nanostructures of conducting materials (e.g. see Figure) generated by the template approach are becoming available through a variety os syntheses, processes, and hosts. Here, a class of electronic composites prepared by the injection of the conducting melt into nanochannel templates is described. The injection process, and the analysis and potential uses of the composite microstructures are discussed.

    4. Optical information processing using alkali-metal vapors (pages 319–322)

      Dr. Bing Ai and Dr. Randall J. Knize

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070317

      Nonlinear optical materials include inorganic single crystals, doped glasses, liquid crystals compound semiconductors and organic dyes. Here, an unusual type of NLP materials, with a very simple structure, alkalimetal vapors, are discussed. The vapors have been found to be among the best nonlinear optical materials for information processing in terms of several figures of merit. The “materials” and their applications are reviewed.

    5. Electrochemistry using plasma (pages 323–325)

      Prof. Zempachi Ogumi, Dr. Yoshiharu Uchimoto and Zen-ichiro Takehara

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19950070318

      A glow-discharge plasma, because of the presence of ions and electrons and because of its potentially high conductivity, can be seen as a conductive fluid which could be used in an electrochemical system. Electrochemistry using such a plasma (see Figure) has bee demonstrated and here its basis and applications, for example in thin film deposition, are discussed.

  6. Book Reviews

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

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