Advanced Materials

Cover image for Advanced Materials

May 1994

Volume 6, Issue 5

Pages fmi–fmi, 343–422

  1. Masthead

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

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060501

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Book Reviews
    1. Basic research in a Japanese electronics corporation (pages 343–345)

      Dr. Shojiro Asai

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060502

      The Advanced Research Laboratory of Hitachi Ltd. was set up in 1985 to conduct basic research—as part of the corporate research and development program—in purpose-built facilities away from the rest of the company. The philosophy bhind the decision to create such a laboratory with its own budget and administrative system is outlined, and the interests and recent achievements of research groups there are briefly surveyed.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Book Reviews
    1. Shock Compression Synthesis of Diamond (pages 346–354)

      Prof. Akira B. Sawaoka, Masanobu Takamatsu and Dr. Tamotsu Akashi

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060503

      Easily obtainable polycrystalline diamond would have many additional applications in industry. Of the synthesis techniques currently in use, shock compression is one of the most promising, crack formation being its major problem. The production of compacts from diamond powders (see Figure) is described and a technique introduced in which the exothermic chemical reaction of additives is used to control the temperature distribution in a compact and thus avoid cracks.

    2. Interpreting STM and AFM Images (pages 355–371)

      Dr. Sergei N. Magonov and Prof. Myung-Hwan Whangbo

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060504

      A rational way of interpreting STM and AFM images is beginning to be developed. Using the examples of rayered transition-metal chalcogenides and halides, organic conducting salts, and alkanes on graphite, it is demonstrated that the STM image of a surface can be simulated by the surface electron density associated with the energy levels near the Fermi level evaluated at the tip-to-surface distance r0 and that the AFM image corresponds to the total electron density ρ(r0). Experimental problems of reproducibility are discussed.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Book Reviews
    1. Photochemical synthesis of polyacrylate–silica hybrid sol–gel materials catalyzed by photoacids (pages 372–374)

      Dr. Yen Wei, Dr. Wei Wang, Jui-Ming Yeh, Bin Wang, Dr. Dachuan Yang and James K. Murray Jr.

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060505

      Photochemical synthesis of hybrid sol–gel materials is demonstrated for the first time. Photoacid-catalyzed sol–gel reactions of tetraethyl orthosilicate with polymer precursors under ultraviolet radiation produce poly-acrylate-silica materials (shown schematically in the Figure). The effect of the concentrations of the photoacids and polymer precursors and the intensity of the radiation is discussed.

    2. Reaction of alkali metal intercalated C60 with oxygen: Deintercalation, activation, and decomposition (pages 374–376)

      G. Jeffrey Snyder and Prof. Arndt Simon

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060506

      The air sensitivity of C60 intercalated with an alkali metal has been known for some years. It is shown here that for K6C6, and Rb6C60 the route by which the deintercalation occurs involves–rather unexpectedly–the formation of the alkali metal carbonates, not the oxides. This observation is used to explain why impurity oxygen does not exist in alkali-metal-intercalated C60 although it is extremely difficult to remove oxygen from non-intercalated C60.

    3. Recrystallization of electrodeposited copper indium diselenide thin films in an atmosphere of elemental selenium (pages 376–379)

      Dr. Jean François Guillemoles, Dr. Alain Lusson, Pierre Cowache, Sylvie Massaccesi, Dr. Jacques Vedel and Dr. Daniel Lincot

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060507

      One use of copper indium dis- elenide (CIS) is in photovoltaic devices. Low-cost films produced by one-step electrodeposition could replace the co-evaporated films used currently if their quality could be improved. It is shown that annealing such CIS films in a selenium atmosphere dramatically improves both their structural properties, as illustrated by the scanning electron micrograph. and electronic properties.

    4. Solar cells with improved efficiency based on electrodeposited copper indium diselenide thin films (pages 379–381)

      Dr. Jean François Guillemoles, Pierre Cowache, Sylvie Massaccesi, Dr. Laurent Thouin, Dr. Sylvie Sanchez, Dr. Daniel Lincot and Dr. Jacques Vedel

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060508

      Solar cells based on CuInSe2 (CIS) thin films prepared as described in the previous contribution have been prepared and characterized. The light and dark current–voltage curves and spectral responses are presented, showing that annealing in a selenium atmosphere makes it possible to fabricate ZnO/CdS/CIS solar cells with improved efficiencies. CIS is of particular interest because its optical properties are well matched to the solar spectrum.

    5. Paramagnetic liquid crystalline nickel(II) compounds (pages 381–384)

      Klaus Griesar, Dr. Yuri Galyametdinov, Maria Athanassopoulou, Prof. Igor Ovchinnikov and Prof. Wolfgang Haase

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060509

      Metallomesogens containing paramagnetic transition metal ions are of interest because the orientation of these mesophases can be controlled by a magnetic field. The first paramagnetic Ni-containing liquid crystals (related to the non-mesogenic compound shown in the Figure) are reported. Their complicated temperature-dependent magnetic behavior is discussed and shown to reflect changes in the coordination core of nickel.

    6. π-Electron delocalization in conformationally distorted oligopyrroles and ploypyrrole (pages 385–388)

      Prof. Giuseppe Zerbi, Dr. Maurizio Veronelli, Dr. Stefano Martina, Prof. Arnulf-Dieter Schlüter and Prof. Gerhard Wegner

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060510

      Effective conjugation coordinate (ECC) theory has previously been used to interpret the Raman spectra of oligopyrroles and polypyrrole, providing information on conjugation and delocalization. However, the materials used in real applications have long alkaline side chains (to aid solubility), which leads to conformational distortion. ECC theory is now applied to “pro-tected” molecules, showing that a quantitative estimate of the extent of localization in conformationally distorted polypyrrole can be obtained from their Raman spectra.

    7. The use of CVD diamond thin films in electrochemical systems (pages 388–392)

      Prof. Greg M. Swain

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060511

      The electrochemical characterization of diamond is just beginning. The study reported here deals with the growth by energy-assisted CVD of impurity-doped diamond electrodes (see Figure) sufficiently conductive for electrochemical measurements. The electrochemical activity of the electrodes towards various analytes, their capacitance and flat-band potentials in several electrolytes, and their photocurrent response are discussed.

    8. Plasma enhanced chemical vapor deposition of vanadium carbide VC1−x and VOx from vanadocene Cp2V (pages 392–395)

      Dr. Lutz Deutschmann, Dr. Johannes Messelhäuser, Prof. Harald Suhr, Prof. Wolfgang A. Herrmann and Dr. Peter Härter

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060512

      Plasma enhanced CVD of vanadium carbides and oxides is reported for the first time. Vanadium carbide and vanadium oxides are of technological interest for hard coatings (VC1–x), storage media (VO2), and smart electrochromic windows (V2O5), and until now have been prepared mainly by physical deposition methods. The advantages of the precursor vanadocene are outlined and the influence of experimental parameters such as the hydrogen flow rate and the substrate temperature on the composition and resistivity of the films described.

    9. Microfibrillar reinforced composites—new materials from polymer blends (pages 395–398)

      Stoyko Fakirov and Dr. Michail Evstatiev

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060513

      Microfibrillar-reinforced composites (MFCs) are a fundamentally new type of polymer composites. MFCs are prepared by a novel technique comprising drawing a polymer blend, which leads to fibrillization (orientation of both components), followed by melting of one component while preserving the oriented structure of the higher melting point component (see Figure), This method is explained in detail by means of an example, and the mechanical parameters of an MFC are presented.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Book Reviews
    1. Scanning Probe microscopy and magnetic resonance (pages 401–404)

      Dr. Yishay Manassen

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060514

      Adaptations of scanning probe microscopy techniques can be used in conjunction with electron spin resonance for surfaces containing isolated paramagnetic spin centers. Scanning the tip over such a surface in the presence of a magnetic field produces reproducible. spatially localized signals. Possible mechanisms explaining this behavior are discussed. The detection of magnetic resonance by atomic force microscopy is also considered. including problems that have had to be overcome and experimental details.

    2. Spiroconjugation: An added dimensi in the design of organic molecular materials (pages 405–407)

      Dr. Przemyslaw Maslak

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060515

      Molecules with predictable electrical, optical, and magnetic properties are required for molecular devices and new materials. One approach to overcoming the disadvantages associated with the quasi-one-dimensional π-conjugated acceptors and donors that have played a big part so far is to use spiroconjugated molecules that are conjugated but not planar. The concepts behind acceptors such as that shown in the Figure are explained.

    3. Rocking-chair or lithium-ion rechargeable lithium batteries (pages 408–412)

      Dr. Dominique Guyomard and Dr. Jean-Marie Tarascon

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060516

      Recent advances in Li-ion rechargeable batteries have left them in a strong position compared to conventional cells: they are environmentally safe, have higher energy densities, and exhibit a good rate capability. Electrochemical aspects of the Li-ion system are briefly reviewed and innovations such as electrolytes that are stable with respect to oxidation, Li-based oxides with a Li reservoir, and carbon-based electrodes with enhanced capacity are discussed. Finally, remaining problems and possible research avenues are summarized.

    4. Chromophore–zeolite composites: The organizing role of molecular sieves (pages 413–416)

      Dr. JÜRgen Caro, Dr. Frank Marlow and Dr. Michael Wübbenhorst

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060517

      Dyes incorporated in molecular sieve crystals can reveal information about the orientation of guests in these crystals through polarization microscopy (see Figure), Raman scattering, and second-harmonic generation measurements. Pyroelectric studies of the dye molecule para-nitro-aniline inserted in the molecular sieve A1P04-5 are described that show which of two rival models explaining the ordering of guests in molecular sieves actually holds.

    5. Surface-activated photopolymer microgels (pages 417–421)

      Dr. Nobumasa Sasa and Prof. Tsuguo Yamaoka

      Article first published online: 15 SEP 2004 | DOI: 10.1002/adma.19940060518

      Enhancement of the sensitivity of photopolymers is needed if photopolymers are to find more extensive applications in the printing and microlithography industries. A new concept is presented for sensitivity enhancement: the use of surface-activated microgels as a heterogeneous polymer matrix. The preparation of the microgels and their effect on the polymerization rate and the sensitivity are described. Examples are given of applications of microgel-based photopolymers as offset printing plates and photographic film.

  6. Book Reviews

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

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