Advanced Functional Materials

Cover image for Vol. 13 Issue 7

July, 2003

Volume 13, Issue 7

Pages 507–582

    1. Inorganic Luminescent Materials: 100 Years of Research and Application (pages 511–516)

      C. Feldmann, T. Jüstel, C.R. Ronda and P.J. Schmidt

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200301005

      Up until approximately 80 years ago, only black-body radiation (including natural sources) was available to illuminate our environment. To realise state-of-the-art lamps, TV sets, monitors, and medical scanners took an enormous scientific and technical effort. Inorganic luminescent materials are key components, which were, are, and will be prerequisite to the functionality and success of many lighting and display systems.

    2. Single-Mode Microwave Synthesis in Organic Materials Chemistry (pages 517–518)

      S. Barlow and S.R. Marder

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200301006

      Some applications of microwave synthesis in organic materials chemistry are highlighted in this contribution, including applications to Knoevanagel reactions used in the synthesis of donor-π-acceptor NLO chromophores, and to Ni0-mediated coupling reactions in the synthesis of poly(fluorene)s.

    3. Discovery and Optimization of New ZnO-Based Phosphors Using a Combinatorial Method (pages 519–524)

      V.Z. Mordkovich, H. Hayashi, M. Haemori, T. Fukumura and M. Kawasaki

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304335

      The results of systematic combinatorial exploration of different binary and ternary ZnO:dopant systems are presented. Bright luminescence in ZnO:(Y,Eu), ZnO:V, ZnO:W, and ZnO:(W,Mg) systems is detected. Careful “zooming in” allows one to find optimum phosphor compositions. The efficiency of the new phosphors is high and shows promise for their prospective use in flat panel display and lighting applications.

    4. Nematic Anisotropic Liquid-Crystal Gels—Self-Assembled Nanocomposites with High Electromechanical Response (pages 525–529)

      C. Huang, Q.M. Zhang and A. Jákli

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304322

      Artificial muscles and microelectromechanical devices could be developed using the homeotropically aligned liquid-crystal gel system reported in this contribution. It is shown that this system in its nematic phase exhibits high electrically induced strain (> 2 %) with an elastic modulus of 100 MPa and a high electromechanical conversion efficiency (75 %) under an electric field of 25 MV/m, caused by a field-induced mesogenic unit reorientation.

    5. Liquid-Crystalline Phase Behavior in a Zwitterionic Tetraazapentacene (pages 531–540)

      A.E. Riley, G.W. Mitchell, P.A. Koutentis, M. Bendikov, P. Kaszynki, F. Wudl and S.H. Tolbert

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304223

      The thermal phase behavior of a 5,7-dioctadecylquinoxalinophenazine zwitterion has been investigated using a variety of techniques. The molecule was designed to include a combination of flexible alkane moieties and a rigid ring system with significant charge separation, to enable a liquid-crystal phase at elevated temperatures. The large dipole combined with liquid-crystal phase behavior makes this material ideal for optoelectronic applications.

    6. Perfluoroalkanoate-Substituted PEDOT for Electrochromic Device Applications (pages 541–547)

      I. Schwendeman, C.L. Gaupp, J.M. Hancock, L. Groenendaal and J.R. Reynolds

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304372

      The first highly fluorinated derivative of poly(3,4-ethylenedioxythiophene) (PEDOT) (see structure, right) is reported as a high contrast electrochromic material, which is highly hydrophobic. Electrochemically prepared films are highly conducting (65 S cm–1), have colorimetrically determined luminance changes of 60 %, exhibit a contact angle of 110°, and show promise as electrochromic device components.

    7. Fabrication and Characterization of Stable Ultrathin Film Micropatterns Containing CdS Nanoparticles (pages 548–552)

      C.H. Lu, N.Z. Wu, F. Wei, X.S. Zhao, X.M. Jiao, J. Xu, C.Q. Luo and W.X. Cao

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304341

      Covalently linked micropatterns are constructed by layer-by-layer electrostatic self-assembly of photoreactive nitro-diazoresin (NDR) and mercaptoacetic acid-capped CdS nanoparticles, followed by selective exposure to UV light through a photomask and subsequent development by sodium dodecyl sulfate aqueous solution. The Figure shows an AFM image of the micropatterned multilayer film.

    8. Synthesis of Indium and Indium Oxide Nanoparticles from Indium Cyclopentadienyl Precursor and Their Application for Gas Sensing (pages 553–557)

      K. Soulantica, L. Erades, M. Sauvan, F. Senocq, A. Maisonnat and B. Chaudret

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304291

      From molecular organometallic to semiconducting nanomaterial: Crystallized In nanoparticles of 15 nm mean diameter quickly result from the reaction of a toluene solution of [In(η5-C5H5)] with methanol at room temperature. Their oxidation yields In2O3 nanoparticles with unchanged morphology and without any sign of coalescence. Used as sensitive layer in a microsensor, these particles are highly sensitive to the presence of sub-ppm amounts of NO2, whereas they exhibit a poor sensitivity to CO.

    9. The Fabrication and Characterization of Carbon Aerogels by Gelation and Supercritical Drying in Isopropanol (pages 558–562)

      R. Fu, B. Zheng, J. Liu, M.S. Dresselhaus, G. Dresselhaus, J.H. Satcher Jr. and T.F. Baumann

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304289

      A new method is reported for the fabrication of carbon aerogels based on direct drying using supercritical isopropanol, followed by carbonization under a nitrogen atmosphere. The carbon aerogels produced by this method have physical properties similar to those of carbon aerogels produced by traditional methods, as characterized by nitrogen adsorption/desorption analysis, high-resolution transmission electron microscopy, magnetic susceptibility, and resistivity measurements. The new synthesis method has numerous advantages from both a technical and a cost standpoint.

    10. Conversion of Fly Ash Cenosphere to Hollow Microspheres with Zeolite/Mullite Composite Shells (pages 563–567)

      D.J. Wang, Y.H. Zhang, A.G. Dong, Y. Tang, Y.J. Wang, J.C. Xia and N. Ren

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304312

      Two groups of hollow microspheres with unique bilayered zeolite/mullite shells were prepared via a convenient and environmentally benign seed-induced in-situ hydrothermal conversion of fly ash cenosphere, a solid waste from coal power stations. The final hollow zeolitic spheres should have advantages in applications such as catalysts, sorbents, controlled release capsules, and storage materials.

    11. Micro-Nanostructured Interfaces Fabricated by the Use of Inorganic Block Copolymer Micellar Monolayers as Negative Resist for Electron-Beam Lithography (pages 569–575)

      R. Glass, M. Arnold, J. Blümmel, A. Küller, M. Möller and J.P. Spatz

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304331

      The combination of two different length scales, patterning by self-assembly of block copolymer micelles (< 100 nm) and e-beam writing (> 50 nm), allows the grouping of nanometer-sized gold clusters in very small numbers in even aperiodic patterns, and separation of these groups by length scales that are not accessible by self-assembly alone. The grouping of Au nanoclusters in different geometries such as squares, rings (see Figure), or spheres is therefore possible.

    12. Nanoweb Formation: 2D Self-Assembly of Semiconductor Gallium Oxide Nanowires/Nanotubes (pages 576–581)

      U.M. Graham, S. Sharma, M.K. Sunkara and B.H. Davis

      Version of Record online: 1 JUL 2003 | DOI: 10.1002/adfm.200304391

      2D networks of nanowires and nanotubes of β-Ga2O3, obtained by exposing a gallium droplet covered substrate to hydrogen/oxygen plasma, are reported (see Figure and also cover). Multiple nucleation from the gallium droplets and growth of 1D structures parallel to the substrate yielded the crystalline network after coalescencing together.