Advanced Materials

Cover image for Vol. 14 Issue 4

February, 2002

Volume 14, Issue 4

Pages 255–326

    1. Contents (pages 255–259)

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<255::AID-ADMA255>3.0.CO;2-Q

    2. You have free access to this content
    3. You have free access to this content
      Online Manuscript Submission (page 263)

      P. Gregory

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<263::AID-ADMA263>3.0.CO;2-U

      Online submission of manuscripts via the Advanced Materials home page is now possible. How the system work, its advantages over conventional postal submission, and the simple steps involved in submitting a manuscript online are described. It is anticipated that this new submission process will be adopted very quickly.

    4. Novel Electrodes from Solution-Processed Layer-Structure Materials (pages 265–268)

      G.L. Frey, K.J. Reynolds and R.H. Friend

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<265::AID-ADMA265>3.0.CO;2-M

      Thin-film semiconducting devices containing inorganic as well as organic layers have been fabricated via solution processing (see Figure). Using high work function transition metal dichalcogenides (TMDCs) it is possible to reduce the barrier to hole injection into the polymer. A blocking barrier layer can be introduced through simple oxidation of the TMDC, which prevents electron extraction from the device and enhances hole injection.

    5. Fabrication of Patterned LiCoO2 Films Deposited on the Membrane Surface of a Paper-like Substrate (pages 268–271)

      S.-W. Song, H. Fujita and M. Yoshimura

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<268::AID-ADMA268>3.0.CO;2-A

      The deposition of LiCoO2 films on a flexible paper-like Teflon substrate has been demonstrated. Two variations of a single-step solution process are reported, the first by electrochemical/hydrothermal, and the second by hydrothermal only, dissolution of Co metal in LiOH and deposition on the Teflon membrane. The Figure show a laser microscopy image of the patterned LiCoO2 membrane film.

    6. Multi-Photon Polymerization of Waveguide Structures Within Three-Dimensional Photonic Crystals (pages 271–274)

      W. Lee, S.A. Pruzinsky and P.V. Braun

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<271::AID-ADMA271>3.0.CO;2-Y

      Photonic crystals with line and point defects are desirable for application as photonic bandgap waveguides and optical cavities, respectively. Here such defects have been introduced into photonic crystals using a laser scanning confocal microscope. High-resolution 3D patterns are created inside the colloidal crystals (see Figure) via multi-photon polymerization.

    7. Asymmetric Block Copolymers with Homopolymers: Routes to Multiple Length Scale Nanostructures (pages 274–276)

      U. Jeong, H.-C. Kim, R.L. Rodriguez, I.Y. Tsai, C.M. Stafford, J.K. Kim, C.J. Hawker and T.P. Russell

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<274::AID-ADMA274>3.0.CO;2-M

      Thin polymer films with cylindrical microdomains of controlled size (see Figure for an AFM image) have been produced from diblock copolymer/homopolymer mixtures. It is demonstrated that not only do the spatial order and orientation of the domains remain unperturbed but also that two distinct sizes of pores can be accessed from the same film.

    8. Selective Growth of Carbon Nanotubes on Pre-patterned Porous Anodic Aluminum Oxide (pages 277–279)

      E.J. Bae, W.B. Choi, K.S. Jeong, J.U. Chu, G.-S. Park, S. Song and I.K. Yoo

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<277::AID-ADMA277>3.0.CO;2-A

      Highly ordered, vertical carbon nanotubes (CNTs) (see Figure) have been grown on a pre-patterned, porous anodic aluminum oxide (AAO) template using a lithographic patterning method and thermal chemical vapor deposition. The AAO template itself plays a catalytic role in CNT growth and the crystallinity of the CNTs is strongly influenced by the presence of cobalt particles at the bottom of the template pores.

    9. Formation of Tellurium Nanotubes Through Concentration Depletion at the Surfaces of Seeds (pages 279–282)

      B. Mayers and Y. Xia

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<279::AID-ADMA279>3.0.CO;2-2

      Tellurium nanotubes with well-controlled structures (see Figure) are obtained via concentration depletion at the surfaces of seeds. The lengths of these inorganic nanotubes can be varied by adjusting the growth time (see cover), and the outer diameters of the tubes can be controlled by changing the initial concentration of the precursor acid.

    10. Synthesis and Electronic Properties of Adducts of Oligothienylenevinylenes and Fullerene C60 (pages 283–287)

      C. Martineau, P. Blanchard, D. Rondeau, J. Delaunay and J. Roncali

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<283::AID-ADMA283>3.0.CO;2-M

      Adducts of oligothienylenevinylenes with fullerene C60 (see Figure) have been synthesized. Their preparation along with some of their electrochemical and optical properties are reported. Owing to the small HOMO–LUMO gap of oligothienylenevinylenes, these compounds are potentially interesting for light harvesting in organic photovoltaic devices.

    11. Colloidal Crystals of Monodisperse FePt Nanoparticles Grown by a Three-Layer Technique of Controlled Oversaturation (pages 287–290)

      E. Shevchenko, D. Talapin, A. Kornowski, F. Wiekhorst, J. Kötzler, M. Haase, A. Rogach and H. Weller

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<287::AID-ADMA287>3.0.CO;2-6

      Colloidal crystals of FePt nanocrystals have been produced by a three-layer oversaturation technique. Faceted triangular and hexagonal platelets, pyramids, and tetrahedrons have been obtained (see Figure), consisting of individual monodisperse FePt nanocrystals aligned in a 3D superlattice. Transition from superparamagnetic to ferromagnetic behavior is observed at 14 K.

    12. Hollow Sphere Selenium Nanoparticles: Their In-Vitro Anti Hydroxyl Radical Effect (pages 290–293)

      X. Gao, J. Zhang and L. Zhang

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<290::AID-ADMA290>3.0.CO;2-U

      Hollow sphere selenium nanoparticles have been produced by an in-situ template-interface reaction. The intriguing anti-hydroxyl radical property of the particles is demonstrated and the important role the surface area plays in this behavior is discussed. The Figure shows the scheme for preparing the nanoparticles.

    13. Dipole Dynamics in the Endohedral Metallofullerene La@C82 (pages 293–296)

      C.J. Nuttall, Y. Hayashi, K. Yamazaki, T. Mitani and Y. Iwasa

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<293::AID-ADMA293>3.0.CO;2-I

      The dielectric activity of endohedral fullerene solids has been investigated. The complicated temperature dependence of the dielectric properties of La@C82 is probed, and information on the dipole dynamics within the molecular solid is gained. The Figure shows the structure of the metallofullerene.

    14. Shape and Phase Control of ZnS Nanocrystals: Template Fabrication of Wurtzite ZnS Single-Crystal Nanosheets and ZnO Flake-like Dendrites from a Lamellar Molecular Precursor ZnS·(NH2CH2CH2NH2)0.5 (pages 296–300)

      S.-H. Yu and M. Yoshimura

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<296::AID-ADMA296>3.0.CO;2-6

      Unusual two-dimensional ZnS nanosheets with micrometer scale lateral dimensions and flake-like ZnO dendrites (see Figure) can be rapidly generated with high yield (>96 %) by using a simple template method. The molecular precursor ZnS·(NH2CH2CH2NH2)0.5, which shows a strong ultraviolet emission band centered at 380 nm at room temperature, lies at the basis of this method.

    15. Biomimetic Morphogenesis of Calcium Carbonate in Mixed Solutions of Surfactants and Double-Hydrophilic Block Copolymers (pages 300–303)

      L. Qi, J. Li and J. Ma

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<300::AID-ADMA300>3.0.CO;2-P

      The morphology of calcium carbonate can be tuned by using aqueous double-hydrophilic block copolymer (DHBC)–surfactant mixtures in a chemical synthesis. Calcite hollow spheres (see Figure) and vaterite discs were obtained at different concentrations of sodium dodecylsulfate (SDS) in a DHBC–SDS system. In contrast, pine-cone shaped particles were obtained by using a DHBC–cetyltrimethylammonium bromide (CTAB) system.

    16. Regular Alumina Nanopillar Arrays (pages 303–306)

      Z.H. Yuan, H. Huang and S.S. Fan

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<303::AID-ADMA303>3.0.CO;2-D

      Arrays of alumina nanopillars with adjustable dimensions (see Figure for a representative example) are fabricated by simple chemical etching of porous anodic alumina with dilute NaOH. The diameter and height of the pillars, as well as interpillar spacing, are a function of the oxide layer thickness, which is controlled by anodizing time and voltage.

    17. Mirrorless Lasing in a Dye-Doped Ferroelectric Liquid Crystal (pages 306–309)

      M. Ozaki, M. Kasano, D. Ganzke, W. Haase and K. Yoshino

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<306::AID-ADMA306>3.0.CO;2-1

      Laser action in a dye-doped ferroelectric liquid crystal (FLC)—at the edge of the photonic stop band—has been demonstrated for the first time. The FLC used is a multicomponent mixture with a well-controlled short pitch of its helical structure whose periodic is equivalent to visible optical wavelengths. The laser emission is optically pumped and can be tuned by changing the temperature, which alters the periodicity of the helical structure. FLCs are expected to find electrooptic applications because of their fast response to an electric field.

    18. Rare Earth (Er, Tm, Yb, Lu) Oxide Nanotubes Templated by Dodecylsulfate Assemblies (pages 309–313)

      M. Yada, M. Mihara, S. Mouri, M. Kuroki and T. Kijima

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<309::AID-ADMA309>3.0.CO;2-Q

      Rare earth oxide nanotubes (see Figure) templated by dodecylsulfate assemblies have been fabricated for the first time by the homogeneous precipitation method using urea. Conversion into hollow nanotubes with an inner diameter of 3 nm and outer diameter of 6 nm can then be effected by anion exchange treatment to remove the surfactant.

    19. Monolithic Photorefractive Organic Glasses with Large Coupling Gain and Strong Beam Fanning (pages 313–317)

      U. Gubler, M. He, D. Wright, Y. Roh, R. Twieg and W.E. Moerner

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<313::AID-ADMA313>3.0.CO;2-9

      A monolithic photorefractive organic glass with large gain coefficients at low electric fields is presented. The molecule DCDHF-6 (see Figure) acts simultaneously as charge transport material and nonlinear optical chromophore. Strong beam fanning is observed with suppression of the initial beam to 25 % of its initial value in samples only 100 μm thick.

    20. Lasing from Semiconductor Quantum Rods in a Cylindrical Microcavity (pages 317–321)

      M. Kazes, D.Y. Lewis, Y. Ebenstein, T. Mokari and U. Banin

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<317::AID-ADMA317>3.0.CO;2-U

      Lasers based on colloidal semiconductor nanostructures can benefit from the remarkable spectral coverage afforded through the quantum confinement effect. The first observation of lasing for colloidal CdSe/ZnS quantum rods in solution using a cylindrical microcavity is reported here (see also inside front cover). Lasing in the same configuration was also observed for spherical nanocrystal quantum dots. For the quantum dots lasing is not polarized, but in quantum rods the laser emission is highly linearly polarized, a desirable feature for laser and photonic applications.

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      Self-Assembled Monolayer Transistors (pages 323–326)

      J.H. Schön, H. Meng and Z. Bao

      Version of Record online: 19 FEB 2002 | DOI: 10.1002/1521-4095(20020219)14:4<323::AID-ADMA323>3.0.CO;2-5

      Field-effect transistors based on self-assembled monolayers (SAMs) of organic, conjugated molecules are presented (see Figure). It is demonstrated that the length of the molecule defines critical device dimensions such as the channel length, eliminating the need to use lithography. Molecular heterostructures can also be fabricated using SAMs, from which more complex molecular devices can be developed.