Advanced Functional Materials

Cover image for Vol. 11 Issue 6

December, 2001

Volume 11, Issue 6

Pages 403–474

    1. Contents (pages 403–405)

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<403::AID-ADFM403>3.0.CO;2-G

    2. Emeraldine Base Polyaniline as an Alternative to Poly(3,4-ethylenedioxythiophene) as a Hole-Transporting Layer (pages 407–412)

      R. W. T. Higgins, N. A. Zaidi and A. P. Monkman

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<407::AID-ADFM407>3.0.CO;2-0

      The performance of emeraldine base polyaniline (see Figure) as a hole transporting layer in bilayer polymer light-emitting polymers is investigated and compared to the performance of commercially available polystyrene sulfonated acid doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS). The effect of the counterion is examined and one emeraldine/counterion combination is found to be superior to PEDOT:PSS.

    3. A Tetrahedral Oligo(phenylenevinylene) Molecule of Intermediate Dimensions: Effect of Molecular Shape on the Morphology and Electroluminescence of Organic Glasses (pages 413–419)

      M. R. Robinson, S. Wang, A. J. Heeger and G. C. Bazan

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<413::AID-ADFM413>3.0.CO;2-C

      Fabrication of LEDs by casting molecules of intermediate dimension directly from solution (see Figure for the fluorescence of a film) is demonstrated here. Organic chromophores that consists of four optoelectronic fragments (“arms”) connected to a tetrahedral point of convergence (carbon) have been used to obtain thin films and their morphology, topology, and PL properties are compared with those of the parent oligo-(phenylenevinylene) arms (see also cover).

    4. Solvation-Induced Morphology Effects on the Performance of Polymer-Based Photovoltaic Devices (pages 420–424)

      J. Liu, Y. Shi and Y. Yang

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<420::AID-ADFM420>3.0.CO;2-K

      Solvent-type dependent performance of photovoltaic donor/acceptor devices is reported by the authors. Composites of the semiconducting polymer MEH-PPV with C60 exhibit smaller photocurrents and greater open-circuit voltages if the device contains non-aromatic solvents (THF, CHCl3) rather than aromatics (xylene, chlorobenzene), the changing morphology of the composite being the key influence (see Figure for xylene vs. THF).

    5. Organic–Inorganic Hybrid Nanocomposites Prepared by Means of Sol–Gel Condensation of Bismethacrylatesilanes in Reactive Diluents (pages 425–429)

      E. Müh, H. Frey, J. E. Klee and R. Mülhaupt

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<425::AID-ADFM425>3.0.CO;2-0

      Stable methacrylate-functional nanoparticle dispersions (see Figure), with average nanoparticle diameter of 3–4 nm, have been fabricated by sol–gel synthesis. The nanoparticle dispersions can be employed as matrix for the preparation of photocurable acrylic nanocomposites. The mechanical properties, such as compressive and flexural strength, as well as Young’s moduli, have been determined.

    6. Pure-Red Dye for Organic Electroluminescent Devices: Bis-Condensed DCM Derivatives (pages 430–434)

      B.-J. Jung, C.-B. Yoon, H.-K. Shim, L.-M. Do and T. Zyung

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<430::AID-ADFM430>3.0.CO;2-G

      The synthesis and properties of high-quality red dyes for use in organic light-emitting diodes (OLEDs) are described. The dyes are formed by 1:2 condensation of 2,6-dimethyl-4-dicyanomethylene-4H-pyran with para-donor (mostly NR2) substituted benzaldehydes (see Figure), rather than 1:1 condensation as for conventional DCM. Devices doped with the bis-condensed DCM derivatives show good luminance and outstanding color purity.

    7. Optical Properties of Quasi One-Dimensional Chains of Gold Nanoparticles (pages 435–440)

      T. Sawitowski, Y. Miquel, A. Heilmann and G. Schmid

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<435::AID-ADFM435>3.0.CO;2-X

      Gold nanoparticles in quasi one-dimensional arrangement (see Figure) are formed when nanopores in alumina serve as reaction vessels for the thermal decomposition of the cluster [Au55(PPh3)12Cl6]. The size of the colloids (4–5 nm) grows to 10–11 nm at decomposition temperatures above 500 °C. Optical properties under normal and polarized light, the anisotropicity of which reflects the wire-like structure, are discussed in detail.

    8. Novel Columnar Tetraphenylethenes via McMurry Coupling (pages 441–446)

      A. Schultz, S. Diele, S. Laschat and M. Nimtz

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<441::AID-ADFM441>3.0.CO;2-8

      Even molecules devoid of a flat core region are able to form columnar mesophases. Here the viability of developing tetraphenylethenes displaying liquid crystallinity is examined. It is revealed that, despite the propeller shape of the tetraphenylethene core, peripheral gallic acid groups provide sufficient stabilization for hexagonal columnar mesophases to form (see Figure for possible arrangement).

    9. Sequential Hydroboration–Alcoholysis and Epoxidation–Ring Opening Reactions of Vinyl Groups in Mesoporous Vinylsilica (pages 447–456)

      T. Asefa, M. Kruk, M. J. MacLachlan, N. Coombs, H. Grondey, M. Jaroniec and G. A. Ozin

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<447::AID-ADFM447>3.0.CO;2-L

      Chemical transformations within the channels of vinyl-functionalized mesoporous silica are described by the authors that allow introduction of the desired functionality into the host. Terminally bonded vinyl groups attached to the silica channel wall of mesoporous vinylsilica can be transformed into alcohol groups through hydroboration followed by alcoholysis or diol groups through epoxidation followed by hydrolysis. These hybrid materials may be useful in catalysis and chiral separations, microelectronics packaging, and chemical sensing.

    10. Switchable Gratings from Polymerized Nematic Emulsions (pages 457–460)

      G. De Filpo, F. P. Nicoletta, M. Macchione, D. Cupelli and G. Chidichimo

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<457::AID-ADFM457>3.0.CO;2-H

      Electrically switchable gratings have been built from nematic emulsion films via an easy two-step photopolymerization. In the first step the substrate is partially covered by a photomask, affording an array of liquid crystal (LC) droplets within a polymer matrix (see Figure). Nematic emulsions allow control of the reaction by varying the temperature and monomer/LC ratio, and yield low-price devices controllable by weak electric fields.

    11. Binary and Ternary Polymer-Mediated “Bricks and Mortar” Self-Assembly of Gold and Silica Nanoparticles (pages 461–465)

      A. K. Boal, T. H. Galow, F. Ilhan and V. M. Rotello

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<461::AID-ADFM461>3.0.CO;2-0

      Extended aggregates of carboxylic acid functionalized gold and silica nanoparticles can be synthesized using an amine-functionalized polymer as backbone component. The versatile three-component process uses stoichiometry and order of addition to determine morphology and Au vs. Si particle distribution; see Figure for a TEM image and also inside front cover. The novel composites are suitable as stability-enhanced, easily processable catalysts.

    12. Author Index (pages 467–468)

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<467::AID-ADFM467>3.0.CO;2-D

    13. Subject Index (pages 469–474)

      Version of Record online: 6 DEC 2001 | DOI: 10.1002/1616-3028(200112)11:6<469::AID-ADFM469>3.0.CO;2-5