Advanced Functional Materials

Cover image for Vol. 13 Issue 3

March, 2003

Volume 13, Issue 3

Pages 179–250

    1. Preparation and Organization of Nanoscale Polyelectrolyte-Coated Gold Nanoparticles (pages 183–188)

      K.S. Mayya, B. Schoeler and F. Caruso

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390028

      Mono- and multilayer polyelectrolyte coatings are formed on gold nanoparticles (< 10 nm diameter) via electrostatic self-assembly. The core–shell nanoparticles can be adsorbed as thin films on substrates, with readily controlled particle density. The versatile strategy presented (see Figure) should be applicable to other nanoparticles, providing a facile means for their controlled surface modification and assembly.

    2. Chemical and Structural Investigations of Biomimetically Grown Fluorapatite–Gelatin Composite Aggregates (pages 189–198)

      S. Busch, U. Schwarz and R. Kniep

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390029

      The fractal morphogenesis of biomimetically grown fluorapatite–gelatin composite aggregates and their chemical and structural properties are reported, providing a deeper insight into the mechanisms of pattern formation and the development of hierarchical structures during the in-vitro biomineralization process. A model is developed describing the organization of the aggregates as a nanocomposite superstructure (see Figure and inside front cover).

    3. Low-k Insulators as the Choice of Dielectrics in Organic Field-Effect Transistors (pages 199–204)

      J. Veres, S.D. Ogier, S.W. Leeming, D.C. Cupertino and S. Mohialdin Khaffaf

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390030

      Gate insulators in organic field-effect transistors (FETs) may influence not just the morphology of the semiconductor, but also the electronic states at the interface. Localized states may be distorted by random interface dipoles and their distribution broadened (see Figure and cover). In this communication it is shown that by using low-k materials as insulators, mobility can be increased and hysteresis reduced, and the underlying physics is discussed.

    4. Near-Infrared Light-Emitting Diodes (LEDs) Based on Poly(phenylene)/Yb-tris(β-Diketonate) Complexes (pages 205–210)

      T.-S. Kang, B.S. Harrison, M. Bouguettaya, T.J. Foley, J.M. Boncella, K.S. Schanze and J.R. Reynolds

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390031

      Near-infrared-emitting polymer light-emitting diodes (PLEDs) based on functionalized poly(p-phenylenes) with Yb3+ complexes show light output at ca. 1000 nm with concomitant quenching of the polymer host’s visible emission. The Figure shows one of the complexes used. A complex using porphyrin-based ligands was shown to have particularly enhanced near-IR output efficiency.

    5. The Effect of Core Delocalization on Intermolecular Interactions in Conjugated Dendrimers (pages 211–218)

      R. Beavington, M.J. Frampton, J.M. Lupton, P.L. Burn and I.D.W. Samuel

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390032

      Core delocalization plays an important role in controlling intermolecular interactions for conjugated dendrimers with chromophores at the core (see Figure). This study of electrochemical, photo-, and electroluminescence measurements of four generations of dendrimers clearly demonstrates that the degree of aggregation is strongly dependent on both the dendrimer generation and the degree of delocalization across the central unit.

    6. Self-Assembled Monolayer Coatings on Nanostencils for the Reduction of Materials Adhesion (pages 219–224)

      M. Kölbel, R.W. Tjerkstra, G. Kim, J. Brugger, C.J.M. van Rijn, W. Nijdam, J. Huskens and D.N. Reinhoudt

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390033

      Nanostencils (shadow masks with submicrometer apertures in a thin silicon nitride membrane) may suffer from clogging of the apertures due to adhesion of evaporated material. Here it is shown that nanostencils coated with self-assembled monolayers show considerably less adhesion of gold compared to bare stencils, in turn producing better defined features (see Figure, gold features defined by uncoated (left) or coated (right) masks with 350 nm pores).

    7. Engineered Sensitivity of Structured Tin Dioxide Chemical Sensors: Opaline Architectures with Controlled Necking (pages 225–231)

      R.W.J. Scott, S.M. Yang, N. Coombs, G.A. Ozin and D.E. Williams

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390034

      Tin dioxide opals have been fabricated utilizing a reverse templating strategy (see Figure, an electron microscopy image of the opals). The neck diameter between spheres in the SnO2 opals can be controlled by variable sintering of the parent silica opals at temperatures between 700 and 1050 °C. The sensor response of the SnO2 opals towards carbon monoxide has been examined and can be understood as a function of the final neck diameter.

    8. Mono-Bisthienylethene Ring-Fused versus Multi-Bisthienylethene Ring-Fused Photochromic Hybrids (pages 233–239)

      Q. Luo, B. Chen, M. Wang and H. Tian

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390035

      Photoregulated phosphorescence switch behavior is shown by platinum complexes of mono- and multi-bisthienylethene-substituted ring-fused photochromic hybrids (such as the one whose structure is shown in the Figure) prepared via a concise synthesis route. The near-IR luminescence of the hybrids can be regulated in a reversible manner by the photoisomerization of the bisthienylethene moiety.

    9. Composites of Perylene Chromophores and Layered Double Hydroxides: Direct Synthesis, Characterization, and Photo- and Chemical Stability (pages 241–248)

      J. Bauer, P. Behrens, M. Speckbacher and H. Langhals

      Version of Record online: 7 MAR 2003 | DOI: 10.1002/adfm.200390036

      Brilliantly coloured pigments can be obtained by direct synthesis when layered double hydroxides (see Figure) are precipitated under controlled conditions in the presence of an organic perylene dye. The figure shows the structural arrangement of the dye molecules between the hydroxide layers. The stability of these organic–inorganic composite structures is not diminished compared to the pristine dye in a harsh application environment.