Advanced Functional Materials

Cover image for Vol. 13 Issue 2

February, 2003

Volume 13, Issue 2

Pages 95–174

    1. Polyol-Mediated Synthesis of Nanoscale Functional Materials (pages 101–107)

      C. Feldmann

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390014

      Nanoscale, monodisperse, and crystalline particles of various functional materials are realized using a synthesis based on the polyol method. The materials synthesized include luminescent materials, color pigments, transparent conductive oxides, and potential catalysts. Average particle diameters between 30 and 200 nm are achieved. The Figure shows scanning electron microscope images of some of the materials.

    2. Preparation and Characterization of Blue-Luminescent Tris(8-hydroxyquinoline)-aluminum (Alq3) (pages 108–112)

      M. Cölle, J. Gmeiner, W. Milius, H. Hillebrecht and W. Brütting

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390015

      A new high-temperature phase of tris(8-hydroxyquinoline)aluminum (δ-Alq3) exhibiting blue luminescence (see Figure), in contrast to the α-phase (Alq3) showing the well-known green light emission, has been prepared by a simple annealing process. This newly found phase contains the facial Alq3 stereoisomer and can be produced in large amounts, offering the possibility to fabricate blue Alq3 light emitting devices.

    3. Magnetic Force Microscopy Images of a Nanometer-Sized, Purely Organic High-Spin Polyradical (pages 113–117)

      M. Miyasaka, Y. Saito and H. Nishide

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390016

      Both the molecular image and the magnetic response of π-conjugated, non-Kekulé- and nondisjoint-type poly(4-phenoxyl-1,2-phenylenevinylene) networks is studied by magnetic force microscopy (MFM). The MFM molecular image is examined as a nanoscale and single-molecule based magnetic dot using purely organic high-spin polyradical samples with different molecular weight and spin concentration.

    4. Organometallic Synthesis of Size-Controlled Polycrystalline Ruthenium Nanoparticles in the Presence of Alcohols (pages 118–126)

      K. Pelzer, O. Vidoni, K. Philippot, B. Chaudret and V. Collière

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390017

      Ruthenium nanoparticles of controlled size have been prepared by decomposition of the organometallic precursor Ru(cod)(cot) (cod = 1,5-cyclooctadiene, cot = 1,3,5-cyclooctatriene) under a H2 atmosphere in organic solutions consisting of either a pure alcohol or an alcohol/THF mixture, and in the absence of stabilizers. The size of the particles can be controlled by adjusting the reaction temperature or the composition of the solvent mixture.

    5. Dendrite-Assisted Growth of Silicon Nanowires in Electroless Metal Deposition (pages 127–132)

      K. Peng, Y. Yan, S. Gao and J. Zhu

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390018

      A simple and inexpensive method to synthesize silicon nanowires is demonstrated and a possible synthesis mechanism is proposed. This method allows the creation of large-area silicon nanowire arrays (see scanning electron microscopy image, Figure) on silicon substrates without templates. Additionally, the synthesis is carried out near room temperature, far cooler than the temperature required for other syntheses.

    6. Meso-SiO2–C12EO10OH–CF3SO3H—A Novel Proton-Conducting Solid Electrolyte (pages 133–138)

      J.D. Halla, M. Mamak, D.E. Williams and G.A. Ozin

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390019

      A lyotropic non-ionic surfactant–triflic acid–silicate liquid crystal is used as a supramolecular template for a “one-pot” synthesis of the material in which the oligoethyleneoxide head groups of the surfactant act in a crown-ether-like fashion towards protons. The proton conductivity of the composite material was examined at different relative humidity values giving some insight into its potential utility as a solid electrolyte.

    7. Single-Crystalline Films of the Homologous Series InGaO3(ZnO)m Grown by Reactive Solid-Phase Epitaxy (pages 139–144)

      H. Ohta, K. Nomura, M. Orita, M. Hirano, K. Ueda, T. Suzuki, Y. Ikuhara and H. Hosono

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390020

      The growth of a single-crystalline film (see Figure) with a controlled chemical composition is possible via high-temperature annealing of bi-layer films consisting of an amorphous InGaO3(ZnO)5 layer and an epitaxial ZnO layer. Thin films of homologous series InGaO3(ZnO)m are fabricated by the reactive solid-phase epitaxy (R-SPE) method and their growth mechanism is elucidated.

    8. Preparation of Metallic Films on Elastomeric Stamps and Their Application for Contact Processing and Contact Printing (pages 145–153)

      H. Schmid, H. Wolf, R. Allenspach, H. Riel, S. Karg, B. Michel and E. Delamarche

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390021

      Elastomeric stamps are useful to quench fluorescence or inject charge carriers into an organic electroluminescent layer (see Figure), and to print patterns of metals and insulators onto various surfaces. The method used to metallize such stamps determines both the morphology of the metallic layer and the ability to transfer it to a substrate or reversibly place it in contact with the substrate.

    9. Influence of Dendronization on Spectral Diffusion and Aggregation in Conjugated Polymers (pages 154–158)

      J.M. Lupton, P. Schouwink, P.E. Keivanidis, A.C. Grimsdale and K. Müllen

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390022

      Dendronization is an appealing method of controlling intermolecular interactions. Whereas dendritic shielding of molecular dyes is readily demonstrated, the case is more complicated for polymers, where a wide range of chain conformations exist. Here it is shown that dendronization of polyfluorene enhances the migration of singlet excitons rather than reducing it, providing new insight into the channels for interchain interaction.

    10. Structural Effects in the Electrodeposition of CdSe Quantum Dots on Mechanically Strained Gold (pages 159–164)

      I. Ruach-Nir, H.D. Wagner, I. Rubinstein and G. Hodes

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390023

      The lattice mismatch between CdSe and Au (shown to influence lateral crystal size) can be changed without changing the chemical interactions by electrodepositing CdSe nanocrystals (see Figure) onto mechanically bent Au substrates. When the bending is in a direction which increases lattice mismatch, the crystal size is reduced, while if the mismatch is reduced by the bending, the high-pressure rocksalt form of CdSe is deposited.

    11. Hybrid Solar Cells Based on Nanoparticles of CuInS2 in Organic Matrices (pages 165–171)

      E. Arici, N.S. Sariciftci and D. Meissner

      Version of Record online: 14 FEB 2003 | DOI: 10.1002/adfm.200390024

      Combining nanocrystalline CuInS2 with organic materials, heterojunction solar cells have been fabricated by spin-coating. Promising cell performance is achieved in double-layer configurations of CuInS2 and fullerene derivatives with an external quantum efficiency of ∼ 5 %. Bulk heterojunctions are also studied by replacing the CuInS2 single layer with a blend of CuInS2 and p-type polymer in the same cell configuration, with a significant increase of the external quantum efficiency up to 20 %.