Advanced Materials

Cover image for Advanced Materials

May, 1998

Volume 10, Issue 7

Pages 515–554

    1. Metal Clusters and Colloids (pages 515–526)

      Günter Schmid and Lifeng F. Chi

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<515::AID-ADMA515>3.0.CO;2-Y

      Regularly arranged nanosized metal particles have potential application as quantum dots in nanoelectronics. The synthesis and properties of ligand-protected metal clusters and colloids as well as their organization in one, two, and three dimensions is reviewed. The Figure is a transmission electron micrograph of a wire of 15 nm gold colloids in a ∼50 nm pore in alumina.

    2. A Novel Synthesis of Cadmium Phosphide Nanoparticles Using the Single-Source Precursor [MeCdPtBu2]3 (pages 527–528)

      Mark Green and Paul O'Brien

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<527::AID-ADMA527>3.0.CO;2-M

      A single-source precursor route to Cd3P2 nanoparticles is reported. Their synthesis via the thermolysis of [MeCdPtBu2]3—itself obtained using an improved procedure—in tri-n-octylphosphine oxide (TOPO) is described. The resulting TOPO-capped cadmium phosphide quantum dots are characterized by a combination of UV-vis and fluorescence emission spectroscopies, high resolution transmission electron microscopy, and elemental analysis. The effect of preparing samples with injection temperatures above 100°C is also investigated.

    3. A New Approach to the Fabrication of a Self-Organizing Film of Heterostructured Polymer/Cu2S Nanoparticles (pages 529–532)

      Huiming Xiong, Minghua Cheng, Zhen Zhou, Xi Zhang and Jiacong Shen

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<529::AID-ADMA529>3.0.CO;2-E

      The fabrication of polymer/Cu2S nanoparticle hybrid films is described, in which metal–ligand interactions are used to self-organize Cu2+-neutralized polyelectrolytes and pyridine-containing polymers into alternately deposited multilayers, as illustrated in the Figure, where the circles represent the copper salt and the polygons the pyridine moiety.

    4. The “Melting Point” of Alkanethiol-Coated Amorphous Fe2O3 Nanoparticles (pages 532–535)

      Tanya Prozorov and Aharon Gedanken

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<532::AID-ADMA532>3.0.CO;2-1

      The “melting point” of alkanethiol-coated amorphous Fe2O3 nanoparticles is investigated. The dependence of the melting temperature on the alkyl chain length is presented and compared with the results obtained by Luedkte and Landman, who carried out a comprehensive theoretical study on the structure and dynamics of nanocrystalline gold passivated by alkanethiol monolayers. It is shown that molecules coated on a chaotic amorphous structure have a “melting” phenomenon similar to that found on well-organized nanocrystalline materials.

    5. Alternate Molecular Layers of Metal Oxides and Hydroxyl Polymers Prepared by the Surface Sol-Gel Process (pages 535–539)

      Izumi Ichinose, Takeshi Kawakami and Toyoki Kunitake

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<535::AID-ADMA535>3.0.CO;2-Q

      Extension of the surface sol-gel process to form molecularly alternate metal oxide/polymer films is reported. The Figure is a schematic illustration of the chemical structure of TiO2/poly(acrylic acid) multilayers grown using this method. It is demonstrated that films can also be assembled using aluminum, zirconium, niobium, and barium titanium alkoxides.

    6. In Situ Preparation of Bulk Crystals with Regularly Doped Structures (pages 539–541)

      Vladimir N. Kurlov and Svetlana V. Belenko

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<539::AID-ADMA539>3.0.CO;2-A

      Crystals with regularly doped structures, particularly those with periodic structures of variable composition, are promising materials for optoelectronic devices. Two techniques for the in-situ preparation of modulated structures are reported—the edge-defined film-fed growth (EFG) method, and the growth from an element of shape (GES) method. These techniques make it possible to control the contrast, period, and ratio heights of doped and undoped regions in a period, as well as the character of dopant distribution within the period.

    7. Electrosynthesis of Highly Electroactive Tetrathiafulvalene-Derivatized Polythiophenes (pages 541–545)

      Laurent Huchet, Said Akoudad and Jean Roncali

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<541::AID-ADMA541>3.0.CO;2-1

      The electrosynthesis of tetrathiafulvane-derivatized polythiophenes (PT-TTFs) from bithiophenic precursors such as that shown in the Figure (m = 3 or 5) is reported. The lower oxidation potential of bithiophene compared to thiophene is suggested to account for the ease of electropolymerization. Highly electroactive, stable polymers result, making them attractive for electrochemical applications.

    8. Synthesis, Structure, and Physical Properties of the Organic–Inorganic Hybrid Salt (BEDT-TTF)6[PMo12O40]·(4CH3CN·6H2O) (pages 545–550)

      Mohamedally Kurmoo, Mario Bonamico, Carlo Bellitto, Vincenzo Fares, Fulvio Federici, Philippe Guionneau, Laurent Ducasse, Hiroshi Kitagawa and Peter Day

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<545::AID-ADMA545>3.0.CO;2-M

      Magnetic superconductors based on organic–inorganic hybrid salts are actively sought-after materials. Salts of bis(ethylenedithio)tetrathiafulvane (BEDT-TTF) and polyoxometallates, which combine the electronic properties of BEDT-TTF with the magnetic properties of the oxo anion, are promising candidates. The X-ray crystal structure and physical properties of (BEDT-TTF)6[PMo12O40]·(4CH3CN·6H2O), one of the phases isolated on electrocrystallization of the material, are reported. The calculated electronic band structure is also presented.

    9. From Easily Oxidized to Easily Reduced Thiophene-Based Materials (pages 551–554)

      Giovanna Barbarella, Laura Favaretto, Massimo Zambianchi, Olga Pudova, Catia Arbizzani, Alessandro Bongini and Marina Mastragostino

      Version of Record online: 26 JAN 1999 | DOI: 10.1002/(SICI)1521-4095(199805)10:7<551::AID-ADMA551>3.0.CO;2-Y

      Thiophene-based materials for n-type semiconductor devices? A new strategy towards this goal that consists of chemically transforming the thienyl sulfurs into the corresponding S,S-dioxides (see Figure) is described. This is shown—for quarter- and quinquethiophenes—to lead to very stable oligomers with increased electron delocalization and electron affinity.