Advanced Functional Materials

Cover image for Vol. 17 Issue 10

July, 2007

Volume 17, Issue 10

Pages 1587–1714

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Full Papers
    5. Index
    1. Cover Picture: Covalent Functionalization of Carbon Nanohorns with Porphyrins: Nanohybrid Formation and Photoinduced Electron and Energy Transfer (Adv. Funct. Mater. 10/2007)

      G. Pagona, A. S. D. Sandanayaka, Y. Araki, J. Fan, N. Tagmatarchis, G. Charalambidis, A. G. Coutsolelos, B. Boitrel, M. Yudasaka, S. Iijima and O. Ito

      Article first published online: 28 JUN 2007 | DOI: 10.1002/adfm.200790034

      Thumbnail image of graphical abstract

      Covalently attaching porphyrin molecules to carbon nanohorns results in a novel nanohybrid system, as schematically depicted in the figure (and on the cover). The carbon nanohorns serve as electron acceptors, whereas photoexcited porphyrin molecules serve as electron donors. A charge-separated state is formed in the nanohybrid as a result of electron transfer between the two species in polar solvents, whereas energy transfer takes place in nonpolar solvents.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Full Papers
    5. Index
  3. Full Papers

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Full Papers
    5. Index
    1. Molecular Barbed Wire: Threading and Interlocking for the Mechanical Reinforcement of Polymers (pages 1595–1602)

      N. T. Tsui, L. Torun, B. D. Pate, A. J. Paraskos, T. M. Swager and E. L. Thomas

      Article first published online: 30 APR 2007 | DOI: 10.1002/adfm.200600707

      Thumbnail image of graphical abstract

      A novel polymer chain contour resembling “molecular barbed wire” (see figure) is created by the incorporation of pendant iptycene units into polyesters. These units contain a unique structural property called internal molecular-free volume and have been shown to induce steric interactions between polymer chains. This method is used to improve the mechanical properties of a family of polyesters.

    2. A Luminescence and Electrochemical Study of Photoinduced Electron Transfer within the Layers of Zirconium Phosphate (pages 1603–1610)

      E. Brunet, M. Alonso, C. Cerro, O. Juanes, J.-C. Rodríguez-Ubis and Á. E. Kaifer

      Article first published online: 10 MAY 2007 | DOI: 10.1002/adfm.200700048

      Thumbnail image of graphical abstract

      Ru(bpy)3derivatives as electron-donors and viologen-based acceptor species are covalently attached to the walls of γ-ZrP (see figure). Photoinduced electron transfer in the solid state among the active species attached to the transparent inorganic matrix was strongly evidenced. The prepared materials may find applications in the clean conversion of light into useful energy.

    3. Design of Nanocomposite Low-Friction Coatings (pages 1611–1616)

      O. Wilhelmsson, M. Råsander, M. Carlsson, E. Lewin, B. Sanyal, U. Wiklund, O. Eriksson and U. Jansson

      Article first published online: 30 MAY 2007 | DOI: 10.1002/adfm.200600724

      Thumbnail image of graphical abstract

      Low-friction coatings are prepared with a new concept design using Ti1-xAlxC as a model system. Al is a weak carbide-forming element and an inherent driving force is established to segregate carbon. During contact, the carbon can be graphitized, which helps lower the friction. The friction coefficient can be lowered by more than 50 % for Al-containing TiC coatings without severe loss in mechanical characteristics (see figure).

    4. Probing the Anisotropic Field-Effect Mobility of Solution-Deposited Dicyclohexyl-α-quaterthiophene Single Crystals (pages 1617–1622)

      S. C. B. Mannsfeld, J. Locklin, C. Reese, M. E. Roberts, A. J. Lovinger and Z. Bao

      Article first published online: 30 MAY 2007 | DOI: 10.1002/adfm.200600865

      Thumbnail image of graphical abstract

      The anisotropy of field-effect mobility is probed using a technique that can be used on organic crystals that are too small to be mechanically handled. Interestingly, an anisotropy curve with two maxima within 180° is obtained for solution-deposited cyclohexyl-substituted quarterthiophene (CH4T) crystals (see figure).

    5. Ambipolar Light-Emitting Transistors of a Tetracene Single Crystal (pages 1623–1628)

      T. Takahashi, T. Takenobu, J. Takeya and Y. Iwasa

      Article first published online: 22 MAY 2007 | DOI: 10.1002/adfm.200700046

      Thumbnail image of graphical abstract

      Light-emitting transistors based on tetracene single crystals with ambipolar transport and a movable light-emission zone are demonstrated (see figure). Because of the utilization of single crystals in an air-free fabrication process employing poly(methyl methacrylate) as a dielectric layer, the set of materials that can be used for light-emitting transistors is expanded to include monomeric molecular semiconductors.

    6. Soft Imprinting: Creating Highly Ordered Porous Anodic Alumina Templates on Substrates for Nanofabrication (pages 1629–1635)

      A. S. Maria Chong, L. K. Tan, J. Deng and H. Gao

      Article first published online: 30 MAY 2007 | DOI: 10.1002/adfm.200600993

      Thumbnail image of graphical abstract

      Highly ordered porous anodic alumina (HOPAA) templates are fabricated on a variety of substrates by combining soft imprinting (Ar plasma etching) with a HOPAA mask, as schematically depicted in the figure. The nanoindentations generated by soft imprinting guide the Al anodization to yield the highly ordered structure shown in the inset of the figure. The scale bar represents 100 nm. Ordered arrays of gold nanowires and titania nanotubes are fabricated using these templates.

    7. “Solvent Annealing” Effect in Polymer Solar Cells Based on Poly(3-hexylthiophene) and Methanofullerenes (pages 1636–1644)

      G. Li, Y. Yao, H. Yang, V. Shrotriya, G. Yang and Y. Yang

      Article first published online: 18 MAY 2007 | DOI: 10.1002/adfm.200600624

      Thumbnail image of graphical abstract

      Polymer solar cells based on poly(3-hexylthiophene) and methanofullerenes are investigated by systematically varying the spin-coating time used during fabrication (see figure). The rate of solvent evaporation profoundly effects the self-organization of the polymer. Very high crystallinity of the polymer and consequently optimal solar-cell performance is achieved for longer “solvent annealing” times.

    8. Micropatterned Polypyrrole: A Combination of Electrical and Topographical Characteristics for the Stimulation of Cells (pages 1645–1653)

      N. Gomez, J. Y. Lee, J. D. Nickels and C. E. Schmidt

      Article first published online: 9 MAY 2007 | DOI: 10.1002/adfm.200600669

      Thumbnail image of graphical abstract

      The patterning of polypyrrole to create 1 and 2 μm wide microchannels using electron-beam lithography and electropolymerization is reported. Polypyrrole is an important biomaterial in neural engineering. Hippocampal neurons cultured on patterned polypyrrole (see figure) establish axons twofold faster than on unpatterned substrates.

    9. Luminescence and Amplified Stimulated Emission in CdSe–ZnS-Nanocrystal-Doped TiO2 and ZrO2 Waveguides (pages 1654–1662)

      J. Jasieniak, J. Pacifico, R. Signorini, A. Chiasera, M. Ferrari, A. Martucci and P. Mulvaney

      Article first published online: 9 MAY 2007 | DOI: 10.1002/adfm.200600955

      Thumbnail image of graphical abstract

      Formation of highly luminescent quantum dot/sol–gel waveguides is explored using two high-refractive- index matrices, titania and zirconia, as hosts. Although both materials can be used as waveguides, zirconia is far superior in terms of luminescence stability and photodegradation (see figure). We conclude that the low electron affinity of zirconia and its inherent high refractive index make it an ideal candidate for nanocrystal-based optical waveguides.

    10. UV-vis-Induced Vitrification of a Molecular Crystal (pages 1663–1670)

      T. Naito, H. Sugawara, T. Inabe, Y. Kitajima, T. Miyamoto, H. Niimi and K. Asakura

      Article first published online: 30 APR 2007 | DOI: 10.1002/adfm.200600583

      Thumbnail image of graphical abstract

      The application of UV-vis illumination or heat to a highly conductive opaque molecular crystal irreversibly alters its appearance and physical properties (see figure). The vitrification is related to the unique one-dimensional structural and electronic characteristics of this material, such as metal instability and strong electron–phonon interactions. Several related solids are also characterized in detail.

    11. Highly Dispersed Mixed Zirconia and Hafnia Nanoparticles in a Silica Matrix: First Example of a ZrO2–HfO2–SiO2 Ternary Oxide System (pages 1671–1681)

      L. Armelao, H. Bertagnolli, D. Bleiner, M. Groenewolt, S. Gross, V. Krishnan, C. Sada, U. Schubert, E. Tondello and A. Zattin

      Article first published online: 29 MAY 2007 | DOI: 10.1002/adfm.200600458

      Thumbnail image of graphical abstract

      A two-step modified sol–gel procedure based on the use of a bifunctional silane, with Hf- and Zr-oxoclusters as molecular building blocks, is used to prepare ternary ZrO2–HfO2–SiO2 film and bulk materials of different compositions (see figure), which are characterized by the presence of homogeneously dispersed oxide nanoclusters.

    12. A Facile Sol–Gel Strategy for the Synthesis of Rod-Shaped Nanocrystalline High-Surface-Area Lanthanum Phosphate Powders and Nanocoatings (pages 1682–1690)

      K. Rajesh, P. Shajesh, O. Seidel, P. Mukundan and K. G. K. Warrier

      Article first published online: 9 MAY 2007 | DOI: 10.1002/adfm.200600794

      Thumbnail image of graphical abstract

      Lanthanum phosphate gels with a high catalytic reactivity have been prepared along with sols of comparable size (see figure). Both sols and gels consist of nanorod-shaped particles of size 40 nm even after calcination. A complete characterization of both sols and gels is presented, and their unique properties may lead to enhanced catalytic activities and more uniform coatings than previously reported for lanthanum phosphates.

    13. Hydrophobic Chromophores in Aqueous Micellar Solution Showing Large Two-Photon Absorption Cross Sections (pages 1691–1697)

      Y. Tian, C.-Y. Chen, Y.-J. Cheng, A. C. Young, N. M. Tucker and A. K.-Y. Jen

      Article first published online: 10 MAY 2007 | DOI: 10.1002/adfm.200600916

      Thumbnail image of graphical abstract

      Micelles derived from an amphiphilic block copolymer are demonstrated to be efficient nanocarriers to encapsulate highly efficient, hydrophobic, two-photon-absorbing chromophores into aqueous solutions. A large two-photon cross section (δ) up to 2790 GM is achieved in aqueous solution, which is more than one order of magnitude higher than most of the hydrophilic 2PA materials that have δ values of less than 100 GM.

    14. Synthesis and Patterning of Luminescent CaCO3–Poly(p-phenylene) Hybrid Materials and Thin Films (pages 1698–1704)

      S. Sindhu, S. Jegadesan, L. Hairong, P. K. Ajikumar, M. Vetrichelvan and S. Valiyaveettil

      Article first published online: 5 JUN 2007 | DOI: 10.1002/adfm.200600547

      Thumbnail image of graphical abstract

      Smart composite materials with controlled morphology and tunable optical properties have been prepared using sulfonated poly(p-phenylenes) and their light-emitting properties are demonstrated (see figure). It is shown that the nature and orientation of the side-chain functional groups on the polymer backbone play a crucial role for the selective morphogenesis of the crystals.

    15. Covalent Functionalization of Carbon Nanohorns with Porphyrins: Nanohybrid Formation and Photoinduced Electron and Energy Transfer (pages 1705–1711)

      G. Pagona, A. S. D. Sandanayaka, Y. Araki, J. Fan, N. Tagmatarchis, G. Charalambidis, A. G. Coutsolelos, B. Boitrel, M. Yudasaka, S. Iijima and O. Ito

      Article first published online: 30 MAY 2007 | DOI: 10.1002/adfm.200700039

      Thumbnail image of graphical abstract

      Covalently attaching porphyrin molecules to carbon nanohorns results in a novel nanohybrid system, as schematically depicted in the figure (and on the cover). The carbon nanohorns serve as electron acceptors, whereas photoexcited porphyrin molecules serve as electron donors. A charge-separated state is formed in the nanohybrid as a result of electron transfer between the two species in polar solvents, whereas energy transfer takes place in nonpolar solvents.

  4. Index

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Full Papers
    5. Index

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