Advanced Functional Materials

Cover image for Advanced Functional Materials

August, 2004

Volume 14, Issue 8

Pages 735–822

    1. Molecules with Linear π-Conjugated Pathways between All Substituents: Omniconjugation (Adv. Funct. Mater. 2004, 14, 215) (page 742)

      M. H. van der Veen, M. T. Rispens, H. T. Jonkman and J. C. Hummelen

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200490016

    2. Butadienes as Novel Photochromes for Color Tuning of Cholesteric Glasses: Influence of Microscopic Molecular Reorganization within the Helical Superstructure (pages 743–748)

      R. Davis, V. A. Mallia, S. Das and N. Tamaoki

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305190

      Thumbnail image of graphical abstract

      The role of dopant-induced microscopic changes of smectic domains in affecting the helical pitch of a glass-forming cholesteric liquid crystal and the use of these host–guest systems for color photoimaging has been demonstrated (see Figure).

    3. A Combined Photolithographic and Molecular-Assembly Approach to Produce Functional Micropatterns for Applications in the Biosciences (pages 749–756)

      D. Falconnet, A. Koenig, F. Assi and M. Textor

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305182

      Thumbnail image of graphical abstract

      Molecular-assembly patterning by lift-off (MAPL) is a chemical patterning technique that combines a top–down approach based on photolithography and a bottom–up strategy through self-organization of multifunctional molecules. Its capability to produce patterns with controlled bioligand densities is believed to be promising for the production of improved biochip surfaces for the genomics, proteomics, and cellomics areas. The Figure shows a single cell on a patterned square.

    4. Effect of Molecular Weight and Annealing of Poly(3-hexylthiophene)s on the Performance of Organic Field-Effect Transistors (pages 757–764)

      A. Zen, J. Pflaum, S. Hirschmann, W. Zhuang, F. Jaiser, U. Asawapirom, J. P. Rabe, U. Scherf and D. Neher

      Version of Record online: 6 AUG 2004 | DOI: 10.1002/adfm.200400017

      Thumbnail image of graphical abstract

      The optical, structural, and electrical properties of thin layers made from poly(3-hexylthiophene) (P3HT) samples of different molecular weights are presented (see Figure). It is concluded that the backbone conformation of the majority of the bulk material, rather than the crystallinity of the layer, is the most crucial parameter controlling charge transport in P3HT layers.

    5. Understanding the Origin of the 535 nm Emission Band in Oxidized Poly(9,9-dioctylfluorene): The Essential Role of Inter-Chain/Inter-Segment Interactions (pages 765–781)

      M. Sims, D. D. C. Bradley, M. Ariu, M. Koeberg, A. Asimakis, M. Grell and D. G. Lidzey

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305149

      Thumbnail image of graphical abstract

      The appearance of a broad and featureless 535 nm (g-band) emission is characteristic of degradation in polyfluorene thin films and results in an undesirable color shift (see Figure, a CIE (1931) chart) away from blue. The role of photogenerated fluorenone moieties is reassessed here and it is shown that whilst they always quench photoluminescence, the g-band is only seen when there is a suitable spatial arrangement for excimer formation.

    6. On the Origin of Green Emission in Polyfluorene Polymers: The Roles of Thermal Oxidation Degradation and Crosslinking (pages 783–790)

      W. Zhao, T. Cao and J. M. White

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305173

      Thumbnail image of graphical abstract

      Green emission from polyfluorene polymers has been investigated by comparing the chemical and physical properties of the soluble and insoluble portions of films. The soluble portion of air-annealed films displays a less intense green emission than its insoluble counterpart (see Figure), but the carbonyl concentration is higher in the soluble portion in comparison to its insoluble portion. The results suggest that crosslinking plays a significant role in green emission.

    7. High Performance Nanotube-Reinforced Plastics: Understanding the Mechanism of Strength Increase (pages 791–798)

      J. N. Coleman, M. Cadek, R. Blake, V. Nicolosi, K. P. Ryan, C. Belton, A. Fonseca, J. B. Nagy, Y. K. Gun'ko and W. J. Blau

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305200

      Thumbnail image of graphical abstract

      Two methods have been demonstrated for the reinforcement of polymers using carbon nanotubes. Large increases in Young's modulus, strength, and toughness have been observed at extremely low nanotube loading levels. The reinforcement appears to be critically dependent on the properties of the interfacial polymer phase (see Figure).

    8. Synthesis and Spectral and Structural Elucidation of Some Pyridinium Betaines of Squaric Acid: Potential Materials for Nonlinear Optical Applications (pages 799–805)

      T. M. Kolev, D. Y. Yancheva and S. I. Stoyanov

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200304354

      Thumbnail image of graphical abstract

      Novel pyridinium betaines of squaric acid (see Figure) with remarkable thermal stability have been synthesized. UV-vis spectral elucidation in five different solvents gives evidence of their clearly distinct negative solvatochromism, characteristic for compounds with charge-transfer character and dipolar ground-state structure. All these features demonstrate potential nonlinear optical and electro-optical properties.

    9. Well-Aligned ZnO Nanorods via Hydrogen Treatment of ZnO Films (pages 806–810)

      J.-J. Wu, H.-I. Wen, C.-H. Tseng and S.-C. Liu

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305092

      Thumbnail image of graphical abstract

      The formation of well-aligned ZnO nanorods (see Figure) has been achieved using H2 treatment of as-grown ZnO films. Structural analyses reveal that the ZnO nanorods on the ZnO films are preferentially oriented in the c-axis direction and exhibit a single-crystalline wurtzite structure.

    10. An Orientation-Controlled Pentacene Film Aligned by Photoaligned Polyimide for Organic Thin-Film Transistor Applications (pages 811–815)

      W.-Y. Chou and H.-L. Cheng

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305047

      Thumbnail image of graphical abstract

      A novel technique used to control the orientation of pentacene has been investigated. Pentacene molecules are aligned by photoaligned polyimide irradiated with UV light to produce films with good orientation of crystalline grains (see Figure). Special benefits are that the mobility is enhanced dramatically and electrically anisotropic characteristics are provided in organic thin-film transistors.

    11. Investigation of the Structure of MCM-41 Samples with a High Copper Content (pages 816–820)

      Y. Kong, H. Y. Zhu, G. Yang, X. F. Guo, W. H. Hou, Q. J. Yan, M. Gu and C. Hu

      Version of Record online: 2 SEP 2004 | DOI: 10.1002/adfm.200305111

      Thumbnail image of graphical abstract

      Cu-MCM-41 containing up to 26 wt.-% copper(II) has been synthesized and the atoms of copper are shown to be incorporated into the MCM-41 framework. The copper species appears to exist in a distorted octahedron coordinating with 4–6 atoms of oxygen in its first coordination sphere. The Figure shows a transmission electron microscope image of sample containg 10 wt.-% copper.