Advanced Functional Materials

Cover image for Advanced Functional Materials

January, 2004

Volume 14, Issue 1

Pages 3–9

    1. Spreading the Full-Paper Materials Story (pages 7–9)

      K. Grieve

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200490001

      After three years of publication, Advanced Functional Materials is recognized as a publication of high-quality in-depth materials research from around the globe. Find out more about the leading full-paper materials science journal in this editorial.

    2. The Singlet–Triplet Exchange Energy in Conjugated Polymers (pages 11–18)

      A. Köhler and D. Beljonne

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200305032

      Measurement of singlet and triplet emission spectra in a large number of conjugated polymers yield an almost constant ΔEST (S1 [RIGHTWARDS ARROW] T1 exchange energy) value close to 0.7 eV (see Figure). Quantum-chemical calculations are performed to address the origin of the constant exchange energy in phenylene-based conjugated polymers.

    3. Microtubule-Templated Biomimetic Mineralization of Lepidocrocite (pages 19–24)

      A. K. Boal, T. J. Headley, R. G. Tissot and B. C. Bunker

      Version of Record online: 30 OCT 2003 | DOI: 10.1002/adfm.200304435

      Protein microtubules (MTs) 25 nm in diameter and tens of micrometers long (see cover) have been used as templates for the biomimetic mineralization of FeOOH. Exposure of MTs to anaerobic aqueous solutions of Fe2+ followed by aerial oxidation (see Figure) lead to the formation of iron oxide coatings with controllable thickness of up to 125 nm on the MT template.

    4. Peptide Templates for Nanoparticle Synthesis Derived from Polymerase Chain Reaction-Driven Phage Display (pages 25–30)

      R. R. Naik, S. E. Jones, C. J. Murray, J. C. McAuliffe, R. A. Vaia and M. O. Stone

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304501

      A unique set of sequences that bind to inorganic surfaces have been identified from a phage peptide-display library using a polymerase chain reaction (PCR)-driven method. These sequences, which bind to Ag and Co nanoparticles, and are a distinct set that would be missed using the regular panning method. Peptides identified by the method also function as templates for the synthesis of Ag and Co–Pt nanoparticles (see inside cover; right – a TEM image).

    5. Designed Self-Assembled β-Sheet Peptide Fibrils as Templates for Silica Nanotubes (pages 31–37)

      J. E. Meegan, A. Aggeli, N. Boden, R. Brydson, A. P. Brown, L. Carrick, A. R. Brough, A. Hussain and R. J. Ansell

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304477

      Self-assembling peptides provide a versatile template system for the production of inorganic nanotubes by controlled sol–gel deposition. Well-defined hollow silica nanotubes (see Figure) have been prepared consisting of 89 % Q4-type silica and of ∼ 20 nm outside diameter with ∼ 3.5 nm diameter central pores using a designed positively charged L-P-3 peptide fibril template.

    6. Effect of Temperature and Illumination on the Electrical Characteristics of Polymer–Fullerene Bulk-Heterojunction Solar Cells (pages 38–44)

      I. Riedel, J. Parisi, V. Dyakonov, L. Lutsen, D. Vanderzande and J. C. Hummelen

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304399

      Understanding the device physics of polymer–fullerene bulk-heterojunction solar cells is imperative to improving their efficiency. For the particular choice of absorber materials, temperature- and light-intensity-dependent profiling reveals that device efficiency is limited by the electrical transport properties of the absorber material (see Figure) and a light-dependent shunt resistance which reduces the efficiency at higher illumination levels.

    7. Optimization of a Quasi-Solid-State Dye-Sensitized Photoelectrochemical Solar Cell Employing a Ureasil/Sulfolane Gel Electrolyte (pages 45–48)

      E. Stathatos, P. Lianos, A. Surca Vuk and B. Orel

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304479

      Quasi-solid-state dye-sensitized photoelectrochemical solar cells (see Figure), where the electrolyte is in the form of a nanocomposite gel, offer many advantages compared with their liquid-electrolyte alternatives. The gel electrolyte employed here is made of ureasil and sulfolane, and the overall cell efficiency is > 5 %.

    8. Synthesis of ZSM-5 Films and Monoliths with Bimodal Micro/Mesoscopic Structures (pages 49–54)

      S. I. Cho, S. D. Choi, J.-H. Kim and G.-J. Kim

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200305118

      Mesoporous aluminosilicate ZSM-5 crystals have been prepared by a solid rearrangement process in the framework of tetrapropylammonium hydroxide (TPAOH)-impregnated mesoporous precursors such as MCM-41 and SBA-15, which contain nanostructured carbons in the pore channels. Such mesoporous ZSM-5 zeolites can be readily obtained in thin film, powder, or monolith form (see Figure, top to bottom, respectively).

    9. Carbon-Nanotube-Reinforced Zr-Based Bulk Metallic Glass Composites and Their Properties (pages 55–63)

      Z. Bian, R. J. Wang, W. H. Wang, T. Zhang and A. Inoue

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304422

      Bulk metallic glass composites containing carbon nanotubes (CNTs) (see Figure) show, besides their excellent mechanical properties, remarkably strong ultrasonic wave absorption ability, which increases dramatically with an increasing volume fraction of CNTs. This may have significant potential applications in shielding of acoustic sound or environmental noise.

    10. Octupolar Dendrimers with Large First Hyperpolarizability (pages 64–70)

      H. C. Jeong, M. J. Piao, S. H. Lee, M.-Y. Jeong, K. M. Kang, G. Park, S.-J. Jeon and B. R. Cho

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304478

      A series of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives and dendrimers have been synthesized. When the octupolar molecules are linked to the 1,3,5-position of the benzene ring by flexible ether linkages, the first hyperpolarizability (β(0)) value increases 1.7 fold. An octupolar monodendron (see Figure) exhibits β(0) = 507 × 10–30 esu, one of the largest β(0) values reported for octupolar molecules.

    11. Synthesis and Properties of a Water-Soluble Single-Walled Carbon Nanotube–Poly(m-aminobenzene sulfonic acid) Graft Copolymer (pages 71–76)

      B. Zhao, H. Hu and R. C. Haddon

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304440

      The synthesis of a water-soluble single-walled carbon nanotube–poly(m-aminobenzene sulphonic acid) graft copolymer (SWNT–PABS; see Figure) is reported. The conductivity of the copolymer is ∼ 5.6 × 10–3 S cm–1, much higher than that of PABS (5.4 × 10–7 S cm–1). The PABS and SWNTs are shown to be covalently bonded, and UV-vis-NIR spectroscopy shows interband transitions of the semiconducting SWNTs and the PABS addend.

    12. Templated Synthesis of Carbon Nanofibers from Polyacrylonitrile Using Sepiolite (pages 77–82)

      R. Fernández-Saavedra, P. Aranda and E. Ruiz-Hitzky

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200305514

      Carbon nanofibers of ca. 1 μm by 20 nm dimensions (see Figure) have been successfully prepared by adsorption of acrylonitrile inside the nanosized pores of sepiolite, followed by polymerization and graphitization. The resulting solids constitute a new class of conductive carbon–clay nanocomposites, useful for applications in diverse electrochemical devices such as lithium batteries, sensors, or electrocatalysts.

    13. Color Tuning in Benzo[1,2,5]thiadiazole-Based Small Molecules by Amino Conjugation/Deconjugation: Bright Red-Light-Emitting Diodes (pages 83–90)

      K. R. Justin Thomas, J. T. Lin, M. Velusamy, Y.-T. Tao and C.-H. Chuen

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200304486

      Donor–acceptor dyads based on benzo-[1,2,5]thiadiazole have been obtained by Stille coupling reactions and found to exhibit interesting absorption/emission color-dependence on donor conjugation (see Figure), enabling tuning of the emission characteristics coupled with good electron/hole affinity and thermal stability. Red-light-emitting devices fabricated from these materials show good performance.

    14. Emission Characteristics and Performance Comparison of Polyfluorene Lasers with One- and Two-Dimensional Distributed Feedback (pages 91–97)

      G. Heliotis, R. Xia, G. A. Turnbull, P. Andrew, W. L. Barnes, I. D. W. Samuel and D. D. C. Bradley

      Version of Record online: 29 JAN 2004 | DOI: 10.1002/adfm.200305504

      The lasing characteristics of blue-light-emitting, poly(9,9-dioctylfluorene)-based, 1D and 2D in-plane distributed feedback structures (see Figure for chemical and schematic 1D structures) are reported. 2D confinement leads to state-of-the-art performance: a 0.8 nJ threshold energy for nanosecond-pulsed optical pumping, a 7.8 % slope efficiency, a nearly diffraction-limited, azimuthally polarized output beam, and a 40 nm tuning range.