Advanced Functional Materials

Cover image for Vol. 17 Issue 1

January, 2007

Volume 17, Issue 1

Pages 3–170

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
    1. Cover Picture: Role of Nanoscale Strain Inhomogeneity on the Light Emission from InGaN Epilayers (Adv. Funct. Mater. 1/2007)

      S. M. de Sousa Pereira, K. P. O'Donnell and E. J. da Costa Alves

      Version of Record online: 4 JAN 2007 | DOI: 10.1002/adfm.200790003

      Nanoscale strain inhomogeneity is shown to play a fundamental role on the spectral properties of InGaN–GaN epilayers. For layers grown above a certain critical thickness, a strong and spatially varying strain profile accompanies a nonplanar surface morphology (see figure and cover), which is associated with a transition from planar 2D to a Stranski-Krastanow-like 2D–3D growth mode.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
    1. Inside Front Cover: Inkjet Printing of Luminescent CdTe Nanocrystal–Polymer Composites (Adv. Funct. Mater. 1/2007)

      E. Tekin, P. J. Smith, S. Hoeppener, A. M. J. van den Berg, A. S. Susha, A. L. Rogach, J. Feldmann and U. S. Schubert

      Version of Record online: 4 JAN 2007 | DOI: 10.1002/adfm.200790004

      Well-defined dots and arrays composed of brightly emitting CdTe nanocrystals in a poly(vinylalcohol) (PVA) matrix are obtained using inkjet printing (see figure and inside cover). Dot uniformity is achieved using ethylene glycol–water as a solvent. The use of PVA as a matrix improves both the morphology and the emission properties of the printed nanocrystal films.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
  4. Guide for Authors

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
  5. Editorial

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
    1. You have free access to this content
      Keeping Apace with Change (pages 15–19)

      K. Grieve

      Version of Record online: 4 JAN 2007 | DOI: 10.1002/adfm.200601204

      Nothing is so constant: Change is an ever-present fact of life, and the engine that drives scientific research. In this Editorial, the Deputy Editor looks at the role of Advanced Functional Materials in communicating the ever-evolving breakthroughs of materials science, and overviews some of the changes in the journal over the past year.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index
    1. Inkjet Printing of Luminescent CdTe Nanocrystal–Polymer Composites (pages 23–28)

      E. Tekin, P. J. Smith, S. Hoeppener, A. M. J. van den Berg, A. S. Susha, A. L. Rogach, J. Feldmann and U. S. Schubert

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adfm.200600587

      Thumbnail image of graphical abstract

      Well-defined dots and arrays composed of brightly emitting CdTe nanocrystals in a poly(vinylalcohol) (PVA) matrix are obtained using inkjet printing (see figure and inside cover). Dot uniformity is achieved using ethylene glycol–water as a solvent. The use of PVA as a matrix improves both the morphology and the emission properties of the printed nanocrystal films.

    2. New Ruthenium Complexes Containing Oligoalkylthiophene-Substituted 1,10-Phenanthroline for Nanocrystalline Dye-Sensitized Solar Cells (pages 29–36)

      C.-Y. Chen, H.-C. Lu, C.-G. Wu, J.-G. Chen and K.-C. Ho

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600059

      Thumbnail image of graphical abstract

      Two new ruthenium complexes are synthesized, characterized, and used as photosensitizers in dye-sensitized solar cells (CYC-P1 and CYC-P2 in figure). The overall efficiencies of the sensitized cells are 6.01 and 3.42 %: a cis-di(thiocyanato)-bis(2,2′-bipyridyl)-4,4′-dicarboxylate ruthenium(II) (N3)-sensitized device has an efficiency of 7.70 %.

    3. Role of Nanoscale Strain Inhomogeneity on the Light Emission from InGaN Epilayers (pages 37–42)

      S. M. de Sousa Pereira, K. P. O'Donnell and E. J. da Costa Alves

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600650

      Thumbnail image of graphical abstract

      Nanoscale strain inhomogeneity is shown to play a fundamental role on the spectral properties of InGaN–GaN epilayers. For layers grown above a certain critical thickness, a strong and spatially varying strain profile accompanies a nonplanar surface morphology (see figure and cover), which is associated with a transition from planar 2D to a Stranski-Krastanow-like 2D–3D growth mode.

    4. Deformation of Top-Down and Bottom-Up Silver Nanowires (pages 43–53)

      A. M. Leach, M. McDowell and K. Gall

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600735

      Thumbnail image of graphical abstract

      Top-down and bottom-up silver nanowires are mechanically characterized using molecular-dynamic simulations. The mechanical response and operant deformation mechanisms are shown to be strongly geometry dependent (see figure). A size effect on the tensile strength is presented for nanowires ranging from 2 to 25 nm in diameter.

    5. Functional Supramolecular Ruthenium Cyclodextrin Dyes for Nanocrystalline Solar Cells (pages 54–58)

      J. Faiz, A. I. Philippopoulos, A. G. Kontos, P. Falaras and Z. Pikramenou

      Version of Record online: 15 NOV 2006 | DOI: 10.1002/adfm.200600188

      Thumbnail image of graphical abstract

      The metallocyclodextrin RuII complex [Ru(dcb)2(α-CD-5-bpy)]Cl2 with surface-anchoring groups is designed, synthesized, and tested in nanocrystalline titania solar cells (see figure). The supramolecular dye shows enhanced short-circuit photocurrent, photovoltage, and power-conversion efficiencies attributed to host–guest interactions between the supramolecular moiety and the iodide/triiodide redox couple.

    6. ZnO–SnO2 Hollow Spheres and Hierarchical Nanosheets: Hydrothermal Preparation, Formation Mechanism, and Photocatalytic Properties (pages 59–64)

      W.-W. Wang, Y.-J. Zhu and L.-X. Yang

      Version of Record online: 29 NOV 2006 | DOI: 10.1002/adfm.200600431

      Thumbnail image of graphical abstract

      ZnO–SnO2 hollow spheres and hierarchical nanosheets (see figure) are successfully synthesized using an aqueous solution containing ZnO rods, SnCl4, and NaOH using a simple hydrothermal method. Both hollow spheres and hierarchical nanosheets show higher photocatalytic activities in the degradation of methyl orange than that of ZnO rods or SnO2.

    7. Siloxane Copolymers for Nanoimprint Lithography (pages 65–70)

      P. Choi, P.-F. Fu and L. J. Guo

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600257

      Thumbnail image of graphical abstract

      Thermoplastic siloxane copolymers are investigated for use as nanoimprint lithography resists. Poly(dimethylsiloxane) (PDMS) imparts the materials with many properties favorable for imprinting (see figure), including low surface energy for easy mold release without delamination and high silicon content for chemical-etch resistance; thus, they can be used for further pattern transfer to underlying layers. Feature sizes of 50 nm, and possibly below, can be imprinted.

    8. On the Origin of Green Emission Bands in Fluorene-Based Conjugated Polymers (pages 71–78)

      F. Montilla and R. Mallavia

      Version of Record online: 20 NOV 2006 | DOI: 10.1002/adfm.200600141

      Thumbnail image of graphical abstract

      Blue-light-emitting polyfluorene diodes have low stability: the polyfluorene rapidly degrades to green-light-emitting products (see figure). Upon electrochemical degradation, a green band at 485 nm develops. This band is different from the 535 nm band usually assigned to fluorenone defects. The product of degradation has a crosslinked character and its emission may be related to intramolecular excimers.

    9. Effect of Immobilized Nerve Growth Factor on Conductive Polymers: Electrical Properties and Cellular Response (pages 79–86)

      D.-H. Kim, S. M. Richardson-Burns, J. L. Hendricks, C. Sequera and D. C. Martin

      Version of Record online: 20 NOV 2006 | DOI: 10.1002/adfm.200500594

      Thumbnail image of graphical abstract

      Biomolecule entrapment within electrochemically polymerized conducting polymers can provide electrically active biomaterials with enhanced cellular attachment. Polypyrrole(PPy)/nerve growth factor (NGF) coatings decrease the impedance amplitude of microelectrodes by almost two orders of magnitude, and PPy/NGF films yield a significant population of differentiated PC-12 cells (see figure), indicating successful delivery of NGF.

    10. Effect of Nanotube Functionalization on the Coefficient of Thermal Expansion of Nanocomposites (pages 87–92)

      S. Wang, Z. Liang, P. Gonnet, Y.-H. Liao, B. Wang and C. Zhang

      Version of Record online: 5 DEC 2006 | DOI: 10.1002/adfm.200600760

      Thumbnail image of graphical abstract

      The effect of nanotube functionalization on the coefficients of thermal expansion (CTE) of SWNT–epoxy nanocomposites is revealed (see figure). The CTE values of the functionalized SWNT–epoxy composites below the glass-transition temperature can be reduced by 52 and 42 % through simple mechanical chopping and oxidization methods, respectively.

    11. A DCM-Type Red-Fluorescent Dopant for High-Performance Organic Electroluminescent Devices (pages 93–100)

      Y.-S. Yao, Q.-X. Zhou, X.-S. Wang, Y. Wang and B.-W. Zhang

      Version of Record online: 23 NOV 2006 | DOI: 10.1002/adfm.200600055

      Thumbnail image of graphical abstract

      A new red-light-emitting dopant, DCQTB (see figure), is synthesized for organic light-emitting diode applications. Compared with the known dopant DCJTB, DCQTB exhibits red-shifted fluorescence but blue-shifted absorption, and a comparable fluorescence quantum yield. Such unique characteristics lead to an improved red color purity and luminous efficiency in DCQTB-based organic light-emitting diodes.

    12. Effect of Molecular Weight on the Structure and Morphology of Oriented Thin Films of Regioregular Poly(3-hexylthiophene) Grown by Directional Epitaxial Solidification (pages 101–108)

      M. Brinkmann and P. Rannou

      Version of Record online: 29 NOV 2006 | DOI: 10.1002/adfm.200600673

      Thumbnail image of graphical abstract

      Oriented thin films of poly(3-hexylthiophene-2,5-diyl) (P3HT) with varying molecular weights are grown by directional epitaxial crystallization. P3HT with a weight-average molecular weight Mw = 7.3 kDa behaves like an oligomeric system, whereas, for Mw ≥ 18.8 kDa, it shows the periodic lamellar structure of a semicrystalline polymer as a result of chain folding (see figure).

    13. Photoresponsive Ferroelectric Liquid-Crystalline Polymers (pages 109–114)

      P. Beyer, M. Krueger, F. Giesselmann and R. Zentel

      Version of Record online: 29 NOV 2006 | DOI: 10.1002/adfm.200600513

      Thumbnail image of graphical abstract

      Photoinduced changes of the ferroelectric properties of an azobenzene-functionalized liquid-crystalline polymer are investigated in detail using both photostationary and time-resolved measurements (see figure). The results give an insight into the effect of trans–cis isomerization on the Curie temperature and ferroelectric properties and the molecular mechanisms leading to this “photoferroelectric effect”, respectively.

    14. Optimizing OLED Efficacy of 2,7-Diconjugated 9,9-Dialkylfluorenes by Variation of Periphery Substitution and Conjugation Length (pages 115–122)

      H. P. Rathnayake, A. Cirpan, Z. Delen, P. M. Lahti and F. E. Karasz

      Version of Record online: 5 DEC 2006 | DOI: 10.1002/adfm.200600089

      Thumbnail image of graphical abstract

      Electroluminescence efficacy of 2,7- bis(phenylethenyl)fluorenes is strongly affected by the choice of substituents at the 9-position of the fluorene unit, and upon the terminal phenyl groups. Shortening the conjugation length by removal of the ethenyl units to give 2,7-diphenyl-9,9-dialkylfluorene (OFPh) derivatives decreases both emission intensity and color purity (see figure), although color purity in the OFPhs could be improved by dilution in poly(methylmethacrylate) matrices.

    15. Highly Organized Mesoporous TiO2 Films with Controlled Crystallinity: A Li-Insertion Study (pages 123–132)

      D. Fattakhova-Rohlfing, M. Wark, T. Brezesinski, B. M. Smarsly and J. Rathouský

      Version of Record online: 12 DEC 2006 | DOI: 10.1002/adfm.200600425

      Thumbnail image of graphical abstract

      Li insertion has been used to study the crystallization behavior of mesoporous TiO2 films (see figure) prepared by a novel poly(ethylene-co-butylene)-b-poly(ethylene oxide) block-copolymer template. Such polymers allow the attainment of high crystallinity in the films by annealing at temperatures of up to 650 °C, whilst maintaining the 3D mesoporous structure.

    16. Ordered Mesoporous Silicate Structures as Potential Templates for Nanowire Growth (pages 133–141)

      R. L. Rice, D. C. Arnold, M. T. Shaw, D. Iacopina, A. J. Quinn, H. Amenitsch, J. D. Holmes and M. A. Morris

      Version of Record online: 5 DEC 2006 | DOI: 10.1002/adfm.200600836

      Thumbnail image of graphical abstract

      Morphological control of mesoporous silica thin film pore structure through guided placement and directionality using lithographically patterned (100)-orientated substrates and a dip-coating method is demonstrated (see figure). The channels within the aligned films are filled with cobalt, allowing high- resolution imaging of the pore using electron microscopy. Channel dimensions control pore packing leading to some variations in pore direction and d-spacing.

    17. Organic Field-Effect Transistors and Unipolar Logic Gates on Charged Electrets from Spin-On Organosilsesquioxane Resins (pages 142–153)

      C. Huang, J. E. West and H. E. Katz

      Version of Record online: 12 DEC 2006 | DOI: 10.1002/adfm.200600690

      Thumbnail image of graphical abstract

      A corona-charging process is used to stably store charge in the bulk of an organosilsesquioxane-based gate dielectric (see figure). The stored charge is used to controllably shift the threshold voltage and modulate the current for an organic field-effect transistor fabricated on top of the dielectric. A unipolar logic gate is demonstrated on the charge- patterned resin using FETs with identical dimensions, as schematically depicted in the figure.

    18. High Molar Extinction Coefficient Ion-Coordinating Ruthenium Sensitizer for Efficient and Stable Mesoscopic Dye-Sensitized Solar Cells (pages 154–160)

      D. Kuang, C. Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, S. M. Zakeeruddin and M. Grätzel

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600483

      Thumbnail image of graphical abstract

      High-efficiency (8.4 %) dye-sensitized solar cells are prepared, based on a new high molar extinction coefficient ion- coordinating ruthenium sensitizer (see figure) and nonvolatile organic-solvent electrolyte, which show excellent stability during long-term accelerated testing under 80 °C in the dark or visible-light soaking at 60 °C (IPCE: incident photo-to-current conversion efficiency).

    19. Study of Martensitic Phase Transformation in a NiTiCu Thin-Film Shape-Memory Alloy Using Photoelectron Emission Microscopy (pages 161–167)

      M. Cai, S. C. Langford, M. Wu, W. Huang, G. Xiong, T. C. Droubay, A. G. Joly, K. M. Beck, W. P. Hess and J. T. Dickinson

      Version of Record online: 24 NOV 2006 | DOI: 10.1002/adfm.200600611

      Thumbnail image of graphical abstract

      Photoelectron emission microscopy is used to probe morphological and surface work-function changes during the thermally induced martensitic phase transformation in a polycrystalline NiTiCu thin film. Low-temperature martensite phase has a micrometer-scale wrinklelike structure on the surface (see figure). When the sample is heated above the transition temperature, the image becomes dark and the wrinklelike structure disappears.

  7. Index

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Guide for Authors
    6. Editorial
    7. Full Papers
    8. Index

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