Advanced Materials

Cover image for Vol. 21 Issue 30

August 14, 2009

Volume 21, Issue 30

Pages 3037–3128

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Progress Reports
    5. Communications
    6. Index
    1. Tunable Full-Color Pixels: Bioinspired Electrochemically Tunable Block Copolymer Full Color Pixels (Adv. Mater. 30/2009)

      Joseph J. Walish, Youngjong Kang, Rafal A. Mickiewicz and Edwin L. Thomas

      Article first published online: 12 AUG 2009 | DOI: 10.1002/adma.200990117

      Thumbnail image of graphical abstract

      The cover represents 1D periodic lamellar block-copolymer photonic gels swollen with methanol and acetic acid and laser-etched to form the outline of a squid. Edwin Thomas and co-workers show on p. 3078 that the gel displays different colors in different areas due to the variation of the relative amounts of the two solvents. In nature, real cephalopods (squid, octopus, and cuttlefish) have the ability to change the chemical environment around their one-dimensional reflectors thus creating naturally tunable photonic elements.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Progress Reports
    5. Communications
    6. Index
    1. Contents: (Adv. Mater. 30/2009) (pages 3037–3042)

      Article first published online: 12 AUG 2009 | DOI: 10.1002/adma.200990118

  3. Progress Reports

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Progress Reports
    5. Communications
    6. Index
    1. Recent Progress in Syntheses and Applications of Dumbbell-like Nanoparticles (pages 3045–3052)

      Chao Wang, Chenjie Xu, Hao Zeng and Shouheng Sun

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200900320

      Thumbnail image of graphical abstract

      Dumbbell-like nanoparticles that contain noble metal and magnetic nanoparticles, or quantum dots, have shown interesting optical and magnetic properties. This progress report reviews the recent advance in the syntheses of dumbbell-like nanoparticles and their potential applications in catalysis and biomedicine.

    2. Layer-by-Layer Hydrogen-Bonded Polymer Films: From Fundamentals to Applications (pages 3053–3065)

      Eugenia Kharlampieva, Veronika Kozlovskaya and Svetlana A. Sukhishvili

      Article first published online: 18 MAY 2009 | DOI: 10.1002/adma.200803653

      Thumbnail image of graphical abstract

      Surface-templated hydrogen-bonded layer-by-layer assembly results in a variety of functional materials, including films of hydrogen-bonded polymers (top), polymer–particle ultrathin coatings, two-component surface hydrogels, and hollow two-component capsules (bottom). These assemblies have promising applications as pH- and/or temperature-responsive drug delivery systems, materials with tunable mechanical properties, release films dissolvable under physiological conditions, and proton-exchange membranes for fuel cells.

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Progress Reports
    5. Communications
    6. Index
    1. Nonuniform Nanowire Doping Profiles Revealed by Quantitative Scanning Photocurrent Microscopy (pages 3067–3072)

      Jonathan E. Allen, Daniel E. Perea, Eric R. Hemesath and Lincoln J. Lauhon

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200803865

      Thumbnail image of graphical abstract

      Scanning photocurrent microscopy (SPCM) is used in semiconductor nanowire devices to establish quantitative potential profiles correlated with nonuniformities in electrical resistivity. Surface doping leads to a nonuniform axial photocurrent (a). Surface etching improves the uniformity of the local photocurrent (b) and reduces the radial and axial carrier concentration gradients (c, blue curve after etching).

    2. Near-Infrared Quantum Cutting for Photovoltaics (pages 3073–3077)

      Bryan M. van der Ende, Linda Aarts and Andries Meijerink

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200802220

      Thumbnail image of graphical abstract

      Efficient quantum cutting by the Pr3+–Yb3+ couple is demonstrated for the conversion of blue/green to near-infrared (NIR) radiation with quantum efficiencies close to 200%. The resonant two-step energy transfer process, which involves one higher-energy photon becoming two NIR photons, may lead to the reduction of energy loss in solar cells, revealing how spectral conversion is a promising avenue for boosting solar-cell efficiency.

    3. Bioinspired Electrochemically Tunable Block Copolymer Full Color Pixels (pages 3078–3081)

      Joseph J. Walish, Youngjong Kang, Rafal A. Mickiewicz and Edwin L. Thomas

      Article first published online: 14 APR 2009 | DOI: 10.1002/adma.200900067

      Thumbnail image of graphical abstract

      A variety of fish and cephalopods use tunable 1D photonic crystals to signal and display information. These animals control the color of the reflectors through chemical secretion by the sympathetic nervous system, which reduces the distance between platelets in reflective cells. This control can be mimicked by a bioinspired, 1D photonic block copolymer that is made tunable (see figure) by the production of chemical species through electrochemistry.

    4. Rapid Microfluidic Generation of Patterned Aldehydes from Hydroxy-Terminated Self-Assembled Monolayers for Ligand and Cell Immobilization on Optically Transparent Indium Tin Oxide Surfaces (pages 3082–3086)

      Abigail Pulsipher, Nathan P. Westcott, Wei Luo and Muhammad N. Yousaf

      Article first published online: 21 APR 2009 | DOI: 10.1002/adma.200802503

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      Selective immobilization of a wide range of ligands on an indium tin oxide (ITO) surface is demonstrated. A chemoselective immobilization strategy to tailor ITO surfaces is developed by selectively oxidizing hydroxyl-terminated phosphonate self-assembled monolayers (SAMs) to aldehyde-presenting SAMs using microfluidic channels and then reacting with oxyamine-containing ligands — all on a chip.

    5. The Role of the Oxygen/Water Redox Couple in Suppressing Electron Conduction in Field-Effect Transistors (pages 3087–3091)

      Carla M. Aguirre, Pierre L. Levesque, Matthieu Paillet, François Lapointe, Benoit C. St-Antoine, Patrick Desjardins and Richard Martel

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200900550

      Thumbnail image of graphical abstract

      The suppression of electron (n-type) conduction observed in back-gated field effect transistors is the result of an electrochemical charge transfer process to the oxygen/water layer adsorbed on hydrophilic substrates. The impact of this phenomenon is demonstrated with nanoscale and thin-film carbon nanotube transistors.

    6. Observation of Unusual Homoepitaxy in Ultrathin Pentacene Films and Correlation with Surface Electrostatic Potential (pages 3092–3098)

      Vivek Kalihari, David J. Ellison, Greg Haugstad and C. Daniel Frisbie

      Article first published online: 22 APR 2009 | DOI: 10.1002/adma.200900362

      Thumbnail image of graphical abstract

      Pentacene second layer grows with a twist (∼76 °) on the first layer, while the third and subsequent layers show commensurism with their respective underlayers. The preferred twisting of the second layer on the first layer gives rise to epitaxial and non-epitaxial domains which also reflect in the surface electrostatic potential measurements.

    7. Low-Temperature Solution-Processed Memory Transistors Based on Zinc Oxide Nanoparticles (pages 3099–3104)

      Hendrik Faber, Martin Burkhardt, Abdesselam Jedaa, Daniel Kälblein, Hagen Klauk and Marcus Halik

      Article first published online: 4 MAY 2009 | DOI: 10.1002/adma.200900440

      Thumbnail image of graphical abstract

      We report on thin!film transistors based on ZnO nanoparticles processed from solution and with a maximum temperature of 100 °C. Electron mobilities up to 2.5 cm2V−1s−1 are obtained, and top-gate TFTs show non-volatile memory properties with a large, stable hysteresis and a memory ratio of 105. Memory TFTs operate in ambient, have good shelf-life (>6 months), and useful endurance properties.

    8. Ultrathin Carbon Nanotube Mat Electrodes for Enhanced Amperometric Detection (pages 3105–3109)

      Ioana Dumitrescu, Jonathan P. Edgeworth, Patrick R. Unwin and Julie V. Macpherson

      Article first published online: 2 JUN 2009 | DOI: 10.1002/adma.200900402

      Thumbnail image of graphical abstract

      A cCVD method for producing transparent, conducting carbon nanotube (CNT) mats of near complete surface coverage is described. Disk-shaped UMEs using the CNT mats reveal reversible electrochemistry for outer sphere redox species and remarkably low capacitance. CNT mat UMEs can be used for the electrochemical detection of dopamine at micromole concentrations in albumin solution, with no decrease in electrode performance even after extensive use.

    9. Altering the Thermodynamics of Phase Separation in Inverted Bulk-Heterojunction Organic Solar Cells (pages 3110–3115)

      Chang Su Kim, Leonard L. Tinker, Brian F. DiSalle, Enrique D. Gomez, Stephanie Lee, Stefan Bernhard and Yueh-Lin Loo

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200803810

      Thumbnail image of graphical abstract

      Organic solar cells: By incorporating nonvolatile additives into blends of P3HT:PCBM, the efficiencies of inverted bulk-heterojunction solar cells are improved almost twofold (see figure). These additives selectively partition into the P3HT phase, effectively increasing phase separation between the P3HT and PCBM.

    10. Directing Colloidal Self-Assembly with Biaxial Electric Fields (pages 3116–3120)

      Mirjam E. Leunissen, Hanumantha Rao Vutukuri and Alfons van Blaaderen

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200900640

      Thumbnail image of graphical abstract

      Hexagonal sheets of colloidal particles self-assemble in a biaxial electric field and can be made permanent by thermal annealing. One can also rapidly switch the suspension structure from isotropic, to 1D ‘strings’ and 2D ‘sheets’, which is useful for applications that require anisotropic suspension properties. Thus, multiaxial fields offer a flexible way to manipulate colloidal interactions and their self-assembled structures.

    11. Ordered Ferroelectric Lead Titanate Nanocellular Structure by Conversion of Anodic TiO2 Nanotubes (pages 3121–3125)

      Jan M. Macak, Cordt Zollfrank, Brian J. Rodriguez, Hiroaki Tsuchiya, Marin Alexe, Peter Greil and Patrik Schmuki

      Article first published online: 21 APR 2009 | DOI: 10.1002/adma.200900587

      Thumbnail image of graphical abstract

      The novel synthesis of ferroelectric perovskite PbTiO3 layers is reported. For that, anodic self-organized TiO2 nanotubes are used as a template for deposition of Pb inside the nanotubes. Upon thermal annealing, the filled template is converted to desired perovskite structure with nanocellular architecture. This approach could be advantageously used for synthesis of other piezoelectric or composite materials.

  5. Index

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Progress Reports
    5. Communications
    6. Index
    1. Author Index and Subject Index Adv. Mater. 30/2009 (pages 3127–3128)

      Article first published online: 12 AUG 2009 | DOI: 10.1002/adma.200990119

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