Advanced Materials

Cover image for Vol. 19 Issue 12

June, 2007

Volume 19, Issue 12

Pages 1543–1648

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Cover Picture: A Germanium Inverse Woodpile Structure with a Large Photonic Band Gap (Adv. Mater. 12/2007)

      F. García-Santamaría, M. Xu, V. Lousse, S. Fan, P. V. Braun and J. A. Lewis

      Version of Record online: 13 JUN 2007 | DOI: 10.1002/adma.200790043

      A germanium inverse woodpile structure exhibiting a 25% wide photonic band gap (PBG) is created by direct-write assembly of a polymeric template (see figure and cover) followed by sequential deposition of a sacrificial oxide bilayer and germanium. Upon removal of the template and sacrificial layers, the reflectance spectrum shows a large peak in the mid-IR region, indicative of a PBG considerably larger than those shown by conventional woodpile structures.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Inside Front Cover: Aromatic Carbonyl Derivative Polymers as High-Performance Li-Ion Storage Materials (Adv. Mater. 12/2007)

      X. Han, C. Chang, L. Yuan, T. Sun and J. Sun

      Version of Record online: 13 JUN 2007 | DOI: 10.1002/adma.200790044

      Aromatic carbonyl derivative sulfide polymers (see figure and inside cover) are described as a novel organic positive-electrode material for Li-ion batteries. The excellent capacity and cycling stability performances, as well as many advantages including, amongst others, high safety, make them a possible replacement for conventional inorganic transition-metal-oxide-based materials.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Device Physics of Polymer:Fullerene Bulk Heterojunction Solar Cells (pages 1551–1566)

      P. W. M. Blom, V. D. Mihailetchi, L. J. A. Koster and D. E. Markov

      Version of Record online: 23 MAY 2007 | DOI: 10.1002/adma.200601093

      Thumbnail image of graphical abstract

      A review of the processes and limitations that govern the device operation of polymer:fullerene bulk heterojunction solar cells is presented, with respect to the charge-carrier transport and photogeneration mechanism. Dissociation of electron–hole pairs at the donor/acceptor interface is an important process that limits the charge generation efficiency (see figure).

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. A Germanium Inverse Woodpile Structure with a Large Photonic Band Gap (pages 1567–1570)

      F. García-Santamaría, M. Xu, V. Lousse, S. Fan, P. V. Braun and J. A. Lewis

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adma.200602906

      Thumbnail image of graphical abstract

      A germanium inverse woodpile structure exhibiting a 25% wide photonic band gap (PBG) is created by direct-write assembly of a polymeric template (see figure and cover) followed by sequential deposition of a sacrificial oxide bilayer and germanium. Upon removal of the template and sacrificial layers, the reflectance spectrum shows a large peak in the mid-IR region, indicative of a PBG considerably larger than those shown by conventional woodpile structures.

    2. Highly Ordered Nanoporous Thin Films from Cleavable Polystyrene-block-poly(ethylene oxide) (pages 1571–1576)

      M. Zhang, L. Yang, S. Yurt, M. J. Misner, J.-T. Chen, E. B. Coughlin, D. Venkataraman and T. P. Russell

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602461

      Thumbnail image of graphical abstract

      A cleavable trityl ether juncture is introduced between polystyrene (PS) and poly(ethylene oxide) (PEO), and thus highly ordered nanoporous thin films have been prepared from self-assembled PS-b-PEO diblock copolymers, via the removal of PEO from solvent-annealed PS-b-PEO thin films in a simple two or one-step process. When patterned substrates are used, addressable nanopore arrays with a high degree of lateral order and a well-defined lattice orientation can be readily produced (see figure).

    3. Self-Assembled Si Quantum-Ring Structures on a Si Substrate by Plasma-Enhanced Chemical Vapor Deposition Based on a Growth-Etching Competition Mechanism (pages 1577–1581)

      L. W. Yu, K. J. Chen, J. Song, J. Xu, W. Li, H. M. Li, M. Wang, X. F. Li and X. F. Huang

      Version of Record online: 23 MAY 2007 | DOI: 10.1002/adma.200602804

      Thumbnail image of graphical abstract

      Self-assembled Si quantum-ring structures on a Si(100) substrate are fabricated by using a PECVD technique based on a growth–etching competition mechanism. The as-grown Si ring structures have superior morphology, excellent rotational symmetry, and ultrathin edge width (down to 10 nm, see figure). This growth model also represents a general scheme for controlling and tailoring the shape, size, and complexity of self-assembled nanostructures.

    4. Efficient Luminescence and Energy Transfer in Erbium Silicate Thin Films (pages 1582–1588)

      M. Miritello, R. Lo Savio, F. Iacona, G. Franzò, A. Irrera, A. M. Piro, C. Bongiorno and F. Priolo

      Version of Record online: 23 MAY 2007 | DOI: 10.1002/adma.200601692

      Thumbnail image of graphical abstract

      Erbium silicate thin films that have a good morphology are synthesized by radiofrequency magnetron sputtering. Properly annealed films exhibit efficient luminescence at 1535 nm, and all of the Er ions in the material (about 1022 cm–3) are demonstrated to be optically active. The possibility to efficiently excite Er ions also through electron–hole mediated processes is demonstrated in nanometer-scale Er–Si–O/Si multilayers (see figure). The results are relevant to the improvement of silicon-based devices.

    5. New Transparent Methylsilsesquioxane Aerogels and Xerogels with Improved Mechanical Properties (pages 1589–1593)

      K. Kanamori, M. Aizawa, K. Nakanishi and T. Hanada

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602457

      Thumbnail image of graphical abstract

      Transparent organic–inorganic hybrid aerogels and xerogels are prepared by using a sol–gel synthesis from a single trifunctional precursor, methyltrimethoxysilane (see figure). Obtained aerogels show a reversible shrinkage–recovery response against uniaxial compression. Aerogel-like xerogels are successfully obtained by evaporation drying under ambient pressure because the gels recover from the temporal shrinkage caused by the capillary force of a drying solvent. Pore properties and nanotextures are well-preserved in the resultant xerogels.

    6. Controlled Light Emission by Nanoencapsulation of Fluorophores in Thin Films of Diblock Copolymer Micelles (pages 1594–1596)

      S. I. Yoo, S. J. An, G. H. Choi, K. S. Kim, G.-C. Yi, W.-C. Zin, J. C. Jung and B.-H. Sohn

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adma.200602621

      Thumbnail image of graphical abstract

      Controlled light emission is generated from thin films of fluorophores that are encapsulated in diblock copolymer micelles. The mutual distance between the two fluorophores is regulated by utilization of the nanometer-sized micellar structure, which enables or restricts energy transfer between the fluorophores. This encapsulation method results in single or simultaneous light emission (see figure).

    7. Bicolor Pixels from a Single Active Molecular Material by Surface-Tension-Driven Deposition (pages 1597–1602)

      I. Viola, F. Della Sala, M. Piacenza, L. Favaretto, M. Gazzano, M. Anni, G. Barbarella, R. Cingolani and G. Gigli

      Version of Record online: 23 MAY 2007 | DOI: 10.1002/adma.200602002

      Thumbnail image of graphical abstract

      The fabrication of a green- and red-emitting pixel structure (see figure, scale bar 10 μm) by the single-step, surface-tension-driven assembly of a single luminescent thiophene-based molecular material is reported. The solid-state organization of the selected thiophene-based oligomer is controlled by exploiting the molecular structural arrangement, induced during a dewetting process and facilitated by the great conformational flexibility of the oligomer, typical of several substituted oligothiophenes.

    8. Generation of Uniformly Sized Alginate Microparticles for Cell Encapsulation by Using a Soft-Lithography Approach (pages 1603–1607)

      C. Qiu, M. Chen, H. Yan and H. Wu

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602574

      Thumbnail image of graphical abstract

      A convenient soft lithography method for the generation of alginate gel microparticles with various shapes and sizes (see figure) that can be used to encapsulate biological cells and other materials is described. The formed gel particles are highly uniform and accurately controllable in size and shape, and the generation process is parallel and involves no organic solvents.

    9. Significant Low-Temperature Redox Activity of Ce0.64Zr0.16Bi0.20O1.90 Supported on γ-Al2O3 (pages 1608–1611)

      N. Imanaka, T. Masui, K. Koyabu, K. Minami and T. Egawa

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200502741

      Thumbnail image of graphical abstract

      A new catalyst CeO2-ZrO2-Bi2O3on La-stabilized γ-Al2O3 is prepared for advanced catalytic converters. The low-temperature redox activity of the catalyst (see figure), which is effective below 100 °C, has, to date, never been attained in conventional catalysts without help of precious metals.

    10. Platinum-Coated, Nanoporous Gold Nanorod Arrays: Synthesis and Characterization (pages 1612–1615)

      S.-H. Yoo and S. Park

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602551

      Thumbnail image of graphical abstract

      The fabrication of Pt-coated, vertically aligned, nanoporous gold-nanorod arrays (see figure, left panel) that display electrocatalytically active large surface areas is described. Epitaxial platinum coatings only 1–2 monolayers thick are prepared by the spontaneous replacement of an electrochemically deposited copper layer with platinum metal. Electrochemical characterization of the resulting nanoporous nanorod arrays (see figure, right panel) is carried out as a method for probing catalytic behavior.

    11. Aromatic Carbonyl Derivative Polymers as High-Performance Li-Ion Storage Materials (pages 1616–1621)

      X. Han, C. Chang, L. Yuan, T. Sun and J. Sun

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602584

      Thumbnail image of graphical abstract

      Aromatic carbonyl derivative sulfide polymers (see figure and inside cover) are described as a novel organic positive-electrode material for Li-ion batteries. The excellent capacity and cycling stability performances, as well as many advantages including, amongst others, high safety, make them a possible replacement for conventional inorganic transition-metal-oxide-based materials.

    12. A Novel Hydrogel with High Mechanical Strength: A Macromolecular Microsphere Composite Hydrogel (pages 1622–1626)

      T. Huang, H. G. Xu, K. X. Jiao, L. P. Zhu, H. R. Brown and H. L. Wang

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602533

      Thumbnail image of graphical abstract

      A novel hydrogel with a new, well- defined network structure is prepared through a two-step method in which the radiation-peroxidized macromolecular microspheres act as both initiators and crosslinkers. The macromolecular microsphere composite hydrogel (see figure) can effectively dissipate applied mechanical stress and has extremely high mechanical strength. Some of the hydrogels can nearly completely recover their original shapes, even after an extremely high strain (99.7%) in compression tests.

    13. In Situ Field Emission of Density-Controlled ZnO Nanowire Arrays (pages 1627–1631)

      X. D. Wang, J. Zhou, C. S. Lao, J. H. Song, N. S. Xu and Z. L. Wang

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602467

      Thumbnail image of graphical abstract

      An effective in situ field-emission measurement system, in which the distance between the emitting source and counter electrode can be accurately measured and finely controlled by setting up a second stage inside a scanning electron microscopy chamber, is developed. It is found that nanowires with a density between 60 and 80 μm–2 (see figure) and of ca. 1 μm in length give the highest emitting current density.

    14. High-Rate, Long-Life Ni–Sn Nanostructured Electrodes for Lithium-Ion Batteries (pages 1632–1635)

      J. Hassoun, S. Panero, P. Simon, P. L. Taberna and B. Scrosati

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602035

      Thumbnail image of graphical abstract

      Ni3Sn4intermetallic electrodes prepared into a revolutionary nanostructure, obtained by electrodeposition on a nanoarchitectured Cu substrate, are described. This structure controls the volume stress that accompanies the electrochemical process yielding a performance rarely observed with lithium metal storage electrodes. The new electrode shows impressive electrochemical behavior and cycles in lithium cells for more than 200 cycles (figure shows electrode after cycling) with a stable high capacity.

    15. High Molecular Permeance in a Poreless Ceramic Membrane (pages 1636–1640)

      Y. Gu and S. T. Oyama

      Version of Record online: 15 MAY 2007 | DOI: 10.1002/adma.200602637

      Thumbnail image of graphical abstract

      A novel composite membrane without continuous pores (see figure) with very high permeance for hydrogen is reported. The membrane is composed of a thin (30 nm) permselective silica layer deposited on a graded γ-alumina multilayer substrate, consisting of size-controlled boehmite (AlOOH) sols deposited in order of decreasing size on a macroporous alumina support. A theory involving jumps of permeating molecules between adjacent solubility sites explains its behavior.

    16. Porous Indium Oxide Nanotubes: Layer-by-Layer Assembly on Carbon-Nanotube Templates and Application for Room-Temperature NH3 Gas Sensors (pages 1641–1645)

      N. Du, H. Zhang, B. D. Chen, X. Y. Ma, Z. H. Liu, J. B. Wu and D. R. Yang

      Version of Record online: 23 MAY 2007 | DOI: 10.1002/adma.200602128

      Thumbnail image of graphical abstract

      Porous and polycrystalline In2O3nanotubes are prepared by layer-by-layer assembly on CNT templates and subsequent calcination (see figure). The as-prepared In2O3 nanotubes exhibit superior sensitivity to NH3 at room temperature, as well as a good reproducibility and short response/recovery time. This novel approach presented herein can be extended to synthesize other metal oxide nanotubes such as NiO, SnO2, Fe2O3, and CuO.

  6. Index

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index

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