Advanced Materials

Cover image for Vol. 19 Issue 21

November, 2007

Volume 19, Issue 21

Pages 3403–3733

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Cover Picture: Functionalization of Crystalline Colloidal Arrays through Click Chemistry (Adv. Mater. 21/2007)

      D. D. Evanoff Jr., S. E. Hayes, Y. Ying, G. H. Shim, J. R. Lawrence, J. B. Carroll, R. D. Roeder, J. M. Houchins, C. F. Huebner and S. H. Foulger

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200790083

      Thumbnail image of graphical abstract

      The preparation of well-defined and regioselectively functionalized ordered colloidal particles through the exploitation of ‘click' transformations is presented; specifically, the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition between azides and terminal alkynes to form 1,2,3-triazoles is utilized. This approach is demonstrated through the attachment of 9-azidomethylanthracene to post-hydrogel stabilized, ordered poly(propargyl acrylate) colloidal particles.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Inside Front Cover: Direct Patterning, Conformal Coating, and Erbium Doping of Luminescent nc-Si/SiO2 Thin Films from Solution Processable Hydrogen Silsesquioxane (Adv. Mater. 21/2007)

      C. M. Hessel, M. A. Summers, A. Meldrum, M. Malac and J. G. C. Veinot

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200790084

      Thumbnail image of graphical abstract

      Hydrogen silsesquioxane is used as a solution-borne molecular precursor in the fabrication of highly luminescent thin films of SiO2 containing silicon nanocrystals. Films are readily formed on non-flat substrates (e.g., optical fibers) and patterned using e-beam lithography (see figure).

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Contents: Adv. Mater. 21/2007 (pages 3403–3419)

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200790081

  4. Correspondence

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Superhydrophobic Surfaces: Adhesive Strongly to Water? (pages 3421–3422)

      W. Li and A. Amirfazli

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200601764

    2. Definition of Superhydrophobic States (pages 3423–3424)

      S. Wang and L. Jiang

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700934

  5. Reviews

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Synthesis and Surface Engineering of Complex Nanostructures by Atomic Layer Deposition (pages 3425–3438)

      M. Knez, K. Nielsch and L. Niinistö

      Article first published online: 2 OCT 2007 | DOI: 10.1002/adma.200700079

      Thumbnail image of graphical abstract

      Atomic layer deposition (ALD) recently became a powerful method to produce or modify nanostructures like nanotubes, nanowires or even electronic devices or photonic crystals. This Review article gives an overview of the rapid development of ALD in the emerging field of nanotechnology.

    2. Metallopolymers: New Multifunctional Materials (pages 3439–3468)

      G. R. Whittell and I. Manners

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200702876

      Thumbnail image of graphical abstract

      Metal-containing and metallosupramolecular polymers offer a wealth of exciting opportunities as materials that combine the easy processing of polymers with the functionality provided by the presence of metal centers. For example, zinc polyphenyleneethynylene (see graphic) is a readily fabricated material with interesting photo-physical properties.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Guided Formation of a Sub-10 nm Silicide Dot Array on an Area Patterned by Electron-Beam Lithography (pages 3469–3472)

      J.-S. Wi, T.-Y. Lee, H.-M. Kim, H.-S. Lee, S. -W. Nam, I. J. Shin, K. H. Shin and K.-B. Kim

      Article first published online: 2 OCT 2007 | DOI: 10.1002/adma.200701043

      Thumbnail image of graphical abstract

      A method for forming sub-10 nm silicide dots is reported. Crystalline Pd2Si dots with a diameter of approximately 8 nm are formed on a pattern with a scale of a few tens of nanometers defined by electron-beam lithography (see figure, scale bar is 200 nm).

    2. Full-Color Mesophase Silicate Thin Film Phosphors Incorporated with Rare Earth Ions and Photosensitizers (pages 3473–3479)

      D. Zhao, S.-J. Seo and B.-S. Bae

      Article first published online: 25 SEP 2007 | DOI: 10.1002/adma.200602562

      Thumbnail image of graphical abstract

      Full-color mesophase silicate thin film phosphors incorporated with rare earth ions and photosensitizers exhibit multicolor photoluminescence that covere the whole visible range under UV excitation. The multiple colors can be finely tuned by varying the relative concentrations of the RE trivalent ions and photosensitizers. The mesophase silica thin films have promising applications in display field.

    3. Self-Walking Gel (pages 3480–3484)

      S. Maeda, Y. Hara, T. Sakai, R. Yoshida and S. Hashimoto

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700625

      Thumbnail image of graphical abstract

      You'll never walk alone? A gel actuator that can generate autonomous motility with a wormlike motion without external driving stimuli is produced. The autonomous motion is produced by dissipating the chemical energy of an oscillating reaction occurring inside the gel. Even though the gel is completely composed of synthetic polymer, it shows an autonomous motion as if it were “alive”. By coupling this with a ratchet mechanism, the gel walks by repeatedly bending and stretching itself like a looper (see figure).

    4. Sol-Gel Inks for Direct-Write Assembly of Functional Oxides (pages 3485–3489)

      E. B. Duoss, M. Twardowski and J. A. Lewis

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200701372

      Thumbnail image of graphical abstract

      Sol-gel inks have been developed for direct-write assembly of functional oxide structures with sub-micron features. Highly uniform, planar and 3D micro-periodic structures (see figure) have been patterned that can be readily converted to titania upon calcination.

    5. Cationic Conjugated Polymer/DNA Complexes for Amplified Fluorescence Assays of Nucleases and Methyltransferases (pages 3490–3495)

      F. Feng, Y. Tang, F. He, M. Yu, X. Duan, S. Wang, Y. Li and D. Zhu

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700165

      Thumbnail image of graphical abstract

      A new method is developed for sensitive, homogeneous, and convenient assays of nucleases and methyltransferases using complexes of cationic conjugated polymers with DNA containing a fluorescein tag at the 5′-terminus (DNA-Fl). The cleavage of DNA by nucleases can be monitored by fluorescence spectra by observing conjugated-polymer or fluorescein emission changes in aqueous solutions.

    6. Realization of Room-Temperature Ferromagnetism and of Improved Carrier Mobility in Mn-Doped ZnO Film by Oxygen Deficiency, Introduced by Hydrogen and Heat Treatments (pages 3496–3500)

      S. Y. Park, P. J. Kim, Y. P. Lee, S. W. Shin, T. H. Kim, J.-H. Kang and J. Y. Rhee

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200602144

      Thumbnail image of graphical abstract

      The room-temperature ferromagnetic (RTFM) ordering with a very low carrier mobility occurs in polycrystalline Mn-doped ZnO film with δ ∼ 0.04. We successfully fabricated RTFM Zn0.96Mn0.04O:H film with a substantially improved carrier mobility (∼ 400% larger than that of the as-grown sample) through the hydrogen-implantation and a subsequent heat treatment.

    7. Self-Assembly and Crystalline Growth of Poly(3,4-ethylenedioxythiophene) Nanofilms (pages 3501–3506)

      J.-Y. Kim, M.-H. Kwon, Y.-K. Min, S. Kwon and D.-W. Ihm

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200602163

      Thumbnail image of graphical abstract

      Vapor-phase polymerization is used for the first time to prepare ultrathin, polycrystalline conducting films of poly(3,4-ethylenedioxythiophene) (PEDOT). The polarized optical microscopy images (see figure) display the progress of crystalline growth at 30 °C: a) initial step of self-assembled PEDOT film formation (amorphous shape); b) nucleation; c) crystalline growth; and d) dendritic growth. The scale is 100 × 100 μm2.

    8. Functionalization of Crystalline Colloidal Arrays through Click Chemistry (pages 3507–3512)

      D. D. Evanoff Jr., S. E. Hayes, Y. Ying, G. H. Shim, J. R. Lawrence, J. B. Carroll, R. D. Roeder, J. M. Houchins, C. F. Huebner and S. H. Foulger

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200602901

      Thumbnail image of graphical abstract

      The preparation of well-defined and regioselectively functionalized ordered colloidal particles through the exploitation of ‘click' transformations is presented; specifically, the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition between azides and terminal alkynes to form 1,2,3-triazoles is utilized. This approach is demonstrated through the attachment of 9-azidomethylanthracene to post-hydrogel stabilized, ordered poly(propargyl acrylate) colloidal particles.

    9. Direct Patterning, Conformal Coating, and Erbium Doping of Luminescent nc-Si/SiO2 Thin Films from Solution Processable Hydrogen Silsesquioxane (pages 3513–3516)

      C. M. Hessel, M. A. Summers, A. Meldrum, M. Malac and J. G. C. Veinot

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700731

      Thumbnail image of graphical abstract

      Hydrogen silsesquioxane is used as a solution-borne molecular precursor in the fabrication of highly luminescent thin films of SiO2 containing silicon nanocrystals. Films are readily formed on non-flat substrates (e.g., optical fibers) and patterned using e-beam lithography (see figure).

    10. Unprecedented “One-Finger-Push”-Induced Phase Transition With a Drastic Color Change in an Inorganic Material (pages 3517–3519)

      M. Gaudon, P. Deniard, A. Demourgues, A.-E. Thiry, C. Carbonera, A. Le Nestour, A. Largeteau, J.-F. Létard and S. Jobic

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700905

      Thumbnail image of graphical abstract

      A drastic color transition from green to brownish-red in the CuMo1–xWxO4 system occurs during a first-order phase transition. This study shows that it is possible to control this transition in terms of temperature or pressure with respect to the tungsten content (see figure). Hence, the use of these compounds for new applications as temperature indicators or shock detectors is feasible.

    11. Microwave Annealing of Polymer Photovoltaic Devices (pages 3520–3523)

      C.-J. Ko, Y.-K. Lin and F.-C. Chen

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700741

      Thumbnail image of graphical abstract

      A selective microwave irradiation annealing method for the preparation of efficient polymer photovoltaic devices is reported. The power conversion efficiency of the devices increases upon increasing the irradiation time. In situ temperature probing suggests that the microwaves could penetrate the anode without any loss of energy, whereas the organic active layer and the cathode were both heated. Furthermore, X-ray diffraction indicated that microwave annealing enhanced the degree of crystallization of the polymer chains.

    12. Flexible Fabrication of Microarrays of Microwells (pages 3524–3528)

      F. Khan, R. Zhang, A. Unciti-Broceta, J. J. Díaz-Mochón and M. Bradley

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700818

      Thumbnail image of graphical abstract

      Arrays of microwells are generated by contact printing on polymer substrate and used successfully to capture suspension cells, K562. This fabrication technique proves useful in a controllable cellular platform for high-throughput screening.

    13. A Novel Anti-inflammatory Surface for Neural Electrodes (pages 3529–3533)

      W. He, G. C. McConnell, T. M. Schneider and R. V. Bellamkonda

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700943

      Thumbnail image of graphical abstract

      An inherently anti-inflammatory surface for neural electrodes is fabricated by immobilization of a neuroimmunomodulatory peptide alpha-MSH. In vitro cell studies and in vivo rodent studies demonstrate that the tethered peptide retains its anti-inflammatory properties, and is able to directly modulate microglial response by modulating the expression of inflammatory cytokine (see figure), thereby suggesting the potential of this strategy to improve the reliability of chronic neural implants in vivo.

    14. Dendronized Ferromagnetic Gold Nanoparticles Self-Organized in a Thermotropic Cubic Phase (pages 3534–3539)

      B. Donnio, P. García-Vázquez, J.-L. Gallani, D. Guillon and E. Terazzi

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701252

      Thumbnail image of graphical abstract

      Gold nanoparticles possessing a positionally ordered 3D liquid crystalline phase in the bulk have been prepared (see figure). Induction of the mesophase results from the synergy between the gold core and the non-mesogenic dendrons. These particles are also ferromagnetic up to 400 K and are able to self-organize in a 2D hexagonal array on solid substrates, opening perspectives in the field of information storage at the molecular level.

    15. Solution Based Self-Assembly of an Array of Polymeric Thin-Film Transistors (pages 3540–3543)

      A. Salleo and A. C. Arias

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700445

      Thumbnail image of graphical abstract

      Spontaneous self-organization of different materials from solution into an array of isolated and encapsulated thin-film-transistors (TFTs) is induced. We demonstrate the self-assembly of a 64 polymer TFT array with a yield higher than 95%. This work constitutes a first step towards self-assembly of multi-layer, multi-component circuits out of solution.

    16. Electrospinning pH-Responsive Block Copolymer Nanofibers (pages 3544–3548)

      L. Wang, P. D. Topham, O. O. Mykhaylyk, J. R. Howse, W. Bras, R. A. L. Jones and A. J. Ryan

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700107

      Thumbnail image of graphical abstract

      Ultrafine fibers of a pH-responsive triblock copolymer with different diameters, alignment, and microdomain order are prepared via electrospinning and solvent-vapor annealing. Fibrous samples display much quicker response times than the corresponding films owing to the increase in external surface area. The fibrils of annealed, aligned, electrospun fibers show a dramatic apparent “1D” pH-induced size-change during the experiment.

    17. Ubiquitous Transference of a Free-Standing Polysaccharide Nanosheet with the Development of a Nano-Adhesive Plaster (pages 3549–3553)

      T. Fujie, Y. Okamura and S. Takeoka

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700661

      Thumbnail image of graphical abstract

      A free-standing polysaccharide nanosheet prepared by using a spin-coating-assisted layer-by-layer method is transferred from silicone rubber onto human skin (see figure) by fabricating a three-layered ‘nano-adhesive plaster' involving a water-soluble sacrificial layer. By using this novel technique, conventional ultrathin films can be made without the need for a solid substrate.

    18. Multicolor Emission from Ordered Assemblies of Organic 1D Nanomaterials (pages 3554–3558)

      Y. S. Zhao, H. Fu, F. Hu, A. D. Peng and J. Yao

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701513

      Thumbnail image of graphical abstract

      Ordered crystalline 1D nanomaterial assemblies are prepared from an organic blue-light-emitting material, 1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene (PPCP). The as-prepared PPCP nanostructures exhibit a novel multicolor emission property, that is, blue, green, and red emission can be achieved when irradiating the PPCP nanomaterial assemblies with different wavelengths.

      Corrected by:

      Correction: Multicolor Emission from Ordered Assemblies of Organic One-Dimensional Nanomaterials

      Vol. 20, Issue 7, Article first published online: 29 APR 2008

    19. Controlling Oxidation States in Uranium Oxides through Epitaxial Stabilization (pages 3559–3563)

      A. K. Burrell, T. M. McCleskey, P. Shukla, H. Wang, T. Durakiewicz, D. P. Moore, C. G. Olson, J. J. Joyce and Q. Jia

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701157

      Thumbnail image of graphical abstract

      We have demonstrated that oxidation states in uranium-oxides such as UO2 and U3O8 can be controlled through epitaxial stabilization by growing single-crystal-like films. We have further shown that the growth of polymorphic uranium oxides is feasible by using different substrates with appropriate in-plane lattice parameters. The clearly improved stability of epitaxial uranium-oxides illustrates the significance of crystal lattice pinning on the control of surface chemistry of materials.

    20. Work Function of a Room-Temperature, Stable Electride [Ca24Al28O64]4+(e)4 (pages 3564–3569)

      Y. Toda, H. Yanagi, E. Ikenaga, J. J. Kim, M. Kobata, S. Ueda, T. Kamiya, M. Hirano, K. Kobayashi and H. Hosono

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700663

      Thumbnail image of graphical abstract

      The work function of the electride [Ca24Al28O64]4+(e-)4 is presented (see figure). The intrinsic value of ca. 2.4 eV is close to that of potassium regardless of its high chemical stability under ambient atmosphere. This property originates from the intrinsic nature of electrons in 3D connected sub-nanometer-sized cages having a positive charge.

    21. High-Field Scanning Probe Lithography in Hexadecane: Transitioning from Field Induced Oxidation to Solvent Decomposition through Surface Modification (pages 3570–3573)

      I. Suez, M. Rolandi, S. A. Backer, A. Scholl, A. Doran, D. Okawa, A. Zettl and J. M. J. Fréchet

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700716

      Thumbnail image of graphical abstract

      High field scanning probe lithography in hexadecane leads to two different chemical reactions depending on surface hydrophilicity. On a hydrophilic surface, oxidation of the sample occurs; a hydrophobic surface, results in solvent decomposition and nanoscale deposition of etch resistant material. The features are characterized with photoelectron emission microscopy and are carbonaceous in nature with a highly cross-linked bonding network. Tone reversal in a fluorinated etch is achieved.

    22. Inkjet-Printed Nanocrystal Photodetectors Operating up to 3 μm Wavelengths (pages 3574–3578)

      M. Böberl, M. V. Kovalenko, S. Gamerith, E. J. W. List and W. Heiss

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700111

      Thumbnail image of graphical abstract

      Solution processable photodetectors operating up to 3 μm cut-off wavelength based on HgTe nanocrystals are demonstrated. Ink-jet printing is employed for the accurate deposition of the nanocrystals on the electrodes. The highly reproducible photodetectors exhibit high sensitivities for small illumination powers, making the devices ideal candidates for night vision applications.

    23. Nanoparticle Self-Assembly Directed by Antagonistic Kinase and Phosphatase Activities (pages 3579–3583)

      G. von Maltzahn, D.-H. Min, Y. Zhang, J.-H. Park, T. J. Harris, M. Sailor and S. N. Bhatia

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200701183

      Thumbnail image of graphical abstract

      Superparamagnetic Fe3O4nanoparticles (NPs) are engineered to reversibly self-assemble in response to antagonistic enzyme inputs. Tyrosine kinase activity directs substrate-NPs and SH2 domain-NPs to coalesce via polyvalent SH2-phosphopeptide binding. Phosphatase antagonizes this process and directs NP dispersion. By coupling assembly to substrate phosphorylation, the kinase activity is imaged via quantitative T2 relaxation changes in MRI.

    24. Fabrication of Double-Length-Scale Patterns via Lithography, Block Copolymer Templating, and Electrodeposition (pages 3584–3588)

      Y.-T. Tseng, W.-H. Tseng, C.-H. Lin and R.-M. Ho

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700042

      Thumbnail image of graphical abstract

      A straightforward and effective method for the fabrication of double-length-scale patterned (i.e., composite micro- and nanopatterned) carbon nanotube (CNT) arrays can be achieved by block copolymer templating on a prepatterned conducting substrate followed by electroplating to deposit Ni (see figure). Significant improvement in the current density with low threshold voltage and high field-emission efficiency can be found in the composite micro- and nanopatterns of CNT arrays.

    25. Snapping Surfaces (pages 3589–3593)

      D. P. Holmes and A. J. Crosby

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700584

      Thumbnail image of graphical abstract

      A simple, robust, biomimetic responsive surface based on controlled elastic instabilities using an array of microlens shells as a surface geometry is presented. The snap-through transition is dictated by geometry, length-scale, and materials properties, thus the transition time, triggering sensitivity, and magnitude change are highly tunable. Their potential use as a rapidly switchable optical device is illustrated.

    26. Achieving Perpendicular Alignment of Rigid Polythiophene Backbones to the Substrate by Using Solvent-Vapor Treatment (pages 3594–3598)

      G. H. Lu, L. G. Li and X. N. Yang

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700014

      Thumbnail image of graphical abstract

      The rigid backbone of the poly(3-butylthiophene) molecule adopts a perpendicular orientation with respect to the substrate by using a solvent-vapor treatment (see figure). Small and closely contacting spherulites instead of conventional whisker-like crystals are achieved. This could be utilized to improve charge-carrier mobility particularly in the direction normal to the film plane by designing and constructing thick crystalline domains in the functional layer.

    27. Efficient White Organic Light-Emitting Devices Based on Phosphorescent Platinum(II)/Fluorescent Dual-Emitting Layers (pages 3599–3603)

      B.-P. Yan, C. C. C. Cheung, S. C. F. Kui, H.-F. Xiang, V. A. L. Roy, S.-J. Xu and C.-M. Che

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200602683

      Thumbnail image of graphical abstract

      Efficient white organic light-emitting devices with uncomplicated architectures are fabricated employing phosphorescent platinum(II) complexes containing extended π-conjugated cyclometalated ligands as a yellow-light source, and fluorescent material 9,10-bis-(β-naphthyl)-anthrene as a blue-light source. Peak external quantum (power) efficiencies of 11.8 % (18.4 lm W–1) are demonstrated (see figure).

    28. Optical and Structural Properties of Single Phase Epitaxial p-Type Transparent Oxide Thin Films (pages 3604–3607)

      H. Luo, M. Jain, T. M. McCleskey, E. Bauer, A. K. Burrell and Q. Jia

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700528

      Thumbnail image of graphical abstract

      Single phase, epitaxial, transparent, and p-type CuAlO2films are successfully grown on c-plane sapphire by polymer-assisted deposition. At wavelengths in the range of 400–1000 nm, the optical transmittance of the films is 60–80 %. The energy band gap is 3.6 eV. The as-synthesized CuAlO2 films are highly resistive, with room-temperature resistivity around 105 Ω cm. The resistivity can be reduced to 103–104 Ω cm by post-annealing films in oxygen.

    29. Drosophila as a Live Substrate for Solid-State Microfabrication (pages 3608–3612)

      A. J. Shum, J. Crest, G. Schubiger and B. A. Parviz

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200602962

      Thumbnail image of graphical abstract

      Drosophila shows a surprisingly high resilience to vacuum exposure. A systematic study shows that some flies survive even after three hours of residence in a few mTorr vacuum. This observation opens the way for using Drosophila as a substrate for direct solid-state microfabrication and incorporation of inorganic microstructures for hybrid biological/abiological manufacturing and microrobotics applications.

    30. Rubrene/Fullerene Heterostructures with a Half-Gap Electroluminescence Threshold and Large Photovoltage (pages 3613–3617)

      A. K. Pandey and J.-M. Nunzi

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701052

      Thumbnail image of graphical abstract

      Light and current generation functions from a rubrene/fullerene heterostructure are integrated into an efficient organic dual device (see figure). Electroluminescence, with the characteristic rubrene color, has a turn-on voltage less than 1 V. Solar-power conversion efficiency reaches 3 % with a 5.3 mA cm–2 short-circuit current density and almost 1 V open- circuit voltage under AM 1.5 illumination. The half-bandgap electroluminescence turn-on voltage is interpreted as an Auger fountain effect.

    31. Molecular Thin Films: A New Type of Magnetic Switch (pages 3618–3622)

      S. Heutz, C. Mitra, W. Wu, A. J. Fisher, A. Kerridge, M. Stoneham, A.  H. Harker, J. Gardener, H.-H. Tseng, T. S. Jones, C. Renner and G. Aeppli

      Article first published online: 2 OCT 2007 | DOI: 10.1002/adma.200701458

      Thumbnail image of graphical abstract

      The magnetic coupling of flexible metal phthalocyanine (MPc) thin films can be modified depending on the polymorphic form adopted by the crystals. A simple annealing procedure can switch the couplings from antiferromagnetic to ferromagnetic (MnPc) or paramagnetic (CuPc), opening up avenues for spintronic applications. Density functional and perturbation theories rationalize these trends and attribute the coupling mechanism to indirect exchange.

    32. Printed Graphene Circuits (pages 3623–3627)

      J.-H. Chen, M. Ishigami, C. Jang, D. R. Hines, M. S. Fuhrer and E. D. Williams

      Article first published online: 5 OCT 2007 | DOI: 10.1002/adma.200701059

      Thumbnail image of graphical abstract

      Flexible and transparent electronic devices with extremely high mobilities are fabricated from a graphene sheet, a single atomic layer of graphite, by using the transfer printing method. “Printed” graphene circuits achieve field effect mobilities of up to 10000 cm2/Vs at room temperature. Our printing technique is scaleable and a more chemically-gentle process for fabricating high quality graphene, and nanoscale devices in general.

    33. Plasmon Hybridization in Stacked Cut-Wire Metamaterials (pages 3628–3632)

      N. Liu, H. Guo, L. Fu, S. Kaiser, H. Schweizer and H. Giessen

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700123

      Thumbnail image of graphical abstract

      Stacked metamaterials consisting of gold cut-wires and a gold mirror are fabricated. The optical properties are determined. Plasmon hybridization allows for the intuitive attribution of the resonances in the optical spectra (see figure). Antisymmetric modes constitute magnetic resonances, which are suited for displaying negative permeability.

    34. Thermoresponsive Microtextured Culture Surfaces Facilitate Fabrication of Capillary Networks (pages 3633–3636)

      Y. Tsuda, M. Yamato, A. Kikuchi, M. Watanabe, G. Chen, Y. Takahashi and T. Okano

      Article first published online: 5 OCT 2007 | DOI: 10.1002/adma.200700988

      Thumbnail image of graphical abstract

      A novel cell culture surface is developed that induces the tubular formation of endothelial cells and facilitates the intact harvesting of fabricated capillary-like structures by utilizing a thermoresponsive polymer, poly(N-isopropylacrylamide). The tubular cell networks, such as the one shown in the figure, may be applicable for the fabrication of 3D vascularized tissue grafts.

    35. Spontaneous Chemical Vapor Growth of NiSi Nanowires and Their Metallic Properties (pages 3637–3642)

      C.-J. Kim, K. Kang, Y. S. Woo, K.-G. Ryu, H. Moon, J.-M. Kim, D.-S. Zang and M.-H. Jo

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700609

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      A simple and controlled growth of metallic NiSi nanowires at low temperatures (< 400 °C) by a chemical vapor deposition using SiH4 at a low supersaturation limit is reported. It is demonstrated that the simple and low temperature synthesis of metallic nanowires is compatible with conventional Si processing and provide interesting strategies for their possible applications as interconnects in Si microelectronics and as field emitters in field emission displays.

    36. Electron and Hole Transport through Mesoporous TiO2 Infiltrated with Spiro-MeOTAD (pages 3643–3647)

      H. J. Snaith and M. Grätzel

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200602085

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      Charge transport in a solid-state dye-sensitized solar cell is investigated. Unexpectedly, hole transport in the organic component (Spiro-MeOTAD) is faster than the electron transport in the inorganic component (TiO2). The electron mobility or diffusion coefficient through TiO2 does not increase with increasing illumination intensity, as would be predicted by the multitrapping model for electron transport. The results highlight that poor electron transport in TiO2 is a key issue for further improvements in device performance.

    37. Controlled Etching of Carbon Nanotubes by Iron-Catalyzed Steam Gasification (pages 3648–3652)

      W. Xia, V. Hagen, S. Kundu, Y. Wang, C. Somsen, G. Eggeler, G. Sun, G. Grundmeier, M. Stratmann and M. Muhler

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700763

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      A localized etching method based on catalytic steam gasification was developed to modify carbon nanotubes in a pre-determined manner. The etching, occurring only at the interface, created different etching patterns depending on the iron catalyst by means of an eco-friendly, low-cost process using water vapor. Both the surface roughness and the number of surface defects such as edge planes were significantly enhanced.

    38. Microdisk and Microring Lasers of Thiophene–Phenylene Co-Oligomers Embedded in Si/SiO2 Substrates (pages 3653–3655)

      F. Sasaki, S. Kobayashi, S. Haraichi, S. Fujiwara, K. Bando, Y. Masumoto and S. Hotta

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200701008

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      Lasing emission with whispering gallery modes is achieved for microcavities of thiophene–phenylene co-oligomers embedded in Si/SiO2 substrates. The microcavities show a lasing threshold that is 20–50 % of the values observed for bulk films. Quality factors of a few thousand are achieved for these structures. The grain boundaries and cracks in the film at the circumferential interface are thought to limit the quality factor and lasing threshold of these microcavities.

    39. Nanostructure of the Interpenetrating Networks in Poly(3-hexylthiophene)/fullerene Bulk Heterojunction Materials: Implications for Charge Transport (pages 3656–3659)

      W. Ma, A. Gopinathan and A. J. Heeger

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700019

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      The fractal dimension, chemical distance, and finally the effect of an applied electric field on the transport within the interpenetrating network of poly(3-hexylthiophene)/fullerene bulk heterojunction materials are calculated. According to simulations, charge carriers travel along a pathway ~4 times longer than the regular Euclidean distance. In an applied electric field, the drift speed of charged carriers is reduced because of field-induced trapping on the tortuous network.

    40. Direct Decomposition of Nitric Oxide over C-Type Cubic (Gd1–xyYxBay)2O3–y Solid Solutions (pages 3660–3663)

      N. Imanaka, T. Masui and H. Masaki

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200602323

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      Direct decomposition of NO into N2 and O2 on a C-type cubic (Gd1–xyYxBay)2O3–y solid solution catalyst is investigated. These novel catalysts are found to exhibit higher activity and conversion rates than conventional La-containing perovskite oxide catalysts for NO decomposition. C-type cubic (Gd1–xyYx-Bay)2O3–y catalysts are therefore considered to be possible candidates for the conversion of harmful exhaust gases.

    41. Patterning of Electrospun Fibers Using Electroconductive Templates (pages 3664–3667)

      D. Zhang and J. Chang

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700896

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      Electrospun mats with complex ordered architectures are fabricated by using patterned conductive collectors. The effect of the diameter of the web wires and the protrusions on the formation of the patterns of the fibrous materials are elaborated and woven structures that have been generated by a time-dependent control of the arrangement of the protrusions in the collector are shown (see figure).

    42. Control of Two-Dimensional Nanopatterns by Adjusting Intermolecular Interactions (pages 3668–3671)

      M. Matsumoto, S. Watanabe, K.-i. Tanaka, H. Kimura, M. Kasahara, H. Shibata, R. Azumi, H. Sakai, M. Abe, Y. Kondo and N. Yoshino

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700447

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      Ultrathin films of small organic molecules are patterned with nanostructures, the size of which is controlled by adjusting intermolecular interactions. Nanowires of controllable widths form in the mixed Langmuir–Blodgett (LB) films of long-chain fatty acid and hybrid carboxylic acid (see figure). Templates, which can confine both organic and inorganic materials, are fabricated from three-component LB films, containing an amphiphilic silane-coupling agent.

    43. Harvesting Triplet Excitons from Fluorescent Blue Emitters in White Organic Light-Emitting Diodes (pages 3672–3676)

      G. Schwartz, M. Pfeiffer, S. Reineke, K. Walzer and K. Leo

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700641

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      A novel concept for white organic light emitting diodes (OLEDs) enabling the utilization of all electrically generated excitons for light generation is introduced. The key feature is a fluorescent blue emitter with high triplet energy, rendering it possible to harvest its triplet excitons by letting them diffuse to an orange phosphorescent iridium complex.

    44. Directed Assembly of Hierarchical CdS Nanotube Arrays from CdS Nanoparticles: Enhanced Solid State Electro-chemiluminescence in H2O2 Solution (pages 3677–3681)

      C. Z. Wang, Y. F. E, L. Z. Fan, Z. H. Wang, H. B. Liu, Y. L. Li, S. H. Yang and Y. L. Li

      Article first published online: 23 OCT 2007 | DOI: 10.1002/adma.200701386

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      Hierarchical CdS nanotube arrays (see figure) are assembled in an anodic aluminum oxide template from CdS nanoparticles by using a controlled solution precipitation method. The hierarchical nanotube arrays, with high porosity and uniform alignment, display considerably varied photoluminescence and enhanced solid state electro-chemiluminescence in H2O2 solution compared with those of random nanoparticle aggregates.

    45. Pseudomorphic Transformation of Inverse Opal Tungsten Oxide to Tungsten Carbide (pages 3682–3686)

      J. C. Lytle, N. R. Denny, R. T. Turgeon and A. Stein

      Article first published online: 23 OCT 2007 | DOI: 10.1002/adma.200700717

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      Pseudomorphic carburizations of nanostructured tungsten oxide inverse opal preforms are demonstrated for the first time, retaining structural features on a sub-100-nm scale.

    46. Direct Covalent Assembly to Fabricate Microcapsules with Ultrathin Walls and High Mechanical Strength (pages 3687–3691)

      Z. Feng, Z. Wang, C. Gao and J. Shen

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700541

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      Direct covalent LBL assembly was performed on silica particles using PGMA and PAH as the building blocks. After core removal, hollow microcapsules with ultrathin shells and good shell completeness were obtained. The microcapsules have good mechanical strength and stability against extreme pHs and elevated temperature too.

    47. Core-Fluorinated Perylene Bisimide Dyes: Air Stable n-Channel Organic Semiconductors for Thin Film Transistors with Exceptionally High On-to-Off Current Ratios (pages 3692–3695)

      R. Schmidt, M. M. Ling, J. H. Oh, M. Winkler, M. Könemann, Z. Bao and F. Würthner

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701478

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      Two core-fluorinated perylene bisimide semiconductors have been synthesized and n-channel field effect transistors have been fabricated by vapor-deposition techniques. Charge carrier mobilities as high as 0.34 cm2V-1s-1 and unprecedented on-to-off current ratios around 107 have been measured for these devices in air.

    48. Forced Soft Lithography (FSL): Production of Micro- and Nanostructures in Thin Freestanding Sheets of Chitosan Biopolymer (pages 3696–3701)

      J. G. Fernandez, C. A. Mills, M. Pla-Roca and J. Samitier

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200601443

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      A “forced” soft lithography (FSL) technique is described for production of micro- and nanostructures into the surface of polymers at room temperature. The technique can be used with polymer/mould combinations that are unsuitable for conventional soft lithography, and has been used to structure the surface of the Chitosan biopolymer. Theoretical descriptions of the filling of the mould cavities and the possible formation of bubbles in the polymer are given.

    49. Fabrication of Aligned Fibrous Arrays by Magnetic Electrospinning (pages 3702–3706)

      D. Yang, B. Lu, Y. Zhao and X. Jiang

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700171

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      Electrospinning magnetic-nanoparticle-doped polymers under the influence of a magnetic field produces aligned arrays of fibers over large areas (see figure). These nanofibers can be transferred onto the surfaces of other substrates. They can also be stacked into multilayer grids.

    50. Fiber-Oriented Liquid Crystal Polarizers Based on Anisotropic Electrospinning (pages 3707–3711)

      Y. F. Yao, Z.-Z. Gu, J. Z. Zhang, C. Pan, Y. Y. Zhang and H. M. Wei

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200701212

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      A novel fiber-oriented scattering polarizer is prepared by infiltrating liquid crystal into an aligned-fiber film (schematically shown in the figure), which is fabricated by using an optimized strategy of anisotropic electrospinning. The new-style polarizer has a high polarizing efficiency, is simple to fabricate and has uniform and controllable optical characteristics. It could be used in flat-panel displays, antiglare sunglasses, photography filters or optical instruments.

    51. Lithiated MoO3 Nanobelts with Greatly Improved Performance for Lithium Batteries (pages 3712–3716)

      L. Q. Mai, B. Hu, W. Chen, Y. Y. Qi, C. S. Lao, R. S. Yang, Y. Dai and Z. L. Wang

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700883

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      α-MoO3nanobelts are successfully lithiated by a secondary reaction. The capacity retention rate of lithiated MoO3 nanobelts is 92 % after 15 cycles, whereas the non-lithiated nanobelts retain only 60 % (see figure). The conductivity is increased by close to two orders of magnitudes after lithiation suggesting that Li+ ions have been introduced into the MoO3 layers during lithiation.

    52. Hierarchically Nanostructured Polymer Films Based on Molecularly Imprinted Surface-Bound Nanofilaments (pages 3717–3720)

      F. Vandevelde, A.-S. Belmont, J. Pantigny and K. Haupt

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200700600

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      Hierarchically nanostructured materials that combine two or more levels of structuring can exhibit a combination of useful features. We have generated surface-bound nanofilaments by nanomolding on nanoporous template surfaces. The filaments also carry molecularly imprinted binding sites that selectively recognize the drug propranolol. The wetting properties of the surface are altered by nanostructuration. We believe that these materials can be useful for applications such as biosensors and biochips.

    53. High Performance Fibres from ‘Dog Bone’ Carbon Nanotubes (pages 3721–3726)

      M. Motta, A. Moisala, I. A. Kinloch and Alan H. Windle

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200700516

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      The direct spinning of carbon nanotubes yields fibres with distinctly encouraging mechanical properties. While the best strength (2.2 N/tex) and stiffness (160 N/tex) promise competition for established carbon fibres, the maximum energy absorbed at fracture (46 J/g) is somewhat higher. The fibres consist of very long double-walled nanotubes of surprisingly large diameter (in the 5–10 nm range), which collapse to give a dog-bone cross section.

  7. Research News

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Assembling DNA into Advanced Materials: From Nanostructured Films to Biosensing and Delivery Systems (pages 3727–3730)

      A. P. R. Johnston, A. N. Zelikin and F. Caruso

      Article first published online: 16 OCT 2007 | DOI: 10.1002/adma.200701147

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      The inherent functional and versatile nature of DNA permits its use as a programmable building block to assemble multifunctional, nanoengineered DNA capsules. DNA can also be encapsulated in polymer capsules, and it can be used to probe the permeability of the capsules through DNA sensing. These nanostructured capsules are expected to find use in applications ranging from therapeutics to diagnostics.

  8. Index

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Correspondence
    6. Reviews
    7. Communications
    8. Research News
    9. Index
    1. Author Index and Subject Index Adv. Mater. 21/2007 (pages 3731–3733)

      Article first published online: 5 NOV 2007 | DOI: 10.1002/adma.200790082

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