Advanced Materials

Cover image for Vol. 19 Issue 2

January, 2007

Volume 19, Issue 2

Pages 163–306

  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: Nanoscale Deposition of Single-Molecule Magnets onto SiO2 Patterns (Adv. Mater. 2/2007)

      R. V. Martínez, F. García, R. García, E. Coronado, A. Forment-Aliaga, F. M. Romero and S. Tatay

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200790007

      Manipulation of molecules with nanoscale accuracy is important in nanotechnology. In the novel process reported here, electrostatic interactions direct the deposition of polycationic Mn12 single-molecule magnets into a predefined region of a 1 cm2 silicon chip with 40 nm accuracy (see figure). The process is based on the integration of local oxidation nanolithography with surface functionalization of the Si substrate.

  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: Excimer-Based White Phosphorescent Organic Light-Emitting Diodes with Nearly 100 % Internal Quantum Efficiency (Adv. Mater. 2/2007)

      E. L. Williams, K. Haavisto, J. Li and G. E. Jabbour

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200790008

      Efficient excimer emission is demonstrated in white organic light-emitting diodes (see figure) based on platinum(II)[2-(4′,6′-difluorophenyl)pyridinato-N, C2′)](2,4-pentanedionato) utilized in devices incorporating the novel host material 2,6-Bis(N-carbazolyl)pyridine (26mCPy). External quantum (power) efficiencies of 15.9 % (12.6 lm W–1) are realized at 500 cd m–2.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Contents: Adv. Mater. 2/2007 (pages 163–171)

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200790005

  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Optical Bandgaps of π-Conjugated Organic Materials at the Polymer Limit: Experiment and Theory (pages 173–191)

      J. Gierschner, J. Cornil and H.-J. Egelhaaf

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200600277

      Thumbnail image of graphical abstract

      Extreme care has to be taken when extrapolating optical properties of conjugated polymers via the oligomer approach and when comparing theoretical and experimental data. This Review introduces conceptual strategies for the correct determination of optical transitions and relevant extrapolation procedures. The impact of conformational, substitution, solvent, and solid-state effects is discussed.

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Index
    1. Robust and Flexible Free-Standing All-Dielectric Omnidirectional Reflectors (pages 193–196)

      R. G. DeCorby, N. Ponnampalam, H. T. Nguyen and T. J. Clement

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601613

      Thumbnail image of graphical abstract

      A chalcogenide glass and a polyamideimide polymer are used to fabricate freestanding membranes (see figure). The membranes are less than 3 μm thick but provide a near-unity omnidirectional reflection band in the near infrared. Optomechanical tuning of the filter response and manual construction of microcavities are demonstrated.

    2. Excimer-Based White Phosphorescent Organic Light-Emitting Diodes with Nearly 100 % Internal Quantum Efficiency (pages 197–202)

      E. L. Williams, K. Haavisto, J. Li and G. E. Jabbour

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200602174

      Thumbnail image of graphical abstract

      Efficient excimer emission is demonstrated in white organic light-emitting diodes (see figure) based on platinum(II)[2-(4′,6′-difluorophenyl)pyridinato-N, C2′)](2,4-pentanedionato) utilized in devices incorporating the novel host material 2,6-Bis(N-carbazolyl)pyridine (26mCPy). External quantum (power) efficiencies of 15.9 % (12.6 lm W–1) are realized at 500 cd m–2.

    3. Colloidal Ceria Nanocrystals: A Tailor-Made Crystal Morphology in Supercritical Water (pages 203–206)

      J. Zhang, S. Ohara, M. Umetsu, T. Naka, Y. Hatakeyama and T. Adschiri

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200600964

      Thumbnail image of graphical abstract

      Control of the morphology of ceria nanocrystals is achieved through a simple, rapid, and green chemistry approach by tuning the reaction of organic ligand molecules with specific crystallographic planes of fluorite cubic ceria crystal during supercritical hydrothermal synthesis, as shown in the figure. It provides a novel self-assembly approach for producing metal oxide nanocrystals with uniform size and well-defined shape.

    4. Polarization Stop Bands in Chiral Polymeric Three-Dimensional Photonic Crystals (pages 207–210)

      M. Thiel, M. Decker, M. Deubel, M. Wegener, S. Linden and G. von Freymann

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200601497

      Thumbnail image of graphical abstract

      High-quality polymeric 3D spiral photonic crystals are fabricated via direct laser writing. Polarization stop bands for circularly polarized light are observed, leading to 5 % transmittance for the circular light polarization, which matches the handedness of the helix, and 95 % for the other polarization (see figure). The experimental results are in good agreement with theoretical calculations.

    5. A Helical Liquid-Crystal Phase Generated by a Chiral Ester with a Bent-Core Molecular Architecture (pages 211–214)

      K. M. Fergusson and M. Hird

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200601002

      Thumbnail image of graphical abstract

      A chiral, nonracemic ester with a bent-core molecular architecture (see figure) has been synthesized and evaluated for mesomorphic behavior and physical properties. The compound has a low melting point, a chiral smectic C phase with a wide temperature range, and it shows an unusually high tilt angle at a very low value of spontaneous polarization. However, the most significant aspect of the compound is the helical structure of the smectic A phase.

    6. Solvent Effects on Chain Orientation and Interchain π-Interaction in Conjugated Polymer Thin Films: Direct Measurements of the Air and Substrate Interfaces by Near-Edge X-ray Absorption Spectroscopy (pages 215–221)

      P. K.-H. Ho, L.-L. Chua, M. Dipankar, X. Y. Gao, D. C. Qi, A. T.-S. Wee, J.-F. Chang and R. H. Friend

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200601285

      Thumbnail image of graphical abstract

      The orientation and π-interaction of the frontier layers of regioregular poly(3-hexylthiophene) at both the air and substrate interfaces are directly measured for the first time using near-edge X-ray absorption fine-structure spectroscopy for thin films cast from a series of solvents (see figure). Results suggest the already high hole mobility in this material is still substantially limited by disorder at the interfaces.

    7. Self-Aligned Nanolenses with Multilayered Ge/SiO2 Core/Shell Structures on Si (001) (pages 222–226)

      H.-C. Chen, S.-W. Lee and L.-J. Chen

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200600307

      Thumbnail image of graphical abstract

      Selective etching of multilayered Ge-quantum-dot/Si-spacer has been used to fabricate stacked Ge@SiO2 nanolenses with the ability to filter and focus 1.5 μm light. These lenses have potential for use as Si-compatible photodetector materials for telecommunications. The left figure is a schematic sketch of the nanolenses and the right figure is a transmission electron microscopy image of the lenses.

    8. Polymer Blends with Azobenzene- Containing Block Copolymers as Stable Rewritable Volume Holographic Media (pages 227–231)

      M. Häckel, L. Kador, D. Kropp and H.-W. Schmidt

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200601458

      Thumbnail image of graphical abstract

      A storage material that is suitable for rewritable volume holographic media with a thickness in the millimeter range is presented (see figure). Writing, reading, and deleting are possible by purely optical means, and inscribed multiplexed gratings exhibit good long-term stability. A two-step method of optical deleting allows for more than 1000 erase–rewrite cycles without a measurable change in the material.

    9. Efficient Photodetection at IR Wavelengths by Incorporation of PbSe–Carbon-Nanotube Conjugates in a Polymeric Nanocomposite (pages 232–236)

      N. Cho, K. Roy Choudhury, R. B. Thapa, Y. Sahoo, T. Ohulchanskyy, A. N. Cartwright, K.-S. Lee and P. N. Prasad

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200600648

      Thumbnail image of graphical abstract

      PbSe quantum dots (QDs) are conjugated onto the surface of single-walled carbon nanotubes by a novel ligation procedure. The nanotubes are first surface-functionalized with thiol groups, which enable the adhesion of large numbers of colloidally prepared PbSe QDs. Polymeric nanocomposite IR photosensitizers made from these conjugate structures (see figure) generate significantly enhanced (≥ 100 %) IR photocurrents compared to devices using only QDs.

    10. Synthesis of Nanogroove-Network-Structured Platinum Nanosheets and Their Carbon-Supported Forms Using a Mixed-Surfactant Templating Approach (pages 237–241)

      G. Sakai, T. Yoshimura, S. Isohata, M. Uota, H. Kawasaki, T. Kuwahara, D. Fujikawa and T. Kijima

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601127

      Thumbnail image of graphical abstract

      Single-crystalline Pt nanosheets with a nanogroove-network structure (see figure) are reported. A method of loading the nanogrooved Pt nanosheets on a carbon support is also described and the resulting nanogroove-networked Pt on a carbon support (Pt/C) is demonstrated to exhibit fairly high electrocatalytic activity for oxygen reduction, which is of interest for fuel cells.

    11. Instant Preparation of Self-Assembled Metal-Complexed Lipid Nanotubes That Act as Templates to Produce Metal-Oxide Nanotubes (pages 242–246)

      M. Kogiso, Y. Zhou and T. Shimizu

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601117

      Thumbnail image of graphical abstract

      Self-assembly of metal-complexed lipid nanotubes results from the simple mixing of two aqueous solutions containing a metal cation and an oligoglycine-based lipid under mild conditions. Mn2+, Fe3+, and Cu2+ in octahedral coordinations tend to form tubular structures with the lipids examined. Calcination using the Cu2+- or Mn2+-complexed lipid nanotubes as templates gives copper or manganese oxide nanotubes in a single step; a schematic illustration of a metal-complexed lipid nanotube is shown in the figure.

    12. Layer-by-Layer Formation of Smart Particle Coatings Using Oppositely Charged Block Copolymer Micelles (pages 247–250)

      S. Biggs, K. Sakai, T. Addison, A. Schmid, S. P. Armes, M. Vamvakaki, V. Bütün and G. Webber

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601553

      Thumbnail image of graphical abstract

      Multilayer coatings of colloidal particle substrates (see figure) formed entirely from block copolymer micelles are demonstrated. Such multilayer coatings provide a highly functional organized coating that may have application across a wide range of technology areas, and provide a coating mechanism for controlled loading and release of active materials.

    13. Low-Temperature Fusion of Polymeric Nanostructures Using Carbon Dioxide (pages 251–254)

      Y. Yang, D. Liu, Y. Xie, L. J. Lee and D. L. Tomasko

      Version of Record online: 19 DEC 2006 | DOI: 10.1002/adma.200601481

      Thumbnail image of graphical abstract

      A low-temperature fusion method for preparing polymeric nanostructures based on low-pressure CO2-enhanced chain mobility at the nanoscale is presented. Characterization of the structures reveals a pressure-tunable rubbery layer on the surface. The successful fusion of polymeric nanostructures (see figure) at temperatures below the bulk glass-transition temperature of the polymer is demonstrated. The technique has potential for the assembly of 3D micro/nanoscale polymeric devices for biomedical applications.

    14. Decorated Electrospun Fibers Exhibiting Superhydrophobicity (pages 255–259)

      M. Ma, M. Gupta, Z. Li, L. Zhai, K. K. Gleason, R. E. Cohen, M. F. Rubner and G. C. Rutledge

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200601449

      Thumbnail image of graphical abstract

      Hierarchically roughened nonwoven fabrics that exhibit superhydrophobic behavior (see figure) are obtained by decorating electrospun fibers (diameter ca. 1 μm) with pores or particles of a diameter of ca. 100 nm, followed by surface hydrophobization. The enhanced hydrophobicity, due to a second level of roughness originating from the introduction of pores or particles, is evidenced by higher contact angles and lower contact-angle hysteresis.

    15. Aligned Inclusion of n-Propionic Acid Tethering Hemicyanine into Silica Zeolite Film for Second Harmonic Generation (pages 260–263)

      H. S. Kim, K. W. Sohn, Y. Jeon, H. Min, D. Kim and K. B. Yoon

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200602101

      Thumbnail image of graphical abstract

      Propionic acid tethering hemicyanine dye molecules preferentially enter the channels of silicalite-1 films with the head part first, in water in the presence of tetrabutylammonium hydroxide (this is shown schematically in the figure), giving rise to high-concentration hemicyanine-incorporating silicalite films with high second-harmonic-generation efficiency.

    16. Growth Confined by the Nitrogen Source: Synthesis of Pure Metal Nitride Nanoparticles in Mesoporous Graphitic Carbon Nitride (pages 264–267)

      A. Fischer, M. Antonietti and A. Thomas

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200602151

      Thumbnail image of graphical abstract

      Metal nitride nanoparticles are synthesized using mesoporous carbon nitride, first as a nanoconfinement matrix and then as a nitrogen source. The reaction-confining matrix is thermally decomposed during synthesis, thus becoming a source of nitrogen donation, and removing the need for further purification and isolation steps. Using this approach, direct copies of silica nanostructures are generated in metal nitride form (see figure).

    17. Tunable Thermoresponsive Polymeric Platforms on Gold by “Photoiniferter”-Based Surface Grafting (pages 268–271)

      E. M. Benetti, S. Zapotoczny and G. J. Vancso

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601554

      Thumbnail image of graphical abstract

      Thermoresponsive brushes with a tunable structure are grafted in a controlled way to gold substrates, exploiting an initiator–transfer–terminator agent (iniferter)-based photopolymerization (see figure). The chain length of the polymers is controlled by using UV light as a trigger and the end groups exposed are shown to be easily exchangeable following the grafting process. Reversible volume shrinkage/expansion, roughening, and variation of adhesion are observed.

    18. Quantized Double-Layer Charging of Rhodium2057(Tridecylamine)321 Clusters Using Differential Pulse and Cyclic Voltammetry (pages 272–275)

      B. A. Kakade, S. S. Shintri, B. R. Sathe, S. B. Halligudi and V. K. Pillai

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601184

      Thumbnail image of graphical abstract

      Rhodium nanoclusters show a series of quantized double-layer-charging events in solution-phase voltammetry at room temperature (see figure). The unusual variation in the FWHM for both the cathodic and anodic regions in differential pulse voltammetry experiments can be explained by several complex factors including reorganization and disproportionation of charged clusters coupled with electron-transfer processes pertaining to the Rh–Rh bonds.

    19. Highly Efficient and Low-Voltage Phosphorescent Organic Light-Emitting Diodes Using an Iridium Complex as the Host Material (pages 276–280)

      T. Tsuzuki and S. Tokito

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200600845

      Thumbnail image of graphical abstract

      Highly efficient, low-voltage OLEDs comprising bis(2-phenylpyridi- nato-N,C2′)iridium(acetylacetonate) ((ppy)2Ir(acac)) as the host and tris(1-phenylisoquinolinolato-C2,N)iridium(III) (Ir(piq)3) as a red phosphorescent guest are fabricated. Reduced driving voltage, increased maximum power efficiency (see figure), and improved durability of the OLEDs are demonstrated.

    20. Addition Energies and Vibrational Fine Structure Measured in Electromigrated Single-Molecule Junctions Based on an Oligophenylenevinylene Derivative (pages 281–285)

      E. A. Osorio, K. O'Neill, N. Stuhr-Hansen, O. F. Nielsen, T. Bjørnholm and H. S. J. van der Zant

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601876

      Thumbnail image of graphical abstract

      Transport trough electromigrated molecular junctions that contain an individual thiol end-capped oligophenylenevinylene molecule has been studied. At low temperatures more than fifteen excitations appear in the differential conductance map (see figure). Their energies agree with energies obtained from optical measurements on the same molecule, and are therefore attributed to vibrational modes. Addition energies are consistently an order of magnitude smaller than the optical HOMO–LUMO gap.

    21. Reactive Microcontact Printing on Block Copolymer Films: Exploiting Chemistry in Microcontacts for Sub-micrometer Patterning of Biomolecules (pages 286–290)

      C. L. Feng, A. Embrechts, I. Bredebusch, J. Schnekenburger, W. Domschke, G. J. Vancso and H. Schönherr

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601047

      Thumbnail image of graphical abstract

      Highly localized, selective deprotection chemistry and efficient grafting reactions in microcontacts between elastomeric stamps and reactive polystyrene-block-poly(tert-butyl acrylate) (PS690-b-PtBA1210) diblock copolymer films are developed. The procedure yields well-defined protein–poly(ethylene glycol) (PEG) nanopatterns (see figure), which may find applications in, for example, cancer-cell–surface interaction studies.

    22. Nanoscale Deposition of Single-Molecule Magnets onto SiO2 Patterns (pages 291–295)

      R. V. Martínez, F. García, R. García, E. Coronado, A. Forment-Aliaga, F. M. Romero and S. Tatay

      Version of Record online: 12 JAN 2007 | DOI: 10.1002/adma.200601999

      Thumbnail image of graphical abstract

      Manipulation of molecules with nanoscale accuracy is important in nanotechnology. In the novel process reported here, electrostatic interactions direct the deposition of polycationic Mn12 single-molecule magnets into a predefined region of a 1 cm2 silicon chip with 40 nm accuracy (see figure). The process is based on the integration of local oxidation nanolithography with surface functionalization of the Si substrate.

    23. Electrodeposition of Thermoelectric Superlattice Nanowires (pages 296–299)

      B. Yoo, F. Xiao, K. N. Bozhilov, J. Herman, M. A. Ryan and N. V. Myung

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200600606

      Thumbnail image of graphical abstract

      Bi2Te3/(Bi0.3Sb0.7)2Te3superlattice thermoelectric nanowires are synthesized by using a template-directed electrodeposition method. Adjustment of the deposition times and potentials enables precise control over the composition and length of each segment of the nanowires. Characterization of the superlattice nanowires by, amongst others, energy dispersive X-ray analysis (see figure) reveals their periodically varying structure.

    24. Crosslinkable Hole-Transport Layer on Conducting Polymer for High-Efficiency White Polymer Light-Emitting Diodes (pages 300–304)

      Y.-H. Niu, M. S. Liu, J.-W. Ka, J. Bardeker, M. T. Zin, R. Schofield, Y. Chi and A. K.-Y. Jen

      Version of Record online: 3 JAN 2007 | DOI: 10.1002/adma.200502769

      Thumbnail image of graphical abstract

      High-efficiency white polymer light-emitting diodes are demonstrated by using a hole-injection/transport bilayer. The excellent solvent resistance of the fully crosslinked hole-injection layer ensures the subsequent solution processing of the light-emitting layer. High power efficiency can be achieved. The device also emits quite stable white light. The figure shows a schematic of the device and the chemical structure of the VB-TCTA layer.

  6. Index

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

SEARCH

SEARCH BY CITATION