Advanced Materials

Cover image for Vol. 18 Issue 17

September, 2006

Volume 18, Issue 17

Pages 2203–2336

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Index
    1. Cover Picture: High-Performance Organic Single-Crystal Transistors on Flexible Substrates (Adv. Mater. 17/2006)

      A. L. Briseno, R. J. Tseng, M.-M. Ling, E. H. L. Falcao, Y. Yang, F. Wudl and Z. Bao

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200690069

      Flexible and conformable organic single crystals as thin as 150 nm are used for fabricating mechanically bendable organic single-crystal field-effect transistors on low-cost plastic substrates (see figure and cover). We report effective field-effect mobility as high as 4.6 cm2 V–1 s–1 for a flexible rubrene single-crystal transistor, on/off ratio of ca. 106, threshold voltage of – 2.1 V, and a normalized subthreshold swing of 0.9 V nF decade–1 cm–2.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Index
    1. Inside Front Cover: Macroscopic Parallel Nanocylinder Array Fabrication Using a Simple Rubbing Technique (Adv. Mater. 17/2006)

      H. Yu, J. Li, T. Ikeda and T. Iyoda

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200690070

      A convenient pathway for controlling defect-free nanoscopic domains over large areas is illustrated. A simple rubbing technique is used to align nanocylinders self-assembled in an amphiphilic diblock liquid-crystalline copolymer by introducing novel supramolecular cooperative motions between mesogens and microphase domains. A 3D macroscopic array of the nanocylinders over a large area is achieved parallel to the rubbing direction (see figure and inside cover).

  3. Contents

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

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Index
    1. Macroscopic Parallel Nanocylinder Array Fabrication Using a Simple Rubbing Technique (pages 2213–2215)

      H. Yu, J. Li, T. Ikeda and T. Iyoda

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600582

      Thumbnail image of graphical abstract

      A convenient pathway for controlling defect-free nanoscopic domains over large areas is illustrated. A simple rubbing technique is used to align nanocylinders self-assembled in an amphiphilic diblock liquid-crystalline copolymer by introducing novel supramolecular cooperative motions between mesogens and microphase domains. A 3D macroscopic array of the nanocylinders over a large area is achieved parallel to the rubbing direction (see figure and inside cover).

    2. Fabrication of Photoluminescent-Dye Embedded Poly(methyl methacrylate) Nanofibers and Their Fluorescence Resonance Energy Transfer Properties (pages 2216–2219)

      K. J. Lee, J. H. Oh, Y. Kim and J. Jang

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600399

      Thumbnail image of graphical abstract

      Dye-infiltrated polymer nanotubes are constructed via a simple vapor deposition polymerization process (see figure). 1D poly(methyl methacrylate) (PMMA) nanofibers doped with two dyes with significant spectral overlap between the donor and the acceptor display special fluorescence resonance energy transfer (FRET) properties.

    3. A Two-Dimensional KTiOPO4 Photonic Crystal Grown Using a Macroporous Silicon Template (pages 2220–2225)

      A. Peña, S. Di Finizio, T. Trifonov, J. J. Carvajal, M. Aguiló, J. Pallarès, A. Rodriguez, R. Alcubilla, L. F. Marsal, F. Díaz and J. Martorell

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200502566

      Thumbnail image of graphical abstract

      2D KTiOPO4 photonic crystals are fabricated using a silicon membrane of air holes as a template. Columns of KTiOPO4 are grown by liquid-phase epitaxy from a substrate into such air holes. The crystallographic orientation of the columns is the same as that of the substrate. The photonic-crystal properties of the fabricated structures and their capability to generate second-harmonic light are experimentally demonstrated.

    4. Enhancement of the High-Rate Capability of Solid-State Lithium Batteries by Nanoscale Interfacial Modification (pages 2226–2229)

      N. Ohta, K. Takada, L. Zhang, R. Ma, M. Osada and T. Sasaki

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200502604

      Thumbnail image of graphical abstract

      The high-rate capability of solid-state, rechargeable lithium batteries with sulfide electrolytes is significantly improved when the LiCoO2 particles are spray-coated with a Li4Ti5O12 film with a thickness of several nanometers (see figure). The power densities of the solid-state battery with the coated LiCoO2 are comparable to those of commercialized lithium-ion cells.

    5. Transparent Image Sensors Using an Organic Multilayer Photodiode (pages 2230–2233)

      H. Tanaka, T. Yasuda, K. Fujita and T. Tsutsui

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600163

      Thumbnail image of graphical abstract

      Transparent organic image sensors with polarization sensitivity have been demonstrated (see figure). When the light is perpendicularly polarized to the molecular orientation axis, the reflectivity of the imaging objects (white and black) is successfully detected by the photodiodes, which are made of stacked layers of a well-aligned 3,4,9,10-perylenetetracarboxylic-bis-benzimidazole and non-aligned titanyl phthalocyanine.

    6. Efficient Light-Harvesting Layers of Homeotropically Aligned Porphyrin Derivatives (pages 2234–2239)

      A. Huijser, T. J. Savenije, A. Kotlewski, S. J. Picken and L. D. A. Siebbeles

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600045

      Thumbnail image of graphical abstract

      Dye-sensitized solar cells are at present based on a nanostructured interpenetrating network of dye and semiconductor, which overcomes the prerequisite of a long exciton diffusion length; however, this also hampers charge-carrier transport. This work demonstrates that efficient light-induced charge separation is not necessarily only obtained in the case of a nanostructured network, but can also be achieved in a bilayer configuration (see figure).

    7. A Rapid Prototyping Approach to Ag Nanoparticle Fabrication in the 10–100 nm Range (pages 2240–2243)

      W.-S. Liao, T. Yang, E. T. Castellana, S. Kataoka and P. S. Cremer

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600589

      Thumbnail image of graphical abstract

      A simple, inexpensive, and rapid method for making metal nanoparticles ranging in size between 10 and 100 nm is demonstrated. The process can be completed in approximately 11 min by making a thin supported TiO2 film on glass for use as a photocatalyst and employing an alumina membrane as a template (see figure). The nanoparticle array formed on the TiO2 surface is nearly monodisperse and the particle surface density is uniform over large areas.

    8. Oriented Colloidal-Crystal Thin Films by Spin-Coating Microspheres Dispersed in Volatile Media (pages 2244–2249)

      A. Mihi, M. Ocaña and H. Míguez

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600555

      Thumbnail image of graphical abstract

      A simple, reproducible, and reliable method to crystallize sub-micrometer-size spherical colloids using a mixture of volatile solvents as dispersion media is presented. Strongly diffracting direct opal structures of high uniformity are attainable over large areas within minutes and without further processing. Thickness and orientation control is also possible through this technique. In the figure, both [111] (left) and [100] (right) oriented lattices deposited on glass slides are shown.

    9. Polymer–Clay Nanocomposites Exhibiting Abnormal Necking Phenomena Accompanied by Extremely Large Reversible Elongations and Excellent Transparency (pages 2250–2254)

      K. Haraguchi, M. Ebato and T. Takehisa

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600143

      Thumbnail image of graphical abstract

      Soft and transparent polymer–clay nanocomposites (see figure), consisting of hydrophobic poly(2-methoxyethylacrylate) and hydrophilic inorganic clay, with a unique clay-network morphology have been synthesized by in situ free-radical polymerization. The nanocomposites exhibit the first observation of abnormal necking behavior accompanied by extremely large reversible elongation (1000–3000 %) and excellent optical transparency, regardless of the clay content (1–30 wt %).

    10. Organization of Charge-Carrier Pathways for Organic Electronics (pages 2255–2259)

      M. Kastler, W. Pisula, F. Laquai, A. Kumar, R. J. Davies, S. Baluschev, M.-C. Garcia–Gutiérrez, D. Wasserfallen, H.-J. Butt, C. Riekel, G. Wegner and K. Müllen

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200601177

      Thumbnail image of graphical abstract

      Controlling self-organization: The chemical variation of alkyl substituents on the discotic hexa-peri-hexabenzocoronene allows the molecular orientation to be controlled with respect to a substrate, which is a key prerequisite to implement such semiconductors into electronic devices (see figure). Charge-carrier mobility determined by a time-of-flight technique reveals a high anisotropy along and perpendicular to the established columnar superstructure.

    11. Evaporation-Induced Self-Assembly (EISA) at Its Limit: Ultrathin, Crystalline Patterns by Templating of Micellar Monolayers (pages 2260–2263)

      T. Brezesinski, M. Groenewolt, A. Gibaud, N. Pinna, M. Antonietti and B. Smarsly

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600258

      Thumbnail image of graphical abstract

      Ultrathin, highly crystalline, mesostructured metal oxide layers, as shown in the figure, have been prepared by sol–gel processing using a modified evaporation-induced self-assembly (EISA) approach. This approach can be exploited for the generation of periodic surface structures featuring a well-defined in-plane mesostructure and a high crystallinity at the same time.

    12. Supramolecular Assemblies of Different Carbon Nanotubes for Photoconversion Processes (pages 2264–2269)

      V. Sgobba, G. M. A. Rahman, D. M. Guldi, N. Jux, S. Campidelli and M. Prato

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200501493

      Thumbnail image of graphical abstract

      Carbon nanotubes are tested as integrative components in multifunctional hybrid photovoltaic cells and reveal their significant promise for applications as photochemical energy-conversion systems. As shown in the figure, they possess monochromatic power-conversion efficiencies of up to 10.7 % for single carbon nanotube/pyrene+/ZnP8– stacks.

    13. Bioinspired Polymer–Inorganic Hybrid Materials (pages 2270–2273)

      S. Ludwigs, U. Steiner, A. N. Kulak, R. Lam and F. C. Meldrum

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600091

      Thumbnail image of graphical abstract

      A general route to patterning crystal growth is described. Structured polymer templates are employed as substrates on which to support crystal growth, resulting in translation of the polymer-film pattern into the crystal nucleation face (see figure). Continued crystal growth results in the formation of polymer–inorganic hybrid materials.

    14. Controlling the Morphology of Carbon Nanotube Films by Varying the Areal Density of Catalyst Nanoclusters Using Block-Copolymer Micellar Thin Films (pages 2274–2279)

      R. D. Bennett, A. J. Hart and R. E. Cohen

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600975

      Thumbnail image of graphical abstract

      The morphologies of carbon nanotube (CNT) thin films are controlled by varying the areal density of catalytic nanoclusters synthesized from a block-copolymer micellar thin film. The morphologies of the CNT films vary from a tangled and sparse arrangement of individual CNTs, through a transition region with locally bunched and self-aligned CNTs, to a rapid growth of thick vertical CNT films (see figure).

    15. Simultaneously Increasing the Ductility and Strength of Nanostructured Alloys (pages 2280–2283)

      Y. H. Zhao, X. Z. Liao, S. Cheng, E. Ma and Y. T. Zhu

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600310

      Thumbnail image of graphical abstract

      Simultaneous increase of the ductility and strength of a bulk nanostructured Al alloy with an average grain size of ∼ 100 nm (curve NS) has been achieved by precipitating Guinier–Preston (G–P) zones, η′, and η particles (curve NS+P). Bulk nanostructured materials usually have high strength, but disappointingly low ductility. All previous attempts to enhance the ductility of nanostructured materials have sacrificed their yield strengths. This strategy is applicable to many nanostructured alloys and composites.

    16. High Mobility, Low Dispersion Hole Transport in 1,4-Diiodobenzene (pages 2284–2288)

      B. Ellman, S. Nene, A. N. Semyonov and R. J. Twieg

      Version of Record online: 3 AUG 2006 | DOI: 10.1002/adma.200500358

      Thumbnail image of graphical abstract

      Single crystals of 1,4-diiodobenzene support almost dispersionless hole transport with mobilities ∼ 13 cm2 V–1 s–1 near room temperature. The mobility slowly increases with decreasing T and has little dependence on electric field. A simple model of hole transport represents the data well. Ab initio calculations (see figure) indicate that the large iodine constituents may play an important role in intermolecular hole transport.

    17. Transduction of Volume Change in pH-Sensitive Hydrogels with Resonance Energy Transfer (pages 2289–2293)

      J. Mao and M. J. McShane

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600040

      Thumbnail image of graphical abstract

      A novel method for the optical transduction of hydrogel swelling using resonance energy transfer between donor and acceptor molecules is described (see figure). This sensitive measurement of volume change can be used to study the intrinsic molecular-scale properties of hydrogels, as well as indicate environmental variables such as pH and ionic strength, and could be coupled with enzymes or other biological receptors to target specific analytes.

    18. The Negative Effect of High-Temperature Annealing on Charge-Carrier Lifetimes in Microcrystalline PCBM (pages 2294–2298)

      J. M. Warman, M. P. de Haas, T. D. Anthopoulos and D. M. de Leeuw

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600554

      Thumbnail image of graphical abstract

      Annealing microcrystalline phenyl- C61-butyric acid methyl ester (PCBM) above 100 °C results in the formation of hole traps. This is observed as an irreversible decrease in the lifetime of the transient conductivity of pulse- ionized microcrystalline PCBM powder at room temperature after annealing at different elevated temperatures (see figure). Caution is therefore advised in the routine use of pre-annealing to “improve” the performance of PCBM-based photovoltaic or field-effect transistor devices.

    19. Polymer/YOx Hybrid-Sandwich Gate Dielectrics for Semitransparent Pentacene Thin-Film Transistors Operating Under 5 V (pages 2299–2303)

      D. K. Hwang, C. S. Kim, J. M. Choi, K. Lee, J. H. Park, E. Kim, H. K. Baik, J. H. Kim and S. Im

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200600409

      Thumbnail image of graphical abstract

      A hybrid-sandwich dielectric—combining the advantages of inorganic high-dielectric-constant dielectrics and ultrathin organic dielectrics—for the gate of pentacene thin-film transistors (TFTs, see figure) is presented. The performance of the TFTs and resistance-load inverters constructed with them is shown to be satisfactory even when the devices are operated at the low voltage of –5 V.

    20. Asymmetric Functionalization of Nanoparticles Based on Thermally Addressable DNA Interconnects (pages 2304–2306)

      F. Huo, A. K. R. Lytton-Jean and C. A. Mirkin

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200601178

      Thumbnail image of graphical abstract

      The synthesis of nanoparticles asymmetrically functionalized with oligonucleotides is reported. The method provides excellent control over the placement of oligonucleotides on the surface of only one hemisphere of each particle (see figure). This new synthetic capability allows one to introduce valency into such structures and then use that valency to direct particle-assembly events.

    21. Nanoscale Domain Control in Multiferroic BiFeO3 Thin Films (pages 2307–2311)

      Y.-H. Chu, Q. Zhan, L. W. Martin, M. P. Cruz, P.-L. Yang, G. W. Pabst, F. Zavaliche, S.-Y. Yang, J.-X. Zhang, L.-Q. Chen, D. G. Schlom, I.-N. Lin, T.-B. Wu and R. Ramesh

      Version of Record online: 8 AUG 2006 | DOI: 10.1002/adma.200601098

      Thumbnail image of graphical abstract

      A 1D periodic structure of ferroelectric domains in epitaxial BiFeO3 films is created. By careful control of the growth mechanism for the SrRuO3 bottom electrode, its in-plane lattice parameters are confined by the underlying DyScO3 (110)O single- crystal substrate, enabling the formation of an expitaxial film of (110)O SrRuO3 with a single structural domain (see figure).

    22. Synthesis and Fabrication of a Thin Film Containing Silica-Encapsulated Face-Centered Tetragonal FePt Nanoparticles (pages 2312–2314)

      C. H. Yu, N. Caiulo, C. C. H. Lo, K. Tam and S. C. Tsang

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600802

      Thumbnail image of graphical abstract

      Self-assembly of monodisperse, silica-encapsulated, face-centered tetragonal FePt nanoparticles forms closely packed 2D arrays (see figure). Placing monodisperse FePt nanoparticles in silica nanocapsules allows the transition from a disordered face-centered cubic phase to a ferromagnetic crystalline face-centered tetragonal structure at elevated temperature without severe sintering. These materials are potential candidates for the generation of ultrahigh-density magnetic recording media.

    23. pH-Triggered Dispersion of Nanoparticle Clusters (pages 2315–2319)

      L. Shi and C. Berkland

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600610

      Thumbnail image of graphical abstract

      The suspense of dispersion! Nanoparticle clusters with a hydrolyzable interparticle barrier have been synthesized. These clusters are able to disperse into a stable colloid at a rate dependent upon the pH of the surrounding solution (see figure). This method could enable novel applications for colloidal clusters paired with environmentally responsive materials.

    24. High-Performance Organic Single-Crystal Transistors on Flexible Substrates (pages 2320–2324)

      A. L. Briseno, R. J. Tseng, M.-M. Ling, E. H. L. Falcao, Y. Yang, F. Wudl and Z. Bao

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600634

      Thumbnail image of graphical abstract

      Flexible and conformable organic single crystals as thin as 150 nm are used for fabricating mechanically bendable organic single-crystal field-effect transistors on low-cost plastic substrates (see figure and cover). We report effective field-effect mobility as high as 4.6 cm2 V–1 s–1 for a flexible rubrene single-crystal transistor, on/off ratio of ca. 106, threshold voltage of – 2.1 V, and a normalized subthreshold swing of 0.9 V nF decade–1 cm–2.

    25. Template-Free Synthesis of SnO2 Hollow Nanostructures with High Lithium Storage Capacity (pages 2325–2329)

      X. W. Lou, Y. Wang, C. Yuan, J. Y. Lee and L. A. Archer

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600733

      Thumbnail image of graphical abstract

      A facile one-step template-free method based on a novel inside-out Ostwald ripening mechanism is developed for inexpensive mass preparation of hollow and hollow core/shell-type SnO2 nanostructures using potassium stannate as the precursor. As-prepared SnO2 hollow nanospheres (see figure) exhibit ultrahigh lithium storage capacity and improved cycle performance as high-energy anode materials in lithium-ion secondary batteries.

    26. Macroporous Li(Ni1/3Co1/3Mn1/3)O2: A High-Power and High-Energy Cathode for Rechargeable Lithium Batteries (pages 2330–2334)

      K. M. Shaju and P. G. Bruce

      Version of Record online: 28 AUG 2006 | DOI: 10.1002/adma.200600958

      Thumbnail image of graphical abstract

      Macroporous Li(Ni1/3Co1/3Mn1/3)O2 is prepared by a simple synthesis procedure. The material has excellent electrochemical performance as a high-energy, high-power intercalation electrode (see figure) for rechargeable lithium batteries. The results illustrate the important role of morphology in determining the performance of lithium-ion cathodes.

  5. Index

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

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