Advanced Materials

Cover image for Vol. 18 Issue 9

May, 2006

Volume 18, Issue 9

Pages 1099–1222

    1. Cover Picture: Fast and Reversible Surface Redox Reaction in Nanocrystalline Vanadium Nitride Supercapacitors (Adv. Mater. 9/2006)

      D. Choi, G. E. Blomgren and P. N. Kumta

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200690036

      Modification of the surface chemistry of nanocrystalline VN yields a new class of supercapacitors that deliver an impressive specific capacitance. The creation of surface nanolayers of VOx (poor electronic conductivity) on the electronically conductive nanocrystalline VN shown in the figure and on the cover gives rise to a series of reversible redox reactions that are thought to be responsible for the high capacitance. Application of the concept to other transition metals is expected to broaden the scope of supercapacitor materials.

    2. Inside Front Cover: Trilayered Ceramic–Metal–Polymer Microcantilevers with Dramatically Enhanced Thermal Sensitivity (Adv. Mater. 9/2006)

      Y.-H. Lin, M. E. McConney, M. C. LeMieux, S. Peleshanko, C. Jiang, S. Singamaneni and V. V. Tsukruk

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200690037

      Trilayered ceramic–metal–polymer thermally sensitive microcantilevers with the topmost polymer nanocomposite layers reinforced with carbon nanotubes and metal nanoparticles are described (see figure and inside cover). These trilayered microcantilevers show dramatically enhanced thermal sensitivity and could be used in next-generation uncooled IR sensor arrays with thermal and spatial resolution many times higher than currently available sensors.

    3. Growing Metal Nanoparticles by Enzymes (pages 1109–1120)

      I. Willner, R. Baron and B. Willner

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200501865

      Thumbnail image of graphical abstract

      Enzymes catalyze the growth of metallic nanoparticles (NPs, see figure). The enzyme-mediated growth of metallic NPs provides a general means to follow biocatalyzed transformations and a route to optical sensors for substrates such as glucose, 3,4,dihydroxy-L-phenylalamine, L-DOPA, alcohols, lactate, or nerve-gas analogs. Dip-pen nanolithography can be used to pattern enzymes on Si surfaces that template growth of nanowires consisting of different metals.

    4. Poly(3,4-alkylenedioxypyrroles): The PXDOPs as Versatile Yet Underutilized Electroactive and Conducting Polymers (pages 1121–1131)

      R. M. Walczak and J. R. Reynolds

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502312

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      The poly(3,4-dioxypyrrole) family of conducting and electroactive polymers may not have received as much attention to date as their poly(3,4-ethylenedioxythiophene) cousins, but that may be about to change. The authors review the synthesis and properties of these versatile systems, demonstrating that these materials may be the final piece in the conjugated polymer puzzle, combining a large bandgap and a low oxidation potential.

    5. Biologically Active Protein Nanoarrays Generated Using Parallel Dip-Pen Nanolithography (pages 1133–1136)

      S. W. Lee, B.-K. Oh, R. G. Sanedrin, K. Salaita, T. Fujigaya and C. A. Mirkin

      Version of Record online: 28 MAR 2006 | DOI: 10.1002/adma.200600070

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      Amine-active N-hydroxysuccinimide-terminated alkyl thiol templates are generated using parallel dip-pen nanolithography (DPN) and are used to covalently couple protein A/G. The protein arrays generated (see figure) are used to capture antibodies through affinity binding, while preserving their biological recognition properties. The versatility of the parallel DPN method for making many similar structures in a relatively high-throughput manner (14 000 dots in 10 min) is described.

    6. A Biocompatible Bottom-Up Route for the Preparation of Hierarchical Biohybrid Materials (pages 1137–1140)

      M. C. Gutiérrez, M. Jobbágy, N. Rapún, M. L. Ferrer and F. del Monte

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502550

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      Ice-segregation-induced self- assembly is a versatile and biocompatible process that facilitates the preparation of hierarchical biohybrid materials exhibiting a very sophisticated structure with up to six levels of space organization: the ternary structure of esterase, the PVA domains surrounding esterase, the silica cages entrapping the PVA domains, and the macroporous structure resulting from ice segregation (see figure). The resulting materials are attractive for biomedical and sensor applications.

    7. Multilamellar-Vesicle-Assisted Electrodeposition of Inorganic Nanodots (pages 1141–1146)

      C. Faure, S. Guillot, P. Weisbecker and H. Saadaoui

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502225

      Thumbnail image of graphical abstract

      Nanodots are produced over large areas with controlled size and density in a new single-step, low-cost process. This process is based on surfactant-made multilamellar vesicles that serve as nanovectors. Copper ions are incorporated inside vesicles by chemical complexation. Vesicles are attracted under a DC electric field towards an electrode, where they are reduced to produce the metal nanodots shown in the figure.

    8. Templated Self-Assembly of Colloidal Nanoparticles Controlled by Electrostatic Nanopatterning on a Si3N4/SiO2/Si Electret (pages 1147–1151)

      S.-D. Tzeng, K.-J. Lin, J.-C. Hu, L.-J. Chen and S. Gwo

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200501542

      Thumbnail image of graphical abstract

      Controlled self-assembly of colloidal nanoparticles onto an electrically nanopatterned electret film is presented (see figure; EFM: electrostatic force microscopy). An unprecedented reolution of 30 nm is achieved for both charge patterning and nanoparticle assembly. Furthermore, only a close-packed monolayer of nanoparticles is assembled, allowing better structural control and the possibility of forming hierarchical nanoparticle structures.

    9. Synthesis of Monodisperse Bicolored Janus Particles with Electrical Anisotropy Using a Microfluidic Co-Flow System (pages 1152–1156)

      T. Nisisako, T. Torii, T. Takahashi and Y. Takizawa

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502431

      Thumbnail image of graphical abstract

      A planar microfluidic system produces monodisperse biphasic droplets that are subsequently polymerized to form bicolored Janus microspheres (see figure). Engineered spheres have a dipolar character and can be electrically actuated for application in a particle-based electronic paper display. A scale-up approach using multiple-channel integration on a chip is also described, which achieves high throughput for practical material production.

    10. Trilayered Ceramic–Metal–Polymer Microcantilevers with Dramatically Enhanced Thermal Sensitivity (pages 1157–1161)

      Y.-H. Lin, M. E. McConney, M. C. LeMieux, S. Peleshanko, C. Jiang, S. Singamaneni and V. V. Tsukruk

      Version of Record online: 6 APR 2006 | DOI: 10.1002/adma.200502232

      Thumbnail image of graphical abstract

      Trilayered ceramic–metal–polymer thermally sensitive microcantilevers with the topmost polymer nanocomposite layers reinforced with carbon nanotubes and metal nanoparticles are described (see figure and inside cover). These trilayered microcantilevers show dramatically enhanced thermal sensitivity and could be used in next-generation uncooled IR sensor arrays with thermal and spatial resolution many times higher than currently available sensors.

    11. Novel One-Step Synthesis of Porous-Supported Catalysts by Activated-Carbon Templating (pages 1162–1165)

      J. Blanco, A. L. Petre, M. Yates, M. P. Martin, S. Suarez and J. A. Martin

      Version of Record online: 6 APR 2006 | DOI: 10.1002/adma.200501061

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      A new, simple, versatile, and easily scaleable one-step preparation method – an impregnated carbon procedure (ICP) – is proposed to produce highly dispersed active phases on supports of tailored porosity (see scheme; AC: activated carbon). This one-step synthesis unites simplicity of preparation with outstanding properties of the final catalysts and offers an interesting pathway towards industrial-catalyst manufacture.

    12. Strong Anisotropy in the Far-Infrared Absorption Spectra of Stretch-Aligned Single-Walled Carbon Nanotubes (pages 1166–1169)

      N. Akima, Y. Iwasa, S. Brown, A. M. Barbour, J. Cao, J. L. Musfeldt, H. Matsui, N. Toyota, M. Shiraishi, H. Shimoda and O. Zhou

      Version of Record online: 6 APR 2006 | DOI: 10.1002/adma.200502505

      Thumbnail image of graphical abstract

      Absorption spectroscopy of stretch-aligned single-walled carbon nanotube (SWNT)/polymer composite films from the terahertz through the visible region of the electromagnetic spectrum reveal that the peak centered near 100 cm–1 is highly polarized along the tube axis (see figure). This result provides new information on the morphology-dependent low-energy response of SWNTs, and may predict application of SWNTs in the terahertz region.

    13. Nanostructuring and High Thermoelectric Efficiency in p-Type Ag(Pb1 – ySny)mSbTe2 + m (pages 1170–1173)

      J. Androulakis, K. F. Hsu, R. Pcionek, H. Kong, C. Uher, J. J. D'Angelo, A. Downey, T. Hogan and M. G. Kanatzidis

      Version of Record online: 6 APR 2006 | DOI: 10.1002/adma.200502770

      Thumbnail image of graphical abstract

      The p-type Ag(Pb1ySny)mSbTe2+m materials shown in the figure demonstrate promising thermoelectric properties that are controlled with the parameters y and m. They can reach a maximum figure of merit of ∼ 1.45 at 630 K. This surpasses the figure of merit of the present state-of-the-art p-type materials such as TAGS (1.2) and PbTe (0.8) at comparable temperatures.

    14. Well-Defined Non-spherical Copper Sulfide Mesocages with Single-Crystalline Shells by Shape-Controlled Cu2O Crystal Templating (pages 1174–1177)

      S. Jiao, L. Xu, K. Jiang and D. Xu

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502386

      Thumbnail image of graphical abstract

      Uniform cubic, octahedral, and star-like copper sulfide mesocages with single-crystalline shells (see figure) are synthesized by the sulfidation of various shape-controlled Cu2O crystals into Cu2O/CuxS core/shell structures, followed by the removal of the inner Cu2O cores. Potential applications of these materials in solar energy conversion, optics, and sensors are envisaged.

    15. Fast and Reversible Surface Redox Reaction in Nanocrystalline Vanadium Nitride Supercapacitors (pages 1178–1182)

      D. Choi, G. E. Blomgren and P. N. Kumta

      Version of Record online: 6 APR 2006 | DOI: 10.1002/adma.200502471

      Thumbnail image of graphical abstract

      Modification of the surface chemistry of nanocrystalline VN yields a new class of supercapacitors that deliver an impressive specific capacitance. The creation of surface nanolayers of VOx (poor electronic conductivity) on the electronically conductive nanocrystalline VN shown in the figure and on the cover gives rise to a series of reversible redox reactions that are thought to be responsible for the high capacitance. Application of the concept to other transition metals is expected to broaden the scope of supercapacitor materials.

    16. Building Nanocrystalline Planar Defects within Self-Assembled Photonic Crystals by Spin-Coating (pages 1183–1187)

      R. Pozas, A. Mihi, M. Ocaña and H. Míguez

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502263

      Thumbnail image of graphical abstract

      A new type of 2D defect within artificial opals is presented. Sequential deposition of a colloidal crystal by convective self-assembly and a slab of oxide nanocrystals by spin-coating gives rise to heterostructures (as shown in the figure). The nanocrystalline layer behaves as an optical dopant, opening transmission windows within the forbidden frequency interval of the lattice, as can be seen in the superimposed transmittance spectra.

    17. A Facile Route to ZnS–Polymer Nanocomposite Optical Materials with High Nanophase Content via γ-Ray Irradiation Initiated Bulk Polymerization (pages 1188–1192)

      C. Lü, Y. Cheng, Y. Liu, F. Liu and B. Yang

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502404

      Thumbnail image of graphical abstract

      Transparent ZnS/polymer bulk nanocomposites with high particle contents are prepared via γ-ray irradiation initiated polymerization. This strategy involves the design and tailoring of the surface of the nanoparticles and choice of the monomer as well as the selection of the polymerization route. The figure shows a TEM image of a bulk nanocomposite containing mercaptoethanol-capped ZnS with a particle content of 20 wt %.

    18. Urea-Melt Solubilization of Single-Walled Carbon Nanotubes (pages 1193–1197)

      W. E. Ford, A. Jung, A. Hirsch, R. Graupner, F. Scholz, A. Yasuda and J. M. Wessels

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502257

      Thumbnail image of graphical abstract

      Water-soluble single-walled carbon nanotubes are readily prepared by treating oxidatively purified nanotubes with molten urea. Evidence is provided for appended amido and ureido groups in the product (see figure), which can be further modified by condensation reactions if p-anisaldehyde is added during the process.

    19. Advanced Hydrogen-Storage Materials Based on Sc-, Ce-, and Pr-Doped NaAlH4 (pages 1198–1201)

      B. Bogdanović, M. Felderhoff, A. Pommerin, F. Schüth and N. Spielkamp

      Version of Record online: 10 APR 2006 | DOI: 10.1002/adma.200501367

      Thumbnail image of graphical abstract

      The most favorable dopants for solid-state hydrogen-storage materials are still considered to be compounds of titanium in spite of intensive research on other catalysts. Here, we show that NaAlH4 doped with ScCl3 is a highly efficient dopant, both with respect to storage capacity and kinetics: 2 mol % ScCl3 exhibits a nearly theoretical hydrogen-storage capacity (4.9 wt %, see graph). Other rare-earth metal trichlorides are also investigated.

    20. High-Efficiency Organic-Dye- Sensitized Solar Cells Controlled by Nanocrystalline-TiO2 Electrode Thickness (pages 1202–1205)

      S. Ito, S. M. Zakeeruddin, R. Humphry-Baker, P. Liska, R. Charvet, P. Comte, M. K. Nazeeruddin, P. Péchy, M. Takata, H. Miura, S. Uchida and M. Grätzel

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502540

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      A mesoscopic bilayer TiO2 film used as an electron collector in conjunction with an acetonitrile- or ionic liquid-based electrolyte greatly improves the performance of dye-sensitized solar cells (see figure). The thickness of the nanocrystalline TiO2 film affects the photovoltaic characteristics, particularly for the ionic-liquid-based electrolyte, owing to a limitation of the photocurrent by the diffusion of I3 ions.

    21. Preparation of a Periodically Ordered Mesoporous Organosilica Material Using Chiral Building Blocks (pages 1206–1209)

      S. Polarz and A. Kuschel

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502647

      Thumbnail image of graphical abstract

      Chiral bis-alkoxysilanes are used as building blocks for the synthesis of new periodically ordered mesoporous organosilica materials (see figure). A bis-alkoxysilane molecule with a chiral group as a bridging organic ligand is prepared via enantioselective organometallic catalysis using a ruthenium catalyst with 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene as a ligand. The synergistic co-assembly is then used to prepare a high-surface-area mesoporous material with an average pore size of about 3 nm.

    22. Technique for Preparing Ultrafine Nanocrystalline Bulk Material of Pure Rare-Earth Metals (pages 1210–1215)

      X. Song, J. Zhang, M. Yue, E. Li, H. Zeng, N. Lu, M. Zhou and T. Zuo

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502619

      Thumbnail image of graphical abstract

      Ultrafine nanocrystalline bulk material of pure rare-earth metals has been prepared using a combination of inert gas condensation and spark plasma sintering (see figure). Some of the bulk properties such as the microhardness and specific heat capacity are remarkably improved compared to the conventional polycrystalline material. This new preparation technique enables the preparation and study of a variety of other nanostructured metal materials.

    23. Highly Efficient Organic Blue Electrophosphorescent Devices Based on 3,6-Bis(triphenylsilyl)carbazole as the Host Material (pages 1216–1220)

      M.-H. Tsai, H.-W. Lin, H.-C. Su, T.-H. Ke, C.-c. Wu, F.-C. Fang, Y.-L. Liao, K.-T. Wong and C.-I Wu

      Version of Record online: 24 APR 2006 | DOI: 10.1002/adma.200502283

      Thumbnail image of graphical abstract

      Blue electrophosphorescence in organic light-emitting diodes (OLEDs) is enhanced by the use of 3,6-bis(triphenylsilyl)carbazole (see figure). This carbazole derivative with sterically bulky and large-gap triphenylsilyl groups is an electrochemically and morphologically stable efficient host material for blue electrophosphorescence. When utilized in OLEDs, high efficiencies of up to 16 %, 30.6 cd A–1, and 26.7 lm W–1 are achieved.

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