Advanced Functional Materials

Cover image for Vol. 21 Issue 5

March 8, 2011

Volume 21, Issue 5

Pages 800–1006

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Graphene: Carbide-Derived Carbons – From Porous Networks to Nanotubes and Graphene (Adv. Funct. Mater. 5/2011) (page 800)

      Volker Presser, Min Heon and Yury Gogotsi

      Article first published online: 25 FEB 2011 | DOI: 10.1002/adfm.201190007

      Thumbnail image of graphical abstract

      Carbide-derived carbon (CDC) can be obtained by selective removal of metal or metalloid atoms from carbides such as, for example, SiC. on page 810, Yury Gogotsi and co-workers review a large variety of carbon nano-structures that can be found in CDC. The cover image visualizes the variety of carbon nanostructures, such as SiC (bottom left) amorphous carbon (top right), carbon nanotubes (upper left), onion-like carbon (bottom right), and graphene ribbons (center of the image). (Image design: Dr. Vadym Mochalin)

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Circular Nanomagnets: Enhanced Nucleation of Vortices in Soft Magnetic Materials Prepared by Silica Nanosphere Lithography (Adv. Funct. Mater. 5/2011) (page 801)

      N. Martin, N. C. Bigall, I. Mönch, T. Gemming, A. Eychmüller, R. Mattheis, R. Schäfer, L. Schultz and J. McCord

      Article first published online: 25 FEB 2011 | DOI: 10.1002/adfm.201190008

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      Circular nanomagnets, that is, arrays of closely packed disks with a special beveled edge geometry, are presented by Norbert Martin, Jeffrey McCord, and co-workers on page 891. A moderate shrinking of the spheres during etching is directly translated to the nanomagnets, resulting in the nucleation of magnetic vortices in the patterned nanomagnets; a key factor to increase magnetic data storage density. The dependence of the nucleation behavior on the bevel angle is simulated, and the picture illustrates the preferred nucleation of magnetic vortices in ferromagnetic disks with beveled edges. Each color and arrow represents one of the four stable vortex states.

  3. Back Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Ferroelectric Materials: Probing Local and Global Ferroelectric Phase Stability and Polarization Switching in Ordered Macroporous PZT (Adv. Funct. Mater. 5/2011) (page 802)

      Martyn A. McLachlan, David W. McComb, Mary P. Ryan, Anna N. Morozovska, Eugene A. Eliseev, E. Andrew Payzant, Stephen Jesse, Katyayani Seal, Arthur P. Baddorf and Sergei V. Kalinin

      Article first published online: 25 FEB 2011 | DOI: 10.1002/adfm.201190009

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      Lead zirconate titanate (PZT) exhibits outstanding fer-roelectric, piezoelectric, and pyroelectric properties, coupled with thermal stability and a relatively easy synthesis. By correlating local and global characterization techniques, Martyn A. McLachlan and co-workers have, for the first time, on page 941, unambiguously demon-strated the formation of tetragonal and ferroelectric PZTs in large-volume nanostructured architectures. The image shows the ordered macroporous surface of a strain-free assembly of PZT. A wide range of materials is available that can be formed into such controlled architectures, opening a pathway towards effective studies on nano-meter-scale ferroelectrics in uniquely large volumes.

  4. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Contents: (Adv. Funct. Mater. 5/2011) (pages 803–809)

      Article first published online: 25 FEB 2011 | DOI: 10.1002/adfm.201190010

  5. Feature Article

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Carbide-Derived Carbons – From Porous Networks to Nanotubes and Graphene (pages 810–833)

      Volker Presser, Min Heon and Yury Gogotsi

      Article first published online: 9 FEB 2011 | DOI: 10.1002/adfm.201002094

      Thumbnail image of graphical abstract

      Carbide-derived carbons (CDCs) are a family of carbon materials that can be obtained by selective extraction of metal or metalloid atoms from carbide precursors. The properties and structures of the resulting CDCs depend on the structures of the carbide precursors as well as on synthesis conditions. Halogenation, for example, yields amorphous porous carbon with an extremely high specific surface area.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Contents
    6. Feature Article
    7. Full Papers
    1. Self-Assembled Conjugated Thiophene-Based Rotaxane Architectures: Structural, Computational, and Spectroscopic Insights into Molecular Aggregation (pages 834–844)

      Leszek Zalewski, Sergio Brovelli, Massimo Bonini, Jeffrey M. Mativetsky, Michael Wykes, Emanuele Orgiu, Thomas Breiner, Marcel Kastler, Florian Dötz, Francesco Meinardi, Harry L. Anderson, David Beljonne, Franco Cacialli and Paolo Samorì

      Article first published online: 13 DEC 2010 | DOI: 10.1002/adfm.201001135

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      Molecular aggregation can be tuned by rotaxination. A conjugated bi-thiophene-based rotaxane and its corresponding dumbbell undergo different self-assembly pathways at surfaces. The dumbbell exhibited a greater propensity to form ordered supramolecular assemblies, as a result of ππ interactions, which are hindered in the rotaxane, as revealed by STM, AFM, and steady-state and time-resolved photoluminescence experiments corroborated by molecular modelling.

    2. Development of Film Sensors Based on Conjugated Polymers for Copper (II) Ion Detection (pages 845–850)

      Fengting Lv, Xuli Feng, Hongwei Tang, Libing Liu, Qiong Yang and Shu Wang

      Article first published online: 19 JAN 2011 | DOI: 10.1002/adfm.201001738

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      Film and microarray detectors for Cu2+. A fluorescent film was prepared by chemical modification of a polyfluorene derivative on a glass-plate surface. This film allows reversible detection of Cu2+ ions with good selectivity and sensitivity in aqueous solution by a mechanism exploiting fluorescence quenching of conjugated polymers. Sensory microarrays for Cu2+ ions based on conjugated polymers were also realized.

    3. A Generalized Mechanism for Ligand-Induced Dipolar Assembly of Plasmonic Gold Nanoparticle Chain Networks (pages 851–859)

      Mei Li, Sara Johnson, Hongtao Guo, Erik Dujardin and Stephen Mann

      Article first published online: 19 JAN 2011 | DOI: 10.1002/adfm.201001754

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      UV-vis spectroscopy and electron microscopy are used to determine the kinetics and structural changes associated with the chain assembly of citrate/mercaptoethanol-capped gold nanoparticles between 5 and 50 °C. Formation of the plasmonic nanoparticle networks is optimized at 25–30 °C and follows first order kinetics. Changes in assembly behavior are related to temperature-dependent ordering and disordering of mercaptoethanol molecules associated with the gold nanoparticle surface.

    4. High-Resolution Near-Field Optical Investigation of Crystalline Domains in Oligomeric PQT-12 Thin Films (pages 860–868)

      Sergei Kuehn, Patrick Pingel, Markus Breusing, Thomas Fischer, Joachim Stumpe, Dieter Neher and Thomas Elsaesser

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201001978

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      The nanoscopic morphology and structure of oligomeric PQT-12 thin films are explored with surface-, diffraction-, and optical near-field methods to reveal the hierarchical order on three length scales, and to explore the reasons for the unexpectedly high field mobility of this material at the crossover region from polymer to molecular crystal.

    5. Fabrication of Graphene–Quantum Dots Composites for Sensitive Electrogenerated Chemiluminescence Immunosensing (pages 869–878)

      Ling-Ling Li, Kun-Ping Liu, Guo-Hai Yang, Chun-Ming Wang, Jian-Rong Zhang and Jun-Jie Zhu

      Article first published online: 19 JAN 2011 | DOI: 10.1002/adfm.201001550

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      Specific, stable, sensitive: Poly (diallyldimethylammonium chloride) (PDDA)-protected graphene–CdSe composites were prepared and used for the construction of an advanced electrogenerated-chemiluminescence immunosensor combined with amplification of PDDA and gold nanoparticles by layer-by-layer assembly. The resulting sensor detected the concentration of human IgG with a low detection limit.

    6. Impact of Metal Contamination in Silicon Solar Cells (pages 879–890)

      Gianluca Coletti, Paula C. P. Bronsveld, Giso Hahn, Wilhelm Warta, Daniel Macdonald, Bruno Ceccaroli, Karsten Wambach, Nam Le Quang and Juan M. Fernandez

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201000849

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      The impact of transition metals on the performance of silicon solar cells is presented. Iron, chromium and titanium reduce the internal quantum efficiency (IQE) at long wavelength, due to a reduced charge-carrier diffusion length. Nickel reduces the IQE at short wavelength via increased recombination in the solar-cell emitter region. Copper reduces the IQE at both short and long wavelengths. A physical model is presented explaining the data.

    7. Enhanced Nucleation of Vortices in Soft Magnetic Materials Prepared by Silica Nanosphere Lithography (pages 891–896)

      Norbert Martin, Nadja-Carola Bigall, Ingolf Mönch, Thomas Gemming, Alexander Eychmüller, Roland Mattheis, Rudolf Schäfer, Ludwig Schultz and Jeffrey McCord

      Article first published online: 8 FEB 2011 | DOI: 10.1002/adfm.201002140

      Thumbnail image of graphical abstract

      Circular nano-magnets with special beveled edge geometry are fabricated by means of silica nanosphere lithography and subsequent ion etching to enhance the nucleation of the vortex phase. The moderate shrinking of the spheres during etching is directly translated to the nanomagnets and therefore forming an optimal bevel angle in order to nucleate magnetic vortices in patterned nano-magnets. This is a key issue to increase magnetic data storage density.

    8. Dicyanovinyl–Substituted Oligothiophenes: Structure-Property Relationships and Application in Vacuum-Processed Small Molecule Organic Solar Cells (pages 897–910)

      Roland Fitzner, Egon Reinold, Amaresh Mishra, Elena Mena-Osteritz, Hannah Ziehlke, Christian Körner, Karl Leo, Moritz Riede, Matthias Weil, Olga Tsaryova, André Weiß, Christian Uhrich, Martin Pfeiffer and Peter Bäuerle

      Article first published online: 27 JAN 2011 | DOI: 10.1002/adfm.201001639

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      A series of A-D-A-type oligothiophenes have been developed as efficient donor materials for application in vacuum-processed organic solar cells. Due to their promising optoelectronic properties and molecular packing in the bulk, these oligomers show high power conversion efficiencies up to 2.8% in planar heterojunction and record efficiencies of 5.2% in bulk heterojunction solar cells prepared by vacuum deposition.

    9. Large-Scale Synthesis of Bi-layer Graphene in Strongly Coupled Stacking Order (pages 911–917)

      Zhiqiang Luo, Ting Yu, Jingzhi Shang, Yingying Wang, Sanhua Lim, Lei Liu, Gagik G. Gurzadyan, Zexiang Shen and Jianyi Lin

      Article first published online: 31 JAN 2011 | DOI: 10.1002/adfm.201002227

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      Bilayer graphene (BLG) is synthesized homogeneously on a large scale by thermal CVD. The splitting of electronic bands in BLG is demonstrated using Raman spectroscopy and optical absorbtion spectroscopy, and carrier dynamics are probed by transient absorption spectroscopy. The successful synthesis of BLG on a large scale is of particular importance for device applications based on their degenerate electronic bands.

    10. Block Copolymer Permeable Membrane with Visualized High-Density Straight Channels of Poly(ethylene oxide) (pages 918–926)

      Takashi Yamamoto, Taro Kimura, Motonori Komura, Yukimitsu Suzuki, Tomokazu Iyoda, Sadayuki Asaoka and Haruyuki Nakanishi

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201002069

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      Microphase separation, photo-crosslinking, and sequential transfer are the key processes integrated in the fabrication of a large-area block copolymer membrane (see graphic). The perpendicularly aligned and hexagonally arranged poly(ethylene oxide) cylindrical domains with a surface density of 1.8 × 1011 cylinders cm−2 are preserved open at both ends across the 480-nm-thick membrane (aspect ratio = 40) throughout the whole fabrication process.

    11. High Photoconductive Responsivity in Solution-Processed Polycrystalline Organic Composite Films (pages 927–931)

      Gerardo Hernandez-Sosa, Nelson. E Coates, Sebastian Valouch and Daniel Moses

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201002518

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      High photoconductive responsivity approaching 25 AW−1 in a solution-processed organic composite of rubrene and 9,10-diphenylanthracene. Studies of photoconductivity, photoluminescence, and structural order ellucidate the role of interfacial traps that lead to a long hole lifetime, which facilitates a high photoconductive gain, resulting in a high photoconductive responsivity.

    12. Anisotropy of Charge Transport in a Uniaxially Aligned and Chain-Extended, High-Mobility, Conjugated Polymer Semiconductor (pages 932–940)

      Mi Jung Lee, Dhritiman Gupta, Ni Zhao, Martin Heeney, Iain McCulloch and Henning Sirringhaus

      Article first published online: 18 JAN 2011 | DOI: 10.1002/adfm.201001781

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      Anisotropy of charge transport is studied in uniaxially aligned PBTTT nanoribbon organic field-effect transistors. In contrast to previous work, high mobility is obtained by controlling the channel interface. Mobility in the fully extended polymer chain direction is 3–5 times faster than that in the π–π stacking direction as a result of intra- and intergrain transport processes involving microstructural disorders.

    13. Probing Local and Global Ferroelectric Phase Stability and Polarization Switching in Ordered Macroporous PZT (pages 941–947)

      Martyn A. McLachlan, David W. McComb, Mary P. Ryan, Anna N. Morozovska, Eugene A. Eliseev, E. Andrew Payzant, Stephen Jesse, Katyayani Seal, Arthur P. Baddorf and Sergei V. Kalinin

      Article first published online: 8 FEB 2011 | DOI: 10.1002/adfm.201002038

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      The characterization, ferroelectric phase stability and polarization switching in strain-free assemblies of PbZr0.3Ti0.7O3 (PZT) nanostructures are described. The local ferroelectric properties are assessed using piezoresponse force spectroscopy and demonstrate spatial mapping of the switching polarisation (see figure). A significant reduction in Curie temperature is observed by variable temperate XRD and is explained using a direct variational method and Landau–Ginzburg–Devonshire (LGD) theory.

    14. Porous Single Crystals of Calcite from Colloidal Crystal Templates: ACC Is Not Required for Nanoscale Templating (pages 948–954)

      Nicola B. J. Hetherington, Alex N. Kulak, Yi-Yeoun Kim, Elizabeth H. Noel, David Snoswell, Michael Butler and Fiona C. Meldrum

      Article first published online: 10 DEC 2010 | DOI: 10.1002/adfm.201001366

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      Calcite single crystals with inverse and direct opal structures are prepared using templates of colloidal crystals and reverse opals, respectively. These nanostructured crystals are prepared in the absence of an amorphous precursor phase via ion-by-ion precipitation. This method is highly versatile and challenges the suggestion that such structures cannot be prepared by simple diffusion of reagents into a template. (ACC = amorphous calcium carbonate)

    15. Highly Stretchable Conducting SIBS-P3HT Fibers (pages 955–962)

      Alberto J. Granero, Pawel Wagner, Klaudia Wagner, Joselito M. Razal, Gordon G. Wallace and Marc in het Panhuis

      Article first published online: 18 JAN 2011 | DOI: 10.1002/adfm.201001460

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      A facile solution processing approach is used to produce conducting and highly ductile poly(3-hexylthiophene) (P3HT) and poly(styrene-β-isobutylene-β-styrene) (SIBS) composite fibers via wet-spinning. These fibers exhibit a reversible gain in electrical resistance upon high elongation and have potential applications in strain sensing or elastic electrodes.

    16. A Thiophene-Based Anchoring Ligand and Its Heteroleptic Ru(II)-Complex for Efficient Thin-Film Dye-Sensitized Solar Cells (pages 963–970)

      Amaresh Mishra, Nuttapol Pootrakulchote, Mingkui Wang, Soo-Jin Moon, Shaik M. Zakeeruddin, Michael Grätzel and Peter Bäuerle

      Article first published online: 20 JAN 2011 | DOI: 10.1002/adfm.201001863

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      A new heteroleptic Ru(II)-complex (BTC-2) is developed as a sensitizer for thin-film dye-sensitized solar cells (DSSCs) in which 5,5′-(2,2′-bipyridine-4,4′-diyl)-bis(thiophene-2-carboxylic acid) is used as an anchoring ligand. Using a 7 + 5 μm mesoporous TiO2 film, BTC-2 achieves a power conversion efficiency of 9.1% with a volatile acetonitrile-based electrolyte. Using a low-volatile electrolyte and 5 μm transparent thin TiO2 films, efficiencies as high as 7% are achieved.

    17. Enhanced Water Retention by Using Polymeric Microcapsules to Confer High Proton Conductivity on Membranes at Low Humidity (pages 971–978)

      Jingtao Wang, Han Zhang, Xinlin Yang, Shuang Jiang, Wenjun Lv, Zhongyi Jiang and Shi Zhang Qiao

      Article first published online: 18 JAN 2011 | DOI: 10.1002/adfm.201001793

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      Enhancedproton conductivity under low humidity is conferred by embedding polymeric microcapsules (PMCs) with superior water retention properties into a membrane matrix. The large lumen of PMCs facilitates high water uptake, while functional groups on the shell of the PMCs manipulate the water state to ensure low water release and provide numerous sites that assist proton conduction.

    18. Flash-Memory Effect for Polyfluorenes with On-Chain Iridium(III) Complexes (pages 979–985)

      Shu-Juan Liu, Zhen-Hua Lin, Qiang Zhao, Yun Ma, Hui-Fang Shi, Ming-Dong Yi, Qi-Dan Ling, Qu-Li Fan, Chun-Xiang Zhu, En-Tang Kang and Wei Huang

      Article first published online: 19 JAN 2011 | DOI: 10.1002/adfm.201001884

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      Nonvolatile flash-memory devices based on polyfluorenes containing iridium(III) complexes were successfully realized. The devices exhibit a high ON/OFF current ratio of more than 105 and low reading, writing, and erasing voltages. Both ON and OFF states are stable under a constant voltage stress and survive up to 108 read cycles at a read voltage of −1.0 V.

    19. Nitrogen-Doped Single-Walled Carbon Nanotubes Grown on Substrates: Evidence for Framework Doping and Their Enhanced Properties (pages 986–992)

      Yu Liu, Zhong Jin, Jinyong Wang, Rongli Cui, Hao Sun, Fei Peng, Li Wei, Zhenxing Wang, Xuelei Liang, Lianmao Peng and Yan Li

      Article first published online: 19 JAN 2011 | DOI: 10.1002/adfm.201002086

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      Nitrogen-doped single-walled carbon nanotubes (SWCNTs) grown on substrates are immediately ready for building devices and characterization. Thermogravimetry mass spectrometry, X-ray-photoelectron-spectroscopy, and Raman spectroscopy measurements present firm evidence for framework doping. The nitrogen-doped SWCNTs show metallic conductivity. They exhibit enhanced sensitivity towards electrophilic species in electrochemical analysis and improved electrocatalytic activity for the oxygen-reduction reaction.

    20. A Systematic Approach to Building Highly Porous, Noninterpenetrating Metal–Organic Frameworks with a Large Capacity for Adsorbing H2 and CH4 (pages 993–998)

      Jeong Yong Lee, Long Pan, Xiaoying Huang, Thomas J. Emge and Jing Li

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201001790

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      Highly porous metal organic framework materials having closely related structures and systematically tunable porosity demonstrate a high capacity for methane and hydrogen adsorption. At room temperature and ≈40 bars, the compounds Zn(BDC)(TED)0.5 and Ni(NDC)(TED)0.5 adsorb 242 cm3 g−1 and 173 cm3 g−1 of CH4, respectively. At 77 K, they take up 4.1 and 5.5 wt% of hydrogen at 40 and 65 bars, respectively.

    21. Open-Ended, N-Doped Carbon Nanotube–Graphene Hybrid Nanostructures as High-Performance Catalyst Support (pages 999–1006)

      Ruitao Lv, Tongxiang Cui, Mun-Suk Jun, Qiang Zhang, Anyuan Cao, Dang Sheng Su, Zhengjun Zhang, Seong-Ho Yoon, Jin Miyawaki, Isao Mochida and Feiyu Kang

      Article first published online: 2 FEB 2011 | DOI: 10.1002/adfm.201001602

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      A hierarchical N-doped carbon nanotube–graphene hybrid nanostructure (NCNT-GHN), in which the graphene layers are distributed inside the inner cavities of open-ended CNTs, is designed to support noble metal (e.g., PtRu) nanoparticles via a convenient and efficient low-temperature chemical reduction route. A synergy enhancement of the hierarchical structure (graphene–CNT hybrid) and electron structure modulation (N-doping) is demonstrated during the methanol electrooxidation reaction, and improved single-cell performances with better long-term operation stability are obtained.

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