Advanced Materials

Cover image for Vol. 22 Issue 9

March 5, 2010

Volume 22, Issue 9

Pages 911–1024

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Photonic Crystals: Integration of Colloidal Photonic Crystals toward Miniaturized Spectrometers (Adv. Mater. 9/2010)

      Shin-Hyun Kim, Hyo Sung Park, Jae Hoon Choi, Jae Won Shim and Seung-Man Yang

      Article first published online: 24 FEB 2010 | DOI: 10.1002/adma.201090022

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      The cover shows a schematic illustration of patterned colloidal photonic crystals with different bandgap positions. When an unknown light source impinges on the patterned photonic crystals, the light information can be identified from the reflection intensity profile of the constituent photonic crystals. The two optical microscopy images and background image display integrated photonic crystals with 20 different bandgaps spanning the entire visible range, and the SEM image shows the cross-section of the photonic crystal stripes, as reported by Shin-Hyun Kim, Seung-Man Yang, and co-workers on p. 946.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Light Harvesting: Artificial Inorganic Leafs for Efficient Photochemical Hydrogen Production Inspired by Natural Photosynthesis (Adv. Mater. 9/2010)

      Han Zhou, Xufan Li, Tongxiang Fan, Frank E. Osterloh, Jian Ding, Erwin M. Sabio, Di Zhang and Qixin Guo

      Article first published online: 24 FEB 2010 | DOI: 10.1002/adma.201090023

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      A natural leaf is a synergy of elaborated structures and functional components, producing a highly complex machinery for photosynthesis in which light harvesting, photoinduced charge separation, and catalysis modules combine to capture solar energy and split water into oxygen and “hydrogen” efficiently. On p. 951, Tongxiang Fan, Di Zhang, and co-workers report on the development of artificial inorganic leaves with enhanced light-harvesting and photocatalytic water splitting abilities, which stem from reproduction of natural leaves' complex structures and self-doping with nitrogen during synthesis.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Contents: (Adv. Mater. 9/2010) (pages 911–916)

      Article first published online: 24 FEB 2010 | DOI: 10.1002/adma.201090024

  4. Progress Report

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Ultralow-Fouling, Functionalizable, and Hydrolyzable Zwitterionic Materials and Their Derivatives for Biological Applications (pages 920–932)

      Shaoyi Jiang and Zhiqiang Cao

      Article first published online: 2 NOV 2009 | DOI: 10.1002/adma.200901407

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      Ultralow-fouling zwitterionic materials such as poly(carboxybetaine) and poly- (sulfobetaine) and their broad range of biomedical and engineering applications are reviewed in this Progress Report. Functionalizable and hydrolyzable properties make poly(carboxybetaine) (pCB; see figure) a unique next-generation biomaterial. Ultralow-fouling mixed-charge materials are also discussed.

  5. Review Article

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Organic Nonvolatile Memory Devices Based on Ferroelectricity (pages 933–945)

      Ronald C. G. Naber, Kamal Asadi, Paul W. M. Blom, Dago M. de Leeuw and Bert de Boer

      Article first published online: 19 AUG 2009 | DOI: 10.1002/adma.200900759

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      A ferroelectric molecule exhibits a bistable polarization due to the alignment of its dipole moment with the applied electric field by means of a conformational rotation of the molecular backbone (as illustrated). Organic nonvolatile memory devices based on ferroelectricity have been realized in recent years with excellent memory characteristics. This Review discusses these developments with a focus on ferroelectric capacitors, field-effect transistors, and diodes.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Integration of Colloidal Photonic Crystals toward Miniaturized Spectrometers (pages 946–950)

      Shin-Hyun Kim, Hyo Sung Park, Jae Hoon Choi, Jae Won Shim and Seung-Man Yang

      Article first published online: 8 DEC 2009 | DOI: 10.1002/adma.200902456

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      Integrated colloidal photonic crystals with different bandgaps are prepared by molding photocurable SiO2 suspensions and subsequent photopolymerization under UV irradiation. The suspensions show spontaneous crystallization of SiO2 particles and reflect iridescent colors (see figure). The bandgap position is precisely controlled by the particle volume fraction. Such photonic structures can be used as mini-spectrometers in lab-on-a-chip devices, and various optical applications.

    2. Artificial Inorganic Leafs for Efficient Photochemical Hydrogen Production Inspired by Natural Photosynthesis (pages 951–956)

      Han Zhou, Xufan Li, Tongxiang Fan, Frank E. Osterloh, Jian Ding, Erwin M. Sabio, Di Zhang and Qixin Guo

      Article first published online: 20 NOV 2009 | DOI: 10.1002/adma.200902039

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      Artificial inorganic leafs are developed by organizing light harvesting, photoinduced charge separation, and catalysis modules (Pt/N-TiO2) into leaf-shaped hierarchical structures using natural leaves as biotemplates (see figure). The enhanced light-harvesting and photocatalytic water-splitting activities stem from the reproduction of the leafs' complex structures and self-doping of nitrogen during synthesis. The research may represent an important first step toward the design of novel artificial solar-energy transduction systems based on natural concepts, particularly on mimicking the structural design.

    3. Optical Encoding of Silver Zeolite Microcarriers (pages 957–960)

      Gert De Cremer, Bert F. Sels, Jun-ichi Hotta, Maarten B. J. Roeffaers, Evelyne Bartholomeeusen, Eduardo Coutiño-Gonzalez, Valentin Valtchev, Dirk E. De Vos, Tom Vosch and Johan Hofkens

      Article first published online: 15 DEC 2009 | DOI: 10.1002/adma.200902937

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      Highly resolved fluorescent patterns are generated in an individual silver-exchanged K-A zeolite crystal using two-photon excitation (see figure). The high stability, brightness, and spatial resolution of the patterns are an important advantage over the current state-of-the-art techniques in optical encoding of microcarriers. Therefore, this material shows high potential as a quality and/or safety label to prevent counterfeiting or as an advanced biolabel.

    4. Compartmentalized Multistable Liquid Crystal Alignment (pages 961–965)

      Jing Zhang, Marius I. Boamfa, Alan E. Rowan and Theo Rasing

      Article first published online: 15 DEC 2009 | DOI: 10.1002/adma.200903045

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      A novel method for compartmentalized multistable liquid crystal alignment is presented (see figure). The compartmentalization allows planar-aligned liquid crystal domains to be switched independently under vertical electric fields. This work opens new routes for the design and fabrication of multistable liquid crystal devices, switchable viewing-angle displays and tunable structures of guest materials within liquid crystal host.

    5. Light-Induced Bipolar-Resistance Effect Based on Metal–Oxide–Semiconductor Structures of Ti/SiO2/Si (pages 966–970)

      Chongqi Yu and Hui Wang

      Article first published online: 10 DEC 2009 | DOI: 10.1002/adma.200903070

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      A novel approach to the control of resistance in a Ti/SiO2/Si structure is demonstrated by use of a laser via a phenomenon referred to as the bipolar-resistance effect (BRE). The most significant features of this BRE are an excellent spatial sensitivity and a large change ratio in resistance as the laser moves along the surface of the structure.

    6. HPW/MCM-41 Phosphotungstic Acid/Mesoporous Silica Composites as Novel Proton-Exchange Membranes for Elevated-Temperature Fuel Cells (pages 971–976)

      Shanfu Lu, Deli Wang, San Ping Jiang, Yan Xiang, Jinlin Lu and Jie Zeng

      Article first published online: 25 NOV 2009 | DOI: 10.1002/adma.200903091

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      A novel inorganic proton-conducting membrane based on highly ordered MCM-41 mesoporous silica with phosphotungstic acid (HPW) nanoparticles assembled within is successfully fabricated by a vacuum-assisted impregnation method (VIM). The results of HPW impregnation by VIM and a conventional method (CIM) are compared (see figure), and the performance of the membranes in fuel cells is reported.

    7. Ultrasensitive Piezoresistive All-Organic Flexible Thin Films (pages 977–981)

      Elena Laukhina, Raphael Pfattner, Lourdes R. Ferreras, Simona Galli, Marta Mas-Torrent, Norberto Masciocchi, Vladimir Laukhin, Concepció Rovira and Jaume Veciana

      Article first published online: 21 DEC 2009 | DOI: 10.1002/adma.200902639

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      In polymeric composite thin films it is possible to translate elastic elongations of the film into reversible nanoscale deformations of the soft organic-crystal components, leading to films with extreme sensitivity to strain changes with durable, fast, and completely reversible responses. Simple prototypes (see image), demonstrate that these sensors are highly promising for a wide range of applications.

    8. Flexible Low-Voltage Organic Transistors and Circuits Based on a High-Mobility Organic Semiconductor with Good Air Stability (pages 982–985)

      Ute Zschieschang, Frederik Ante, Tatsuya Yamamoto, Kazuo Takimiya, Hirokazu Kuwabara, Masaaki Ikeda, Tsuyoshi Sekitani, Takao Someya, Klaus Kern and Hagen Klauk

      Article first published online: 8 DEC 2009 | DOI: 10.1002/adma.200902740

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      Flexible transistors and circuits based on dinaphtho-[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT), a conjugated semiconductor with a large ionization potential (5.4 eV), are reported. The transistors have a mobility of 0.6 cm2 V−1 s−1 and the ring oscillators have a stage delay of 18 µs. Due to the excellent stability of the semiconductor, the devices and circuits maintain 50% of their initial performance for a period of 8 months in ambient air.

    9. Unprecedented Binary Semiconductors Based on TCNQ: Single-Crystal X-ray Studies and Physical Properties of Cu(TCNQX2) X=Cl, Br (pages 986–989)

      Nazario Lopez, Hanhua Zhao, Akira Ota, Andrey V. Prosvirin, Eric W. Reinheimer and Kim R. Dunbar

      Article first published online: 15 DEC 2009 | DOI: 10.1002/adma.200903217

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      Single crystals of a new structure typefor the M+(TCNQ)•− binary family are isolated from reactions of dihalogenated TCNQ derivatives and CuI ions (see figure; Cu: pink C: black, N: blue, Br: orange, H: light blue). The new compound Cu(TCNQCl2) exhibits the highest conductivity of the M+(TCNQ)•− series to date, despite the larger separation of TCNQCl2 units in the stacks. Conductive properties of Cu(TCNQX2) where X = Cl, Br is attributed to charge-carrier transport through copper ions, which is unprecedented in M+(TCNQ)•− materials.

    10. Designed Suppression of Aggregation in Polypyrene: Toward High-Performance Blue-Light-Emitting Diodes (pages 990–993)

      Teresa M. Figueira-Duarte, Pablo G. Del Rosso, Roman Trattnig, Stefan Sax, Emil J. W. List and Klaus Müllen

      Article first published online: 15 DEC 2009 | DOI: 10.1002/adma.200902744

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      A novel non-aggregating polypyrene, which can be synthesized via a simple three-step chemical route from pyrene in good yields, is presented. Poly-7-tert-butyl-1,3-pyrenylene shows a high solid-state fluorescence quantum yield with blue emission, excellent solubility and stability, no aggregation in thin films, and good electro-optical performance in single-layer organic light-emitting diodes (see figure).

    11. Reactive Layer-by-Layer Assembly of Suspended Thin Films and Semipermeable Membranes at Interfaces Created Between Aqueous and Organic Phases (pages 994–998)

      Maren E. Buck and David M. Lynn

      Article first published online: 24 NOV 2009 | DOI: 10.1002/adma.200903054

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      Thin films of polymer suspended across the openings of pores, channels, and microcavities are of interest in a broad range of fundamental and applied contexts. A “reactive” layer-by-layer approach is demonstrated for the fabrication of suspended thin films and semipermeable membranes that makes use of liquid/liquid interfaces created between immiscible aqueous and organic phases as templates for film fabrication (see image).

    12. Surface-Energy Generator of Single-Walled Carbon Nanotubes and Usage in a Self-Powered System (pages 999–1003)

      Zheng Liu, Kaihong Zheng, Lijun Hu, Ji Liu, Caiyu Qiu, Haiqing Zhou, Haibo Huang, Haifang Yang, Meng Li, Changzhi Gu, Sishen Xie, Lijie Qiao and Lianfeng Sun

      Article first published online: 4 JAN 2010 | DOI: 10.1002/adma.200902153

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      A surface-energy generator (SEG) using single-walled carbon nanotubes is demonstrated to harvest the surface energy of ethanol. The SEG can drive thermistors in a self-powered system. The performance can be significantly enhanced by the Marangoni effect. These SEGs show the advantages of a smaller inner resistance, no moving parts, and no need for the application of an obvious external force.

    13. Fluidic Carbon Precursors for Formation of Functional Carbon under Ambient Pressure Based on Ionic Liquids (pages 1004–1007)

      Je Seung Lee, Xiqing Wang, Huimin Luo and Sheng Dai

      Article first published online: 1 DEC 2009 | DOI: 10.1002/adma.200903403

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      A new strategy for the preparation of functional porous carbons is developed via direct, ambient-pressure, thermal pyrolysis of task-specific ionic liquids (ILs). The simple synthesis lies in the synergistic use of the negligible volatility of the ILs and incorporation of the crosslinkable nitrile groups in the anions. The resulting carbon materials at 800 °C retain an extremely high content of nitrogen (up to 18 at%).

    14. Bipolar Charge Transport in Fullerene Molecules in a Bilayer and Blend of Polyfluorene Copolymer and Fullerene (pages 1008–1011)

      Abay Gadisa, Kristofer Tvingstedt, Koen Vandewal, Fengling Zhang, Jean V. Manca and Olle Inganäs

      Article first published online: 24 NOV 2009 | DOI: 10.1002/adma.200902579

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      Efficient polymer solar cells typically contain the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which promotes dissociation of excited states and enhances charge transport. The ability of PCBM to transport holes in solar cell bulk heterojunction films is monitored via the electroluminescence emission of a bulk heterojunction blend of PCBM and a polyfluorene copolymer. In polymer/fullerene bilayer diodes, fullerene emission is also observed.

    15. Influence of Device Geometry on Sensor Characteristics of Planar Organic Electrochemical Transistors (pages 1012–1016)

      Fabio Cicoira, Michele Sessolo, Omid Yaghmazadeh, John A. DeFranco, Sang Yoon Yang and George G. Malliaras

      Article first published online: 8 DEC 2009 | DOI: 10.1002/adma.200902329

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      The response of PEDOT:PSS planar electrochemical transistors to H2O2 can be tuned by varying the ratio between the areas of the channel and the gate electrode. Devices with small gates show lower background signal and higher sensitivity. The detection range, on the other hand, is found to be rather independent of the gate/channel area ratio.

    16. Efficient Organic Solar Cells Using a High-Quality Crystalline Thin Film as a Donor Layer (pages 1017–1020)

      Bo Yu, Lizhen Huang, Haibo Wang and Donghang Yan

      Article first published online: 10 DEC 2009 | DOI: 10.1002/adma.200903023

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      An efficient organic solar cell is fabricated by the weak-epitaxy-growth method and the achieved power conversion efficiency is over 3% (see figure). A Single-crystal-like thin film improves the carrier mobility and reduces the electron–hole recombination. Deposition of a zinc phthalocyanine (ZnPc):C60 mixed layer at 100 °C results in a better interpenetrating interface and the device performance is improved further.

  7. Research News

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Progress Report
    6. Review Article
    7. Communications
    8. Research News
    1. Bioinspired Smart Gating of Nanochannels Toward Photoelectric-Conversion Systems (pages 1021–1024)

      Liping Wen, Xu Hou, Ye Tian, Fu-Qiang Nie, Yanlin Song, Jin Zhai and Lei Jiang

      Article first published online: 28 DEC 2009 | DOI: 10.1002/adma.200903161

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      Learning from nature has inspired the creation of intelligent materials to better understand and imitate biology. Bio inspired smart gating of micro/nanochannel systems has been achieved by introducing various kinds of responsive molecules that allow for closely mimicking the gating mechanism of biological nanochannels (see figure) and show potential applications in many fields, such as photoelectric-conversion systems.

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