Advanced Materials

Cover image for Vol. 24 Issue 26

July 10, 2012

Volume 24, Issue 26

Pages 3437–3576

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Aerographite: Ultra Lightweight, Flexible Nanowall, Carbon Microtube Material with Outstanding Mechanical Performance (Adv. Mater. 26/2012) (page 3437)

      Matthias Mecklenburg, Arnim Schuchardt, Yogendra Kumar Mishra, Sören Kaps, Rainer Adelung, Andriy Lotnyk, Lorenz Kienle and Karl Schulte

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290158

      Thumbnail image of graphical abstract

      ZnO network templates are converted into aerographite, a novel carbon-based material, by R. Adelung and co-workers on page 3486. While parts of the ZnO crystals are missing and etched, on the outside carbon tubes have already been formed. Aerographite tubes are like an inflated version of multiwalled carbon nanotubes, with increased microscopic diameter but unchanged nanoscopic wall thickness. These tubes are interconnected to form a superlow-density material with a volume of several cubic centimeters and remarkable mechanical, electrical, and optical properties.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Metamaterials: Reversibly Stretchable and Tunable Terahertz Metamaterials with Wrinkled Layouts (Adv. Mater. 26/2012) (page 3438)

      Seungwoo Lee, Seongnam Kim, Teun-Teun Kim, Yushin Kim, Muhan Choi, Seung Hoon Lee, Ju-Young Kim and Bumki Min

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290159

      Thumbnail image of graphical abstract

      When metamaterials are arranged in a stretchable platform, their practical applications (e.g., reconfigurable optoelectronic devices and biological sensors) can be greatly extended. B. Min and co-workers take inspiration from the wrinkled structures of various bio-organisms to develop a generic strategy for reversibly stretchable metamaterials. The structural integrities of the wrinkled THz metamaterials described on page 3491 remain intact after repeated stretching/relaxing, and the wrinkled metamaterial makes a mechanically reversible transition between artificial homogeneous and inhomogeneous broadenings.

  3. Back Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Covalent Cross-Linking: Stable Functionalization of Small Semiconducting Polymer Dots via Covalent Cross-Linking and Their Application for Specific Cellular Imaging (Adv. Mater. 26/2012) (page 3577)

      Jiangbo Yu, Changfeng Wu, Xuanjun Zhang, Fangmao Ye, Maria Elena Gallina, Yu Rong, I-Che Wu, Wei Sun, Yang-Hsiang Chan and Daniel T. Chiu

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290160

      Thumbnail image of graphical abstract

      Stable and highly fluorescent small semiconducting polymer dots (Pdots) are prepared by D. T. Chiu and co-workers using a covalent cross-linking strategy described on page 3498. In this confocal fluorescence microscopy image, microtubules in HeLa cells are specifically labeled by the cross-linked Pdots, and individual tubular structures can be seen under 488 nm laser illumination. Cross-linked Pdots are shown to have desirable characteristics for improved labeling efficiency and sensitivity in cellular assays.

  4. Masthead

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Masthead: (Adv. Mater. 26/2012)

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290161

  5. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
  6. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Mo-Si-B Alloys for Ultrahigh-Temperature Structural Applications (pages 3445–3480)

      J. A. Lemberg and R. O. Ritchie

      Article first published online: 19 JUN 2012 | DOI: 10.1002/adma.201200764

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      Mo-Si-B alloys potentially offer a higher-temperature alternative to nickel-base superalloys for gas/power turbines as they could operate structurally at several hundred degrees hotter. We describe here their structure versus properties, focusing on strength, ductility, toughness, creep, oxidation and fatigue resistance. As many of these properties are mutually exclusive, we document ways to optimize their nano/microstructures to achieve a right balance of properties.

  7. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Multilayer Graphene-Coated Atomic Force Microscopy Tips for Molecular Junctions (Adv. Mater. 26/2012) (page 3481)

      Yugeng Wen, Jianyi Chen, Yunlong Guo, Bin Wu, Gui Yu and Yunqi Liu

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290156

      Thumbnail image of graphical abstract

      A reliable molecular junction with reproducible electronic behavior is fabricated by Y. Liu and co-workers on page 3482 using multilayer graphene-coated AFM tips. Molecular junctions using graphene tips show very small tip-to-tip variance, excellent operational stability, good endurance, and long shelf-life. These properties, together with a high yield and the simplicity of the process involved, suggest that mass production of graphene tips is viable for future practical molecular electronic and AFM-based applications.

  8. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Multilayer Graphene-Coated Atomic Force Microscopy Tips for Molecular Junctions (pages 3482–3485)

      Yugeng Wen, Jianyi Chen, Yunlong Guo, Bin Wu, Gui Yu and Yunqi Liu

      Article first published online: 12 JUN 2012 | DOI: 10.1002/adma.201200579

      Thumbnail image of graphical abstract

      Multilayer graphene tips are developed for conducting probe atomic force microscopy for the formation of molecular junctions. Molecular junctions using graphene tips show very small tip-to-tip variance, excellent operational stability, good endurance, and long shelf-life. These properties, together with high yield and the simple processing involved, suggest that commercial mass-production of graphene tips is viable for molecular electronic applications.

    2. Aerographite: Ultra Lightweight, Flexible Nanowall, Carbon Microtube Material with Outstanding Mechanical Performance (pages 3486–3490)

      Matthias Mecklenburg, Arnim Schuchardt, Yogendra Kumar Mishra, Sören Kaps, Rainer Adelung, Andriy Lotnyk, Lorenz Kienle and Karl Schulte

      Article first published online: 12 JUN 2012 | DOI: 10.1002/adma.201200491

      Thumbnail image of graphical abstract

      An ultra lightweight carbon microtube material called Aerographite is synthesized by a novel single-step chemical vapor deposition synthesis based on ZnO networks, which is presently the lightest known material with a density smaller than μg/cm3. Despite its low density, the hierarchical design leads to remarkable mechanical, electrical, and optical properties. The first experiments with Aerographite electrodes confirm its applicability.

    3. Reversibly Stretchable and Tunable Terahertz Metamaterials with Wrinkled Layouts (pages 3491–3497)

      Seungwoo Lee, Seongnam Kim, Teun-Teun Kim, Yushin Kim, Muhan Choi, Seung Hoon Lee, Ju-Young Kim and Bumki Min

      Article first published online: 12 JUN 2012 | DOI: 10.1002/adma.201200419

      Thumbnail image of graphical abstract

      The use of wrinkling provides a generic route to stretchable metamaterials, with unprecedented terahertz tunability. The wrinkled metamaterial can be stretched reversibly up to 52.5%; the structural integrity can be maintained during at least 100 stretching/relaxing cycles. Importantly, the wrinkling of meta-atoms offers a deterministic way to achieve controlled broadening of electrical resonance.

    4. Stable Functionalization of Small Semiconducting Polymer Dots via Covalent Cross-Linking and Their Application for Specific Cellular Imaging (pages 3498–3504)

      Jiangbo Yu, Changfeng Wu, Xuanjun Zhang, Fangmao Ye, Maria Elena Gallina, Yu Rong, I-Che Wu, Wei Sun, Yang-Hsiang Chan and Daniel T. Chiu

      Article first published online: 11 JUN 2012 | DOI: 10.1002/adma.201201245

      Thumbnail image of graphical abstract

      A facile cross-linking strategy covalently links functional molecules to semiconducting polymer dots (Pdots) while simultaneously providing functional groups for biomolecular conjugation. In addition to greatly enhanced stability, the formed Pdots are small (<10 nm), which can be difficult to achieve with current methods but is highly desirable for most biological applications. These characteristics are significant for improving labeling efficiency and sensitivity in cellular assays that employ Pdots.

    5. Superhydrophobic Photocatalytic Surfaces through Direct Incorporation of Titania Nanoparticles into a Polymer Matrix by Aerosol Assisted Chemical Vapor Deposition (pages 3505–3508)

      Colin R. Crick, Joseph C. Bear, Andreas Kafizas and Ivan P. Parkin

      Article first published online: 18 JUN 2012 | DOI: 10.1002/adma.201201239

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      A new class of superhydrophobic photocatalytic surfaces that are self-cleaning through light-induced photodegradation and the Lotus effect are presented. The films are formed in a single-step aerosol-assisted chemical vapor deposition (AACVD) process. The films are durable and show no degradation on continuous exposure to UV-C radiation.

    6. Achieving High Field-Effect Mobility in Amorphous Indium-Gallium-Zinc Oxide by Capping a Strong Reduction Layer (pages 3509–3514)

      Hsiao-Wen Zan, Chun-Cheng Yeh, Hsin-Fei Meng, Chuang-Chuang Tsai and Liang-Hao Chen

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201200683

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      An effective approach to reduce defects and increase electron mobility in a-IGZO thin-film transistors (a-IGZO TFTs) is introduced. A strong reduction layer, calcium, is capped onto the back interface of a-IGZO TFT. After calcium capping, the effective electron mobility of a-IGZO TFT increases from 12 cm2 V−1 s−1 to 160 cm2 V−1 s−1. This high mobility is a new record, which implies that the proposed defect reduction effect is key to improve electron transport in oxide semiconductor materials.

    7. Resistive Switching and Magnetic Modulation in Cobalt-Doped ZnO (pages 3515–3520)

      Guang Chen, Cheng Song, Chao Chen, Shuang Gao, Fei Zeng and Feng Pan

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201201595

      Thumbnail image of graphical abstract

      A combination of resistive switching and magnetic modulation gives rise to the integration of room temperature ferromagnetism (spin) and electrical properties (charge) into a simple Pt/Co:ZnO/Pt structure due to the formation of oxygen vacancy-based conductive filaments. This is promising for broadening the applications of random access memories to encode quaternary information.

    8. An Amorphous Mesophase Generated by Thermal Annealing for High-Performance Organic Photovoltaic Devices (pages 3521–3525)

      Hideyuki Tanaka, Yoko Abe, Yutaka Matsuo, Junya Kawai, Iwao Soga, Yoshiharu Sato and Eiichi Nakamura

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201200490

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      Thermal annealing of a p-i-n organic photovoltaic device containing a crystalline benzoporphyrin donor and solvated crystals of a silylmethylfullerene acceptor increases the device performance at a temperature where partial desolvation of the acceptor produces an amorphous mesophase. This suggests that the mesophase improves the hierarchical ordering of the materials, that is, the morphology of the n-layer and the interfacial contact and, hence, the carrier generation efficiency at the donor–acceptor interface.

    9. Nanotransfer Printing with sub-10 nm Resolution Realized using Directed Self-Assembly (pages 3526–3531)

      Jae Won Jeong, Woon Ik Park, Lee-Mi Do, Jong-Hyun Park, Tae-Heon Kim, Geesung Chae and Yeon Sik Jung

      Article first published online: 5 JUN 2012 | DOI: 10.1002/adma.201200356

      Thumbnail image of graphical abstract

      An extraordinarily facile sub-10 nm fabrication method using the synergic combination of nanotransfer printing and the directed self-assembly of block copolymers is introduced. The approach is realized by achieving the uniform self-assembly of polydimethylsiloxane (PDMS)-containing block copolymers on a PDMS mold through the stabilization of the block copolymer thin films. This simple printing method can be applied on oxides, metals, polymers, and non-planar substrates without pretreatments. The fabrication of well-aligned metallic and polymeric functional nanostructures and crossed wire structures is also presented.

    10. Piezotronic Effect on the Transport Properties of GaN Nanobelts for Active Flexible Electronics (pages 3532–3537)

      Ruomeng Yu, Lin Dong, Caofeng Pan, Simiao Niu, Hongfei Liu, Wei Liu, Soojin Chua, Dongzhi Chi and Zhong Lin Wang

      Article first published online: 30 APR 2012 | DOI: 10.1002/adma.201201020

      Thumbnail image of graphical abstract

      The transport properties of GaN nanobelts (NBs) are tuned using a piezotronic effect when a compressive/tensile strain is applied on the GaN NB. This is mainly due to a change in Schottky barrier height (SBH). A theoretical model is proposed to explain the observed phenomenon.

    11. Graphene-Confined Sn Nanosheets with Enhanced Lithium Storage Capability (pages 3538–3543)

      Bin Luo, Bin Wang, Xianglong Li, Yuying Jia, Minghui Liang and Linjie Zhi

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201201173

      Thumbnail image of graphical abstract

      Novel graphene-confined tin nanosheets (G/Sn/G) are constructed using an elaborately designed glucose-assisted chemical protocol. The as-synthesized G/Sn/G are featured with significantly enhanced lithium storage properties when compared with other graphene-based 0D/2D composite nanostructures, disclosing the merits of the 2D/2D composite featured with a surface-to-surface integration formula between graphene and the second 2D phase.

      Corrected by:

      Correction: Correction: Graphene-Confined Sn Nanosheets with Enhanced Lithium Storage Capability

      Vol. 24, Issue 41, 5525, Article first published online: 26 OCT 2012

    12. Design of Vesicles Using Capillary Microfluidic Devices: From Magnetic to Multifunctional Vesicles (pages 3544–3548)

      Anjali Seth, Gaëlle Béalle, Enric Santanach-Carreras, Ali Abou-Hassan and Christine Ménager

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201200757

      Thumbnail image of graphical abstract

      In the core, in the shell, or both: a microfluidic device is used to design magnetic vesicles (liposomes and polymersomes) through chemical modification of the nanoparticle surface. Hydrophilic, hydrophobic and fluorescent quantum dot nanoparticles are used for elaborating the vesicles. Hybrid vesicles are easily obtained with a very high yield and excellent monodispersity.

    13. GaS and GaSe Ultrathin Layer Transistors (pages 3549–3554)

      Dattatray J. Late, Bin Liu, Jiajun Luo, Aiming Yan, H. S. S. Ramakrishna Matte, Matthew Grayson, C. N. R. Rao and Vinayak P. Dravid

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201201361

      Thumbnail image of graphical abstract

      Room-temperature, bottom-gate, field-effect transistor characteristics of 2D ultrathin layer GaS and GaSe prepared from the bulk crystals using a micromechanical cleavage technique are reported. The transistors based on active GaS and GaSe ultrathin layers demonstrate typical n-and p-type conductance transistor operation along with a good ON/OFF ratio and electron differential mobility.

  9. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Microcontact Printing: Microcontact Printing of Ultrahigh Density Gold Nanoparticle Monolayer for Flexible Flash Memories (Adv. Mater. 26/2012) (page 3555)

      Su-Ting Han, Ye Zhou, Zong-Xiang Xu, Long-Biao Huang, Xiong-Bo Yang and V. A. L. Roy

      Article first published online: 3 JUL 2012 | DOI: 10.1002/adma.201290157

      Thumbnail image of graphical abstract

      V. A. L. Roy and co-workers show on page 3556 how uniform monolayers of alkanethiol-protected gold nanoparticle arrays can be used as microcontact-printable chargingtrapping layers for application in flash memory. Large-area close-packed gold nanoparticles are first transferred to a poly(dimethysiloxane) stamp and then onto a flexible substrate. A large memory window and long retention times have been obtained due to the enhanced trapping sites with almost no lateral leakage, indicating the great potential for scaling down the current state-of-art flash memory.

  10. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Back Cover
    5. Masthead
    6. Contents
    7. Review
    8. Frontispiece
    9. Communications
    10. Frontispiece
    11. Communications
    1. Microcontact Printing of Ultrahigh Density Gold Nanoparticle Monolayer for Flexible Flash Memories (pages 3556–3561)

      Su-Ting Han, Ye Zhou, Zong-Xiang Xu, Long-Biao Huang, Xiong-Bo Yang and V. A. L. Roy

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201201195

      Thumbnail image of graphical abstract

      A uniform monolayer of alkanethiol-protected gold nanoparticle arrays with ultrahigh density have been used as microcontact-printable charge-trapping layers for the application in flexible flash memories. The new devices are compared to two reference devices with a floating gate created by thermal evaporation and electrostatic self-assembly, and show a large memory window, long retention times and good endurance properties.

    2. Sodium Terephthalate as an Organic Anode Material for Sodium Ion Batteries (pages 3562–3567)

      Yuwon Park, Dong-Seon Shin, Seung Hee Woo, Nam Soon Choi, Kyung Hee Shin, Seung M. Oh, Kyu Tae Lee and Sung You Hong

      Article first published online: 8 JUN 2012 | DOI: 10.1002/adma.201201205

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      Disodium terephthalate and its various derivatives are synthesized via simple acid-base chemistry for anode materials in Na ion batteries. They show excellent electrochemical performance, including little capacity fading over 90 cycles, ideal redox potential, and excellent rate performance, making them promising candidates for Na ion batteries.

    3. Toward Quantitative Prediction of Charge Mobility in Organic Semiconductors: Tunneling Enabled Hopping Model (pages 3568–3572)

      Hua Geng, Qian Peng, Linjun Wang, Haijiao Li, Yi Liao, Zhiying Ma and Zhigang Shuai

      Article first published online: 11 JUN 2012 | DOI: 10.1002/adma.201104454

      Thumbnail image of graphical abstract

      A tunneling-enabled hopping mechanism is proposed, providing a pratical tool to quantitatively assess charge mobility in organic semiconductors. The paradoxical phenomena in TIPS-pentacene is well explained in that the optical probe indicates localized charges while transport measurements show bands of charge.

    4. Resistance Switching Characteristics of Solid Electrolyte Chalcogenide Ag2Se Nanoparticles for Flexible Nonvolatile Memory Applications (pages 3573–3576)

      Jaewon Jang, Feng Pan, Kyle Braam and Vivek Subramanian

      Article first published online: 12 JUN 2012 | DOI: 10.1002/adma.201200671

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      Solution-processed mechanically flexible resistive random access memories are fabricated using Ag2Se nanoparticles; the fabricated Ag/Ag2Se/Au memory devices on flexible poly-ethylene-naphthalate substrates show bipolar switching memory characteristics, with low voltage (<1.5 V) operation, no significant retention loss after 105 s, and no degradation in endurance after 104 switching cycles, with stable operation even under a mechanical strain of 0.38%.

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