Small

Cover image for Vol. 8 Issue 9

May 7, 2012

Volume 8, Issue 9

Pages 1289–1454

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Graphene: Chemical Vapor Deposition of Graphene on Copper from Methane, Ethane and Propane: Evidence for Bilayer Selectivity (Small 9/2012) (page 1289)

      Jonathan K. Wassei, Matthew Mecklenburg, Jaime A. Torres, Jesse D. Fowler, B. C. Regan, Richard B. Kaner and Bruce H. Weiller

      Article first published online: 2 MAY 2012 | DOI: 10.1002/smll.201290052

      Thumbnail image of graphical abstract

      The cover image shows a schematic pathway of how ethane gas can be used to grow AB-stacked, bilayer graphene through chemical vapor deposition on copper foils. The background is a selective area transmission electron microscopy image of bilayer graphene, and the foreground displays a scanning electron microscopy image of graphene with the bilayer regions–blue false-colored–lifted above to demonstrate the high bilayer coverage. The effects of different hydrocarbon gases have been studied to elucidate that the growth process of graphene on copper catalysts is not only based on the concentration of carbon in the reaction, but also on the different decomposition pathways of each hydrocarbon. For more information, please read the Full Paper “Chemical Vapor Deposition of Graphene on Copper from Methane, Ethane and Propane: Evidence for Bilayer Selectivity” by R. B. Kaner, B. H. Weiller, and co-workers, beginning on page 1415.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Gold Nanorods: Watching Single Gold Nanorods Grow (Small 9/2012) (page 1290)

      Zhongqing Wei, Hua Qi, Min Li, Bochong Tang, Zhengzheng Zhang, Ruiling Han, Jiaojiao Wang and Yuliang Zhao

      Article first published online: 2 MAY 2012 | DOI: 10.1002/smll.201290053

      Thumbnail image of graphical abstract

      The cover picture, captured by atomic force microscopy, shows the evolution of two single-crystalline gold nanorods as growth time progresses. The gold nanorods are grown directly on silicon surfaces, to which gold seed particles of ca. 4 nm diameters had been previously linked via covalent bonding. The growth propagation of the nanorods is monitored by precisely measuring their 3D size, and their growth kinetics is then derived from these direct measurements rather than from statistical analyses as in other techniques. The quantitative study presented here represents an important approach toward gaining a better understanding of the seed-mediated growth mechanism of gold nanorods using a straightforward scanning probe microscopy method, which may ultimately lead to improved gold nanorod synthesis, controllable surface growth, and aligned nanorod array. For more information, please read the Communication “Watching Single Gold Nanorods Grow” by Z. Wei and co-workers, beginning on page 1331.

  3. Masthead

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Masthead: (Small 9/2012)

      Article first published online: 2 MAY 2012 | DOI: 10.1002/smll.201290054

  4. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Contents: (Small 9/2012) (pages 1291–1297)

      Article first published online: 2 MAY 2012 | DOI: 10.1002/smll.201290050

  5. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Nanotube Dispersion: Carbon Nanotubes in the Liquid Phase: Addressing the Issue of Dispersion (Small 9/2012) (page 1298)

      Thathan Premkumar, Raffaele Mezzenga and Kurt E. Geckeler

      Article first published online: 2 MAY 2012 | DOI: 10.1002/smll.201290051

      Thumbnail image of graphical abstract

      The image features the dispersion of carbon nanotubes (CNTs) in liquids and the clarification of the term and process. Based on the controversy existing in the scientific community, research involving the dispersion of CNTs in liquids, particularly in water, are analyzed and reviewed. According to fundamental approaches and concepts, the term dispersion is shown to be more appropriate than the term solution. In addition, the dispersion in different media, the stability, and the interactions between CNTs and solvents are evaluated. The image illustrates the dispersion of CNTs in a liquid both in the agglomerated and well-dispersed state.

  6. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Carbon Nanotubes in the Liquid Phase: Addressing the Issue of Dispersion (pages 1299–1313)

      Thathan Premkumar, Raffaele Mezzenga and Kurt E. Geckeler

      Article first published online: 19 MAR 2012 | DOI: 10.1002/smll.201101786

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      The fundamental question when dealing with carbon nanotubes in liquids, particularly in water, is: are they dissolved or dispersed? In this article, we highlight and discuss this issue and controversy in literature considering their size, nature of existence in the liquid, stability, and their behavior in the liquid medium. Consequently, it is suggested to use the term dispersion rather than solution.

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Porous Protein Crystals as Reaction Vessels for Controlling Magnetic Properties of Nanoparticles (pages 1314–1319)

      Satoshi Abe, Masahiko Tsujimoto, Ko Yoneda, Masaaki Ohba, Tatsuo Hikage, Mikio Takano, Susumu Kitagawa and Takafumi Ueno

      Article first published online: 2 MAR 2012 | DOI: 10.1002/smll.201101866

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      Magnetic bimetallic CoPt nanoparticles are synthesized in the solvent channels of hen egg white lysozyme crystals by the reduction of Co2+ and Pt2+ ions pre-organized on the interior surface of the solvent channels. By using different lysozyme crystal systems, the magnetic properties of CoPt nanoparticles can be controlled.

    2. The Role of Defects on the Assembly and Stability of DNA Nanostructures (pages 1320–1325)

      Daniel G. Greene, Jung-Won Keum and Harry Bermudez

      Article first published online: 22 FEB 2012 | DOI: 10.1002/smll.201102221

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      Defects are known to underlie the mechanical properties of materials, especially so at the nanoscale. Using four compositionally identical DNA triangles, defect density is found to be inversely correlated with assembly efficiency and melting temperature. These findings are supported by a series of experiments with more complex DNA pyramids. Because they are naturally responsive to stresses, defects present an attractive opportunity as design elements for responsive DNA materials.

    3. Electrochemistry: An Efficient Way to Chemically Modify Individual Monolayers of Graphene (pages 1326–1330)

      Lin Gan, Dayong Zhang and Xuefeng Guo

      Article first published online: 22 FEB 2012 | DOI: 10.1002/smll.201102302

      Thumbnail image of graphical abstract

      Fast and efficient surface functionalization of graphene is achieved by the electrochemical formation of aryl radicals from diazonium salts under mild conditions. Precise control of the ratio of electron-deficient nitro groups to electron-rich amino groups is also demostrated, potentially resulting in the controllable tuning of the electrical properties of graphenes.

    4. Watching Single Gold Nanorods Grow (pages 1331–1335)

      Zhongqing Wei, Hua Qi, Min Li, Bochong Tang, Zhengzheng Zhang, Ruiling Han, Jiaojiao Wang and Yuliang Zhao

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201102426

      Thumbnail image of graphical abstract

      The consecutive evolution process of single gold nanorods is monitored using atomic force microscopy (AFM). The single-crystal gold nanorods investigated are grown directly on surfaces to which gold seed particles are covalently linked. The growth kinetics for single nanorods is derived from the 3D information recorded by AFM. A better understanding of the seed-mediated growth mechanism may ultimately lead to the direct growth of aligned nanorods on surfaces.

    5. Gold-Nanoparticle-Embedded Polydimethylsiloxane Elastomers for Highly Sensitive Raman Detection (pages 1336–1340)

      Gang Lu, Hai Li and Hua Zhang

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201102258

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      A simple, convenient, and efficient method for highly sensitive Raman detection is made by using a Au nanoparticle (AuNP)-embedded polydimethylsiloxane (PDMS) elastomer, referred to as AuNP-PDMS. When this AuNP-PDMS layer is applied to a surface, it can dramatically enhance the Raman signal of detected molecules. Moreover, it can be used for sensitive chemical imaging on solid substrates. As a proof of concept, patterned chemical images of p-aminothiophenol and methylene blue on a Ag substrate are obtained after this chemically patterned Ag substrate is covered by AuNP-PDMS.

    6. Biomimetic Assembly of Proteins into Microcapsules on Oil-in-Water Droplets with Structural Reinforcement via Biomolecular-Recognition-Based Cross-Linking of Surface Peptides (pages 1341–1344)

      Yoshiaki Maeda, Zengyan Wei and Hiroshi Matsui

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201102571

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      By mimicking the stabilization of bacterial membranes with S-layer proteins, a novel process to fabricate highly stable protein microcapsules is introduced. In this strategy, engineered collagen peptides with site-specific biotinylation are assembled into microcapsules on the oil-in-water droplets, and the resulting microcapsules are reinforced by biomolecular-recognition-based cross-linking with the protein. Furthermore the microcapsules are shown to be versatile scaffolds for developing functionalized hierarchical colloidosomes for important biotechnological applications.

    7. Electrochemically Induced Maskless Metal Deposition on Micropore Wall (pages 1345–1349)

      Jie Liu, Clément Hébert, Pascale Pham, Fabien Sauter-Starace, Vincent Haguet, Thierry Livache and Pascal Mailley

      Article first published online: 2 MAR 2012 | DOI: 10.1002/smll.201102327

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      By applying an external electric field across a micropore via an electrolyte, metal ions in the electrolyte can be reduced locally onto the inner wall of the micropore, which was fabricated in a silica-covered silicon membrane. This maskless metal deposition on the silica surface is a result of the pore membrane polarization in the electric field.

    8. Nanoplasmon-Enhanced Transparent Plasma Display Devices (pages 1350–1354)

      Seong Min Lee, Donghyuk Kim, Duk Young Jeon and Kyung Cheol Choi

      Article first published online: 1 MAR 2012 | DOI: 10.1002/smll.201102015

      Thumbnail image of graphical abstract

      Plasmon-enhanced transparent plasma display devices are demonstrated via the resonant interface between Ag nanoparticles and a Eu3+-doped phosphor. Enhanced emission from the phosphor by metallic nanoparticles leads to an increase of the luminous efficacy in the transparent plasma display device. This is a prototype of the plasmon-enhanced transparent plasma display device.

    9. Amplified Spontaneous Emission of Surface Plasmon Polaritons with Unusual Angle-Dependent Response (pages 1355–1359)

      Yu-Hui Chen, Jiafang Li, Ming-Liang Ren and Zhi-Yuan Li

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201101806

      Thumbnail image of graphical abstract

      Loss issues are fundamentally crucial for the application of surface plasmon polaritons (SPPs). In this study the amplified spontaneous emission (ASE) of SPPs in a typical Kretschmann configuration is observed and shows an unusually broadened angular response with increased pump intensity. Theoretical models are further developed to verify the results and understand the amplification of SPPs in Fourier space.

    10. Carbon–Silicon Schottky Barrier Diodes (pages 1360–1364)

      Chanyoung Yim, Niall McEvoy, Ehsan Rezvani, Shishir Kumar and Georg S. Duesberg

      Article first published online: 5 MAR 2012 | DOI: 10.1002/smll.201101996

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      The simple fabrication of high-performance Schottky barrier diodes between silicon and conductive carbon films (C-Films) is reported. By optimizing the interface, ideality factors as low as n = 1.22 for pyrolytic photoresist films (PPF) have been obtained. These remarkable values, which are not far away from those of commercial products are obtained repeatedly on non-optimized substrates with fully scalable processes.

  8. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Frontispiece
    7. Review
    8. Communications
    9. Full Papers
    1. Probing the Effect of Molecular Orientation on the Intensity of Chemical Enhancement Using Graphene-Enhanced Raman Spectroscopy (pages 1365–1372)

      Xi Ling, Juanxia Wu, Weigao Xu and Jin Zhang

      Article first published online: 23 FEB 2012 | DOI: 10.1002/smll.201102223

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      A planar molecule, copper phthalocyanine (CuPc), is used to study molecular orientation effects in graphene-enhanced Raman spectroscopy. Annealing allows the CuPc molecule in a Langmuir–Blodgett film to change orientation from upstanding to lying down. The magnitude of the chemical enhancement, which is highly sensitive to molecular orientation, can be used to evaluate the degree of interaction between the molecules and graphene.

    2. Small-Caliber Vascular Prosthesis Prototype Based on Controlled Release of Heparin from Mesochannels and Its Enhanced Biocompatibility (pages 1373–1383)

      Yu Zhou, Kun Li, Jia Yuan Yang, Chen Xi Guan, Ying Wang, Chang Jian Liu and Jian Hua Zhu

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201101270

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      A vascular prosthesis prototype is prepared by directly modifying expanded polytetrafluoroethylene (ePTFE) grafts with mesochannels through in situ epitaxial growth of mesoporous silica nanoparticles on ePTFE grafts. Slow and sustained release of heparin from the mesochannels is achieved, and thrombin is inactivated by antithrombin III (AT III). The performance of artificial blood vessels is thus improved.

    3. Converting Graphene Oxide Monolayers into Boron Carbonitride Nanosheets by Substitutional Doping (pages 1384–1391)

      Tsung-Wu Lin, Ching-Yuan Su, Xin-Quan Zhang, Wenjing Zhang, Yi-Hsien Lee, Chih-Wei Chu, Hsin-Yu Lin, Mu-Tung Chang, Fu-Rong Chen and Lain-Jong Li

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201101927

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      Boron and nitrogen atoms are incorporated into graphene oxide to form boron carbonitride nanosheets with randomly distributed boron nitride (BN) nanodomains in the graphene lattice. The content of BN increases with increasing reaction temperature, which in turn affects the optical bandgap of the nanosheets. BN-doped graphene nanosheets exhibit an ambipolar semiconductor behavior.

    4. Nanostructure Formation and Passivation of Large-Area Black Silicon for Solar Cell Applications (pages 1392–1397)

      Yaoping Liu, Tao Lai, Hailing Li, Yan Wang, Zengxia Mei, Huili Liang, Zhilei Li, Fengming Zhang, Wenjing Wang, Andrej Yu Kuznetsov and Xiaolong Du

      Article first published online: 20 FEB 2012 | DOI: 10.1002/smll.201101792

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      Nanoscale textured silicon is explored by simple low-cost metal-assisted chemical etching; large-area black silicon is fabricated both on single-crystalline Si and multicrystalline Si for solar cell applications. The Ag nanoparticles tend to form at the kinks, steps, and other defects first, and these initial nanoparticles become bigger than the others and catalyze the oxidation of Si more effectively.

    5. Facile Synthesis of Au-Nanoparticle/Polyoxometalate/Graphene Tricomponent Nanohybrids: An Enzyme-Free Electrochemical Biosensor for Hydrogen Peroxide (pages 1398–1406)

      Rongji Liu, Shiwen Li, Xuelian Yu, Guangjin Zhang, Suojiang Zhang, Jiannian Yao, Bineta Keita, Louis Nadjo and Linjie Zhi

      Article first published online: 21 FEB 2012 | DOI: 10.1002/smll.201102298

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      Well-defined Au-nanoparticle/polyoxometalate/graphene tricomponent nanohybrids are synthesized by a green, facile, one-pot method. The promising application of enzyme-free biosensor for H2O2 is selected as a preliminary test of the electrocatalytic behaviors of the prepared nanohybrids. Encouragingly, such a nanohybrid offers a remarkably improved sensitivity, selectivity, and stability for H2O2 detection.

    6. DNA-Wrapped Carbon Nanotubes as Sensitive Electrochemical Labels in Controlled-Assembly-Mediated Signal Transduction for the Detection of Sequence-Specific DNA (pages 1407–1414)

      Huagui Nie, Zhi Yang, Shaoming Huang, Zhan Wu, Hongqi Wang, Ruqin Yu and Jianhui Jiang

      Article first published online: 5 MAR 2012 | DOI: 10.1002/smll.201102071

      Thumbnail image of graphical abstract

      A novel electrochemical strategy based on DNA-wrapped carbon nanotubes acting as electrochemical labels, is developed for detection of sequence-specific DNA. The strategy is demonstrated to be desirably sensitive and specific for the target DNA.

    7. Chemical Vapor Deposition of Graphene on Copper from Methane, Ethane and Propane: Evidence for Bilayer Selectivity (pages 1415–1422)

      Jonathan K. Wassei, Matthew Mecklenburg, Jaime A. Torres, Jesse D. Fowler, B. C. Regan, Richard B. Kaner and Bruce H. Weiller

      Article first published online: 20 FEB 2012 | DOI: 10.1002/smll.201102276

      Thumbnail image of graphical abstract

      To study the effects of hydrocarbon precursor gases, graphene is grown using chemical vapor deposition from methane, ethane, and propane on copper foils. The larger molecules are found to more readily produce multilayer graphene, owing to a higher carbon concentration and different decomposition processes. Additionally, single- and bilayer graphene can be grown with good selectivity in a simple, one-step process by varying the pressure of ethane.

    8. Reversible Single-Molecule Switching in an Ordered Monolayer Molecular Dipole Array (pages 1423–1428)

      Yu Li Huang, Yunhao Lu, Tian Chao Niu, Han Huang, Satoshi Kera, Nobuo Ueno, Andrew Thye Shen Wee and Wei Chen

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201101967

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      The reversible switching of single chloroaluminum phthalocyanine (ClAlPc) dipole molecules is controlled by voltage pulses applied through an atomically sharp metal tip in a scanning tunneling microscopy system. The switching is repeatable and well-localized. A label “N” written on the close-packed monolayer is demonstrated. The easy reading, writing, and erasing of binary information on the molecular dipole array suggests a model molecular system for ultra-high-density data storage.

    9. Growth, Characterization, and Properties of Nanographene (pages 1429–1435)

      Wei Yang, Congli He, Lianchang Zhang, Yi Wang, Zhiwen Shi, Meng Cheng, Guibai Xie, Duoming Wang, Rong Yang, Dongxia Shi and Guangyu Zhang

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201101827

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      Nanographene is a type of hybrid structure of graphene with typical sizes of tens of nanometers. The growth, characterization, and properties of nanographene films made of densely packed nanographene islands are investigated systematically. Devices with thick and thin films show different gate dependence of conductivity.

    10. Preparation of Continuous Gold Nanowires by Electrospinning of High-Concentration Aqueous Dispersions of Gold Nanoparticles (pages 1436–1441)

      Katharina Gries, Henning Vieker, Armin Gölzhäuser, Seema Agarwal and Andreas Greiner

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201102308

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      Gold nanowires are prepared by electrospinning of highly concentrated aqueous dispersions of gold nanoparticles (AuNPs) in the presence of poly(vinyl alcohol) and subsequent annealing. Continuous wires of sintered AuNPs are obtained. The wires are characterized by techniques including helium ion microscopy.

    11. Plasmonic-Coupling-Based Sensing by the Assembly and Disassembly of Dipycolylamine-Tagged Gold Nanoparticles Induced by Complexing with Cations and Anions (pages 1442–1448)

      Dong Xiang Li, Jun Feng Zhang, Yoon Hee Jang, Yu Jin Jang, Dong Ha Kim and Jong Seung Kim

      Article first published online: 29 FEB 2012 | DOI: 10.1002/smll.201102335

      Thumbnail image of graphical abstract

      Plasmonic-coupling-based ion sensing is achieved by using dipycolylamine-tagged gold nanoparticles (AuNP@DPA), which act as highly selective sensors of cations and anions via plasmonic-coupling-induced color changes driven by their assembly and disassembly upon complexing with target ions. The AuNP@DPA-based molecular recognition system also demonstrates a viable performance for the detection of total selective metal ions present in different types of water analytes.

    12. Sticky Bio-inspired Micropillars: Finding the Best Shape (pages 1449–1454)

      Giuseppe Carbone and Elena Pierro

      Article first published online: 1 MAR 2012 | DOI: 10.1002/smll.201102021

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      The design of mushroom micropillars plays a key role in developing bio-inspired microstructured surfaces with amazing adhesive properties. A relatively simple methodology to optimize these microstructures and assess their performance is presented. The predictions are in excellent agreement with experimental results and show that the terminal plate of the mushroom pillars plays the most fundamental rule in determining the adhesive performance of the surface.

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