Small

Cover image for Vol. 6 Issue 10

May 21 2010

Volume 6, Issue 10

Pages 1071–1155

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. Thin films: Small 10/2010

      Dipanjan Sen, Kostya S. Novoselov, Pedro M. Reis and Markus J. Buehler

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.201090030

      Thumbnail image of graphical abstract

      The cover picture shows the mechanics of the tearing of a ribbon from a single-layer graphene sheet attached to an adhesive substrate, simulated using molecular dynamics with a first-principles-based reactive force field. The overlay shows the torn part of the sheet and the resulting rough edges at the atomic scale largely consist of characteristic armchair surface termination. The underlying color plot shows the out-of-plane deformation in the section of the sheet still attached to the substrate. The concentrated region of large deformation (red and blue color) right below the tearing flap in contrast to zero deformation in regions away from the flap (green color) causes large shear stresses, leading to shear rupture in the sheet. The tearing results in the formation of tapered nanoribbons, where the tapering angle can be controlled by adhesion strength to the substrate and number of graphene layers torn off. Considering graphene as a model 2D material, experiments, atomistic simulation, and theory provide fundamental insight into the energetics of tearing that can be extended to other 2D nanoscale thin films attached to substrates. For more information, please read the Full Paper “Tearing Graphene Sheets From Adhesive Substrates Produces Tapered Nanoribbons” by M. J. Buehler et al., beginning on page 1108.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. Quantum dots: Small 10/2010

      Hongguang Liu, Xiaofen Zhang, Bengang Xing, Peizhen Han, Sanjiv Sam Gambhir and Zhen Cheng

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.201090031

      Thumbnail image of graphical abstract

      The cover picture shows a new method to illuminate quantum dots (QDs) by radiation luminescence as an internal light source. Taking advantage of the radioactive luminescent light at the visible and NIR range, many different fluorophores such as QDs can be exited to emit fluorescence for optical imaging. Three CdSe/ZnS core/shell QDs are chosen and irradiated by a β emitter, 131I. The excited QDs can produce fluorescence for both in vitro and in vivo imaging. This study demonstrates an alternate strategy for the design of self-illuminating optical-imaging agents. Radiation-luminescence-excited fluorophores could also be readily adapted for dual-modality imaging. For more information, please read the Communication “Radiation-Luminescence-Excited Quantum Dots for in vivo Multiplexed Optical Imaging” by Z. Cheng et al., beginning on page 1087.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. Contents: Small 10/2010 (pages 1071–1075)

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.201090032

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. Nanomaterial patterning

      Matrix-Assisted Dip-Pen Nanolithography and Polymer Pen Lithography (pages 1077–1081)

      Ling Huang, Adam B. Braunschweig, Wooyoung Shim, Lidong Qin, Jong Kuk Lim, Sarah J. Hurst, Fengwei Huo, Can Xue, Jae-Won Jang and Chad A. Mirkin

      Version of Record online: 2 NOV 2009 | DOI: 10.1002/smll.200901198

      Thumbnail image of graphical abstract

      The controlled patterning of nanomaterials presents a major challenge to the field of nanolithography because of differences in size, shape, and solubility of these materials. Matrix-assisted dip-pen nanolithography and polymer-pen lithography provide a solution to this problem by utilizing a polymeric matrix that encapsulates the nanomaterials and delivers them to surfaces with precise control of feature size (see image).

    2. Molecular printing

      Force- and Time-Dependent Feature Size and Shape Control in Molecular Printing via Polymer-Pen Lithography (pages 1082–1086)

      Xing Liao, Adam B. Braunschweig, Zijian Zheng and Chad A. Mirkin

      Version of Record online: 26 OCT 2009 | DOI: 10.1002/smll.200901538

      Thumbnail image of graphical abstract

      Polymer-pen lithography is a scanning-probe contact-printing method that can control feature diameter from many micrometers to sub-100nm in a single writing operation as a result of force- and time-dependent ink transport. A quantitative model that relates the force between the elastomeric tips and the substrate to the feature edge length has been derived and experimentally confirmed (see image).

    3. Quantum dots

      Radiation-Luminescence-Excited Quantum Dots for in vivo Multiplexed Optical Imaging (pages 1087–1091)

      Hongguang Liu, Xiaofen Zhang, Bengang Xing, Peizhen Han, Sanjiv Sam Gambhir and Zhen Cheng

      Version of Record online: 14 MAY 2010 | DOI: 10.1002/smll.200902408

      Thumbnail image of graphical abstract

      A new method to illuminate quantum dots (QDs) by radiation luminescence as an internal light source is reported. The excited QDs can produce fluorescence for both in vitro and in vivo imaging. This study provides an alternate strategy for the design of self-illuminated optical imaging agents. Radiation-luminescence-excited QDs can also be readily adapted for dual-modality imaging.

    4. Nanotube sensors

      Peptide-Nanotube Biochips for Label-Free Detection of Multiple Pathogens (pages 1092–1095)

      Roberto de la Rica, Christophe Pejoux, Cesar Fernandez-Sanchez, Antonio Baldi and Hiroshi Matsui

      Version of Record online: 3 MAY 2010 | DOI: 10.1002/smll.201000151

      Thumbnail image of graphical abstract

      Peptide nanotubes are integrated with microfabricated transducer arrays for bacterial detection. On each microelectrode of the array, circulating antibody-modified peptide nanotubes agglutinate bacteria as pathogen catchers and generate an impedance signal on the transducer. The pathogen microarray can detect as few as 102 cells of E. coli or S. typhi within one hour and the sensor chip can be easily reused for multiple measurements.

    5. Nanotube templates

      Synthesis of TaS2 Nanotubes From Ta2O5 Nanotube Templates (pages 1096–1099)

      Phoebe Li, Christopher L. Stender, Emilie Ringe, Laurence D. Marks and Teri W. Odom

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.201000226

      Thumbnail image of graphical abstract

      Multi-walled TaS2 nanotubes are synthesized from anodized Ta2O5 nanotube templates in a gas-phase reaction, with control over the length, diameter, and number of TaS2 layers within a nanotube. TaS2 nanotubes exhibit elevated superconducting transition temperatures and suppressed charge density wave transition temperatures compared to bulk, offering a straightforward method of characterizing other transition metal dichalcogenide materials in reduced dimensions.

    6. Graphene

      Production of Graphene Sheets by Direct Dispersion with Aromatic Healing Agents (pages 1100–1107)

      Ming Zhang, Rishi R. Parajuli, Daniel Mastrogiovanni, Boya Dai, Phil Lo, William Cheung, Roman Brukh, Pui Lam Chiu, Tao Zhou, Zhongfan Liu, Eric Garfunkel and Huixin He

      Version of Record online: 6 MAY 2010 | DOI: 10.1002/smll.200901978

      Thumbnail image of graphical abstract

      A simple and scalable exfoliation approach is developed to produce high-quality single-layer graphene sheets without the use of toxic reduction agents of expensive solvents. Graphite powders are exfoliated in a water solution of pyrene derivatives, which act as dispersion agents, healing agents, and electric “glue” during the thermal annealing process.

  5. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. Thin films

      Tearing Graphene Sheets From Adhesive Substrates Produces Tapered Nanoribbons (pages 1108–1116)

      Dipanjan Sen, Kostya S. Novoselov, Pedro M. Reis and Markus J. Buehler

      Version of Record online: 6 MAY 2010 | DOI: 10.1002/smll.201000097

      Thumbnail image of graphical abstract

      Tearing of graphene layers from adhesive substrates, such as SiO2 and poly(methyl methacrylate), leads to the formation of tapered ribbons, the angle of tapering increasing with adhesion strength. Being a truly two-dimensional material, the tearing mechanics are governed by the in-plane stretching energy of the graphene sheet, deviating from the behavior of macroscopic thin films.

    2. Multimaterial nanostructures

      Mimicking Electrodeposition in the Gas Phase: A Programmable Concept for Selected-Area Fabrication of Multimaterial Nanostructures (pages 1117–1124)

      Jesse J. Cole, En-Chiang Lin, Chad R. Barry and Heiko O. Jacobs

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.200901547

      Thumbnail image of graphical abstract

      Clusters of charged nanoparticles in the gas phase are selectively deposited onto electrically grounded surfaces. Similar to electroplating, the continued deposition of Au nanoparticles onto underlying traces increases the overall line conductivity. Alternatively, semiconducting ZnO and Ge nanomaterials can be sequentially deposited between interdigitated electrodes and serve as addressable sensor-active areas.

    3. Graphene surfaces

      Selective Chemical Modification of Graphene Surfaces: Distinction Between Single- and Bilayer Graphene (pages 1125–1130)

      Fabian M. Koehler, Arnhild Jacobsen, Klaus Ensslin, Christoph Stampfer and Wendelin J. Stark

      Version of Record online: 6 MAY 2010 | DOI: 10.1002/smll.200902370

      Thumbnail image of graphical abstract

      The chemical modification of graphene with diazonium chemistry is analyzed by confocal Raman spectroscopy. The reaction shows a clear selectivity between single- (1L) and bilayer (2L) graphene after ten minutes of reaction. The edge of the single-layer-graphene areas has an increased reactivity to the diazonium reagent and the local carbon hybridization changes from sp2 to sp3, altering the electronic properties of graphene.

    4. Self-assembled nanostructures

      Diverse Morphologies of Self-Assemblies from Homoditopic 1,18-Nucleotide-Appended Bolaamphiphiles: Effects of Nucleobases and Complementary Oligonucleotides (pages 1131–1139)

      Rika Iwaura, Tomohiko Iizawa, Hiroyuki Minamikawa, Mayumi Ohnishi-Kameyama and Toshimi Shimizu

      Version of Record online: 6 MAY 2010 | DOI: 10.1002/smll.200902262

      Thumbnail image of graphical abstract

      Diverse nanostructures are formed by single-com ponent self-assembly of homoditopic 1,18-nucleotide-appended bolaamphiphiles and binary self-assembly with complementary single-stranded oligonucleotides. The self-assembled morphologies—nanosheets, nanofibers, nanorods, and nanoparticles—strongly depend both on the nature of the nucleobase moieties and DNA templates.

    5. AFM tips

      Preventing Nanoscale Wear of Atomic Force Microscopy Tips Through the Use of Monolithic Ultrananocrystalline Diamond Probes (pages 1140–1149)

      J. Liu, D. S. Grierson, N. Moldovan, J. Notbohm, S. Li, P. Jaroenapibal, S. D. O'Connor, A. V. Sumant, N. Neelakantan, J. A. Carlisle, K. T. Turner and R. W. Carpick

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.200901673

      Thumbnail image of graphical abstract

      Monolithic diamond probes with integrated tips possessing small radii, smooth surfaces, and controlled geometry are fabricated by a wafer-level process. The tips have superior wear resistance to that of SiNx tips under contact-mode scanning conditions at low and high humidity, and under stresses in the 2–8 GPa range.

    6. Graphene

      Gating of Single-Layer Graphene with Single-Stranded Deoxyribonucleic Acids (pages 1150–1155)

      Jian Lin, Desalegne Teweldebrhan, Khalid Ashraf, Guanxiong Liu, Xiaoye Jing, Zhong Yan, Rong Li, Mihri Ozkan, Roger K. Lake, Alexander A. Balandin and Cengiz S. Ozkan

      Version of Record online: 14 MAY 2010 | DOI: 10.1002/smll.200902379

      Thumbnail image of graphical abstract

      Adenine nucleoside is physisorbed on the graphene supercell where the π orbitals of the base interact with the π orbitals of the graphene layer. Micro-Raman spectroscopy of the 2D band of pristine graphene and single-stranded DNA (ssDNA)/graphene systems indicates a shift of ≈4 cm−1 as a result of ssDNA patterning. The ssDNA fragments act as negative-potential gating agents.

  6. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Contents
    5. Communications
    6. Full Papers
    7. Corrigendum
    1. You have free access to this content
      Size-Tunable UV-Luminescent Silicon Nanocrystals

      Naoto Shirahata, Tsuyoshi Hasegawa, Yoshio Sakka and Tohru Tsuruoka

      Version of Record online: 19 MAY 2010 | DOI: 10.1002/smll.201090033

      This article corrects:

      Size-Tunable UV-Luminescent Silicon Nanocrystals1

      Vol. 6, Issue 8, 915–921, Version of Record online: 15 APR 2010

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