Cover image for Vol. 10 Issue 24

Early View (Online Version of Record published before inclusion in an issue)

  1. Reviews

    1. Asymmetric Block Copolymers for Supramolecular Templating of Inorganic Nanospace Materials

      Bishnu Prasad Bastakoti, Yunqi Li, Tatsuo Kimura and Yusuke Yamauchi

      Article first published online: 23 DEC 2014 | DOI: 10.1002/smll.201402573

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      This review focuses on polymeric micelles consisting of asymmetric block copolymers as designed templates for several inorganic nanospace materials with a wide variety of compositions. The presence of chemically distinct domains of asymmetric triblock and diblock copolymers provides self-assemblies with more diverse morphological and functional features, thereby affording well-designed nanospace materials.

    2. Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells

      Isabella Concina and Alberto Vomiero

      Article first published online: 18 DEC 2014 | DOI: 10.1002/smll.201402334

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      This Review provides a brief summary of the most recent research developments in the synthesis and application of nanostructured metal oxide semiconductors for dye-sensitized and quantum dot-sensitized solar cells, and illustrates the critical role of photoanode preparation to boost charge photogeneration and collection, to inhibit charge recombination and to increase photoconversion efficiency in these devices.

    3. Glowing Graphene Quantum Dots and Carbon Dots: Properties, Syntheses, and Biological Applications

      Xin Ting Zheng, Arundithi Ananthanarayanan, Kathy Qian Luo and Peng Chen

      Article first published online: 17 DEC 2014 | DOI: 10.1002/smll.201402648

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      Glowing carbon nanocrystals (graphene quantum dots and carbon dots) are emerging zero-dimensional materials exhibiting unique and tunable photoluminescence, exceptional physicochemical properties, high photostability, biocompatibility, and molecular size. They promise a wide range of novel biological applications including bioimaging, optical biosensing, drug delivery, and theranostics.

  2. Communications

    1. Topological Crystalline Insulator Pb1-xSnxSe Nanowires with {100} Facets

      Qisheng Wang, Muhammad Safdar, Zhenxing Wang, Xueying Zhan, Kai Xu, Fengmei Wang and Jun He

      Article first published online: 17 DEC 2014 | DOI: 10.1002/smll.201403159

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      Surface states properties of topological crystalline insulator Pb1-xSnxSe are strongly dependent on crystallographic plane orientation. Rectangular prismatic PbxSn1-xSe nanowires and nanoplates are grown with distinct {100} surfaces on mica sheets. Substrate surface chemical properties are found to be the critical factors that affect the vapor deposition process and final shapes of Pb1-xSnxSe nanostructures.

  3. Full Papers

    1. Improved Optical Sintering Efficiency at the Contacts of Silver Nanowires Encapsulated by a Graphene Layer

      Seung-Bok Yang, HongKyw Choi, Da Som Lee, Choon-Gi Choi, Sung-Yool Choi and Il-Doo Kim

      Article first published online: 17 DEC 2014 | DOI: 10.1002/smll.201402474

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      Optical sintering with intense pulsed light (IPL) offers an effective welding method for silver nanowire (AgNW) junctions. Graphene overlayers coated on AgNWs facilitate the heat transfer from graphene to AgNWs by effectively absorbing IPL energy, resulting in improved sintering efficiency at the contact between Ag wires.

  4. Communications

    1. Precisely Tailoring the Stoichiometric Stacking of Perylene-TCNQ Co-Crystals towards Different Nano and Microstructures with Varied Optoelectronic Performances

      Weigang Zhu, Yuanping Yi, Yonggang Zhen and Wenping Hu

      Article first published online: 17 DEC 2014 | DOI: 10.1002/smll.201402330

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      Organic charge-transfer co-crystals with varied donor–acceptor stoichiometric ratios and molecular packing structures are controllably prepared with the morphology of nanowires or microblocks. They have distinct charge transport behavior and photoresponsivity. These interesting results pave the way for rational design and preparation of co-crystals with desired functions.

  5. Full Papers

    1. Effective Gene Delivery into Human Stem Cells with a Cell-Targeting Peptide-Modified Bioreducible Polymer

      Jagadish Beloor, Suresh Ramakrishna, Kihoon Nam, Chang Seon Choi, Jongkil Kim, Sung Hwa Kim, Hyong Jin Cho, HeungSoo Shin, Hyongbum Kim, Sung Wan Kim, Sang-Kyung Lee and Priti Kumar

      Article first published online: 16 DEC 2014 | DOI: 10.1002/smll.201402933

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      The potentiation of gene delivery by combining the activities of a nicotinic acetylcholine receptor-binding peptide RVG and a polymer PAM-ABP that releases nucleic acids in a cytoplasm-responsive manner are detailed. RVG-engrafted PAM-ABP quantitatively and qualitatively enhances plasmid DNA transfection into human mesenchymal and embryonic stem cells by synergizing ligand-mediated cellular entry with the environment-sensitive release property of the bioreducible polymer.

    2. A Brown Mesoporous TiO2-x/MCF Composite with an Extremely High Quantum Yield of Solar Energy Photocatalysis for H2 Evolution

      Mingyang Xing, Jinlong Zhang, Bocheng Qiu, Baozhu Tian, Masakazu Anpo and Michel Che

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201403056

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      The maximum quantum yield for photo­catalytic H2 production previously observed for TiO2-based semiconductors was 35%. Now, a brown mesoporous fluorine-doped TiO2-x/MCF composite is synthesized via vacuum activation. It exhibits excellent solar absorption and a record-breaking quantum yield of 46% for solar light-activated photocatalytic H2 production.

  6. Reviews

    1. Crystal Networks in Silk Fibrous Materials: From Hierarchical Structure to Ultra Performance

      Anh Tuan Nguyen, Qiao-Ling Huang, Zhen Yang, Naibo Lin, Gangqin Xu and Xiang Yang Liu

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402985

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      The correlation between the mesoscopic structures and the mechanical properties of silk soft fibrous materials are addressed based on the hierarchical crystal network models. In particular, two types of hierarchical networks are discussed: the weak nanofibril–nanofibril interaction case (silk fibroin hydrogels), and the strong nanofibril–nanofibril interaction case (silk fibers).

  7. Communications

    1. Low-voltage Driven Graphene Foam Thermoacoustic Speaker

      Wenwen Fei, Jianxin Zhou and Wanlin Guo

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402982

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      A low-voltage driven thermoacoustic speaker is fabricated based on three-dimensional graphene foams synthesized by a nickel-template assisted chemical vapor deposition method. The corresponding thermoacoustic performances are found to be related to its microstructure. Graphene foams exhibit low heat-leakage to substrates and feasible tunability in structures and thermoacoustic performances, having great promise for applications in flexible or ultrasonic acoustic devices.

  8. Reviews

    1. Band Engineering for Novel Two-Dimensional Atomic Layers

      Qingsheng Zeng, Hong Wang, Wei Fu, Yongji Gong, Wu Zhou, Pulickel M. Ajayan, Jun Lou and Zheng Liu

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402380

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      Band engineering of novel two-dimensional materials is reviewed with a focus on three approaches, including the synthesis of ternary materials via alloying, the preparation of vertical and lateral heterostructures via stacking or epitaxially growing materials with similar atomic structure, and the control of thickness. The variations of band structures and the resulting physical properties are systematically discussed.

    2. A Revolution in Electrodes: Recent Progress in Rechargeable Lithium–Sulfur Batteries

      Xin Fang and Huisheng Peng

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402354

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      On the list of cutting-edge batteries for future power systems, the lithium–sulfur battery is a promising candidate applicable in electrical vehicles and portable devices. In this review, recent progress in lithium–sulfur battery is outlined regarding the evolution of the electrodes, considering the various cathodes to modified anodes, and presenting exciting prospects for future development.

  9. Full Papers

    1. Direct Growth of Ultrafast Transparent Single-Layer Graphene Defoggers

      Lifang Tan, Mengqi Zeng, Qiong Wu, Linfeng Chen, Jiao Wang, Tao Zhang, Jürgen Eckert, Mark H. Rümmeli and Lei Fu

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402427

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      A facile method for the fabrication of transparent graphene defoggers via direct growth of large area and continuous single-layer graphene films is reported for the first time. The strong interaction forces between the graphene films and the substrate contribute to the ultrafast defogging (within 6 s) when supplied with a safe voltage of 32 V and excellent defogging robustness.

    2. Mechanistic Insight into the Yolk@Shell Transformation of MnO@Silica Nanospheres Incorporating Ni2+ Ions toward a Colloidal Hollow Nanoreactor

      Jin Goo Kim, Soo Min Kim and In Su Lee

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402379

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      A solid-state approach for functionalizing the interior of hollow particles is devised by determining the mechanism of incorporating Ni2+ ions into MnO@SiO2 nanospheres. This results in a Ni nanocrystal inside the hollow silicate shell. The synthesized powder is employed as a colloidal nanoreactor in the catalysis of the reduction of nitroarene compounds, and recycled via magnetic recovery.

    3. Oxidative Intercalation for Monometallic Ni2+-Ni3+ Layered Double Hydroxide and Enhanced Capacitance in Exfoliated Nanosheets

      Feng Gu, Xing Cheng, Shufen Wang, Xu Wang and Pooi See Lee

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402603

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      Monometallic Ni2+-Ni3+ layered double hydroxide is prepared using a simple oxidative intercalation process. Superior capacitive behavior of the exfoliated Ni(OH)2 unilamellar sheets stranded in carbon nanotubes networks is achieved because of the complete interfacial storage.

    4. Layered Perovskite Nanofibers via Electrospinning for Overall Water Splitting

      Nils C. Hildebrandt, Julia Soldat and Roland Marschall

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402679

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      (111)-layered perovskite nanofibers are prepared via facile electrospinning process, and used for photocatalytic hydrogen generation and overall water splitting. The formation of poly­crystalline barium niobate and tantalate nanofibers occurs via intermediate barium carbonate formation, strengthening the nanofiber morphology for the calcination process. Layered perovskite nanofibers show improved photocatalytic activities compared to regular powder samples.

  10. Communications

    1. Self-Aligned Colloidal Lithography for Controllable and Tuneable Plasmonic Nanogaps

      Tao Ding, Lars O. Herrmann, Bart de Nijs, Felix Benz and Jeremy J. Baumberg

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402639

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      Au nanoparticles (NPs) deposited on a substrate function as ring shaped colloidal shadow masks. Using e-beam evaporation of gold, nanometer sized gaps are formed as a result. The size of these gaps can be accurately tuned by controlling the thickness of the gold deposition, thereby tuning the plasmonic coupling of the NPs with the substrate. The clean cavity produced between the Au NPs and the Au film provides an excellent SERS platform for trace molecule detection.

    2. Nanopatterned Surfaces Based on Template-Assisted Multilayer Electrodeposition

      Minsoo Kim, Jooncheol Kim and Mark Allen

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402584

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      Selective, template-assisted growth of electrodeposited, layered materials leads to the top-down designable realization of nanopatterned surfaces with a large surface area (>1 cm2) comprised of multi­dimensional, multiscale (10 nm–1 μm) features, without the need of standard nanolithography. This process opens a manufacturable route to functional nanodevices that rely on anisotropic, nanoscale surface structures with controlled dimensions.

  11. Full Papers

    1. Hydrophobic, Electrostatic, and Dynamic Polymer Forces at Silicone Surfaces Modified with Long-Chain Bolaform Surfactants

      Michael V. Rapp, Stephen H. Donaldson Jr., Matthew A. Gebbie, Saurabh Das, Yair Kaufman, Yonas Gizaw, Peter Koenig, Yuri Roiter and Jacob N. Israelachvili

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402229

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      Direct force measurements reveal that long-chain (polydimethylsiloxane) bolaform surfactants self-assemble on silicone surfaces to form dynamically fluctuating nanostructures that protrude into solution. Sparingly low concentrations of these surfactants mediate remarkably strong adhesion between a polymer and a mineral surface in aqueous solution, via both specific Coulombic bonds and non-specific hydrophobic interactions.

  12. Communications

    1. Trajectory-Based Co-Localization Measures for Nanoparticle-Cell Interaction Studies

      Juan A. Varela, Christoffer Åberg, Jeremy C. Simpson and Kenneth A. Dawson

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201401849

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      High-resolution live cell microscopy will soon have a fundamental role in understanding bio-nano interactions, providing material that can be exploited using single particle tracking techniques. The present work uses 3D timelapse images obtained with confocal microscopy, to temporally resolve the co-localization between polystyrene nanoparticles and lysosomes in live cells through object-based measurements.

  13. Reviews

    1. Particle-Based Optical Sensing of Intracellular Ions at the Example of Calcium – What Are the Experimental Pitfalls?

      Karsten Kantner, Sumaira Ashraf, Susana Carregal-Romero, Carolina Carrillo-Carrion, Mayeul Collot, Pablo del Pino, Wolfram Heimbrodt, Dorleta Jimenez De Aberasturi, Uwe Kaiser, Lyubov I. Kazakova, Marco Lelle, Natalia Martinez de Baroja, Jose Maria Montenegro, Moritz Nazarenus, Beatriz Pelaz, Kalina Peneva, Pilar Rivera Gil, Nadeem Sabir, Lorenz Maximilian Schneider, Lyudmila I. Shabarchina, Gleb B. Sukhorukov, Margarita Vazquez, Fang Yang and Wolfgang J. Parak

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402110

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      Quantitative determination of ions in cells is crucial, but presents us with certain difficulties. The delivery and intracellular location of particle-based fluorophores as well as the local ion concentration determination need to be addressed, but yield the issue of crosstalk of the fluorescence read-out with pH, and spectral overlap.

  14. Full Papers

    1. Mechanism of Versatile Catalytic Activities of Quaternary CuZnFeS Nanocrystals Designed by a Rapid Synthesis Route

      Amit Dalui, Umamahesh Thupakula, Ali Hossain Khan, Tanmay Ghosh, Biswarup Satpati and Somobrata Acharya

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402837

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      Highly crystalline, single-phase CuZnFeS nanocrystals (NCs) are synthesized just in 30 s. Ligand exchange with hydrazine allows robust catalytic degradation of multiple organic dyes and the hydrogenation of nitro-organics. Valence and conduction energy levels extracted from scanning tunneling spectroscopy and UV photoelectron spectroscopy spectroscopy reveal favorable pathways for robust catalytic activities.

    2. Flexible a-Si:H Solar Cells with Spontaneously Formed Parabolic Nanostructures on a Hexagonal-Pyramid Reflector

      Wan Jae Dong, Chul Jong Yoo, Hyoung Won Cho, Kyoung-Bo Kim, Moojin Kim and Jong-Lam Lee

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402781

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      Flexible amorphous silicon (a-Si:H) solar cells with high photoconversion efficiency (PCE) are demonstrated with hexagonal pyramidal reflectors and parabolic nanostructures that form spontaneously on them. The nanostructures constructed by nanoimprint lithography using soft materials allow excellent durability under repeated bending. The light scattering and antireflective nature of the nanostructures enhances light trapping in a-Si:H solar cells.

    3. A Supramolecular Strategy to Leverage the Liquid-Phase Exfoliation of Graphene in the Presence of Surfactants: Unraveling the Role of the Length of Fatty Acids

      Sébastien Haar, Artur Ciesielski, Joseph Clough, Huafeng Yang, Raffaello Mazzaro, Fanny Richard, Simone Conti, Nicolas Merstorf, Marco Cecchini, Vittorio Morandi, Cinzia Casiraghi and Paolo Samorì

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402745

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      A systematic study of liquid-phase exfoliation (LPE) of graphene in N-methyl-2-pyrrolidone, ortho-dichlorobenzene, 1,2,4-trichlorobenzene, and N,N-dimethyl­formamide, harnessed by the presence of simple molecular modules as surfactants, is reported. In particular, by increasing the length of alkanes exposing a carboxylic acid head group and used during LPE, both quantity and quality of graphene dispersion can be highly improved, as ruled by thermodynamics.

    4. Intravital Multiphoton Imaging of the Selective Uptake of Water-Dispersible Quantum Dots into Sinusoidal Liver Cells

      Xiaowen Liang, Jeffrey E. Grice, Yian Zhu, David Liu, Washington Y. Sanchez, Zhen Li, Darrell H. G. Crawford, David G. Le Couteur, Victoria C. Cogger, Xin Liu, Zhi Ping Xu and Michael S. Roberts

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402698

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      Spatiotemporal disposition of water dispersible quantum dots (QDs) is explored in liver in vivo using multi­photon microscopy with fluorescence lifetime imaging. After intravenous injection, negatively charged QDs are distributed in the sinusoids and selectively taken up by sinusoidal cells, while fluorescent mole­cules (rhodamine 123 and fluo­rescein) are taken up by hepatocytes and excreted into the bile.

    5. Nanotentacle-Structured Magnetic Particles for Efficient Capture of Circulating Tumor Cells

      Seong-Min Jo, Joong-jae Lee, Woosung Heu and Hak-Sung Kim

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402619

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      Nanotentacle-structured magnetic particles are constructed using filamentous M13-bacteriophages for the efficient capture of circulating tumor cells (CTCs). The nanotentacle-structured magnetic particles show significantly enhanced binding avidity toward CTCs, leading to high capture purity and capture efficiency compared to flat-surfaced particles. These results suggest that the nanotentacle-structured magnetic particles can be effectively used for CTC-based cancer diagnosis.

  15. Communications

    1. Rapid and Up-Scalable Fabrication of Free-Standing Metal Oxide Nanosheets for High-Performance Lithium Storage

      Yuan-Li Ding, Yuren Wen, Peter A. van Aken, Joachim Maier and Yan Yu

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402502

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      Free-standing α-Fe2O3 nanosheets, SnO2 mesoporous nanosheets and sandwich-like polyaniline (PAN)/SnO2/PAN nanosheets are fabricated at very mild conditions (room temperature or 60 °C) via a galvanic replacement method for the first time. These nanosheets show excellent high-rate capability and long-term durability as anodes for lithium-ion batteries.

    2. Space-Confined Creation of Nanoframes In Situ on Reduced Graphene Oxide

      Yanyan Zhao, Hongyu Sun, Li-Min Liu, Ruilong Zong, Huaqiang Cao, Zhicheng Zhang, Xun Wang, Jun Luo and Jing Zhu

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201402438

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      Nanoframes (NFs) are created in situ on reduced graphene oxide (rGO) through confining the evolutions of precursor nanosheets, such as ZnS(EN)0.5 (EN = ethylenediamine), and nanoparticles within quasi-two-dimensional spaces generated from graphene oxide. The resultant composites of ZnS-NF@rGO exhibit excellent photocurrent responses. This work provides a new strategy to synthesize and modulate nanostructures and nanomaterials for rGO composites.

    3. A Versatile ‘Click Chemistry’ Route to Size-Restricted, Robust, and Functionalizable Hydrophilic Nanocrystals

      Tong Bian, Chao Wang, Zhenda Lu, Renguo Xie, Qing-Zheng Yang, Li-Zhu Wu, Chen-Ho Tung, Zhuang Liu, Yadong Yin and Tierui Zhang

      Article first published online: 15 DEC 2014 | DOI: 10.1002/smll.201400673

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      A versatile addition-crosslinking route is developed to transfer various hydrophobic nanocrystals into water. By assembling amphiphilic ligands and then crosslinking through ‘click chemistry’, a monolayer of polymer forms on the nanocrystal surface, leading to excellent stability and limited increase in hydrodynamic diameter. These nanocrystals can also be further functionalized easily for various applications such as catalysis, bioimaging, and medical therapy.

    4. Compact Halo-Ligand-Conjugated Quantum Dots for Multicolored Single-Molecule Imaging of Overcrowding GPCR Proteins on Cell Membranes

      Akihito Komatsuzaki, Tatsuya Ohyanagi, Yoshikazu Tsukasaki, Yukihiro Miyanaga, Masahiro Ueda and Takashi Jin

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201402508

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      To detect single molecules within the optical diffraction limit (< ca. 200 nm), a multicolored imaging technique is developed using Halo-ligand conjugated quantum dots (Halo-QDs; <6 nm in diameter). Using three types of Halo-QDs, multicolored single-molecule fluorescence imaging of GPCR proteins in Dictyostelium cells is achieved.

  16. Full Papers

    1. Tumor-Targeting Multifunctional Rattle-Type Theranostic Nanoparticles for MRI/NIRF Bimodal Imaging and Delivery of Hydrophobic Drugs

      Yunfeng Jiao, Yangfei Sun, Xiaoling Tang, Qingguang Ren and Wuli Yang

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201402297

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      A multifunctional rattle-type nano­particle (MRTN) is prepared for simultaneous cancer diagnosis and therapy with Fe3O4 as the core and functional mesoporous silica as the shell. MRTN shows tumor-targeting specificity, enhanced loading ability of paclitaxel and great potential as a MRI/NIRF bimodal imaging probe. Such features are very important for a theranostic nanoparticle in the application of cancer treatment.

  17. Communications

    1. Mimosa-Inspired Design of a Flexible Pressure Sensor with Touch Sensitivity

      Bin Su, Shu Gong, Zheng Ma, Lim Wei Yap and Wenlong Cheng

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201403036

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      A bio-inspired flexible pressure sensor is generated with high sensitivity (50.17 kPa−1), quick responding time (<20 ms), and durable stability (negligible loading-unloading signal changes over 10 000 cycles). Notably, the key resource of surface microstructures upon sensor substrates results from the direct molding of natural mimosa leaves, presenting a simple, environment-friendly and easy scale-up fabrication process for these flexible pressure sensors.

  18. Reviews

    1. 1D Copper Nanostructures: Progress, Challenges and Opportunities

      Sushrut Bhanushali, Prakash Ghosh, Anuradda Ganesh and Wenlong Cheng

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201402295

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      Recent progress in 1D copper nanostructures is reviewed comprehensively. Their synthetic methods, properties, and emerging application in flexible displays, low cost solar cells, artificial skins, and sensors are described. In addition, the challenges and opportunities are discussed with relevant examples pertaining to this rapidly evolving research field.

  19. Full Papers

    1. Superwetting Surfaces under Different Media: Effects of Surface Topography on Wettability

      Pengchao Zhang, Shasha Wang, Shutao Wang and Lei Jiang

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201401869

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      Regulating the surface topographies (i.e., smooth, micro, nano, and micro-/nanostructures), the static and dynamic behaviors of liquids (water and oil) and air on the surfaces, as well as the transition of wetting states under various media (i.e., air, water, and oil) can be easily controlled.

  20. Reviews

    1. Ternary Sn–Ti–O Based Nanostructures as Anodes for Lithium Ion Batteries

      Hongkang Wang, He Huang, Chunming Niu and Andrey L. Rogach

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201402682

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      Synergistic advantages of Sn and SnOx (high specific capacity) and TiO2 (excellent cycle performance) based anode materials have driven the development of Sn–Ti–O based composite systems, often in combination with carbon-based nanomaterials, for high performance lithium ion batteries. Recent achievements in the fabrication strategies and nanostructure design of these hybrid systems, leading to their improved electrochemical properties, are reviewed.

  21. Communications

    1. Inhibiting EGFR Clustering and Cell Proliferation with Gold Nanoparticles

      Chiara Paviolo, James W. M. Chon and Andrew H. A. Clayton

      Article first published online: 12 DEC 2014 | DOI: 10.1002/smll.201402701

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      Gold nanoparticles are functionalized with epidermal growth factor (EGF) molecules and incubated with HeLa cells. These new complexes mechanically interfere with the activation of EGF receptors in a length-dependent manner. Protein-functionalized gold nanoparticles hold great potential for unveiling the fundamental characteristics of cell receptors and for future pharmacological studies on receptor targeting.

    2. DNA-Templated Silver Nanoclusters for Multiplexed Fluorescent DNA Detection

      Ying Zhang, Changfeng Zhu, Lei Zhang, Chaoliang Tan, Jian Yang, Bo Chen, Lianhui Wang and Hua Zhang

      Article first published online: 10 DEC 2014 | DOI: 10.1002/smll.201402044

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      Novel label-free/conjugation-free molecular beacons are designed based on DNA templated-silver nanoclusters for multiplexed DNA detection. The assay is implemented in solution, which makes it easy for the in-situ and real-time analysis. This study demonstrates a new method for multiplexd detection of biological molecules by using fluorescent Ag nanocluster-based molecular beacon probes.

  22. Full Papers

    1. Sculpting Asymmetric, Hollow-Core, Three-Dimensional Nanostructures Using Colloidal Particles

      Xu A. Zhang, Bin Dai, Zhiyuan Xu and Chih-Hao Chang

      Article first published online: 8 DEC 2014 | DOI: 10.1002/smll.201402750

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      A variety of hollow-core, 3D nanostructures with complex symmetries are sculpted using multiple oblique illuminations of colloidal particles. Enabled solely by particle–light interactions and without the need for complex hardware, the proposed technique is versatile, low cost, and high throughput. The fabricated asymmetric nanostructures can find potential application in nanoneedles, nanonozzles, and materials with anisotropic properties.

    2. Ultrasmall Integrin-Targeted Silica Nanoparticles Modulate Signaling Events and Cellular Processes in a Concentration-Dependent Manner

      Miriam Benezra, Evan Phillips, Michael Overholtzer, Pat B. Zanzonico, Esa Tuominen, Ulrich Wiesner and Michelle S. Bradbury

      Article first published online: 3 DEC 2014 | DOI: 10.1002/smll.201402331

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      The interactions of nanoparticles with biological systems require a better understanding of endocytic trafficking as a driver and regulator of signal transduction pathways and cellular events. Exposure of integrin-expressing human melanoma and endothelial cells to a sub-10-nm fluorescent silica nanoparticle displaying cRGD peptides modestly activates integrin-signaling pathways, promoting migration and proliferation.

  23. Communications

    1. Bandgap-Opened Bilayer Graphene Approached by Asymmetrical Intercalation of Trilayer Graphene

      Da Zhan, Jia Xu Yan, Zhen Hua Ni, Li Sun, Lin Fei Lai, Lei Liu, Xiang Yang Liu and Ze Xiang Shen

      Article first published online: 2 DEC 2014 | DOI: 10.1002/smll.201402728

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      A novel graphene structure formed by asymmetrical intercalation of FeCl3 molecules into a trilayer graphene is reported. The trilayer graphene is divided into a single layer and a bilayer graphene by the inserted FeCl3 layer. Theoretical calculation shows that such graphene bilayers with broken inversion symmetry present a prominent opened bandgap of ∼0.13 eV.

  24. Full Papers

    1. Magnetic Tweezers-Based 3D Microchannel Electroporation for High-Throughput Gene Transfection in Living Cells

      Lingqian Chang, Marci Howdyshell, Wei-Ching Liao, Chi-Ling Chiang, Daniel Gallego-Perez, Zhaogang Yang, Wu Lu, John C. Byrd, Natarajan Muthusamy, L. James Lee and Ratnasingham Sooryakumar

      Article first published online: 2 DEC 2014 | DOI: 10.1002/smll.201402564

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      An efficient magnetic tweezers-based 3D microchannel electroporation technique uses gentle magnetic forces and low voltages to rapidly transfect 104–106 cells with approximately 90% transfection efficiency and cell viability. Alignment is rapid, automated, and does not adversely affect the cell membranes. Clinical applications are demonstrated by delivering the GATA2 molecular beacon into leukemia cells for the detection of intracellular mRNA.

  25. Communications

    1. Study on the Diffusion Mechanism of Graphene Grown on Copper Pockets

      Zhijuan Zhao, Zhifa Shan, Cankun Zhang, Qiongyu Li, Bo Tian, Zhiyi Huang, Weiyi Lin, Xiangping Chen, Hengxing Ji, Weifeng Zhang and Weiwei Cai

      Article first published online: 2 DEC 2014 | DOI: 10.1002/smll.201402483

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      A correlation between graphene domains grown on the outer and the inner surfaces of Cu pockets is found, which discloses a new graphene growth mechanism based on the fast diffusion of carbon atoms through the 25 micro­meter-thick Cu foil, confirmed by isotopic labeling. Subsequently, on the outer surface of the Cu pocket, bilayer graphene with a coverage of about 78% is grown.

  26. Full Papers

    1. Enhancing Optical Forces on Fluorescent Up-Converting Nanoparticles by Surface Charge Tailoring

      Héctor Rodríguez-Rodríguez, Paloma Rodríguez Sevilla, Emma Martín Rodríguez, Dirk H. Ortgies, Marco Pedroni, Adolfo Speghini, Marco Bettinelli, Daniel Jaque and Patricia Haro-González

      Article first published online: 1 DEC 2014 | DOI: 10.1002/smll.201402587

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      The magnitude of optical forces acting on fluorescent up-converting nanoparticles can be enhanced by more than one order of magnitude by controlled modification of the particle/medium interface (changing the Z potential). Substitution of cationic species at the surface by other species with higher mobility could lead to nanoparticle trapping with constants comparable to those of spherical metallic nanoparticles.

  27. Communications

    1. Tuning Polymeric Amphiphilicity via Se–N Interactions: Towards One-Step Double Emulsion for Highly Selective Enzyme Mimics

      Xiaopeng Huang, Ruochen Fang, Dingguan Wang, Jian Wang, Huaping Xu, Yapei Wang and Xi Zhang

      Article first published online: 26 NOV 2014 | DOI: 10.1002/smll.201402271

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      A selenium-containing small molecule is exploited to controllably tune the polymer amphiphilicity, leading to fabrication of appropriate polymer surfactants through which one-step double emulsions can be obtained in a facile, scalable, surfactant-free approach. After solvent evaporation, these resulting porous microparticles are shown to be the exceptional artificial GPx enzyme mimics.

  28. Full Papers

    1. Doping Modulated Carbon Nanotube Synapstors for a Spike Neuromorphic Module

      Alex Ming Shen, Kyunghyun Kim, Andrew Tudor, Dongwon Lee and Yong Chen

      Article first published online: 25 NOV 2014 | DOI: 10.1002/smll.201402528

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      A synapstor with a carbon nanotube (CNT) transistor structure is fabricated and integrated with a Si “soma” circuit to emulate the spike analog signal processing, memory, and plasticity of a neural network. The doping profile in the CNT channel is modulated to reduce its power consumption and establish postsynaptic current and plasticity in the synapstor.

  29. Communications

    1. Surface Adhesive Forces: A Metric Describing the Drag-Reducing Effects of Superhydrophobic Coatings

      Mengjiao Cheng, Mengmeng Song, Hongyu Dong and Feng Shi

      Article first published online: 22 NOV 2014 | DOI: 10.1002/smll.201402618

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      Nanomaterials with superhydrophobic properties are promising as drag-reducing coatings. However, debates regarding whether superhydrophobic surfaces are favorable for drag reduction require further clarification. A quantified water adhesive force measurement is proposed as a metric and its effectiveness demonstrated using three typical superhydrophobic coatings on model ships with in situ sailing tests.

    2. High-Performance Hybrid Complementary Logic Inverter through Monolithic Integration of a MEMS Switch and an Oxide TFT

      Yong-Ha Song, Sang-Joon Kenny Ahn, Min-Wu Kim, Jeong-Oen Lee, Chi-Sun Hwang, Jae-Eun Pi, Seung-Deok Ko, Kwang-Wook Choi, Sang-Hee Ko Park and Jun-Bo Yoon

      Article first published online: 22 NOV 2014 | DOI: 10.1002/smll.201402841

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      A hybrid complementary logic inverter consisting of a microelectromechanical system switch as a promising alternative for the p-type oxide thin film transistor (TFT) and an n-type oxide TFT is presented for ultralow power integrated circuits. These heterogeneous microdevices are monolithically integrated. The resulting logic device shows a distinctive voltage transfer characteristic curve, very low static leakage, zero-short circuit current, and exceedingly high voltage gain.

    3. Superparamagnetic Iron Oxide Nanoparticle Micelles Stabilized by Recombinant Oleosin for Targeted Magnetic Resonance Imaging

      Kevin B. Vargo, Ajlan Al Zaki, Robert Warden-Rothman, Andrew Tsourkas and Daniel A. Hammer

      Article first published online: 22 NOV 2014 | DOI: 10.1002/smll.201402017

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      Recombinant surfactants present a new platform for stabilizing and targeting nanoparticle imaging agents. Superparamagnetic iron oxide nanoparticle-loaded micelles for MRI contrast are stabilized by an engineered variant of the naturally occurring protein oleosin and targeted using a Her2/neu affibody-oleosin fusion. The recombinant oleosin platform allows simple targeting and the ability to easily swap the ligand for numerous targets.

    4. Fabricating Surfaces with Tunable Wettability and Adhesion by Ionic Liquids in a Wide Range

      Hongliang Liu, Yi Ding, Zhuo Ao, Yahong Zhou, Shutao Wang and Lei Jiang

      Article first published online: 19 NOV 2014 | DOI: 10.1002/smll.201403021

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      A series of surfaces that can either be fully wetted or non-wetted by three kinds of ionic liquids (ILs) are successfully designed by rationally controlling surface chemistries and structures. Meanwhile, the adhesion forces between these surfaces and the ILs can also be effectively modulated in a wide range. This fundamental research will greatly promote the development of IL-based materials in practical applications.

  30. Full Papers

    1. Electrical Coupling Between Cells and Graphene Transistors

      Lucas H. Hess, Christoph Becker-Freyseng, Michael S. Wismer, Benno M. Blaschke, Martin Lottner, Felix Rolf, Max Seifert and Jose A. Garrido

      Article first published online: 19 NOV 2014 | DOI: 10.1002/smll.201402225

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      Experimental data and a model are presented on the coupling between living cells and graphene solution-gated field-effect transistors. The ion dynamics in the cell–transistor cleft and the transistors' ion sensitivity are analyzed to account for the differences between the established point-contact model and the experimental data revealing a significant increase in the total ionic strength in the cleft.

    2. Storage of Gold Nanoclusters in Muscle Leads to their Biphasic in Vivo Clearance

      Xiao-Dong Zhang, Zhentao Luo, Jie Chen, Hao Wang, Sha-Sha Song, Xiu Shen, Wei Long, Yuan-Ming Sun, Saijun Fan, Kaiyuan Zheng, David Tai Leong and Jianping Xie

      Article first published online: 18 NOV 2014 | DOI: 10.1002/smll.201402233

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      GSH-protected ultrasmall Au nanoparticles (1–2 nm) which, from a size perspective, would normally be cleared from the internal organs within a few days post injection, can actually remain and accumulate to high concentrations for a much longer time (>60 days) in the muscle versus other internal organs. Subsequently, this accumulation in the muscle starts to release the nanoparticles back into the vascular circulation and initiates another phase of nanoparticle biodistribution.

  31. Reviews

    1. Low Voltage Transmission Electron Microscopy of Graphene

      Alicja Bachmatiuk, Jiong Zhao, Sandeep Madhukar Gorantla, Ignacio Guillermo Gonzalez Martinez, Jerzy Wiedermann, Changgu Lee, Juergen Eckert and Mark Hermann Rummeli

      Article first published online: 18 NOV 2014 | DOI: 10.1002/smll.201401804

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      The technical aspects of transmission electron microscopes relevant to graphene are introduced. The reader is then introduced to different specimen preparation techniques, the different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy, electron diffraction and electron energy loss spectroscopy, in situ electron microscopy and, finally, a brief overview of other 2D materials.

  32. Communications

    1. Photo-induced Reversible Structural Transition of Cationic Diphenylalanine Peptide Self-Assembly

      Hongchao Ma, Jinbo Fei, Qi Li and Junbai Li

      Article first published online: 18 NOV 2014 | DOI: 10.1002/smll.201402140

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      The photo-induced self-assembly of a cationic diphenylalanine peptide (CDP) is investigated using a photoswitchable sulfonic azobenzene as the manipulating unit. A reversible structural transition between a branched structure and a vesicle-like structure is observed by alternating between UV and visible light irradiation.

  33. Full Papers

    1. Metal–Organic Framework-Derived Bamboo-like Nitrogen-Doped Graphene Tubes as an Active Matrix for Hybrid Oxygen-Reduction Electrocatalysts

      Qing Li, Hengyu Pan, Drew Higgins, Ruiguo Cao, Guoqi Zhang, Haifeng Lv, Kangbing Wu, Jaephil Cho and Gang Wu

      Article first published online: 17 NOV 2014 | DOI: 10.1002/smll.201402069

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      An iron-containing metal–organic framework, MIL-100(Fe), is employed to prepare a new oxygen-reduction non-precious metal catalyst containing bamboo-like nitrogen-doped graphene tubes (diameter > 100 nm). The highly active graphene tubes are further integrated with Pt nanoparticles in order to build a hybrid electrocatalyst, exhibiting significantly improved activity and stability compared to conventional Pt/C catalysts in acid electrolyte.

    2. Probing DNA Helicase Kinetics with Temperature-Controlled Magnetic Tweezers

      Benjamin Gollnick, Carolina Carrasco, Francesca Zuttion, Neville S. Gilhooly, Mark S. Dillingham and Fernando Moreno-Herrero

      Article first published online: 14 NOV 2014 | DOI: 10.1002/smll.201402686

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      A thermally stabilized magnetic tweezers instrument is used to study single-molecule translocation along double-stranded DNA by the bacterial helicase-nuclease enzyme AddAB. The customized temperature control system affords experiments from ambient to physiological conditions and suggests implementations in other microscope layouts. Mean translocation velocities, obtained from individual measurements at various temperatures, satisfy an Arrhenius relationship that complies with results from bulk assays.

  34. Communications

    1. Vertically Architectured Stack of Multiple Graphene Field-Effect Transistors for Flexible Electronics

      Jie Meng, Jing-Jing Chen, Liang Zhang, Ya-Qing Bie, Zhi-Min Liao and Da-Peng Yu

      Article first published online: 14 NOV 2014 | DOI: 10.1002/smll.201402422

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      Vertically architectured stack of multiple graphene field-effect transistors (GFETs) on a flexible substrate show great mechanical flexibility and robustness. The four GFETs are integrated in the vertical direction, and dually gated GFETs with graphene channel, PMMA dielectrics, and graphene gate electrodes are realized.

  35. Full Papers

    1. Evaluation of Polymeric Nanoparticle Formulations by Effective Imaging and Quantitation of Cellular Uptake for Controlled Delivery of Doxorubicin

      Khin Yin Win, Choon Peng Teng, Enyi Ye, Michelle Low and Ming-Yong Han

      Article first published online: 14 NOV 2014 | DOI: 10.1002/smll.201402073

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      An evaluation platform to screen engineered polymeric nanoparticles for controlled release delivery systems is developed using highly luminescent and photostable quantum dots as model drug and imaging labels. This approach enables detection and quantitation of cellular uptake of such formulations, which is a necessary pre­requisite to their efficacy at the site of action.

  36. Reviews

    1. Theoretical and Computational Investigations of Nanoparticle–Biomembrane Interactions in Cellular Delivery

      Hong-ming Ding and Yu-qiang Ma

      Article first published online: 11 NOV 2014 | DOI: 10.1002/smll.201401943

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      Nanoparticles have recently been widely used as drug delivery carriers. This review summarizes the recent progresses on the theoretical and computational investigations of nanoparticle-biomembrane interactions in cellular delivery. The factors that govern cellular uptake of nanoparticles are discussed in detail, and their interactions in intracellular trafficking are also illustrated. Finally, the challenging problems of this field in the future are given.

    2. Engineering the Cell–Semiconductor Interface: A Materials Modification Approach using II-VI and III-V Semiconductor Materials

      Lauren E. Bain and Albena Ivanisevic

      Article first published online: 11 NOV 2014 | DOI: 10.1002/smll.201401450

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      A broad materials modification approach can be used to tune the response of cell systems as well as the broader physiology to an implanted material. Using semiconductors in these applications enables development of neural probes or biosensors based on functional materials. This review assesses strategies for selecting and preparing semiconductor materials for use in biosensitive applications.

    3. Tuning Soft Nanostructures in Self-assembled Supramolecular Gels: From Morphology Control to Morphology-Dependent Functions

      Li Zhang, Xiufeng Wang, Tianyu Wang and Minghua Liu

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201402075

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      Supramolecular gelation can be strongly affected by the external conditions, and nanostructures can be produced which have many unique features, such as the flexibility to respond to the external stimuli, morphological diversity, ease of fabrication in large quantities, and so on.

  37. Full Papers

    1. High-Performance Asymmetric Supercapacitors Based on Multilayer MnO2/Graphene Oxide Nanoflakes and Hierarchical Porous Carbon with Enhanced Cycling Stability

      Yufeng Zhao, Wei Ran, Jing He, Yizhong Huang, Zhifeng Liu, Wei Liu, Yongfu Tang, Long Zhang, Dawei Gao and Faming Gao

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201401922

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      MnO2/GO (graphene oxide) composites with a novel multilayer nanoflake structure and a carbon material with genetic 3D hierarchical porous structure are prepared. An asymmetric supercapacitor based on these materials is fabricated, and it exhibits a maximum energy density of 46.7 Wh kg−1. A superior long cycle life along with ∼93% capacitance retention after 4000 cycles is also obtained.

  38. Communications

    1. Cathodoluminescence and Photoconductive Characteristics of Single-Crystal Ternary CdS/CdSe/CdS Biaxial Nanobelts

      Linfeng Hu, Jian Yan, Yong Kim, Guangtao Fei, Kentaro Watanabe, Takashi Sekiguchi, Lide Zhang and Xiaosheng Fang

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201402545

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      The cathodoluminescence and optoelectronic properties based on an individual CdS/CdSe/CdS biaxial nanobelt are revealed in the present study. Both typical CdS and CdSe emissions are detected from as-grown CdS/CdSe/CdS nanobelts. The photodetector based on this nanobelt exhibits high sensitivity and excellent cycle stability. This opens a door to rational design of germanium chalcogenide compounds with unique optical properties.

    2. Stereoselective Uptake of Cell-Penetrating Peptides is Conserved in Antisense Oligonucleotide Polyplexes

      Marco Emanuele Favretto and Roland Brock

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201402101

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      Stereochemistry matters. A significant conceptual advancement is presented toward the understanding of how functional characteristics of delivery peptides can translate into functional characteristics of peptide-based oligoplexes.

    3. Broadband Metallic Absorber on a Non-Planar Substrate

      Xianyu Ao, Xuyue Wang, Guanbo Yin, Kangkang Dang, Yali Xue and Sailing He

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201401895

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      Absorbers for visible and near-infrared light are realized by depositing a thin iron layer on arrays of cones which are replicated from a porous template. The replicated conic structure itself is of several micrometers and ineffective at antireflection, but the subsequent deposition of iron on top generates nano­meter-size columnar structures, and thus broadband absorption enhancement is achieved.

  39. Full Papers

    1. Hybrid Organic–Inorganic Colloidal Composite ‘Sponges’ via Internal Crosslinking

      Bradley Duncan, Ryan F. Landis, Huda A. Jerri, Valery Normand, Daniel Benczédi, Lahoussine Ouali and Vincent M. Rotello

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201401753

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      Covalent crosslinking using a hydrophobic maleic anhydride copolymer induces a morphology change in oil-in-water Pickering emulsions formed using hydrophilic amine-functionalized silica nanoparticles. The resulting porous nanocomposites maintain discrete microparticle structures and retain payloads in their oil phase even when incubated in competitive solvents such as ethanol.

    2. Quantifying Lipid Contents in Enveloped Virus Particles with Plasmonic Nanoparticles

      Amin Feizpour, Xinwei Yu, Hisashi Akiyama, Caitlin M. Miller, Ethan Edmans, Suryaram Gummuluru and Björn M. Reinhard

      Article first published online: 10 NOV 2014 | DOI: 10.1002/smll.201402184

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      Lipids, such as PS and GM1, play an important role in virus–host cell interactions. A quantitative characterization of lipids in viral membranes remains, however, difficult. Here, an optical assay is introduced to characterize the content of gold nanoparticle-labeled lipids. The technology provides the means for quantifying targeted lipids with small number of virus particles.

  40. Reviews

    1. Elemental Analogues of Graphene: Silicene, Germanene, Stanene, and Phosphorene

      Sivacarendran Balendhran, Sumeet Walia, Hussein Nili, Sharath Sriram and Madhu Bhaskaran

      Article first published online: 7 NOV 2014 | DOI: 10.1002/smll.201402041

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      A wide range of two-dimensional (2D) materials are gaining increased attention owing to their unique properties that can be exploited for a plethora of applications. This article reviews the class of 2D elemental materials – silicene, germanene, stanene, and phosphorene – with emphasis on fundamental properties, synthesis techniques, and their future prospects.

  41. Communications

    1. Brittlestar-Inspired Microlens Arrays Made of Calcite Single Crystals

      Xiaozhou Ye, Fei Zhang, Yurong Ma and Limin Qi

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402765

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      Unique concave microlens arrays (MLAs) made of calcite single crystals with tunable crystal orientations can be readily fabricated by template-assisted epitaxial growth in solution without additives under ambient conditions. While the non-birefringent calcite (001) MLA showed excellent imaging performance like brittlestar's microlens arrays, the birefringent calcite (104) MLA exhibited remarkable polarization-dependent optical properties.

  42. Full Papers

    1. A High Energy and Power Li-Ion Capacitor Based on a TiO2 Nanobelt Array Anode and a Graphene Hydrogel Cathode

      Huanwen Wang, Cao Guan, Xuefeng Wang and Hong Jin Fan

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402620

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      A hybrid Li-ion capacitor is developed using a porous graphene hydrogel cathode, TiO2 nanobelt arrays as the anode, and LiPF6 electrolyte. The demonstrated high energy and power densities of such a hybrid device could bridge the gap between Li-ion batteries and EDLC supercapacitors.

  43. Communications

    1. Epidermal Electronics with Advanced Capabilities in Near-Field Communication

      Jeonghyun Kim, Anthony Banks, Huanyu Cheng, Zhaoqian Xie, Sheng Xu, Kyung-In Jang, Jung Woo Lee, Zhuangjian Liu, Philipp Gutruf, Xian Huang, Pinghung Wei, Fei Liu, Kan Li, Mitul Dalal, Roozbeh Ghaffari, Xue Feng, Yonggang Huang, Sanjay Gupta, Ungyu Paik and John A. Rogers

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402495

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      Epidermal electronics with advanced capabilities in near field communications (NFC) are presented. The systems include stretchable coils and thinned NFC chips on thin, low modulus stretchable adhesives, to allow seamless, conformal contact with the skin and simultaneous capabilities for wireless interfaces to any standard, NFC-enabled smartphone, even under extreme deformation and after/during normal daily activities.

    2. Controlled Growth of Few-Layer Hexagonal Boron Nitride on Copper Foils Using Ion Beam Sputtering Deposition

      Haolin Wang, Xingwang Zhang, Junhua Meng, Zhigang Yin, Xin Liu, Yajuan Zhao and Liuqi Zhang

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402468

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      Ion beam sputtering deposition (IBSD) is used to synthesize high quality few-layer hexagonal boron nitride (h-BN) on copper foils. Compared to the conventional chemical vapor deposition, the IBSD technique avoids the use of unconventional precursors and is much easier to control, which should be very useful for the large-scale production of h-BN in the future.

  44. Full Papers

    1. Optical Heating and Temperature Determination of Core–Shell Gold Nanoparticles and Single-Walled Carbon Nanotube Microparticles

      Alexey Yashchenok, Admir Masic, Dmitry Gorin, Olga Inozemtseva, Bong Sup Shim, Nicholas Kotov, Andre Skirtach and Helmuth Möhwald

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201401697

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      Heating of gold plasmonic micro­particles is achieved by irradiation by both green and NIR lasers. In situ acquiring Anti-stokes and Stokes intensities of the G-band of single-walled carbon nanotubes can be used for determining the effective temperature at the surface of gold nanoparticles. The results shown in this work can be used for sensing, patterning, and deriving the temperature from heated entities.

  45. Communications

    1. Fracture Strain of SiC Nanowires and Direct Evidence of Electron-Beam Induced Amorphisation in the Strained Nanowires

      Shiliang Wang, Yueqin Wu, Liangwu Lin, Yuehui He and Han Huang

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402202

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      SiC nanowires with diameters ranging from 29 to 270 nm exhibit an average strain of 5.5% with a maximum of up to 7.0%. The brittle fracture of the nano­wires being measured was confirmed by transmission electron microscopy (TEM) analysis. This study demonstrates that amorphisation occurs in the stained SiC nanowires during normal TEM examination, which could be induced by electron irradiation.

    2. Electronic Transport in Heterostructures of Chemical Vapor Deposited Graphene and Hexagonal Boron Nitride

      Zhengqing John Qi, Sung Ju Hong, Julio A. Rodríguez-Manzo, Nicholas J. Kybert, Rajatesh Gudibande, Marija Drndić, Yung Woo Park and A. T. Charlie Johnson

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402543

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      CVD graphene devices on stacked CVD hexagonal boron nitride (hBN) are demonstrated using a novel low-contamination transfer method, and their electrical performance is systematically compared to devices on SiO2. An order of magnitude improvement in mobility, sheet resistivity, current density, and sustained power is reported when the oxide substrate is covered with five-layer CVD hBN.

  46. Full Papers

    1. Biocompatible Conjugated Polymer Nanoparticles for Efficient Photothermal Tumor Therapy

      Junlong Geng, Chunyang Sun, Jie Liu, Lun-De Liao, Youyong Yuan, Nitish Thakor, Jun Wang and Bin Liu

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402092

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      An efficient conjugated polymer based photothermal agent is developed by a facile precipitation apporach utilzing DSPE-PEG2000 as the encapsulation matrix. The obtained nanoparticles exhibit strong NIR absorption, excellent photostability, superb biocompatibility, and high photothermal conversion efficiency, which show good cancer therapeutic effect in both in vitro and in vivo studies.

  47. Communications

    1. Fabrication of Highly Oriented Hexagonal Boron Nitride Nanosheet/Elastomer Nanocomposites with High Thermal Conductivity

      Zhiqiao Kuang, Yulong Chen, Yonglai Lu, Li Liu, Shui Hu, Shipeng Wen, Yingyan Mao and Liqun Zhang

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402569

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      A homogeneous dispersion of hexagonal boron nitride nanosheets (BNNSs) in elastomers is obtained by solution compounding methods, and a high orientation of BNNSs is achieved by strong shearing. The composites show high thermal conductivities, especially when BNNS loading exceeds 17.5 vol%, indicating that the material is promising for thermal-management applications which need high thermal conductivity, low dielectric constant, and adequate softness.

    2. Three-Dimensional Nitrogen-Doped Graphene Nanoribbons Aerogel as a Highly Efficient Catalyst for the Oxygen Reduction Reaction

      Liang Chen, Ran Du, Jinghan Zhu, Yueyuan Mao, Cheng Xue, Na Zhang, Yanglong Hou, Jin Zhang and Tao Yi

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201402472

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      A highly conductive, ultralight, neat and versatile nitrogen-doped GNRs aerogel has been fabricated by a new hydrothermal method for the first time. The newly developed aerogel shows a very promising performance when used as a novel ORR catalyst in both alkaline and acidic solutions.

  48. Reviews

    1. Dendritic Silica Particles with Center-Radial Pore Channels: Promising Platforms for Catalysis and Biomedical Applications

      Xin Du and Shi Zhang Qiao

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201401201

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      Dendritic silica particles are a kind of newly created porous material, with unique open three-dimensional dendritic superstructures with center-radial pore channels and highly accessible surface areas, which may enable them become useful and powerful platforms for promising applications in catalysis, biomedicine, and other important fields.

  49. Communications

    1. Quasi-2D Cu2S Crystals on Graphene: In-situ Growth and ab-initio Calculations

      Ferdaous Ben Romdhane, Ovidiu Cretu, Lamjed Debbichi, Olle Eriksson, Sébastien Lebègue and Florian Banhart

      Article first published online: 3 NOV 2014 | DOI: 10.1002/smll.201400444

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      Two-dimensional crystals of beta-copper sulfide are synthesized in an in-situ electron microscopy experiment. Copper crystals are deposited on an amorphous carbon film containing sulfur. The carbon film graphitizes upon heating and electron irradiation and allows the reaction of Cu and S towards two-dimensional Cu2S crystals. These are energetically favourable and bonded via van der Waals interactions to the graphitic substrate.

  50. Full Papers

    1. One-Dimensional Densely Aligned Perovskite-Decorated Semiconductor Heterojunctions with Enhanced Photocatalytic Activity

      Mengye Wang, Dajiang Zheng, Meidan Ye, Chuchu Zhang, Binbin Xu, Changjian Lin, Lan Sun and Zhiqun Lin

      Article first published online: 31 OCT 2014 | DOI: 10.1002/smll.201402692

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      Using one-dimensional rutile TiO2nanorod arrays as the structure-directing scaffold as well as the TiO2 source to two consecutive hydrothermal reactions, densely aligned SrTiO3-modified rutile TiO2 heterojunction photocatalysts are crafted for the first time. Such one-dimensional perovskite-decorated semiconductor nanoarrays exhibit high photocatalytic performance and are attractive for optoelectronic applications in photovoltaics, water-splitting, etc.

    2. Overcoming Concealment Effects of Targeting Moieties in the PEG Corona: Controlled Permeable Polymersomes Decorated with Folate-Antennae for Selective Targeting of Tumor Cells

      Mohamed A. Yassin, Dietmar Appelhans, Ralf Wiedemuth, Petr Formanek, Susanne Boye, Albena Lederer, Achim Temme and Brigitte Voit

      Article first published online: 31 OCT 2014 | DOI: 10.1002/smll.201402581

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      Polymersomes bearing freely accessible folate antennae on their surfaces overcome the concealment of folate moieties in the PEG corona. Thus, the selective internalization of such polymersomes into tumor cells is improved. The polymersomes have a pH-sensitive membrane, prohibiting premature Dox release until they are triggered in the acidic endosomal compartment.

    3. High-Responsivity Graphene/InAs Nanowire Heterojunction Near-Infrared Photodetectors with Distinct Photocurrent On/Off Ratios

      Jinshui Miao, Weida Hu, Nan Guo, Zhenyu Lu, Xingqiang Liu, Lei Liao, Pingping Chen, Tao Jiang, Shiwei Wu, Johnny C. Ho, Lin Wang, Xiaoshuang Chen and Wei Lu

      Article first published online: 31 OCT 2014 | DOI: 10.1002/smll.201402312

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      In this paper, graphene/InAs nanowire heterojunction near-infrared photodetectors are fabricated with a high Ilight/Idark ratio of 5 × 102. The photo­responsivity of these heterojunction near-infrared photodetectors is ∼0.5 A/W, which is much larger than that of graphene infrared photodetectors (∼0.1 mA/W). Moreover, the back-gated voltage can control the carrier density of the detectors.

  51. Reviews

    1. Metallic Nanocatalysis: An Accelerating Seamless Integration with Nanotechnology

      Yihu Dai, Ye Wang, Bin Liu and Yanhui Yang

      Article first published online: 31 OCT 2014 | DOI: 10.1002/smll.201400847

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      Metallic nanocatalysts exhibit structure-sensitive catalytic activities. In this review article, recent progress on shaped metallic nanocatalysts is examined and several influential parameters including particle size, composition, shape, and ligand effects are discussed, as well as finally highlight single-atom metallic catalysts and our perspectives on nanocatalysis.

    2. Perovskite Solar Cells: From Materials to Devices

      Hyun Suk Jung and Nam-Gyu Park

      Article first published online: 30 OCT 2014 | DOI: 10.1002/smll.201402767

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      Since the first report on a perovskite-sensitized solar cell developed in 2009, and long-term durable solid-state perovskite solar cell developed in 2012, power conversion efficiencies (PCEs) of over 15% have been reported. The highest PCE of a laboratory cell was 19.3%, which was developed by UCLA in 2014. Perovskite solar cells keep on surging, where better understanding of the opto-electronic properties of perovskite light absorbers is crucial to design higher-performing perovskite solar cells.

    3. Organized Chromophoric Assemblies for Nonlinear Optical Materials: Towards (Sub)wavelength Scale Architectures

      Jialiang Xu, Sergey Semin, Theo Rasing and Alan E. Rowan

      Article first published online: 30 OCT 2014 | DOI: 10.1002/smll.201402085

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      Efficient and multifunctional low-dimensional (sub)wavelength scale nonlinear optical materials are highly desired for the next generation of photonic devices. Varieties of organic chromophores demonstrate nonlinear optical activity when excited with an intense laser light. Use of different “bottom-up” fabrication techniques results in well-ordered structures from these building blocks, which significantly increases their nonlinear optical response compared to the disordered states.

  52. Full Papers

    1. Physical Deposition Improved SERS Stability of Morphology Controlled Periodic Micro/Nanostructured Arrays Based on Colloidal Templates

      Honghua Zhang, Mao Liu, Fei Zhou, Dilong Liu, Guangqiang Liu, Guotao Duan, Weiping Cai and Yue Li

      Article first published online: 30 OCT 2014 | DOI: 10.1002/smll.201402630

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      Via a colloidal template-induced precursor solution dipping strategy, a semi-hollow sphere array is formed, and its morphology changed to a novel ordered honeycomb-shaped micro/nanostructured array after magnetron sputtering deposition. After coating a gold thin layer, the periodic array is used as SERS active substrate and demonstrates very stable SERS performance.

  53. Communications

    1. Sperm Dynamics in Tubular Confinement

      Veronika Magdanz, Britta Koch, Samuel Sanchez and Oliver G. Schmidt

      Article first published online: 30 OCT 2014 | DOI: 10.1002/smll.201401881

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      An on-chip system that mimics tubular microenvironments is presented for the study of spermatozoa motion in confinement. Using rolled up transparent silicon oxide/dioxide microtubes, the influence of tube diameter on the velocity, directionality, and linearity of spermatozoa is investigated. Tubular microenvironments of diameters 20–45 μm facilitate sperm migration through channels.

  54. Full Papers

    1. Seed-Induced Growth of Flower-Like Au–Ni–ZnO Metal–Semiconductor Hybrid Nanocrystals for Photocatalytic Applications

      Yuanzhi Chen, Deqian Zeng, Michael B. Cortie, Annette Dowd, Huizhang Guo, Junbao Wang and Dong-Liang Peng

      Article first published online: 30 OCT 2014 | DOI: 10.1002/smll.201401853

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      Au–Ni–ZnO ternary metal–semiconductor hybrid nanocrystals are synthesized using a method that utilizes Au@Ni seeds formed in situ to induce the epitaxial growth of ZnO {0001} facets on Ni {111} facets. Excellent photocatalytic properties along with magnetic recycling ability are achieved. The prepared nanocrystals possess plasmonic, semiconducting, and magnetic functionalities and are expected to find wide application in multiple technological fields.

  55. Reviews

    1. Dynamic Biointerfaces: From Recognition to Function

      Baisong Chang, Mingxi Zhang, Guangyan Qing and Taolei Sun

      Article first published online: 29 OCT 2014 | DOI: 10.1002/smll.201402038

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      A dynamic biointerface based on synergetic chiral H-bonding interactions can transform weak signals of molecular or chiral recognitions into changes of the macroscopic behaviors of cells and biomolecules, which can break the limitation of conventional polymers and has the ability to solve the big challenges in life sciences.

  56. Full Papers

    1. In vivo Gold Nanoparticle Delivery of Peptide Vaccine Induces Anti-Tumor Immune Response in Prophylactic and Therapeutic Tumor Models

      Joao Paulo Mattos Almeida, Adam Yuh Lin, Elizabeth Raquel Figueroa, Aaron Edward Foster and Rebekah Anna Drezek

      Article first published online: 29 OCT 2014 | DOI: 10.1002/smll.201402179

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      Gold nanoparticles (AuNPs) have a demonstrated efficacy in the delivery of cancer immunotherapies. This study demonstrates that AuNP-mediated delivery of the ovalbumin antigen and the CpG adjuvant induces strong antigen-specific immune responses. These responses subsequently result in anti-tumor activity and increased survival in prophylactic and established in vivo tumor models.

  57. Communications

    1. Cell-Imprinted Antimicrobial Bionanomaterials with Tolerable Toxic Side Effects

      Zhijun Zhang, Meng Li, Jinsong Ren and Xiaogang Qu

      Article first published online: 27 OCT 2014 | DOI: 10.1002/smll.201402400

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      Taking advantage of imprinting technology, artificial antibody-microbial imprinted Ag-TiO2 materials are fabricated for microbial inactivation using a facile and green method. Due to the induced shape and size recognition elements, the artificial antibodies specifically recognize and kill target microbes under visible-light irradiation with minimal toxic side effects toward mammalian cells.

  58. Full Papers

    1. Double-Walled Au Nanocage/SiO2 Nanorattles: Integrating SERS Imaging, Drug Delivery and Photothermal Therapy

      Feng Hu, Yan Zhang, Guangcun Chen, Chunyan Li and Qiangbin Wang

      Article first published online: 27 OCT 2014 | DOI: 10.1002/smll.201401360

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      A novel type of nanomedical platform, the double-walled Au nanocage/SiO2 nanorattle, is fabricated by combining two excavation strategies—galvanic replacement and surface-protected etching. The as-prepared nanorattle is demonstrated as a sensitive SERS substrate, an effective NIR photothermal agent, and a highly efficient drug carrier with a controllable release feature. This could inspire the controlled synthesis of other complicated nanostructures and the multifunctionality of the nanorattles will find wide application.

    2. You have full text access to this OnlineOpen article
      Near-Unity Quantum Yields from Chloride Treated CdTe Colloidal Quantum Dots

      Robert C. Page, Daniel Espinobarro-Velazquez, Marina A. Leontiadou, Charles Smith, Edward A. Lewis, Sarah J. Haigh, Chen Li, Hanna Radtke, Atip Pengpad, Federica Bondino, Elena Magnano, Igor Pis, Wendy. R. Flavell, Paul O'Brien and David J. Binks

      Article first published online: 27 OCT 2014 | DOI: 10.1002/smll.201402264

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      Photoluminescence with nearly 100% quantum yield is obtained from CdTe colloidal quantum dots by treating the surface with chloride ions. This process achieves near-complete passivation of the surface traps caused by dangling bonds, which otherwise cause significant non-radiative recombination, and also reduces the degradation of quantum yield with oxidation exposure.

    3. Core–Shell Si/C Nanospheres Embedded in Bubble Sheet-like Carbon Film with Enhanced Performance as Lithium Ion Battery Anodes

      Wenyue Li, Yongbing Tang, Wenpei Kang, Zhenyu Zhang, Xia Yang, Yu Zhu, Wenjun Zhang and Chun-Sing Lee

      Article first published online: 27 OCT 2014 | DOI: 10.1002/smll.201402072

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      A novel bubble sheet-like carbon film-supported core–shell Si/C composite is successfully fabricated via a facile thermal reduction/glucose carbonization process with the sodium chloride as the template. With enhanced electrode conductivity and sufficient free space for silicon expansion during the lithiation process, this material shows a much better cycle life and rate capability than silicon nanoparticles.

    4. Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts: Emission Color-Tuning with Counter Anions and Application for Optical Waveguides

      Fang Hu, Guanxin Zhang, Chi Zhan, Wei Zhang, Yongli Yan, Yongsheng Zhao, Hongbing Fu and Deqing Zhang

      Article first published online: 22 OCT 2014 | DOI: 10.1002/smll.201402051

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      Pyridinium-substituted tetraphenylethylene salts with seven different anions show almost the same emission behavior in an amorphous state, except the salt with I, but their crystalline solids have different emission colors varying from green to yellow. These can be tuned using the counter anions; in addition, microrods of certain salts can function as great optical waveguides.

  59. Concepts

    1. Regulating the Electrical Behaviors of 2D Inorganic Nanomaterials for Energy Applications

      Feng Feng, Junchi Wu, Changzheng Wu and Yi Xie

      Article first published online: 21 OCT 2014 | DOI: 10.1002/smll.201402346

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      Synergetic advantages of superior electrical conductivity and excellent reaction activity from inorganic lattices render 2D nanomaterials ideal candidates for electrode active materials in electrochemical applications towards energy conversion and storage. In this concept article, recent progress on regulating the electrical behaviors of two-dimensional inorganic nanomaterials for energy applications are discussed.

  60. Full Papers

    1. Single-Mode Lasing from Colloidal Water-Soluble CdSe/CdS Quantum Dot-in-Rods

      Francesco Di Stasio, Joel Q. Grim, Vladimir Lesnyak, Prachi Rastogi, Liberato Manna, Iwan Moreels and Roman Krahne

      Article first published online: 21 OCT 2014 | DOI: 10.1002/smll.201402527

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      In optoelectronic device fabrication, water solubility of nanocrystal materials is advantageous for simple and environmentally friendly processing routes. Towards LEDs, highly luminescent core–shell quantum dot-in-rods (QDRs) demonstrate excellent performance as emitters. Increasing in shell thickness allows the transfer of CdSe/CdS QDRs into aqueous solution without reducing their emission, and drop deposition leads to single mode microlasers with low threshold.

    2. Tailoring the Height of Ultrathin PbS Nanosheets and Their Application as Field-Effect Transistors

      Thomas Bielewicz, Sedat Dogan and Christian Klinke

      Article first published online: 21 OCT 2014 | DOI: 10.1002/smll.201402144

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      Controlled synthesis of large, two-dimensional PbS nanosheets with tunable height is presented. Through a variation in ligand concentration it is possible to tailor the height of the PbS nanosheets, which show different optical and electronic characteristics as a function of their height.

    3. Rapid Quantification of Live Cell Receptors Using Bioluminescence in a Flow-Based Microfluidic Device

      Ramesh Ramji, Cheong Fook Chiong, Hiroaki Hirata, Abdur Rub Abdur Rahman and Chwee Teck Lim

      Article first published online: 21 OCT 2014 | DOI: 10.1002/smll.201401674

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      A new method of quantifying live cell surface receptor numbers by integrating bioluminescence with microfluidics and lens-free optics is presented. This significantly improves upon other methods by providing miniaturized detection modules with higher sensitivity, specificity, lower consumption of analytes, reduced assay times, and by allowing multiplex functions for high-throughput cell screening assays.

  61. Communications

    1. Kinetically Controlled Synthesis of PdNi Bimetallic Porous Nanostructures with Enhanced Electrocatalytic Activity

      Chengzhou Zhu, Dan Wen, Martin Oschatz, Matthias Holzschuh, Wei Liu, Anne-Kristin Herrmann, Frank Simon, Stefan Kaskel and Alexander Eychmüller

      Article first published online: 21 OCT 2014 | DOI: 10.1002/smll.201401432

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      A class of 3D PdNi bimetallic nano­materials with porous nanostructures is synthesized using a facile and versatile approach at room temperature. Due to their porous nanostructures, their clean surfaces, as well as the synergistic effect between their compositions, the as-prepared PdNi exhibit greatly enhanced activity and stability towards methanol electrooxidation in an alkaline medium, holding great promise in fuel cells.