Nano Research (NANO RES)

Publications in this journal

• Article: Durable, superhydrophobic, antireflection and low haze glass surfaces using scalable metal dewetting nanostructuring

  Daniel Infante, Karl W. Koch, Prantik Mazumder, Lili Tian, Albert Carrilero, Domenico Tulli, David Baker, Valerio Pruneri
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  ABSTRACT: In this paper we report a multifunctional nanostructured surface on glass that, for the first time, combines a wide range of optical, wetting and durability properties, including low omnidirectional reflectivity, low haze, high transmission, superhydrophobicity, oleophobicity, and high mechanical resistance. Nanostructures have been fabricated on a glass surface by reactive ion etching through a nano-mask, which is formed by dewetting ultrathin metal films (<10nm thickness) subjected to rapid thermal annealing (RTA). The nanostructures strongly reduce the initial surface reflectivity (~4%), to less than 0.4% in the 390-800 nm wavelength range while keeping the haze at low values (<0.9%). The corresponding water contact angle (θc) is ~24.5°, while that on a flat surface is ~43.5°. The hydrophilic wetting nanostructure can be changed into a superhydrophobic and oleophobic surface by applying a fluorosilane coating, which achieves contact angles for water and oil of ~156.3° and ~116.2°, respectively. The multicomponent composition of the substrate (Corning® glass) enables ion exchange through the surface, so that the nanopillars’ mechanical robustness increases, as is demonstrated by the negligible changes in surface morphology and optical performance after 5000-run wipe test. The geometry of the nanoparticles forming the nano-mask depends on the metal material, initial metal thickness and RTA parameters. In particular we show that by simply changing the initial thickness of continuous Cu films we can tailor the metal nanoparticles’ surface density and size. The developed surface nanostructuring does not require expensive lithography, thus it can be controlled and implemented on an industrial scale, which is crucial for applications.
  Nano Research 04/2013;
• Article: Lithographically directed assembly of one-dimensional DNA nanostructures via bivalent binding interactions

  Risheng Wang, Matteo Palma, Erika Penzo, Shalom Wind
  Nano Research 01/2013;
• Article: Multiplexed cytokine detection on plasmonic gold substrates with enhanced near-infrared fluorescence

  Bo Zhang, Jordan Price, Guosong Hong, Scott M. Tabakman, Hailiang Wang, Justin A. Jarrell, Ju Feng, Paul J. Utz, Hongjie Dai
  Nano Research 12/2012;
• Article: Upconversion nanoparticles dramatically promote plant growth without toxicity

  juanjuan peng, yun sun, qian liu, yang yang, jing zhou, wei feng, xianzhong zhang, fuyou li
  Nano Research 10/2012; 5(11):770-782.
• Article: Shell-Doping of GaAs Nanowires with Si for n-Type Conductivity

  Emmanouil Dimakis, Manfred Ramsteiner, Abbes Tahraoui, Henning Riechert, and Lutz Geelhaar
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  ABSTRACT: We demonstrate the potential of using Si as n-type dopant in GaAs nanowires grown by molecular beam epitaxy. The amphoteric behavior of Si that typically accompanies the vapor–liquid–solid growth mode is adequately controlled when a shell doping scheme is utilized instead, i.e. when a Si-doped GaAs shell layer is grown conformally around the undoped GaAs nanowire core in the vapor–solid mode. The incorporation site of Si was evaluated by Raman spectroscopy, and correlated with the growth conditions of the doped shell. In that way, we identified a growth window that ensures the incorporation of Si as donor, and obtained donor concentrations up to 1 × 1019 cm–3, with the compensation level by Si acceptors remaining below 10%. Finally, resistivity measurements on planarized shell-doped nanowire ensembles were employed to probe the doping efficiency and the surface depletion of free-carriers. The achievement of n-type conductivity for nanowires is essential for the realization of functional devices, and is particularly significant when a dopant as well understood and advantageous as Si is employed.
  Nano Research 09/2012; 5(11):796.
• Article: Engineering Manganese Oxide/Nanocarbon Hybrid Materials for Oxygen Reduction Electrocatalysis

  Ju Feng, Yongye Liang, Hailiang Wang, Yanguang Li, Bo Zhang, Jigang Zhou, Jian Wang, Tom Regier, Hongjie Dai
  Nano Research 09/2012; 5(10):718.
• Article: Ni3Si2O5(OH)4 multi-walled nanotubes with tunable magnetic properties and their application as anode materials for lithium batteries

  Yan Yang, Qingqin Liang, Jinghong Li, Yuan Zhuang, Yunhua He, Bo Bai, Xun Wang
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  ABSTRACT: Highly crystalline and thermally stable pure multi-walled Ni3Si2O5(OH)4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200–210 °C using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni3Si2O5(OH)4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA·h·g−1 after 21 cycles at a rate of 20 mA·g−1. Furthermore, after the nanotubes were calcined (600 °C, 4 h) or reduced (180 °C, 10 h), the corresponding discharge capacities increased to 277.2 mA·h·g−1 and 308.5 mA·h·g−1, respectively. KeywordsSilicate nanotubes–Ni nanocrystals–lithium battery–magnetic properties
  Nano Research 05/2012; 4(9):882-890.
• Article: Optical properties of SiO2 and ZnO nanostructured replicas of butterfly wing scales

  Zhe Xu, Ke Yu, Bo Li, Rong Huang, Ping Wu, Huibing Mao, Na Liao, Ziqiang Zhu
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  ABSTRACT: SiO2 and ZnO inverse structure replicas have been synthesized using butterfly wings as templates. The laser diffraction performance of the SiO2 inverse structure replica was investigated and it was found that the zero-order light spot split into a matrix pattern when the distance between the screen and the sample was increased. This unique diffraction phenomenon is closely related to the structure of the SiO2 inverse structure replica. On the other hand, by analyzing the photoluminescence spectrum of the ZnO replica, optical anisotropy in the ultraviolet band was demonstrated for this material. KeywordsSiO2 –biotemplate–diffraction–ZnO–optical anisotropy
  Nano Research 05/2012; 4(8):737-745.
• Article: Strain-induced semiconductor to metal transition in the two-dimensional honeycomb structure of MoS2

  Emilio Scalise, Michel Houssa, Geoffrey Pourtois, Valery Afanas’ev, André Stesmans
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  ABSTRACT: The electronic properties of two-dimensional honeycomb structures of molybdenum disulfide (MoS2) subjected to biaxial strain have been investigated using first-principles calculations based on density functional theory. On applying compressive or tensile bi-axial strain on bi-layer and mono-layer MoS2, the electronic properties are predicted to change from semiconducting to metallic. These changes present very interesting possibilities for engineering the electronic properties of two-dimensional structures of MoS2. KeywordsMoS2 –quasi-2D chalcogenide materials–first-principles modeling–strain-induced semiconductor to metal transition
  Nano Research 05/2012; 5(1):43-48.
• Article: Novel photodetectors based on double-walled carbon nanotube film/TiO2 nanotube array heterodimensional contacts

  Mingjie Yang, Jia-Lin Zhu, Wei Liu, Jia-Lin Sun
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  ABSTRACT: A new kind of photodetector based on a double-walled carbon nanotube (DWCNT) film and a TiO2 nanotube array with hetrodimensional non-ohmic contacts has been fabricated. Due to the dimensionality difference effect, the DWCNT film/TiO2 nanotube array photodetector exhibits a much higher photocurrent-to-dark current ratio and photoresponse relative to an Au film/TiO2 nanotube array device, even at small bias voltage. The photocurrent-to-dark current ratio reached four orders of magnitude and a high photoresponse of 2467 A/W was found upon irradiation at 340 nm. Furthermore, the photosensitive regions could be extended into the visible range. The photocurrent-to-dark current ratio reached approximately three orders of magnitude upon irradiation at 532 nm, where the photon energy is much lower than the band gap of TiO2. KeywordsPhotodetectors–double-walled carbon nanotube (DWCNT) films–TiO2 nanotube arrays–heterodimensional contacts
  Nano Research 05/2012; 4(9):901-907.
• Article: Production of graphene nanospheres by annealing of graphene oxide in solution

  Jian Zheng, Hongtao Liu, Bin Wu, Yunlong Guo, Ti Wu, Gui Yu, Yunqi Liu, Daoben Zhu
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  ABSTRACT: We report a simple method to produce graphene nanospheres (GNSs) by annealing graphene oxide (GO) solution at high-temperature with the assistance of sparks induced by the microwave absorption of graphite flakes dispersed in the solution. The GNSs were formed by rolling up of the annealed GO, and the diameters were mostly in the range 300–700 nm. The GNS exhibited a hollow sphere structure surrounded by graphene walls with a basal spacing of 0.34 nm. Raman spectroscopy and X-ray photoelectron spectroscopy of the GNSs confirmed that the GO was efficiently reduced during the fabrication process. The resulting GNSs may open up new opportunities both for fundamental research and applications, and this method may be extended to the synthesis of other nanomaterials and the fabrication of related nanostructures. KeywordsGraphene–nanosphere–self-assembly–microwave–anneal
  Nano Research 05/2012; 4(7):705-711.
• Article: In Situ TEM observation of the gasification and growth of carbon nanotubes using iron catalysts

  Xiaofeng Feng, See Wee Chee, Renu Sharma, Kai Liu, Xu Xie, Qunqing Li, Shoushan Fan, Kaili Jiang
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  ABSTRACT: We report the in situ transmission electron microscope (TEM) observation of the catalytic gasification and growth of carbon nanotubes (CNTs). It was found that iron catalysts can consume the CNTs when pumping out the precursor gas, acetylene, at the growth temperature, and reinitiate the growth when acetylene is re-introduced. The switching between gasification and growth of CNTs can be repeated many times with the same catalyst. To understand the phenomenon, thermogravimetric analysis (TGA) coupled with mass spectroscopy was used to study the mechanism involved. It was shown that the residual water molecules in the growth chamber of the TEM react with and remove carbon atoms of CNTs as carbon monoxide vapor under the action of the catalyst, when the precursor gas is pumped out. This result contributes to a better understanding of the water-assisted and oxygen-assisted synthesis of CNT arrays, and provides useful clues on how to extend the lifetime and improve the activity of the catalysts. KeywordsCarbon nanotubes–gasification–growth–iron catalyst–environmental transmission electron microscopy (ETEM)–thermogravimetric analysis (TGA)
  Nano Research 05/2012; 4(8):767-779.
• Article: CuI-Si heterojunction solar cells with carbon nanotube films as flexible top-contact electrodes

  Peixu Li, Shanshan Wang, Yi Jia, Zhen Li, Chunyan Ji, Luhui Zhang, Hongbian Li, Enzheng Shi, Zuqiang Bian, Chunhui Huang, Jinquan Wei, Kunlin Wang, Hongwei Zhu, Dehai Wu, Anyuan Cao
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  ABSTRACT: We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes (CNTs) as a transparent electrode. A flexible CNT network was transferred onto the top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide (ITO) glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface. KeywordsCarbon nanotubes–flexible electrodes–heterojunction solar cells
  Nano Research 05/2012; 4(10):979-986.
• Article: Synthesis of Pd nanocrystals enclosed by {100} facets and with sizes

  Mingshang Jin, Hongyang Liu, Hui Zhang, Zhaoxiong Xie, Jingyue Liu, Younan Xia
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  ABSTRACT: The catalytic activity of noble-metal nanocrystals is mainly determined by their sizes and the facets exposed on the surface. For single crystals, it has been demonstrated that the Pd(100) surface is catalytically more active than both Pd(110) and Pd(111) surfaces for the CO oxidation reaction. Here we report the synthesis of Pd nanocrystals enclosed by {100} facets with controllable sizes in the range of 6–18 nm by manipulating the rate of reduction of the precursor. UV-vis spectroscopy studies indicate that the rate of reduction of Na2PdCl4 can be controlled by adjusting the concentrations of Br− and Cl− ions added to the reaction mixture. Pd nanocrystals with different sizes were immobilized on ZnO nanowires and evaluated as catalysts for CO oxidation. We found that the activity of this catalytic system for CO oxidation showed a strong dependence on the nanocrystal size. When the size of the Pd nanocrystals was reduced from 18 nm to 6 nm, the maximum conversion rate was significantly enhanced by a factor of ∼10 and the corresponding maximum conversion temperature was lowered by ∼80 °C. KeywordsPalladium–nanocubes–CO oxidation–size-dependence
  Nano Research 05/2012; 4(1):83-91.