Plasmon-Enhanced Photoconductivity in Amorphous Silicon Thin Films by Use of Thermally Stable Silica-Coated Gold Nanorods

Chemistry of Materials

DOI: 10.1021/cm504086z

Chi-Sheng Chang and Lewis J. Rothberg
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Structural Characteristics and Eutaxy in the Photo-Deposited Amorphous Iron Oxide Oxygen Evolution Catalyst

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00878

Joshua A. Kurzman, Kevan E. Dettelbach, Andrew J. Martinolich, Curtis P. Berlinguette and James R. Neilson
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Electrically Configurable Graphene Field-Effect Transistors with a Graded-Potential Gate

Nano Letters

DOI: 10.1021/acs.nanolett.5b00396

Xiaowei Wang, Xingbin Jiang, Ting Wang, Jia Shi, Mingju Liu, Qibin Zeng, Zhihai Cheng and Xiaohui Qiu
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Electrode/Electrolyte Interface of Composite α-Li3V2(PO4)3 Cathodes in a Nonaqueous Electrolyte for Lithium Ion Batteries and the Role of the Carbon Additive

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00447

Nellymar Membreño, Kyusung Park, John B. Goodenough and Keith J. Stevenson
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High-Density Lithium-Ion Energy Storage Utilizing the Surface Redox Reactions in Folded Graphene Films

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00314

Tianyuan Liu, Ki Chul Kim, Reza Kavian, Seung Soon Jang and Seung Woo Lee
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Surface Segregation in Chromium-Doped NiCr Alloy Nanoparticles and Its Effect on Their Magnetic Behavior

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00837

Murtaza Bohra, Panagiotis Grammatikopoulos, Rosa E. Diaz, Vidyadhar Singh, Junlei Zhao, Jean-François Bobo, Antti Kuronen, Flyura Djurabekova, Kai Nordlund and Mukhles Sowwan
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Vibrational Mismatch of Metal Leads Controls Thermal Conductance of Self-Assembled Monolayer Junctions

Nano Letters

DOI: 10.1021/nl504844d

Shubhaditya Majumdar, Jonatan A. Sierra-Suarez, Scott N. Schiffres, Wee-Liat Ong, C. Fred Higgs, Alan J. H. McGaughey and Jonathan A. Malen
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High Yield of GaAs Nanowire Arrays on Si Mediated by the Pinning and Contact Angle of Ga

Nano Letters

DOI: 10.1021/nl504437v

Eleonora Russo-Averchi, Jelena Vukajlovic Plestina, Gözde Tütüncüoglu, Federico Matteini, Anna Dalmau-Mallorquí, Maria de la Mata, Daniel Rüffer, Heidi A. Potts, Jordi Arbiol, Sonia Conesa-Boj and Anna Fontcuberta i Morral
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Hexagonal Boron Nitride Cover on Pt(111): A New Route to Tune Molecule–Metal Interaction and Metal-Catalyzed Reactions

Nano Letters

DOI: 10.1021/acs.nanolett.5b01205

Yanhong Zhang, Xuefei Weng, Huan Li, Haobo Li, Mingming Wei, Jianping Xiao, Zhi Liu, Mingshu Chen, Qiang Fu and Xinhe Bao
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Structure-related antibacterial activity of a titanium nanostructured surface fabricated by glancing angle sputter deposition

The aim of this study was to reproduce the physico-mechanical antibacterial effect of the nanocolumnar cicada wing surface for metallic biomaterials by fabrication of titanium (Ti) nanocolumnar surfaces using glancing angle sputter deposition (GLAD). Nanocolumnar Ti thin films were fabricated by GLAD on silicon substrates. S. aureus as well as E. coli were incubated with nanostructured or reference dense Ti thin film test samples for one or three hours at 37 °C. Bacterial adherence, morphology, and viability were analyzed by fluorescence staining and scanning electron microscopy and compared to human mesenchymal stem cells (hMSCs). Bacterial adherence was not significantly different after short (1 h) incubation on the dense or the nanostructured Ti surface. In contrast to S. aureus the viability of E . coli was significantly decreased after 3 h on the nanostructured film compared to the dense film and was accompanied by an irregular morphol...

Christina Sengstock, Michael Lopian, Yahya Motemani, Anna Borgmann, Chinmay Khare, Pio John S Buenconsejo, Thomas A Schildhauer, Alfred Ludwig and Manfred Köller

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Facile synthesis of Pt/Pd nanodendrites for the direct oxidation of methanol

The demand for clean and energy-efficient fuel cell systems requires electrocatalysts with greater activity and stability. Here, we report a facile wet-chemical approach for the synthesis of high-quality three-dimensional (3D) Pt/Pd bimetallic nanodendrites. The simple and unique process developed here used oleylamine as a reducing agent, and hydrogen gas to control the morphology. The as-prepared Pt/Pd nanodendrites were characterized by transmission electron microscopy, x-ray diffraction and energy dispersive x-ray spectroscopy, cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The nanodendrites showed superior electrocatalytic activity (609.565 mA mg −1 Pt) for the oxidation of methanol compared with Pt nanoparticle electrocatalysts. This method could provide a general approach for the morphology-controlled synthesis of bimetallic Pt-based nanocatalysts, which are promising materials for applications in fuel cells.

Hai Wu, Sujuan Mei, Xueqin Cao, Junwei Zheng, Ming Lin, Jianxin Tang, Fangfang Ren, Yukou Du, Yue Pan and Hongwei Gu

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Detection of hydrogen sulfide through photoluminescence quenching of penicillamine-copper nanocluster aggregates

We have developed a one-pot, inexpensive, simple and rapid method to synthesize photoluminescent copper nanocluster (Cu NC) aggregates from Cu 2+ ions in 65% (v v −1 ) dimethylformamide aqueous solution containing penicillamine (PA) as a capping and reducing agent. As-prepared PA-Cu NC aggregates emit at 580 nm when excited at 326 nm, with a quantum yield of 2.0%. The photoluminescence of PA-Cu NC aggregates originate from ligand-to-metal charge transfer, which is supported by a long lifetime (126.5 ns) and a large Stokes shift (254 nm). As-prepared PA-Cu NC aggregates have different emission wavelengths with the same excitation wavelength in various organic-aqueous solutions. The PA-Cu NC aggregates are highly selective and sensitive to the detection of hydrogen sulfide (H 2 S), based on analyte-induced photoluminescence quenching through the formation of CuS nanoparticles. The probe allows the detection of H 2 S, with a linear range of 1–100...

Jia-Ying Ma, Po-Cheng Chen and Huan-Tsung Chang

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pH sensitive quantum dot–anthraquinone nanoconjugates

Semiconductor quantum dots (QDs) have been shown to be highly sensitive to electron or charge transfer processes, which may alter their optical properties. This feature can be exploited for different sensing applications. Here, we demonstrate that QD-anthraquinone conjugates can function as electron transfer-based pH nanosensors. The attachment of the anthraquinones on the surface of QDs results in the reduction of electron hole recombination, and therefore a quenching of the photoluminescence intensity. For some anthraquinone derivatives tested, the quenching mechanism is simply caused by an electron transfer process from QDs to the anthraquinone, functioning as an electron acceptor. For others, electron transfer and energy transfer (FRET) processes were found. A detailed analysis of the quenching processes for CdSe/ZnS QD of two different sizes is presented. The photoluminescence quenching phenomenon of QDs is consistent with the pH sensitive anthraquinone redox chemistry. The ...

Maria Jose Ruedas-Rama and Elizabeth A H Hall

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Micelle-templated composite quantum dots for super-resolution imaging

Quantum dots (QDs) have tremendous potential for biomedical imaging, including super-resolution techniques that permit imaging below the diffraction limit. However, most QDs are produced via organic methods, and hence require surface treatment to render them water-soluble for biological applications. Previously, we reported a micelle-templating method that yields nanocomposites containing multiple core/shell ZnS–CdSe QDs within the same nanocarrier, increasing overall particle brightness and virtually eliminating QD blinking. Here, this technique is extended to the encapsulation of Mn-doped ZnSe QDs (Mn–ZnSe QDs), which have potential applications in super-resolution imaging as a result of the introduction of Mn 2+ dopant energy levels. The size, shape and fluorescence characteristics of these doped QD-micelles were compared to those of micelles created using core/shell ZnS–CdSe QDs (ZnS–CdSe QD-micelles). Additionally, the stability of both types of particles to photo-...

Jianquan Xu, Qirui Fan, Kalpesh D Mahajan, Gang Ruan, Andrew Herrington, Kayvan F Tehrani, Peter Kner and Jessica O Winter

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Fabrication of highly ordered/switchable polymer nanogratings for nano-actuators using nanoimprint lithography

Polymer micro/nano-actuators are attracting tremendous interest due to their potential applications in micro/nano-mechanical systems and lab-on-a-chip systems. To achieve this, thin films of stimuli-responsive polymers are required to be patterned at the micro/nanometer scale, and also to possess highly ordered orientation in the responsive component. We demonstrate here that nanoscale patterning and uniaxial alignment of liquid crystalline mesogens can be simultaneously achieved by nanoimprint lithography performed in the liquid crystalline mesophase. Photoactive azobenzene mesogens were aligned parallel to the nanogratings imprinted in the films. The degree of alignment depended on the extent of nanoconfinement. The nanogratings expanded in the direction perpendicular to the film upon exposure to uniform UV irradiation, because of trans -to- cis isomerization. In addition, the reversible deformation amplitude strongly depended on the degree of alignment of the photo...

Donghai Du, Hongying Wen, Zhijun Hu, Yuyan Weng and Weidong Zhang

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Local nanotip arrays sculptured by atomic force microscopy to enhance the light-output efficiency of GaN-based light-emitting diode structures

In this work, local nanotip arrays on GaN-based light-emitting (LED) structures were fabricated through nano-oxidation using an atomic force microscope (AFM). The photoluminescence (PL) intensity of the InGaN/GaN multiple quantum wells (MQWs) active layer and the light extraction efficiency of the LED structure were enhanced by forming this nanotips structure to serve as a graded-refractive index layer, which is further validated by the finite-difference time-domain analysis. The PL emission peak of the MQWs active layer has a blue-shift phenomenon that is caused by a partial reduction of the strain on the InGaN well. It is expected that our approach opens a promising route for simultaneously enhancing both the internal quantum efficiency and the light extraction efficiency of GaN-based LEDs. The proposed AFM-based method will be of importance for local patterning the light emitting components for optoelectronic applications.

Chun-Ying Huang, Yung-Chi Yao, Ya-Ju Lee, Tai-Yuan Lin, Wen-Jang Kao, Jih Shang Hwang, Ying-Jay Yang and Ji-Lin Shen

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Transmission electron microscopy analysis for the process of crystallization of ##IMG## [http://ift.tt/1ihVmZF] {$\text{C}{{\text{u}}_{2}}\text{ZnSn}{{\text{S}}_{4}}$} film from sputtered Zn/CuSn precursor

The mechanism of crystallization of ##IMG## [http://ift.tt/1jUUXZQ] {$\text{C}{{\text{u}}_{2}}\text{ZnSn}{{\text{S}}_{4}}$} (CZTS) made by the sulfurization of a sputtered Zn/CuSn stack was studied by transmission electron microscopy. At ##IMG## [http://ift.tt/1ihVnfT] {$250\;{}^\circ \text{C}$} , the Zn buried at the bottom of the metallic stack was found to be driven to the upper layer by alloying with Cu and reacting with S to form ZnS. At ##IMG## [http://ift.tt/1ihVnfV] {$500\;{}^\circ \text{C}$} , CZTS was found to be formed and elemental Sn was observed in the vicinity of the back contact region, while large quantities of ##IMG## [http://ift.tt/1jUUZAL] {$\text{C}{{\text{u}}_{2}}\text{S}$} and ZnS were segregated at the ...

Wei Li, Jian Chen, Chang Yan, Fangyang Liu and Xiaojing Hao

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Model of a realistic InP surface quantum dot extrapolated from atomic force microscopy results

We report on numerical simulations of a zincblende InP surface quantum dot (QD) on ##IMG## [http://ift.tt/1jUUW8h] {$\text{I}{{\text{n}}_{0.48}}\text{G}{{\text{a}}_{0.52}}\text{P}$} buffer. Our model is strictly based on experimental structures, since we extrapolated a three-dimensional dot directly by atomic force microscopy results. Continuum electromechanical, ##IMG## [http://ift.tt/1jUUWoz] {$\vec{k}\;\cdot \;\vec{p}$} bandstructure and optical calculations are presented for this realistic structure, together with benchmark calculations for a lens-shape QD with the same radius and height of the extrapolated dot. Interesting similarities and differences are shown by comparing the results obtained with the two different structures, leading to the conclusion that the use of a more realistic structure can provide significant improvements in the modelin...

Daniele Barettin, Roberta De Angelis, Paolo Prosposito, Matthias Auf der Maur, Mauro Casalboni and Alessandro Pecchia

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High intensity induced photocurrent polarity switching in lead sulfide nanowire field effect transistors

We report an optoelectronic investigation of lead sulfide nanowires (NWs) by scanning photocurrent microscopy. The photocurrent in p-type lead sulfide NW field effect transistors has demonstrated unusually nonlinear dependence on the intensity of local excitation. Surprisingly, the photocurrent polarity can be reversed under high illumination intensity on the order of 100 W cm −2 . The origin of this photocurrent polarity switching is that the photo-injected carriers flip the direction of the electric field near the contact. These observations shed light on the nonlinear optoelectronic characteristics in semiconductor nanostructures and may provide an innovative method for optically tailoring local band structures.

Yiming Yang, Xingyue Peng and Dong Yu

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Proton Channels along Oxygen Octahedral Chains in La3NbO7

The Journal of Physical Chemistry C

DOI: 10.1021/jp501791r

Kunitada Kato, Kazuaki Toyoura, Atsutomo Nakamura and Katsuyuki Matsunaga

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