Structure-dependent electrical conductivity of protein: its differences between alpha-domain and beta-domain structures

Electron transports in the ? -domain and ? -domain of proteins have been comprehensively investigated. The structure-dependent electron transport of proteins has been experimentally measured and theoretically simulated, and both the theoretical and experimental results demonstrate significant differences in electrical conductivity between the ? -domain and ? -domain. By controlling the feedback system of the scanning tunneling microscope (STM), the conductance of a single ? -domain protein hemoglobin (Hgb) and a ? -domain protein superoxide dismutase enzyme (SOD) were measured, respectively. The current signal of Hgb is obviously stronger, indicating that the ? -domain is more conductive. To confirm our finding, molecular orbitals of both the ? -domain in SOD and ? -domain in Hgb have been analyzed based on first-principles calculations. As expected, tunneling transport and hopping in the ? -domain are both more efficien...

X Y Zhang, Jian Shao, S X Jiang, Biao Wang and Yue Zheng

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Realization of improved efficiency on nanostructured multicrystalline silicon solar cells for mass production

We report the realization of both excellent optical and electrical properties of nanostructured multicrystalline silicon solar cells by a simple and industrially compatible technique of surface morphology modification. The nanostructures are prepared by Ag-catalyzed chemical etching and subsequent NaOH treatment with controllable geometrical parameters and surface area enhancement ratio. We have examined in detail the influence of different surface area enhancement ratios on reflectance, carrier recombination characteristics and cell performance. By conducting a quantitative analysis of these factors, we have successfully demonstrated a higher-than-traditional output performance of nanostructured multicrystalline silicon solar cells with a low average reflectance of 4.93%, a low effective surface recombination velocity of 6.59 m s ?1 , and a certified conversion efficiency of 17.75% on large size (156???156 mm 2 ) silicon cells, which is ?0.3% higher than the ac...

X X Lin, Y Zeng, S H Zhong, Z G Huang, H Q Qian, J Ling, J B Zhu and W Z Shen

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One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix

Developing an ability to fabricate high-resolution, 3D metal nanostructures in a stretchable 3D matrix is a critical step to realizing novel optoelectronic devices such as tunable bulk metal-dielectric optical devices and THz metamaterial devices that are not feasible with alternative techniques. We report a new chemistry method to fabricate high-resolution, 3D silver nanostructures using a femtosecond-laser direct metal writing technique. Previously, only fabrication of 3D polymeric structures or single-/few-layer metal structures was possible. Our method takes advantage of unique gelatin properties to overcome such previous limitations as limited freedom in 3D material design and short sample lifetime. We fabricate more than 15 layers of 3D silver nanostructures with a resolution of less than 100 nm in a stable dielectric matrix that is flexible and has high large transparency that is well-matched for potential applications in the optical and THz metamaterial regimes. This is a...

SeungYeon Kang, Kevin Vora and Eric Mazur

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Influence of surface stresses on indentation response

Surface stresses lead to an effective change in the elastic constants of thin films and at surfaces. The development of modern scanning probe techniques like contact resonance atomic force microscopy empowers the experimenter to measure at scales where these effects become increasingly relevant. In this paper we employ a computational multiscale approach where we compare density functional theory (DFT) and molecular dynamics simulations as tools to calculate the thin-film/surface elastic behavior for silicon and strontiumtitanate. From the surface elastic constants gained by DFT calculations we develop a continuum finite-element multilayer model to study the impact of surface stresses on indentation experiments. In general the stress field of an indenter and thus the impact of surface stresses on the indentation modulus depends on its contact radius and on its particular shape. We propose an analytical model that describes the behavior of the indentation modulus as a function of ...

J Buchwald and S G Mayr

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Plasmon-enhanced photocatalytic hydrogen production over visible-light responsive Cu/TiO 2

Cheap and visible-light responsive Cu/TiO 2 photocatalysts were fabricated by illuminating ultraviolet (UV) to a mixture of TiO 2 nanoparticles (NPs) and Cu 2 O NPs in an evacuated reaction chamber. The Cu 2 O NPs were reduced by UV in an oxygen-free reaction chamber, and hence, metallic Cu NPs with size less than 5 nm were uniformly loaded on TiO 2 . Due to the plasmon resonance of the Cu NPs, the Cu/TiO 2 exhibited a good performance of water-splitting hydrogen production under visible light in the presence of glycerol as a hole scavenger. The optimum hydrogen production rate of Cu/TiO 2 was 0.24 mmol h ?1 g ?1 . The Cu/TiO 2 also showed high stability of the photocatalytic performance in the evacuated chamber; however, the visible-light responsive photocatalytic properties dramatically and rapidly decreased when exposed to air.

Jong Min Kum, Yang Jeong Park, Hyun Jin Kim and Sung Oh Cho

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Rapid synthesis of flexible conductive polymer nanocomposite films

Polymer nanocomposite films with nanoparticle-specific properties are sought out in novel functional materials and miniaturized devices for electronic and biomedical applications. Sensors, capacitors, actuators, displays, circuit boards, solar cells, electromagnetic shields and medical electrodes rely on flexible, electrically conductive layers or films. Scalable synthesis of such nanocomposite films, however, remains a challenge. Here, flame aerosol deposition of metallic nanosliver onto bare or polymer-coated glass substrates followed by polymer spin-coating on them leads to rapid synthesis of flexible, free-standing, electrically conductive nanocomposite films. Their electrical conductivity is determined during their preparation and depends on substrate composition and nanosilver deposition duration. Accordingly, thin (<500 nm) and flexible nanocomposite films are made having conductivity equivalent to metals (e.g.5???10 4 S cm ?1 ), even during repetit...

C O Blattmann, G A Sotiriou and S E Pratsinis

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Caution for monitoring the surface modification of dually emitted ZnSe quantum dots by time-resolved photoluminescence

This work wants to give a caution for monitoring the surface modification of dually emitted ZnSe quantum dots (QDs) by using time-resolved photoluminescence (PL). Aqueous ZnSe QDs have two emission bands: namely ZnSe band gap emission centered at 395 nm and ZnSe trap emission centered at 470 nm. By fitting the measured PL spectra by two peaks, serious overlapping of two emission bands can be found in the range of 360?430 nm. As a result, the measured PL lifetimes at 395 nm (the peak position of ZnSe band gap emission) is just an apparent value, composing of both ZnSe band emission (contribution proportion about 80%) and ZnSe trap emission (contribution proportion about 20%). Due to the much smaller PL lifetime of ZnSe band gap emission (less than 20 ns) than that of ZnSe trap emission (about 50?70 ns), the elevated contribution proportion of ZnSe band gap emission at improved QD surface modification will lead to the decreased average PL lifetime at 395 nm. This result is complete...

Chunlei Wang, Zhiyang Hu, Shuhong Xu, Shujie Zhou, Zhuyuan Wang and Yiping Cui

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Hydrogen plasma-mediated modification of the electrical transport properties of ZnO nanowire field effect transistors

We investigated the effects of hydrogen plasma treatment on the electrical transport properties of ZnO nanowire field effect transistors (FETs) with a back gate configuration. After hydrogen plasma treatment of the FET devices, the effective carrier density and mobility of the nanowire FETs increased with a threshold voltage shift toward a negative gate bias direction. This can be attributed to the desorption of oxygen molecules adsorbed on the surface of the nanowire channel, to passivation and to doping effects due to the incorporation of energetic hydrogen ions generated in plasma.

Woong-Ki Hong, Jongwon Yoon and Takhee Lee

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Bloch surface plasmon enhanced blue emission from InGaN/GaN light-emitting diode structures with Al-coated GaN nanorods

InGaN/GaN light-emitting diode structures with Al-coated GaN nanorods were fabricated by using soft ultraviolet nanoimprint lithography. The intensity of light emission was found to be greatly enhanced due to the strong near-fields confined at the interface of Al/GaN and extended to the multiple quantum wells (MQWs) active region. The dynamics of carrier recombination and plasmon-enhanced Raman scattering were also investigated, providing a progressive view on the effective energy transfer between MQWs and surface plasmons.

Guogang Zhang, Zhe Zhuang, Xu Guo, Fang-Fang Ren, Bin Liu, Haixiong Ge, Zili Xie, Ling Sun, Ting Zhi, Tao Tao, Yi Li, Youdou Zheng and Rong Zhang

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Magnetic force microscopy using tip magnetization modulated by ferromagnetic resonance

In magnetic force microscopy (MFM), the tip?sample distance should be reduced to analyze the microscopic magnetic domain structure with high spatial resolution. However, achieving a small tip?sample distance has been difficult because of superimposition of interaction forces such as van der Waals and electrostatic forces induced by the sample surface. In this study, we propose a new method of MFM using ferromagnetic resonance (FMR) to extract only the magnetic field near the sample surface. In this method, the magnetization of a magnetic cantilever is modulated by FMR to separate the magnetic field and topographic structure. We demonstrate the modulation of the magnetization of the cantilever and the identification of the polarities of a perpendicular magnetic medium.

Eiji Arima, Yoshitaka Naitoh, Yan Jun Li, Satoru Yoshimura, Hitoshi Saito, Hikaru Nomura, Ryoichi Nakatani and Yasuhiro Sugawara

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Biocompatible ¿-carrageenan-¿-maghemite nanocomposite for biomedical applications ¿ synthesis, characterization and in vitro anticancer efficacy

Background: Carrageenans are naturally occurring hydrophilic, polyanionic polysaccharide bioploymers with wide application in pharmaceutical industries for controlled drug delivery. Magnetic nanoparticles with their exceptional properties enable them to be an ideal candidate for the production of functional nanostructures, thus facilitating them for biomedical applications. The development of novel nanocomposite by coupling the synergistic effects of the sulfated polysaccharide (iota carrageenan) and a magnetic nanoparticle (maghemite) may offer new interesting applications in drug delivery and cancer therapy. The nanocomposite was characterized by ultraviolet–visible spectroscopy, high resolution scanning electron microscopy, dynamic light scattering analysis, Fourier transform infrared spectroscopy and powder XRD to highlight the possible interaction between the two components. Biocompatibility and the anticancer efficacy of the nanocomposite were assayed and analysed in vitro. Results: Results suggested that iota carrageenans have electrostatically entrapped the maghemite nanoparticles in their sulfate groups. Biocompatibility of the nanocomposite (at different concentrations) against normal cell lines (HEK-293 and L6) was confirmed by MTT assay. Hoechst 33342 and 7-AAD staining studies under fluorescent microscopy revealed that the nanocomposite is able to induce appoptosis as the mode of cell death in human colon cancer cell line (HCT116). Cell apoptosis here is induced by following the ROS-mediated mitochondrial pathway, combined with downregulation of the expression levels of mRNA of XIAP and PARP-1 and upregulation of caspase3, Bcl-2 and Bcl-xL. Conclusions: This novel nanocomposite is biocompatible with potential properties to serve in magnet aided targeted drug delivery and cancer therapy.

Maya Raman

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Heterogeneous Crystallization of the Phase Change Material GeTe via Atomistic Simulations

The Journal of Physical Chemistry C

DOI: 10.1021/acs.jpcc.5b00296

Gabriele C. Sosso, Matteo Salvalaglio, Jörg Behler, Marco Bernasconi and Michele Parrinello

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Highly Dynamic Alloying and Dealloying in the Model System Gold–Silicon (AuSi)

The Journal of Physical Chemistry C

DOI: 10.1021/jp512008n

Hendrik Reinhardt, Kerstin Bücker, Fang Yang, Philipp Nürnberger and Norbert A. Hampp

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Influence of Molecular Organization on the Electrical Characteristics of π-Conjugated Self-Assembled Monolayers

The Journal of Physical Chemistry C

DOI: 10.1021/jp512991d

Xavier Lefèvre, Fabrice Moggia, Olivier Segut, Yu-Pu Lin, Younal Ksari, Grégory Delafosse, Kacem Smaali, David Guérin, Vincent Derycke, Dominique Vuillaume, Stéphane Lenfant, Lionel Patrone and Bruno Jousselme

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Theory of Singlet Fission in Polyenes, Acene Crystals, and Covalently Linked Acene Dimers

The Journal of Physical Chemistry C

DOI: 10.1021/jp5124019

Karan Aryanpour, Alok Shukla and Sumit Mazumdar

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Combined STM and TPD Study of Rh(111) Under Conditions of High Oxygen Coverage

The Journal of Physical Chemistry C

DOI: 10.1021/acs.jpcc.5b00635

Jonathan Derouin, Rachael G. Farber and Daniel R. Killelea

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Size and Temperature Dependence of Electron Transfer between CdSe Quantum Dots and a TiO2 Nanobelt

The Journal of Physical Chemistry C

DOI: 10.1021/jp5110278

De Nyago Tafen and Oleg V. Prezhdo

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In Situ Synthesis of PbS Nanocrystals in Polymer Thin Films from Lead(II) Xanthate and Dithiocarbamate Complexes: Evidence for Size and Morphology Control

Chemistry of Materials

DOI: 10.1021/cm504765z

Edward A. Lewis, Paul D. McNaughter, Zhongjie Yin, Yiqiang Chen, Jack R. Brent, Selina A. Saah, James Raftery, Johannes A. M. Awudza, M. Azad Malik, Paul O’Brien and Sarah J. Haigh

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Transforming Hybrid Organic Inorganic Perovskites by Rapid Halide Exchange

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00281

Norman Pellet, Joël Teuscher, Joachim Maier and Michael Grätzel

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Transforming Hybrid Organic Inorganic Perovskites by Rapid Halide Exchange

Chemistry of Materials

DOI: 10.1021/acs.chemmater.5b00281

Norman Pellet, Joël Teuscher, Joachim Maier and Michael Grätzel

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