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O A Goryacheva, N V Beloglazova, A M Vostrikova, M V Pozharov, A M Sobolev, I Yu Goryacheva
Förster resonance energy transfer (FRET) between lanthanide ion complexes (L) acting as donors and luminescent semiconductor quantum dots (QD) acting as acceptors is discussed in the terms of advantages and disadvantages for its application in immunoassay. L-QD-FRET is potentially a powerful tool that can be used to detect and confirm formation of immunocomplexes, but until now it had very limited practical analytical application. Therefore, the main aim of this review is to analyze all possibilities, advantages, and disadvantages of L-QD-FRET in immunoassay applications...
March 1, 2017: Talanta
Akram Alhussein, Sofiane Achache, Regis Deturche, Frederic Sanchette, Cesar Pulgarin, John Kiwi, Sami Rtimi
This article presents the evidence for the significant effect of copper accelerating the bacterial inactivation on Ti-Nb-Ta-Zr (TNTZ) sputtered films on glass up to a Cu content of 8.3 at.%. These films were deposited by dc magnetron co-sputtering of an alloy target Ti-23Nb-0.7Ta-2Zr (at.%) and a Cu target. The fastest bacterial inactivation of E. coli on this later TNTZ-Cu surface proceeded within ∼75min. The films deposited by magnetron sputtering are chemically homogenous. The film roughness evaluated by atomic force spectroscopy (AFM) on the TNTZ-Cu 8...
January 15, 2017: Colloids and Surfaces. B, Biointerfaces
Christian Kern, Muamer Kadic, Martin Wegener
Effectively inverting the sign of material parameters is a striking possibility arising from the concept of metamaterials. Here, we show that the electrical properties of a p-type semiconductor can be mimicked by a metamaterial solely made of an n-type semiconductor. By fabricating and characterizing three-dimensional simple-cubic microlattices composed of interlocked hollow semiconducting tori, we demonstrate that sign and magnitude of the effective metamaterial Hall coefficient can be adjusted via a tori separation parameter-in agreement with previous theoretical and numerical predictions...
January 6, 2017: Physical Review Letters
Jingjing Liu, Yanlong Yin, Longhai Yu, Yaocheng Shi, Di Liang, Daoxin Dai
Graphene is attractive for realizing optoelectronic devices, including photodetectors because of the unique advantages. It can easily co-work with other semiconductors to form a Schottky junction, in which the photo-carrier generated by light absorption in the semiconductor might be transported to the graphene layer efficiently by the build-in field. It changes the graphene conduction greatly and provides the possibility of realizing a graphene-based conductive-mode photodetector. Here we design and demonstrate a silicon-graphene conductive photodetector with improved responsivity and response speed...
January 20, 2017: Scientific Reports
J Baumann, C Herzog, M Spanier, D Grötzsch, L Lühl, K Witte, A Jonas, S Günther, F Förste, R Hartmann, M Huth, D Kalok, D Steigenhöfer, M Krämer, T Holz, R Dietsch, L Strüder, B Kanngießer, I Mantouvalou
Grazing incidence and grazing emission X-ray fluorescence spectroscopy (GI/GE-XRF) are techniques that enable nondestructive, quantitative analysis of elemental depth profiles with a resolution in the nanometer regime. A laboratory setup for soft X-ray GEXRF measurements is presented. Reasonable measurement times could be achieved by combining a highly brilliant laser produced plasma (LPP) source with a scanning-free GEXRF setup, providing a large solid angle of detection. The detector, a pnCCD, was operated in a single photon counting mode in order to utilize its energy dispersive properties...
January 10, 2017: Analytical Chemistry
Song Bai, Lili Wang, Zhengquan Li, Yujie Xiong
The facet-engineered surface and interface design for photocatalytic materials has been proven as a versatile approach to enhance their photocatalytic performance. This review article encompasses some recent advances in the facet engineering that has been performed to control the surface of mono-component semiconductor systems and to design the surface and interface structures of multi-component heterostructures toward photocatalytic applications. The review begins with some key points which should receive attention in the facet engineering on photocatalytic materials...
January 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
David Kiefer, Liyang Yu, Erik Fransson, Andrés Gómez, Daniel Primetzhofer, Aram Amassian, Mariano Campoy-Quiles, Christian Müller
Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm(-1) and Seebeck coefficient from 100 to 60 μV K(-1) upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends...
January 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Laipan Zhu, Longfei Wang, Fei Xue, Libo Chen, Jianqiang Fu, Xiaolong Feng, Tianfeng Li, Zhong Lin Wang
The piezo-phototronic effect is about the enhanced separation, transport, and recombination of the photogenerated carriers using the piezoelectric polarization charges present in piezoelectric-semiconductor materials. Here, it is presented that the piezo-phototronic effect can be effectively applied to improve the relative conversion efficiency of a flexible solar cell based on n-ZnO/p-SnS core-shell nanowire array for 37.3% under a moderate vertical pressure. The performance of the solar cell can be effectively enhanced by a gentle bending of the device, showing its potential for application in curly geometries...
January 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Chenguang Qiu, Zhiyong Zhang, Mengmeng Xiao, Yingjun Yang, Donglai Zhong, Lian-Mao Peng
High-performance top-gated carbon nanotube field-effect transistors (CNT FETs) with a gate length of 5 nanometers can be fabricated that perform better than silicon complementary metal-oxide semiconductor (CMOS) FETs at the same scale. A scaling trend study revealed that the scaled CNT-based devices, which use graphene contacts, can operate much faster and at much lower supply voltage (0.4 versus 0.7 volts) and with much smaller subthreshold slope (typically 73 millivolts per decade). The 5-nanometer CNT FETs approached the quantum limit of FETs by using only one electron per switching operation...
January 20, 2017: Science
Pooja D, Sonia Saini, Anupma Thakur, Baban Kumar, Sachin Tyagi, Manoj K Nayak
Carbon quantum dots (CQDs) have emerged out as promising fluorescent probes for hazardous heavy metals detection in recent past. In this study, water soluble CQDs were synthesized by facile microwave pyrolysis of citric acid & cysteamine, and functionalized with ditheritheritol to impart thiol functionalities at surface for selective detection of toxic arsenite in water. Microscopic analysis reveals that the synthesized CQDs are of uniform size (diameter ∼5nm) and confirmed to have surface SH groups by FT-IR...
January 12, 2017: Journal of Hazardous Materials
Hui Wang, Xianshun Sun, Dandan Li, Xiaodong Zhang, Shichuan Chen, Wei Shao, Yupeng Tian, Yi Xie
Excitonic effects, arising from the Coulomb interactions between photogenerated electrons and holes, dominate the optical excitation properties of semiconductors, whereas their influences on photocatalytic processes have seldom been discussed. In view of the competitive generation of exciton and hot carrier, exciton dissociation herein was proposed as an alternative strategy for hot-carrier harvesting in photocatalysts. Herein, by taking heptazine-based melon as an example, we verified that enhanced hot-carrier generation could be obtained in semicrystalline polymeric photocatalysts that contain abundant order-disorder interfaces, ascribing to the accelerated exciton dissociation...
January 19, 2017: Journal of the American Chemical Society
Yuanyuan Huang, Lipeng Zhu, Qiyi Zhao, Yaohui Guo, Zhaoyu Ren, Jin Tao Bai, Xin Long Xu
Surface optical rectification was observed from the layered semiconductor molybdenum disulfide (MoS2) crystal via terahertz (THz) time-domain surface emission spectroscopy under linearly polarized femtosecond laser excitation. The radiated THz amplitude of MoS2 has a linear dependence on ever-increasing pump fluence and thus quadratic with the pump electric field, which discriminates from the surface Dember field induced THz radiation in InAs and the transient photocurrent induced THz generation in graphite...
January 18, 2017: ACS Applied Materials & Interfaces
Jie Jian, Xuejing Wang, Leigang Li, Meng Fan, Wenrui Zhang, Jijie Huang, Zhimin Qi, Haiyan Wang
Vanadium dioxide (VO2) thin films with controlled thicknesses are deposited on c-cut sapphire substrates with Al-doped ZnO (AZO) buffer layers by pulsed laser deposition. The surface roughness of AZO buffer layers is varied by controlling oxygen pressure during growth. The strain in the VO2 lattice is found to be dependent on the VO2 thickness and the VO2/AZO interface roughness. The semiconductor-to-metal transition (SMT) properties of VO2 thin films are characterized and the transition temperature (Tc) is successfully tuned by the VO2 thickness as well as the VO2/AZO interface roughness...
January 18, 2017: ACS Applied Materials & Interfaces
Giovanni Ligorio, Marco Vittorio Nardi, Norbert Koch
The scaling of non-volatile memory (NVM) devices based on resistive filament switching to below 100 nm2 footprint area without employing cumbersome lithography is demonstrated. Nanocolumns of the organic semiconductor 4,4-bis[N-(1-naphthyl)-N-phenyl-amino]diphenyl (-NPD) were grown by glancing angle deposition on a silver electrode. Individual NVM devices were electrically characterized by conductive atomic force microscopy with the tip of a conductive cantilever serving as second electrode. The resistive switching mechanism is unambiguously attributed to Ag filament formation between the electrodes...
January 18, 2017: Nano Letters
Xiaojing Long, Yao Gao, Hongkun Tian, Chuandong Dou, Donghang Yan, Yanhou Geng, Jun Liu, Lixiang Wang
In this communication, we report a series of polymer semiconductors based on a novel electron-deficient building block, double B←N bridged bipyridine (BNBP). These polymers show ambipolar or unipolar n-channel charge-transporting characteristics with electron mobilities in the range of 0.02-0.32 cm(2) V(-1) s(-1) in organic thin film transistors.
January 18, 2017: Chemical Communications: Chem Comm
Resul Ozdemir, Donghee Choi, Mehmet Ozdemir, Hyekyoung Kim, Sinem Tuncel Kostakoğlu, Mustafa Erkartal, Hyungsug Kim, Choongik Kim, Hakan Usta
A new solution-processable and air-stable liquid-crystalline n-channel organic semiconductor (α,ω-2OD-TIFDMT) employing a donor-acceptor-donor (D-A-D) type of π-conjugation has been designed, synthesized, and fully characterized. The new semiconductor exhibits a low LUMO energy (-4.19 eV) and a narrow optical band gap (1.35 eV). Typical pseudo focal-conic fan-shaped texture of a hexagonal columnar liquid crystalline (LC) phase was observed over a wide temperature range. The spin-coated semiconductor thin-films shows the formation of large (~0...
January 17, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Toshiya Sakata, Yusuke Matsuse
Cellular dynamics is very closely related to ionic behaviors, most of which have been hardly monitored in real time, whereas semiconductor-based biosensors have the unique advantage of direct detection of ionic charges in a real-time and noninvasive manner. In this study, we monitored the invasion process of cancer cells into the vascular endothelial layer in real time by a label-free method using a field-effect transistor (FET) biosensor. Endothelial cells were cultured on the sensing surface of the FET gate, to form a basement membrane between the endothelial cells and the sensing surface...
January 18, 2017: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Mingjie Liu, Vasilii I Artyukhov, Boris I Yakobson
Recent production of long carbyne chains, concurrent with advances in synthesis of pure boron fullerenes and atom-thin layers, motivates an exploration of possible one-dimensional boron. By means of first-principles calculations we find two isomers- two-atom wide ribbon and single-atom chain-linked by a tension-driven (negative- pressure) transformation. We explore the stability and unusual properties of both phases, demonstrating mechanical stiffness on par with the highest-performing known nanomaterials, and a phase transition between stable 1D metal and an antiferromagnetic semiconductor, with the phase boundary effectively forming a stretchable 1D Schottky junction...
January 18, 2017: Journal of the American Chemical Society
Sigal Trattner, Anjali Chelliah, Peter Prinsen, Carrie B Ruzal-Shapiro, Yanping Xu, Sachin Jambawalikar, Maxwell Amurao, Andrew J Einstein
OBJECTIVE: The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children. MATERIALS AND METHODS: Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials...
January 17, 2017: AJR. American Journal of Roentgenology
Tao Li, Pankaj Sharma, Alexey Lipatov, Hyungwoo Lee, Jung-Woo Lee, Mikhail Y Zhuravlev, Tula R Paudel, Yuri A Genenko, Chang-Beom Eom, Evgeny Y Tsymbal, Alexander Sinitskii, Alexei Gruverman
Hybrid structures composed of ferroelectric thin films and functional two-dimensional (2D) materials may exhibit unique characteristics and reveal new phenomena due to the cross-interface coupling between their intrinsic properties. In this report, we demonstrate a symbiotic interplay between spontaneous polarization of the ultrathin BaTiO3 ferroelectric film and conductivity of the adjacent molybdenum disulfide (MoS2) layer, a 2D narrow-band semiconductor. Polarization-induced modulation of the electronic properties of MoS2 results in a giant tunneling electroresistance effect in the hybrid MoS2/BaTiO3/SrRuO3 ferroelectric tunnel junctions (FTJs) with an OFF/ON resistance ratio as high as 104 - a 50-fold increase in comparison with the same type of FTJs with metal electrodes...
January 17, 2017: Nano Letters
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