| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Corradini, M., et al.
(författare)
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Experimental apparatus for annihilation cross-section measurements of low energy antiprotons
- 2013
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 711, s. 12-20
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear physics program of the ASACUSA experiment at the Antiproton Decelerator (AD) at CERN is concerned with the measurements of antiproton-nuclei cross-sections at low energies (from 5.3 MeV down to the 100 keV region). These measurements are expected to contribute to understand the dynamics of the annihilation process. We give here a full description of the experimental apparatus used for the measurements at 5.3 MeV. © 2013 Elsevier B.V.
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| 3. |
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| 4. |
- Vomiero, Alberto, et al.
(författare)
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ZnO/ TiO2 nanonetwork as efficient photoanode in excitonic solar cells
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 95:19
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Tidskriftsartikel (refereegranskat)abstract
- An innovative nanonetwork composed of TiO2 nanoparticles and single-crystalline ZnO nanowires is demonstrated as efficient photoanode in excitonic solar cells. Such architecture benefits of the capability of high sensitizer loading offered by the nanoparticles and of the direct conduction path for electrons guaranteed by the nanowires. The combination of these features leads to improved light absorption, electron photogeneration, and charge collection. The nanonetwork was implemented in a dye-sensitized solar-cell architecture demonstrating threefold enhancement of the efficiency with respect to a nanowire photoanode of the same thickness. Cell efficiency of 1.6% was obtained in 1.5 μm thick nanonetwork. © 2009 American Institute of Physics.
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| 5. |
- Concina, Isabella, et al.
(författare)
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One pot synthesis of bi-linker stabilised CdSe quantum dots
- 2010
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 244
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Tidskriftsartikel (refereegranskat)abstract
- In this study we exploited the classic Murray's synthesis for generating a hydrophilic CdSe quantum dot system in a single step procedure, with the aim of directly obtaining a material responding to the characteristic of polarity required in many end applications. 6-phosphonohexanoic acid was used as both ligand for generating the active monomer during the synthesis of the quantum dots and final stabiliser. Diffraction measurements identified the cubic phase of cadmium selenide. Energy dispersive spectroscopy analysis revealed non-stoichiometric quantum dots, being the Cd/Se ratio 60/40. This feature suggests a configuration in which Cd2+ ions are present on the nanocrystal surface. Diffuse reflectance infrared Fourier transform analysis was applied in order to investigate the structure of the quantum dot system: the results indicate a configuration in which the carboxylic function of 6-phosphonohexanoic acid establishes only a partial interaction with the quantum dot surface, being set in a pseudo-ester configuration. © 2010 IOP Publishing Ltd.
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| 6. |
- Gisenti, A, et al.
(författare)
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Synthesis and characterization of Ag/CeO2 nanocomposites
- 2010
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Ingår i: Materials Research Society Symposium Proceedings. - : Materials Research Society. - 9781605112343 ; , s. 323-328
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Konferensbidrag (refereegranskat)abstract
- Two Ag/CeO2 nanocomposite samples were prepared by deposition-precipitation (Ag/Ce nominal atomic ratio = 0.03 and 0.12). XPS data suggest the possible presence of traces of Ce(III). Beside Ag (0), oxidized silver species are also revealed in the Ag/CeO2 sample with lower metal content. The deposition of metal increases surface hydroxylation and carbonation. Methanol interacts molecularly and dissociatively with the samples; oxidation products are observed from low temperature and depend on Ag content. Both the samples reveal a high activity in methanol complete oxidation; traces of partial oxidation products are observed in the sample with lower Ag content
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| 7. |
- Sberveglieri, G., et al.
(författare)
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Semiconducting tin oxide nanowires and thin films for Chemical Warfare Agents detection
- 2009
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 517:22, s. 6156-6160
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Tidskriftsartikel (refereegranskat)abstract
- In this work we report the preparation and structural characterization of tin oxide nanowires as functional materials for the development of chemical sensors. Aspects of material preparation relevant for gas sensing applications, such as the control of the wire diameter, are emphasized. The functional characterization is focused on the detection of Chemical Warfare Agents (CWAs) simulants, with particular regard to poisoning effects induced by dimethyl methyl phosphonate (DMMP), a simulant for Sarin nerve agent. Tin oxide thin films, prepared by means of rheotaxial growth and thermal oxidation (RGTO) technique, are used as reference to better compare the performance of nanowires with thin films traditionally used in gas sensing field. © 2009 Elsevier B.V. All rights reserved.
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| 8. |
- Vomiero, Alberto, et al.
(författare)
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Integration of metal oxide nanowires in dye sensitized solar cells
- 2009
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Ingår i: 2009 34th IEEE Photovoltaic Specialists Conference : (PVSC 2009). - Piscataway, NJ : IEEE Communications Society. - 9781424429509 ; , s. 001325-001326
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Konferensbidrag (refereegranskat)abstract
- One of the most promising architectures of third generation solar cells is integration of single crystalline nanowires as electron transporters in anodes of electrochemical cells.[1-3] The nanowire-based cells aim at significantly increase cell efficiency thanks to the higher mobility of electrons along the single crystalline lattice of the nanowires with respect to traditional polycrystalline networks, greatly reducing electron-hole recombination controllable by passivation, functionalization or coaxial coating of the nanowire. The nanonetworks have been integrated in DSCs using the traditional N719 dye and the I-3/I-3 redox couple. The functional properties of the cells under 1 sun irradiation have been compared with traditional polycrystalline TiO2 photoanodes. ©2009 IEEE.
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| 9. |
- Bianchi, S., et al.
(författare)
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Indium oxide quasi-monodimensional low temperature gas sensor
- 2006
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 118:1-2, s. 204-207
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the sensing properties of indium oxide nanostructures and tailored the deposition conditions in order to obtain nano-wires of indium oxide. We have comparatively tested the gas sensing properties of nano-wires with micrometric or even nanometric size. The micro-wires feature interesting gas sensitivity at room temperature, particularly in the case of nitrogen dioxide detection. The sensing performance is improved as the lateral dimension of the wire decreases. © 2006 Elsevier B.V. All rights reserved.
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| 10. |
- Comini, E., et al.
(författare)
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Functional nanowires of tin oxide
- 2007
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 89:1, s. 73-76
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Tidskriftsartikel (refereegranskat)abstract
- Quasi-one-dimensional nanostructures of tin oxide were produced in controlled conditions through condensation from the vapor phase. The preparation was assisted by noble metal catalysts and uniform single-crystalline nanowires were produced. The nucleation of nanowires was achieved at 470 °C, owing to the vapor-liquid-solid growth mechanism activated by the catalytic Pt clusters. The peculiar microstructural properties of these semiconducting metal oxide nanostructures will be summarized. The high aspect ratio and the high degree of crystallinity achieved for the nanowires foresee their functional exploitation. © 2007 Springer-Verlag.
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| 11. |
- Comini, E., et al.
(författare)
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Quasi-one dimensional metal oxide semiconductors : Preparation, characterization and application as chemical sensors
- 2009
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Ingår i: Progress in Materials Science. - : Elsevier BV. - 0079-6425 .- 1873-2208. ; 54:1, s. 1-67
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Tidskriftsartikel (refereegranskat)abstract
- The continuous evolution of nanotechnology in these years led to the production of quasi-one dimensional (Q1D) structures in a variety of morphologies such as nanowires, core-shell nanowires, nanotubes, nanobelts, hierarchical structures, nanorods, nanorings. In particular, metal oxides (MOX) are attracting an increasing interest for both fundamental and applied science. MOX Q1D are crystalline structures with well-defined chemical composition, surface terminations, free from dislocation and other extended defects. In addition, nanowires may exhibit physical properties which are significantly different from their coarse-grained polycrystalline counterpart because of their nanosized dimensions. Surface effects dominate due to the increase of their specific surface, which leads to the enhancement of the surface related properties, such as catalytic activity or surface adsorption: key properties for superior chemical sensors production. High degree of crystallinity and atomic sharp terminations make nanowires very promising for the development of a new generation of gas sensors reducing instabilities, typical in polycrystalline systems, associated with grain coalescence and drift in electrical properties. These sensitive nanocrystals may be used as resistors, and in FET based or optical based gas sensors. This article presents an up-to-date review of Q1D metal oxide materials research for gas sensors application, due to the great research effort in the field it could not cover all the interesting works reported, the ones that, according to the authors, are going to contribute to this field's further development were selected and described. © 2008 Elsevier Ltd. All rights reserved.
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| 12. |
- Guidi, V., et al.
(författare)
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Diffusion-equation approach to describe ionic mobility in nanostructured titania
- 2005
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 72:15
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Tidskriftsartikel (refereegranskat)abstract
- The linear diffusion equation is proposed to provide a macroscopic description of ionic mobility in nanostructures. This approach has been demonstrated to account for diffusion processes in nanostructured titania-based films. The formulation of a classical diffusion inverse problem and the experimental determination of concentration profiles by Rutherford backscattering spectrometry were used for the purpose. The model has allowed the measurement of the diffusion coefficient of W and Mo impurities in titania. © 2005 The American Physical Society.
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| 13. |
- Jimenez-Cadena, G., et al.
(författare)
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Synthesis of different ZnO nanostructures by modified PVD process and potential use for dye-sensitized solar cells
- 2010
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 124:1, s. 694-698
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Tidskriftsartikel (refereegranskat)abstract
- Different ZnO nanostructures were synthesized by physical vapor deposition on glass-ITO substrates. Nanowires and nanosheets were obtained by a single step process using gold nanoparticles and gold thin films as catalyst. 3D nanoarchitectures were obtained by a two-step modified process; the morphology of these structures depends on the catalyst used for the second deposition: gold nanoparticles or zinc acetate seeds. All the nanostructures were characterized by SEM and TEM analyses, which showed the different morphology under same conditions of temperature, pressure, oxide precursor and deposition time. Dye-sensitized solar cells based on these ZnO structures were successfully assembled, using N179 as sensitizer with efficiencies between 0.1% and 0.5%. In spite of the low efficiency of the cells, a novel double PVD process is presented and its integration capability into solar cell devices has been proven. © 2010 Elsevier B.V. All rights reserved.
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| 14. |
- Ortolani, L., et al.
(författare)
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Electrical and holographic characterization of gold catalyzed titania-based layers
- 2007
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 27:13-15, s. 4131-4134
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Tidskriftsartikel (refereegranskat)abstract
- The sensing properties of titanium oxide have been tailored through doping with niobium and dispersion of nanosized Au particles. The microstructural features of the gold-titania composite system were investigated by transmission electron microscopy and the electronic properties of Au nanoparticles were specifically investigated by electron holography. Holography provides quantitative determination of the mean inner potential with the high spatial resolution attained by transmission electron microscopy. Large increase of the mean inner potential has been measured for ultra small Au particles arising from the nano-scale assembling. Electrical tests were performed at low operating temperatures and demonstrated the considerable enhancement of CO sensitivity owing to the extremely high catalytic activity of gold particles. © 2007 Elsevier Ltd. All rights reserved.
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| 15. |
- Sberveglieri, G., et al.
(författare)
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Preparation of transparent conducting oxide nanostructures for dye-sensitized solar cells
- 2008
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Ingår i: 2008 33rd IEEE Photovoltaic Specialists Conference. - Piscataway, NJ : IEEE Communications Society. - 9781424416417
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Konferensbidrag (refereegranskat)abstract
- ZnO, SnO2, Indium-tin oxide (ITO) nanostructures have been produced on glass substrates coated with a transparent conducting oxide (TCO) electrode for application in dye sensitized solar cells (DSC). Quasi one-dimensional (1D) nanostructures of different TCOs have been synthesized using the vapour transport-and-condensation technique. Nanostructures with different shape and aspect-ratio can be obtained by properly tailoring of the condensation conditions and the substrate preparation. A multi technique approach, using electron microscopy and DC electrical characterization, has been applied for micro-structural and functional characterization of the nanostructures. © 2008 IEEE.
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| 16. |
- Sberveglieri, G., et al.
(författare)
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Synthesis and characterization of semiconducting nanowires for gas sensing
- 2007
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 121:1, s. 208-213
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Tidskriftsartikel (refereegranskat)abstract
- Quasi one-dimensional nanostructures of semiconducting metal oxides are promising for the development of nano-devices. Tin, indium, and zinc oxides were produced in form of single-crystalline nanowires through condensation from vapor phase. Such a growth occurs in controlled thermodynamical condition and size reduction effects on the electrical and optical response to gases have been exploited. Preparation, microstructural, and electrical characterization of nanowires are presented and the peculiarities of these innovative structures are highlighted. © 2006 Elsevier B.V. All rights reserved.
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| 17. |
- Vomiero, Alberto, et al.
(författare)
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Application of ion beam analysis to the selective sublimation processing of thin films for gas sensing
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 249:1-2 SPEC. ISS., s. 302-305
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Tidskriftsartikel (refereegranskat)abstract
- Ion beam analysis was successfully applied to a novel technique, named selective sublimation process (SSP), for deposition of nanostructured gas-sensing films through reactive sputtering. The method consists of the co-deposition of a mixed oxide, one of which has a relatively low sublimation temperature. Annealing at suitable temperature causes the sublimation of the most volatile compound, leaving a layer with adjustable composition. The appropriate choice of thermal treatments and the consequent tailoring of the composition play a crucial role in the determination of the microstructural properties. We developed a model based on diffusion equations that provides a useful guide to control the deposition and processing parameters and we applied the model on the systems TiO2-WO3 and TiO2-MoO3. Rutherford backscattering (RBS) was demonstrated to be effective for the characterization of the diffusion and sublimation processes during SSP. Experimental results fully agree with theoretical prediction, and allowed the calculation of all the parameters involved in SSP. © 2006 Elsevier B.V. All rights reserved.
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| 18. |
- Vomiero, Alberto, et al.
(författare)
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In2O3 nanowires for gas sensors : morphology and sensing characterisation
- 2007
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 515:23, s. 8356-8359
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Tidskriftsartikel (refereegranskat)abstract
- Thin and densely packed In2O3 nanowires have been synthesised on alumina substrates via transport and condensation method, starting from nanoparticles of indium or palladium as catalysts for the condensation process. Indium catalyst promoted wires growth according to vapour-solid (VS) mechanism, while palladium catalyst leads to wires formation based on vapour-liquid-solid (VLS) condensation. Electron microscopy and related diffraction analysis demonstrated that the wires are monocrystalline, with atomically sharp termination of the lateral sides, and are free from extended defects. The sensing properties of nanowires bundles have been tested to acetone using the flow through technique in the temperature range between 100 and 500 °C. © 2007 Elsevier B.V. All rights reserved.
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| 19. |
- Vomiero, Alberto, et al.
(författare)
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Nanoscience for innovative dye sensitized solar cells
- 2010
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Ingår i: ISOPE-2010, Beijing. - Cupertino, Calif : ISOFE. - 9781880653777 ; , s. 538-541
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Konferensbidrag (refereegranskat)abstract
- Innovative nanonetwork composed of oxide nanoparticles and single-crystalline ZnO nanowires is demonstrated as efficient photoanode in excitonic solar cells. Such architecture benefits of the capability of high sensitizer loading offered by the nanoparticles and of the direct conduction path for electrons guaranteed by the single-crystal nanowires. The combination of these features leads to improved light absorption, electron photogeneration, and charge collection. Various types of nanonetwork were implemented in a dye-sensitized solar cell architecture demonstrating great enhancement of the efficiency with respect to a nanowire photoanode of the same thickness. © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).
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| 20. |
- Vomiero, Alberto, et al.
(författare)
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One-dimensional nanostructured oxides for thermoelectric applications and excitonic solar cells
- 2012
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855. ; 1:3, s. 372-390
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Tidskriftsartikel (refereegranskat)abstract
- Among the most interesting features offered by one-dimensional (1D) nanostructured oxides are their functional properties that can be usefully exploited in the field of energy conversion, in applications such as thermoelectrics and excitonic solar cells. Peculiar characteristics of 1D oxide structures with respect to polycrystalline or bulk counterpart, mainly related to their adjustable electronic conduction, render them strong candidates for the next generation of energy conversion devices. Furthermore, many of these materials are characterized by low-cost production, are non-toxic and relatively easy to produce, allowing a good perspective in large-scale assembly for the fabrication of end-user devices. In this paper we review the most recent achievements on 1D nanostructured oxides applied to thermoelectric devices and excitonic solar cells, highlighting the benefits offered by 1D shape on the functional properties of the devices and the possibility to manage energy transduction mechanisms in more efficient ways. © 2012 Elsevier Ltd.
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| 21. |
- Vomiero, Alberto, et al.
(författare)
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Preparation of radial and longitudinal nanosized heterostructures of in2O3 and SnO2
- 2007
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 7:12, s. 3553-3558
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Tidskriftsartikel (refereegranskat)abstract
- Radial and longitudinal nanosized In2O3-SnO 2 heterostructures were produced by applying a suitable methodology of transport and condensation. Sequential evaporation-condensation over In-seeded alumina promotes the formation of a radial heterostructure, driven by the direct vapor-solid growth mechanism. The single-crystalline In 2O3 nanowire nucleates and acts as the backbone for condensation of a polycrystalline SnO2 sheath. Fabrication of longitudinal heterostructures over sapphire is achieved through the application of a nanosized gold catalyst: the gold particles promote nucleation according to the vapor-liquid-solid mechanism, and lead to the formation of single-crystalline In2O3 nanowires with a gold droplet at the apex. Gold maintains its catalytic activity even during subsequent evaporation of SnO2 and induces the nucleation of a SnO2 single-crystal nanowire from the termination of an In2O3 nanowire. The electrical characterization of the longitudinally assembled In2O3-SnO2 structure highlighted a peculiar behavior, as the heterojunction of two n-type semiconducting oxides was revealed, tin oxide being reversely biased. These results hold great potential for the application of precisely shaped heterojunctions. © 2007 American Chemical Society.
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