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Horsley S.A.R.,University of Exeter | Wu J.-H.,Jilin University | Artoni M.,Instituto Nazionale Of Ottica | Artoni M.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | La Rocca G.C.,Normal School of Pisa
Physical Review Letters | Year: 2013

Reciprocity is fundamental to light transport and is a concept that holds also in rather complex systems. Yet, reciprocity can be switched off even in linear, isotropic, and passive media by setting the material structure into motion. In highly dispersive multilayers this leads to a fairly large forward-backward asymmetry in the pulse transmission. Moreover, in multilevel systems, this transport phenomenon can be all-optically enhanced. For atomic multilayer structures made of three-level cold Rb87 atoms, for instance, forward-backward transmission contrast around 95% can be obtained already at atomic speeds in the meter per second range. The scheme we illustrate may open up avenues for optical isolation that were not previously accessible. © 2013 American Physical Society.


Wu J.-H.,Jilin University | Horsley S.A.R.,University of Exeter | Artoni M.,European Laboratory for Nonlinear Spectroscopy | Artoni M.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | La Rocca G.C.,Normal School of Pisa
Light: Science and Applications | Year: 2013

The typically tiny effect of radiation damping on a moving body can be amplified to a favorable extent by exploiting the sharp reflectivity slope at one edge of an optically induced stop-band in atoms loaded into an optical lattice. In this paper, this phenomenon is demonstrated for the periodically trapped and coherently driven cold 87Rb atoms, where radiation damping might be much larger than that anticipated in previous proposals and become comparable with radiation pressure. Such an enhancement could be observed even at speeds of only a few meters per second with less than 1.0% absorption, making radiation damping experimentally accessible. © 2013 CIOMP. All rights reserved.


Braga A.,Jaume I University | Braga A.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Gimenez S.,Jaume I University | Concina I.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2011

The use of narrow band gap semiconductors such as PbS may expand the light absorption range to the near-infrared region in quantum-dot-sensitized solar cells (QDSCs), increasing the generated photocurrent. However, the application of PbS as a sensitizer in QDSCs causes some problems of stability and high recombination. Here, we show that the direct growth of a CdS coating layer on previously deposited PbS by the simple method of successive ionic layer adsorption and reaction (SILAR) minimizes these problems. A remarkable short-circuit current density for PbS/CdS QDSCs is demonstrated, ∼11 mA/cm2, compared to that of PbS QDSCs, with photocurrents lower than 4 mA/cm2, using polysulfide electrolyte in both cells. The cell efficiency reached a promising 2.21% under 1 sun of simulated irradiation (AM1.5G, 100 mW/cm2). Enhancement of the solar cell performance beyond the arithmetic addition of the efficiencies of the single constituents (PbS and CdS) is demonstrated for the nanocomposite PbS/CdS configuration. PbS dramatically increases the obtained photocurrents, and the CdS coating stabilizes the solar cell behavior. © 2011 American Chemical Society.


Kholmanov I.N.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Edgeworth J.,University of Texas at Austin | Cavaliere E.,University of Brescia | Gavioli L.,University of Brescia | And 2 more authors.
Advanced Materials | Year: 2011

Studies of the healing of artificial defects in the surface of highly oriented pyrolitic graphite (HOPG) by chemical vapor deposition (CVD) of acetylene show that only single-layer depth defects could be healed completely during the CVD treatment. A promising method is introduced for defect control in surfaces of graphite, graphene, and graphene-based materials, with important implications for their application. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zappa D.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Comini E.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Sberveglieri G.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Nanotechnology | Year: 2013

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases. Functional measurements showed very good sensing performances towards ethanol and acetone at 500°C, and NO2 at 200°C, indirectly confirming the n-type behaviour of the material. The influence of the humidity on the response has been explored. In practical conditions the interference of humidity is very small, and could be neglected in many applications. Simultaneous measurements on different devices from the same batch confirm the high reproducibility of the response within the batch. © 2013 IOP Publishing Ltd.


Araneo R.,University of Rome La Sapienza | Falconi C.,University of Rome Tor Vergata | Falconi C.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Nanotechnology | Year: 2013

Quasi-1D piezoelectric nanostructures may offer unprecedented sensitivity for transducing minuscule input mechanical forces into high output voltages due to both scaling laws and increased piezoelectric coefficients. However, until now both theoretical and experimental studies have suggested that, for a given mechanical force, lateral bending of piezoelectric nanowires results in lower output electric potentials than vertical compression. Here we demonstrate that this result only applies to nanostructures with a constant cross-section. Moreover, though it is commonly believed that the output electric potential of a strained piezo-semiconductive device can only be reduced by the presence of free charges, we show that the output piezopotential of laterally bent tapered nanostructures, with typical doping levels and very small input forces, can be even increased up to two times by free charges. Our analyses confirm that, though not optimal for piezoelectric energy harvesting, lateral bending of tapered nanostructures with typical doping levels can be ideal for transducing tiny input mechanical forces into high and accessible piezopotentials. Our results provide guidelines for designing high-performance piezo-nano-devices for energy harvesting, mechanical sensing, piezotronics, piezo-phototronics, and piezo-controlled chemical reactions, among others. © 2013 IOP Publishing Ltd.


Comini E.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Sberveglieri G.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Materials Today | Year: 2010

It is almost a decade since the first presentation of metal oxide nanowires as chemical sensors. Significant advances have been made both in terms of preparation procedures and their integration into functional sensing devices, whilst the progress in their fundamental understanding of functional properties has been slow. In fact, the full integration still remains a challenge that has been wisely approached in different ways. In this article we review the most recent developments in bottom up and top down approaches for applications of chemical sensors. © 2010 Elsevier Ltd.


Memarian N.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Concina I.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Braga A.,CNR Institute of Acoustics and Sensors Orso Mario Corbino | Rozati S.M.,Guilan University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Spray pyrolysis is effective in the formation of a nanoengineered photoanode. An unprecedented photoconversion efficiency of 7.5-% for ZnO-based dye-sensitized cells was achieved on a photoelectrode consisting of polydispersed ZnO aggregates of nanocrystallites over a compact ZnO buffer layer at a firing temperature of 450°C. FTO= fluorine-doped tin oxide. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Comini E.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Sensors (Switzerland) | Year: 2013

Metal oxide nanowires are very promising active materials for different applications, especially in the field of gas sensors. Advances in fabrication technologies now allow the preparation of nanowires on flexible substrates, expanding the potential market of the resulting sensors. The critical steps for the large-scale preparation of reliable sensing devices are the elimination of high temperatures processes and the stretchability of the entire final device, including the active material. Direct growth on flexible substrates and post-growth procedures have been successfully used for the preparation of gas sensors. The paper will summarize the procedures used for the preparation of flexible and wearable gas sensors prototypes with an overlook of the challenges and the future perspectives concerning this field. © 2013 by the authors; licensee MDPI, Basel, Switzerland.


Araneo R.,University of Rome La Sapienza | Lovat G.,University of Rome La Sapienza | Burghignoli P.,University of Rome La Sapienza | Falconi C.,University of Rome Tor Vergata | Falconi C.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Advanced Materials | Year: 2012

The piezopotential in floating, homogeneous, quasi-1D piezo-semiconductive nanostructures under axial stress is an anti-symmetric (i.e., odd) function of force. Here, after introducing piezo-nano-devices with floating electrodes for maximum piezo-potential, we show that breaking the anti-symmetric nature of the piezopotential-force relation, for instance by using conical nanowires, can lead to better nanogenerators, piezotronic and piezophototronic devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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