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185 results on '"Zavelani-Rossi, Margherita"'

51. Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals

Author

Pinchetti, Valerio, primary, Meinardi, Francesco, additional, Camellini, Andrea, additional, Sirigu, Gianluca, additional, Christodoulou, Sotirios, additional, Bae, Wan Ki, additional, De Donato, Francesco, additional, Manna, Liberato, additional, Zavelani-Rossi, Margherita, additional, Moreels, Iwan, additional, Klimov, Victor I., additional, and Brovelli, Sergio, additional

Published
2016
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52. Ultrafast Optical Mapping of Nonlinear Plasmon Dynamics in Cu 2– x Se Nanoparticles

Author

Della Valle, Giuseppe, Scotognella, Francesco, Kandada, Ajay Ram Srimath, Zavelani-Rossi, Margherita, Dorfs, Dirk, Miszta, Karol, Conforti, Matteo, Longhi, Stefano, Manna, Liberato, Lanzani, Guglielmo, Tassone, Francesco, Politecnico di Milano [Milan] (POLIMI), Dipartimento di Ingegneria dell'Informazione [Brescia], and Università degli Studi di Brescia [Brescia]

Subjects
[PHYS]Physics [physics], Materials science, business.industry, Nanoparticle, Physics::Optics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Molecular physics, 0104 chemical sciences, Wavelength, Nonlinear system, Optics, Nanocrystal, General Materials Science, Physical and Theoretical Chemistry, Surface plasmon resonance, 0210 nano-technology, business, Ultrashort pulse, Excitation, Plasmon
Abstract

International audience; We report on the experimental investigation and theoretical modeling of the ultrafast nonlinear optical response exhibited by Cu2-xSe nanoparticles in a broad range of wavelengths, from the red to the near-infrared, under excitation with intense femtosecond-laser pulses. The ultrafast dynamics of the localized plasmon resonance of the system is mapped by pump-probe differential transmission measurements. Deviations from theoretical predictions based on standard two-temperature model (TTM) are revealed in the subpicosecond time-scale where the nonlinear phenomenon is more pronounced. The key-role played by nonthermalized carriers is investigated in detail on the basis of an extended TTM.

Published
2013
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53. Self-assembled CdSe/CdS nanorod micro-lasers fabricated from solution by capillary jet deposition

Author

ZAVELANI ROSSI, Margherita, Krahne, R., DELLA VALLE, Giuseppe, Longhi, Stefano, Franchini, I. R., Girardo, S., Scotognella, Francesco, Pisignano, D., Manna, L., Lanzani, Guglielmo, Tassone, F., M., Zavelani Rossi, R., Krahne, G., Della Valle, S., Longhi, I. R., Franchini, S., Girardo, F., Scotognella, Pisignano, Dario, L., Manna, G., Lanzani, and F., Tassone

Published
2012
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54. Ultrafast Exciton Dynamics in Colloidal CdSe/CdS Octapod Shaped Nanocrystals

Author

Scotognella, Francesco, Miszta, Karol, Dorfs, Dirk, Zavelani-Rossi, Margherita, Brescia, Rosaria, Marras, Sergio, Manna, Liberato, Lanzani, Guglielmo, and Tassone, Francesco

Abstract

We studied the carrier dynamics in colloidal octapod-shaped cadmium selenide/cadmium sulfide (CdSe/CdS) nanocrystals in the solution phase via pump–probe optical techniques with subpicosecond resolution. We could resolve bleaching from two different types of electronic states having distinct dynamics and assigned them to states delocalized in the pods and mildly localized in the core based on the good agreement of energies found with effective mass modeling. Contrary to other CdSe/CdS core/shell nanocrystals, such a mild localization has geometrical origins as the best agreement was found for negligible conduction band offset. Moreover, even though the large surface of the CdSe/CdS heterointerface results into a weak signature of electron trapping in the bleaching spectrum, we found that a relevant fraction of electrons do remain delocalized in pod states for long times and are thus available for diffusion in photovoltaic applications where the highly branched geometry is expected to advantageously yield to effective percolation in dense assemblies.

Published
2024
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57. Transient Optical Response of a Single Gold Nanoantenna: The Role of Plasmon Detuning

Author

Zavelani-Rossi, Margherita, primary, Polli, Dario, additional, Kochtcheev, Serguei, additional, Baudrion, Anne-Laure, additional, Béal, Jérémie, additional, Kumar, Vikas, additional, Molotokaite, Egle, additional, Marangoni, Marco, additional, Longhi, Stefano, additional, Cerullo, Giulio, additional, Adam, Pierre-Michel, additional, and Della Valle, Giuseppe, additional

Published
2015
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70. Plasmon Dynamics in Colloidal Cu2–xSe Nanocrystals

Author

Scotognella, Francesco, primary, Della Valle, Giuseppe, additional, Srimath Kandada, Ajay Ram, additional, Dorfs, Dirk, additional, Zavelani-Rossi, Margherita, additional, Conforti, Matteo, additional, Miszta, Karol, additional, Comin, Alberto, additional, Korobchevskaya, Kseniya, additional, Lanzani, Guglielmo, additional, Manna, Liberato, additional, and Tassone, Francesco, additional

Published
2011
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74. Two-Photon Poly(phenylenevinylene) DFB Laser

Author

Scotognella, Francesco, primary, Puzzo, Daniel P., additional, Zavelani-Rossi, Margherita, additional, Clark, Jenny, additional, Sebastian, Maria, additional, Ozin, Geoffrey A., additional, and Lanzani, Guglielmo, additional

Published
2010
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82. Ultrafast optical modulation of polymer nano-structured lasers

Author

Perissinotto, Stefano, primary, Carvelli, Marco, additional, Zavelani-Rossi, Margherita, additional, Lanzani, Guglielmo, additional, Bertarelli, Chiara, additional, Zerbi, Giuseppe, additional, Salerno, Marco, additional, Troisi, Luca, additional, and Gigli, Giuseppe, additional

Published
2008
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86. Mapping local field distribution at metal nanostructures by near-field second-harmonic generation

Author

Celebrano, Michele, primary, Zavelani-Rossi, Margherita, additional, Biagioni, Paolo, additional, Polli, Dario, additional, Finazzi, Marco, additional, Duò, Lamberto, additional, Cerullo, Giulio, additional, Labardi, Massimiliano, additional, Allegrini, Maria, additional, Grand, Johan, additional, Royer, Pascal, additional, and Adam, Pierre-Michel, additional

Published
2007
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93. Tuning the transient opto-electronic properties of few-layer MoS2 nanosheets via substrate nano-patterning.

Author

Michinel, H., Costa, M.F., Frazao, O., Camellini, Andrea, Mennucci, Carlo, Mazzanti, Andrea, Martella, Christian, Lamperti, Alessio, Molle, Alessandro, Buatier de Mongeot, Francesco, Della Valle, Giuseppe, and Zavelani-Rossi, Margherita

Subjects
NANOPATTERNING, IONIC liquids, PLASMONICS, PHOTOLUMINESCENCE, OPTOFLUIDICS
Abstract

We study the optical properties of Molybdenum Disulphide nanosheets deposited by chemical vapor deposition onto a nanopatterned substrate endowed with a uniaxial corrugation. The uniaxial nanocorrugation leads to a polarization dependence in steady state and an anisotropic relaxation around the C resonance. Finite element numerical simulations allow to better disclose the scenario. Our findings point towards new possibilities for the manipulation of the optical properties of two-dimensional transition metal dichalcogenides via substrate nanopatterning. [ABSTRACT FROM AUTHOR]

Published
2020
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96. Coherent Dynamics of Photoexcited Green Fluorescent Proteins

Author

Cinelli, Riccardo A. G., primary, Tozzini, Valentina, additional, Pellegrini, Vittorio, additional, Beltram, Fabio, additional, Cerullo, Giulio, additional, Zavelani-Rossi, Margherita, additional, De Silvestri, Sandro, additional, Tyagi, Mudit, additional, and Giacca, Mauro, additional

Published
2001
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98. Evidence for the Band‐Edge Exciton of CuInS2 Nanocrystals Enables Record Efficient Large‐Area Luminescent Solar Concentrators.

Author

Anand, Abhinav, Zaffalon, Matteo L., Gariano, Graziella, Camellini, Andrea, Gandini, Marina, Brescia, Rosaria, Capitani, Chiara, Bruni, Francesco, Pinchetti, Valerio, Zavelani‐Rossi, Margherita, Meinardi, Francesco, Crooker, Scott A., and Brovelli, Sergio

Subjects
MONTE Carlo method, SOLAR concentrators, EXCITON theory, STOKES shift, NANOCRYSTALS, SOLAR cells, VALENCE bands
Abstract

Ternary I‐III‐VI2 nanocrystals (NCs), such as CuInS2, are receiving attention as heavy‐metals‐free materials for solar cells, luminescent solar concentrators (LSCs), LEDs, and bio‐imaging. The origin of the optical properties of CuInS2 NCs are however not fully understood. A recent theoretical model suggests that their characteristic Stokes‐shifted and long‐lived luminescence arises from the structure of the valence band (VB) and predicts distinctive optical behaviours in defect‐free NCs: the quadratic dependence of the radiative decay rate and the Stokes shift on the NC radius. If confirmed, this would have crucial implications for LSCs as the solar spectral coverage ensured by low‐bandgap NCs would be accompanied by increased re‐absorption losses. Here, by studying stoichiometric CuInS2 NCs, it is revealed for the first time the spectroscopic signatures predicted for the free band‐edge exciton, thus supporting the VB‐structure model. At very low temperatures, the NCs also show dark‐state emission likely originating from enhanced electron‐hole spin interaction. The impact of the observed optical behaviours on LSCs is evaluated by Monte Carlo ray‐tracing simulations. Based on the emerging device design guidelines, optical‐grade large‐area (30×30 cm2) LSCs with optical power efficiency (OPE) as high as 6.8% are fabricated, corresponding to the highest value reported to date for large‐area devices. [ABSTRACT FROM AUTHOR]

Published
2020
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99. Band-edge ultrafast pump-probe spectroscopy of core/shell CdSe/CdS rods: assessing electron delocalization by effective mass calculations.

Author

Lupo MG, Scotognella F, Zavelani-Rossi M, Lanzani G, Manna L, and Tassone F

Abstract

CdSe/CdS dot/rods nanocrystals show interesting physical properties related to the band-alignment at the hetero-interface, which controls the band-edge electron delocalization over the rods. Here the differential transmission spectra of CdSe/CdS nanorod samples with different core sizes have been measured using excitation resonant to the core transition. The photo bleaching ratio between dot and rod transitions increases with the dot size, indicating a trend towards electron localization. This trend has been further quantified by performing effective mass calculations in which the conduction band misalignment was varied in order to reproduce the observed bleaching feature ratio. The best agreement was found for negligible conduction band misalignment for small dots of around 2.3 nm in diameter, and about -0.1 eV misalignment was estimated for the larger dots, above 3.5 nm in diameter. This shows that the band misalignment might be dependent on the geometry of the system, and we argue that this might be related to different strain developed at the hetero-interface.

Published
2012
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100. Distributed feedback lasing from a composite poly(phenylene vinylene)-nanoparticle one-dimensional photonic crystal.

Author

Puzzo DP, Scotognella F, Zavelani-Rossi M, Sebastian M, Lough AJ, Manners I, Lanzani G, Tubino R, and Ozin GA

Subjects
Crystallization methods, Equipment Design, Equipment Failure Analysis, Feedback, Materials Testing, Particle Size, Photons, Scattering, Radiation, Lasers, Nanostructures chemistry, Nanostructures ultrastructure, Nanotechnology instrumentation, Polymers chemistry
Abstract

Nanoparticle one-dimensional photonic crystals exhibit intense, broadband reflectivity coupled with a unique mesoporosity. The latter property allows for infiltration of the one-dimensional photonic crystal with functional materials, such as emitting polymers, which in turn can lead to the fabrication of composites whereby the emitter's emission can be modulated by the photon density of states of the photonic crystal. We exploit this interaction in order to produce efficient distributed feedback lasing from a composite poly(phenylene vinylene)-infiltrated nanoparticle one-dimensional photonic crystal.

Published
2009
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