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  • 151.
    Comini, Elisabetta
    et al.
    INFM-CNR Sensor Lab.
    Baratto, Camilla
    INFM-CNR Sensor Lab.
    Faglia, Guido
    INFM-CNR Sensor Lab.
    Ferroni, Matteo
    INFM-CNR Sensor Lab.
    Vomiero, Alberto
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Sberveglieri, Giorgio
    INFM-CNR Sensor Lab.
    Highly sensitive single crystalline metal oxide nanowires gas sensors2006Inngår i: Proceedings of the 2006 Conference on Optoelectronic and Microelectronic Materials and Devices: 6-8 December 2006, Perth, Australia., Piscataway, NJ: IEEE Communications Society, 2006, s. 315-320, artikkel-id 4429946Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Interest in nanowires of metal oxide oxides has been exponentially growing in the last years, due to the attracting potential of application in electronic, optical and sensor field. We have focused our attention on the sensing properties of semiconducting nanowires as conductometric and optical gas sensors. Single crystal nanostructures In2O3, SnO 2, and ZnO were synthesized to explore and study their capability in form of multi-nanowires sensors. © 2006 IEEE.

  • 152.
    Comini, Elisabetta
    et al.
    CNR IDASC SENSOR Lab.
    Faglia, Guido
    CNR IDASC SENSOR Lab.
    Ferroni, Matteo
    CNR IDASC SENSOR Lab.
    Ponzoni, Andrea
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    INFM-CNR Sensor Lab.
    Sberveglieri, Giorgio
    CNR IDASC SENSOR Lab.
    Metal oxide nanowires: Preparation and application in gas sensing2009Inngår i: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 305, nr 1-2, s. 170-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quasi one-dimensional nanowires of metal oxides are promising for the development of nano-devices. Sn, In, and Zn oxides were produced in form of single-crystalline nanowires through condensation from vapor phase. Furthermore longitudinal and radial heterostructures have been prepared. Nanowires growth occurs in controlled condition and allows the exploitation of size reduction effects on the electrical response to gases. Preparation, microstructural, morphological and electrical characterizations of nanowires are presented and the peculiarities of these innovative structures are highlighted. © 2009 Elsevier B.V. All rights reserved.

  • 153.
    Comini, Elisabetta
    et al.
    INFM-CNR Sensor Lab.
    Ferroni, Matteo
    INFM-CNR Sensor Lab.
    Guidi, Vincenzo
    INFM-CNR Sensor Lab.
    Vomiero, Alberto
    INFN - Legnaro National Laboratories.
    Merli, Pier Giorgio
    CNR.
    Morandi, Vittorio
    CNR.
    Sacerdoti, Michele
    Dipartimento di Scienze della Terra, via Laterina 8, 53100 Siena.
    Mea, Gianantonio Della
    INFN - Legnaro National Laboratories.
    Sberveglieri, Giorgio
    INFM-CNR Sensor Lab.
    Effects of Ta/Nb-doping on titania-based thin films for gas-sensing2005Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 108, nr 1-2 SPEC. ISS., s. 21-28Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thin films of titania with the addition of niobium and tantalum have been achieved by reactive sputtering process. Structural and morphological studies have been carried out by means of XRD, RBS, TEM and AFM in order to correlate the microstructural features to the sensing performance of the layers. The films proved sensitive to ethanol and carbon monoxide and ammonia. In the case of niobium addition, it was shown that annealing temperature and niobium content strongly influence the gas response of the films converting a n-type response, which is typical of pure TiO2 and of most of metal-oxide sensors, to a p-type response; this peculiarity is crucial for the discrimination of different gases. In the case of tantalum addition, the annealing treatment at 800 °C led only to a phase transformation that reduced the sensing performance of the layer. High sensitivity to CO is achieved with anatase or mixed anatase and rutile phases, while the rutile phase only exhibit a low gas sensitivity. © 2005 Elsevier B.V. All rights reserved.

  • 154.
    Concina, Isabella
    et al.
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Bornsek, M
    Pivovarna Union Dd, Ljubljana.
    Baccilliere, S
    ARPAV, Dipartimento Reg, Lab SL di Padova.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab, University of Brescia.
    Gobbi, Emanuela
    Biodivers SPA, Brescia,, Univ Udine.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Alicyclobacillus spp Detection in soft drinks by Electronic Nose2010Inngår i: Food Research International, ISSN 0963-9969, E-ISSN 1873-7145, Vol. 43, nr 8, s. 2108-214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper the skill of an electronic nose to early diagnose the natural contamination by Alicyclobacillus spp in commercial flavoured drinks is presented The instrument was able to identify contaminated products at very low bacterial loads (tens of copies/ml) with an excellent classification rate (almost 100%) The identification of Alicyclobacillus spp by means of the electronic nose was not based on the analysis of the secondary metabolites as it is done by classical analytical techniques thus allowing a surprising capability in recognising the contaminated products at early stage of growth This study strongly suggests the use of the Electronic Noses as screening tools in industrial quality control laboratories but at the same time it underlines some limits still present in the technology

  • 155.
    Concina, Isabella
    et al.
    INFM-CNR Sensor Lab.
    Bornsek, M
    Pivovarna Union Dd, Ljubljana.
    Baccilliere, S
    ARPAV, Dipartimento Reg, Lab SL di Padova.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab, University of Brescia.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Electronic Nose: A Promising Tool For Early Detection Of Alicyclobacillus spp In Soft Drinks2009Inngår i: Olfaction and electronic nose, 2009, Vol. 1137, s. 535-536Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the present work we investigate the potential use of the Electronic Nose EOS835 (SACMI scarl, Italy) to early detect Alicyclobacillus spp in two flavoured soft drinks. These bacteria have been acknowledged by producer companies as a major quality control target microorganisms because of their ability to survive commercial pasteurization processes and produce taint compounds in final product. Electronic Nose was able to distinguish between uncontaminated and contaminated products before the taint metabolites were identifiable by an untrained panel. Classification tests showed an excellent rate of correct classification for both drinks (from 86% no to 100%). High performance liquid chromatography analyses showed no presence of the main metabolite at a level of 200 ppb, thus confirming the skill of the Electronic Nose technology in performing an actual early diagnosis of contamination.

  • 156.
    Concina, Isabella
    et al.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Comini, Elisabetta
    University of Brescia, CNR IDASC SENSOR Lab.
    Kacilius, S.
    CNR-ISMN, Institute for the Study of Nanostructured Materials, Rome.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Quantum dots as mediators in gas sensing: A case study of CdS sensitized WO3 sensing composites2014Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 290, s. 295-300Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study the proof of principle of the use of naked semiconductor directly generated on metal oxide surface as mediators in gas sensing is provided. Successive ionic layer absorption and reaction (SILAR) technique has been applied to sensitize a WO3 thin film with CdS quantum dots. Response to gases of bare WO3 is deeply modified: quantum dots dramatically increase the metal oxide conductance, otherwise rather poor, and modify the capability of detecting environmental pollutants, such as CO and NO2. A modified sensing mechanism is proposed to rationalize the mediation exerted by the semiconducting active layer on the interaction between gaseous species and WO3 surface.

  • 157.
    Concina, Isabella
    et al.
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Falasconi, Matteo
    University of Brescia.
    Gobbi, Emanuela
    Univ Udine, Biodivers SPA, Brescia,.
    Bianchi, F
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Musci, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Mattarozzi, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Pardo, Matteo
    Department of Physics and Chemistry, INFM — University of Brescia.
    Mangia, A
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Careri, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Early detection of microbial contamination in processed tomatoes by electronic nose2009Inngår i: Food Control, ISSN 0956-7135, E-ISSN 1873-7129, Vol. 20, nr 10, s. 873-880Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microbial contamination can easily affect processed tomato, thus determining both organoleptic adulterations and potential health risks for customers. Innovative techniques for a rapid and reliable diagnose of spoilage, such as electronic nose technology, are highly requested in order to guarantee food safety and to improve production. In this work canned peeled tomatoes were artificially spoiled with different kinds of microbial flora and then were analyzed by means of an electronic nose based on thin film metal oxide gas sensors. Preliminary analyses by dynamic-headspace gas chromatographic-mass spectrometry showed significant differences in the semi-quantitative volatile compounds profile of spoiled tomato samples just after few hours from contamination, thus suggesting to employ the electronic nose for an early diagnose of microbial presence. The electronic nose was indeed able to reveal contamination, even at early stages depending on the type of contaminant (e.g. for Saccharomyces cerevisiae and Escherichia coli), and to recognize spoiled tomato samples with good classification performances.

  • 158.
    Concina, Isabella
    et al.
    CNR IDASC SENSOR Lab.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Electronic Noses As Flexible Tools For Evaluating Food Quality And Safety: Can We Trust Them?2011Inngår i: OLFACTION AND ELECTRONIC NOSE, 2011, s. 109-110Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Since most food adulterations are reflected on volatile chemical profile, Electronic Noses (ENs) appear as excellent candidates for process monitoring, freshness evaluation, shelf-life investigation, sensory and authenticity assessment, microbial contamination diagnosis [1]. In this study three applications recently carried out in our laboratory are presented and discussed, with the aim to illustrate three paradigmatic and diverse issues related to food quality control in which EN can find application and discuss the reliability of sensor technology in food analysis.

  • 159.
    Concina, Isabella
    et al.
    CNR-IDASC SENSOR Laboratory.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab, University of Brescia.
    Sberveglieri, Veronica
    CNR IDASC SENSOR Lab, University of Brescia.
    Electronic noses as flexible tools to assess food quality and safety: Should we trust them?2012Inngår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 12, nr 11, s. 3232-3237, artikkel-id 6189022Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents three different applications of an electronic nose (EN) based on a metal oxide sensor array, in order to illustrate the broad spectrum of potential uses of the technique in food quality control. The following scenarios are considered: 1) the screening of a typical error that may occur during the processing of tomato pulp, which leads to sensory damage of the product; 2) the detection of microbial contamination by Alicyclobacillus spp. (ACB) affecting soft drinks; and 3) the proof of evidence of extra virgin olive oil fraudulently adulterated with hazelnut oil. In each case, the EN is able to identify the spoiled product by means of the alterations in the pattern of volatile compounds, reconstructed by principal component analysis of the sensor responses.

  • 160.
    Concina, Isabella
    et al.
    CNR IDASC SENSOR Lab.
    Frison, Enrico
    Dipartimento di Scienze Chimiche, Università di Catania.
    Braga, Antonio
    CNR IDASC SENSOR Lab.
    Silvestrini, Simone
    Dipartimento di Scienze Chimiche, Università di Catania.
    Maggini, Michele
    Dipartimento di Scienze Chimiche, Università di Catania.
    Sberveglieri, Giorgio
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    SENSOR Lab, Department of Chemistry and Physics, Brescia University and CNR-IDASC.
    Carofiglio, Tommaso
    Dipartimento di Scienze Chimiche, Università di Catania.
    On-line monitoring and active control of dye uptake in dye-sensitised solar cells2011Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, nr 42, s. 11656-11658Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Real-time monitoring of dye loading (N3 and N719) under continuous flow conditions on TiO2 photoanodes for dye-sensitized solar cells has been applied to quantitatively investigate dye uptake kinetics, demonstrating that static impregnation provides in all cases higher dye loading and, as a consequence, better working devices. © 2011 The Royal Society of Chemistry.

  • 161.
    Concina, Isabella
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Ibupoto, Zafar Hussain
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Dr. M. A. Kazi Institute of Chemistry University of Sindh Jamshoro, Sindh, Pakistan.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Semiconducting metal oxide nanostructures for water splitting and photovoltaics2017Inngår i: Advanced Energy Materials, ISSN 1614-6832, Vol. 7, nr 23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal oxide (MOx) semiconducting nanostructures hold the potential for playing a critical role in the development of a new platform for renewable energies, including energy conversion and storage through photovoltaic effect, solar fuels, and water splitting. Earth-abundant MOx nanostructures can be prepared through simple and scalable routes and integrated in operating devices, which enable exploitation of their outstanding optical, electronic, and catalytic properties. In this review, the latest research results in this field are illustrated, highlighting the versatility of MOx nanostructures in meeting the stringent requirements to boost the efficiency of different systems. The functional properties inherently correlate to the morphology and the crystalline habit of MOx, which in most of the cases are organized in complex heterostructures. Tailoring the assembly of heterojunctions and their electronic band structure, the catalytic surface properties and the charge transport through complex networks represent the main challenge for the transition of MOx from the research to the real-life in the field of energy conversion and storage.

  • 162.
    Concina, Isabella
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Ibupoto, Zafar
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Kazi Institute of Chemistry University of Sindh Jamshoro.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Electrochemical Water Splitting: Semiconducting Metal Oxide Nanostructures for Water Splitting and Photovoltaics2017Inngår i: Advanced Energy Materials, ISSN 1614-6832, Vol. 7, nr 23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Semiconducting metal oxide nanostructures represent an appealing class of materials to be applied as efficient electrodes in electrochemical and photoelectrochemical water splitting and in photovoltaics. In article number 1700706, Isabella Concina, Zafar Hussain Ibupoto, and Alberto Vomiero review the latest achievements in the field, illustrating how the structural and functional properties of metal oxides and metal oxide composites can be optimized for targeted applications.

  • 163.
    Concina, Isabella
    et al.
    Dipartimento di Ingegneria dell’Informazione, Università di Brescia.
    Manzoni, Cristian
    Istituto di Fotonica e Nanotecnologie (IFN)-CNR, Politecnico di Milano.
    Granchini, Giulia
    Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia.
    Celikin, Mert
    INRS Centre for Energy, Materials and Telecommunications.
    Soudi, Afsoon
    INRS Centre for Energy, Materials and Telecommunications.
    Rosei, Federico
    INRS Centre for Energy, Materials and Telecommunications.
    Zavelani-Rossi, Margherita
    Dipartimento di Fisica, Politecnico di Milano, Istituto di Fotonica e Nanotecnologie (IFN)-CNR.
    Cerullo, Giulio
    Dipartimento di Fisica, Politecnico di Milano, Istituto di Fotonica e Nanotecnologie (IFN)-CNR.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Modulating Exciton Dynamics in Composite Nanocrystals for Excitonic Solar Cells2015Inngår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 6, nr 13, s. 2489-2495Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quantum dots (QDs) represent one of the most promising materials for third-generation solar cells due to their potential to boost the photoconversion efficiency beyond the Shockley-Queisser limit. Composite nanocrystals can challenge the current scenario by combining broad spectral response and tailored energy levels to favor charge extraction and reduce energy and charge recombination. We synthesized PbS/CdS QDs with different compositions at the surface of TiO2 nanoparticles assembled in a mesoporous film. The ultrafast photoinduced dynamics and the charge injection processes were investigated by pump-probe spectroscopy. We demonstrated good injection of photogenerated electrons from QDs to TiO2 in the PbS/CdS blend and used the QIN to fabricate solar cells. The fine-tuning of chemical composition and size of lead and cadmium chalcogenide QDs led to highly efficient PV devices (3% maximum photoconversion efficiency). This combined study paves the way to the full exploitation of QDs in next-generation photovoltaic (PV) devices.

  • 164.
    Concina, Isabella
    et al.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Memarian, N.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Selopal, G. S.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Natile, M. M.
    CNR-ISTM.
    Sberveglieri, G.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Vomiero, Alberto
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Spray-assisted silar deposition of cadmium sulphide quantum dots on metal oxide films for excitonic solar cells2013Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 240, s. 736-744Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The proof of principle of the successful application of spray deposition to the SILAR (successive ionic layer absorption and reaction) technique, one of the most effective strategies to sensitized TiO2 scaffold with QDs, is demonstrated. Systematically improved optical features of the materials (higher optical density together with reduced nanocrystal sizes) as well as of the functional performances of QD solar cells (photoconversion efficiency, fill factor, short circuit current, open circuit voltage) sensitized via SD-SILAR, with respect to traditional SILAR sensitization based on impregnation, are demonstrated. © 2013 Elsevier B.V. All rights reserved.

  • 165.
    Concina, Isabella
    et al.
    CNR IDASC SENSOR Lab.
    Natile, M.
    Department of Chemical Sciences and INSTM Padova, Padova University.
    Braga, A.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    Department of Physics and Chemistry for Materials and Engineering and CNR-IDASC SENSOR Lab, Brescia University.
    Morandi, V.
    CNR-IMM Sezione di Bologna.
    Ortolani, L.
    CNR-IMM Sezione di Bologna.
    Ferroni, M.
    CNR IDASC SENSOR Lab.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    One pot synthesis of bi-linker stabilised CdSe quantum dots2010Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 244, artikkel-id 12067Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 166.
    Concina, Isabella
    et al.
    CNR IDASC SENSOR Lab.
    Natile, M. M.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Ferroni, M.
    CNR IDASC SENSOR Lab.
    Migliori, A.
    CNR-IMM Sezione di Bologna.
    Morandi, V.
    CNR-IMM Sezione di Bologna.
    Ortolani, L.
    CNR-IMM Sezione di Bologna.
    Vomiero, Alberto
    CNR IDASC SENSOR Lab.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    CdSe spherical quantum dots stabilised by thiomalic acid: Biphasic wet synthesis and characterisation2011Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 12, nr 4, s. 863-870Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CdSe quantum dots stabilised by thiomalic acid have been synthesised by an aqueous biphasic ligand exchange reaction in air. The materials are completely water-soluble and were found to be stable over a long time. X-ray diffraction and transmission electron microscopy reveal the formation of CdSe nanocrystals with cubic structure (a=0.6077 nm; spatial group: F-43m). The average particle size is about 5 nm. Energy dispersive X-ray analysis shows that the nanocrystals are nonstoichiometric, with a Cd/Se ratio varying between 60/40 and 70/30, and indicates the presence of Cd2+ ions at the nanocrystal surface. Diffuse reflectance infrared Fourier transform measurements suggest that thiomalic acid chelates CdSe through the thiol group and one carboxylic function, while the second COOH group is semi-free. A complex-like structure is proposed, in which thiomalic acid forms a five-membered chelate ring with the Cd2+ ions present on the nanocrystal surface. Chelate effect accounts for the easiness of ligand exchange and is expected to additionally stabilise the nanosystem. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 167.
    Concina, Isabella
    et al.
    CNR-IDASC SENSOR Laboratory.
    Natile, Marta Maria
    Universita Degli Studi di Padova.
    Tondello, Eugenio
    CNR-ISTM, INSTM, University of Padova.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Growth kinetics of CdSe quantum dots generated in polar polymers2012Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, nr 47, s. 14354-14359Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Growth kinetics of CdSe nanocrystals generated inside three selected polymers (polyvinylpyrrolidone-PVP, polyethyleneglycol-PEG and polyvinylalcohol-PVA) are demonstrated to follow a self-catalytic path, with growth rates depending on the nature of the polymer, i.e. on the capability to activate the cadmium species present in the solution of a metal precursor. A two-step process drives the size evolution of nanocrystals and a critical diameter value can be identified at which the growth regime changes. The medium-term stability evaluation of nanocomposites indicates that, after an initial rearrangement, polymers keep stable the embedded CdSe nanocrystals

  • 168.
    Concina, Isabella
    et al.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Selopal, Gurpreet S.
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Milan, Riccardo
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Sberveglieri, Giorgio
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Vomiero, Alberto
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Light harvester band gap engineering in excitonic solar cells: A case study on semiconducting quantum dots sensitized rainbow solar cells2014Inngår i: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 86, nr 5, s. 575-584Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A systematic study on the fabrication of quantum dots sensitized solar cells (QDSSCs) exploiting hybrid networks of semiconducting light harvesters is presented, which shows how the engineering of band gaps of the device components by a very simple technique allows improving the solar energy conversion performances. Panchromatic devices are fabricated and tested, and correspondent functional parameters analyzed in order to highlight both advantages and drawbacks of the most common (CdS, CdSe, PbS) quantum dots applied for light collection in QDSSCs. Judicious engineering of the light harvester layer is demonstrated as a simple and powerful strategy for boosting device performances, through the management of light collection in a rather broad range of solar spectrum and photogenerated charges injection and collection. © 2014 IUPAC & De Gruyter.

  • 169.
    Concina, Isabella
    et al.
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Selopal, Gurpreet S.
    Department of Information Engineering, University of Brescia, CNR-INO SENSOR Lab.
    Milan, Riccardo
    Department of Information Engineering, University of Brescia, CNR-INO SENSOR Lab.
    Vomiero, Alberto
    Department of Information Engineering, University of Brescia and SENSOR Laboratory, CNR-INO.
    Sberveglieri, Giorgio
    Department of Information Engineering, University of Brescia, CNR-INO SENSOR Lab.
    Engineering metal oxide structures for efficient photovoltaic devices2014Inngår i: Oxide-based materials and devices V: 2 - 5 February 2014, San Francisco, California, United States ; [proceedings of the Fifth Annual Oxide Based Materials and Devices Conference ... held at SPIE photonics west] / [ed] Ferechteh Hosseini Teherani, Bellingham, Wash.: SPIE - International Society for Optical Engineering, 2014, artikkel-id 89872EKonferansepaper (Fagfellevurdert)
    Abstract [en]

    Metal oxide-based photoanodes are critical components of dye sensitized solar cells (DSSCs), which are photoelectrochemical cells for the conversion of solar energy, promising to have several benefits as compared with their traditional counterparts. A careful engineering of the wide band gap metal oxide composing the photoanode, as well as their process design, is strategic for improving device performances and for planning a near future production scale up, especially devoted to reducing the environmental impact of the device fabrication. Herein, we present the application of ZnO hierarchical structures as efficient materials to be applied as photoanodes in DSSC, in the perspective of looking for alternative to TiO2 nanoparticles, currently the most exploited metal oxide in these devices. © 2014 SPIE.

  • 170.
    Concina, Isabella
    et al.
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells2015Inngår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 11, nr 15, s. 1744-1774Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This Review provides a brief summary of the most recent research developments in the synthesis and application of nanostructured metal oxide semiconductors for dye sensitized and quantum dot sensitized solar cells. In these devices, the wide bandgap semiconducting oxide acts as the photoanode, which provides the scaffold for light harvesters (either dye molecules or quantum dots) and electron collection. For this reason, proper tailoring of the optical and electronic properties of the photoanode can significantly boost the functionalities of the operating device. Optimization of the functional properties relies with modulation of the shape and structure of the photoanode, as well as on application of different materials (TiO2, ZnO, SnO2) and/or composite systems, which allow fine tuning of electronic band structure. This aspect is critical because it determines exciton and charge dynamics in the photoelectrochemical system and is strictly connected to the photoconversion efficiency of the solar cell. The different strategies for increasing light harvesting and charge collection, inhibiting charge losses due to recombination phenomena, are reviewed thoroughly, highlighting the benefits of proper photoanode preparation, and its crucial role in the development of high efficiency dye sensitized and quantum dot sensitized solar cells.

  • 171.
    Concina, Isabella
    et al.
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Solar Cells: Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells2015Inngår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 11, nr 15, s. 1743-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal oxide semiconductors are an appealing class of material, extensively used as photoanodes in excitonic solar cells such as dye- and quantum dot-sensitized solar cells. On page 1744, I. Concina and A. Vomiero describe how proper tailoring of the shape, composition, and crystalline structure of these materials can significantly boost the performances of these solar energy converting devices by ameliorating the processes of exciton separation, charge transport, and collection, while reducing charge losses due to recombination and back reactions.

  • 172.
    Concina, Isabella
    et al.
    CNR-IDASC SENSOR Laboratory.
    Zecca, M
    CNR IDASC SENSOR Lab.
    Stabilisation of monometallic nanoparticles by polyamide 62011Inngår i: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, nr 3, s. 1289-1300Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monometallic metal nanoparticles (Pd, Pt, Ag and Ru) stabilised by polyamide 6 (PA6) have been prepared via a polyol process sustained by microwave irradiation. PA6 proved to be a good stabiliser, being spherical particles with little dimensional dispersion identified by transmission electron microscopy. Due to the inclusion of the metals in small amount (up to 3% w/w) into the macromolecular lattice, the polymer underwent changes in thermal behaviour, which, however, do not impair the possibility to process the material. The observed changes in differential scanning calorimetry curves indicated that metal containing PA6 materials are less crystalline and ordered than pure PA6. This was confirmed by diffuse reflectance infrared Fourier transform analysis, which indicated that the introduction of the metal nanoparticles lowered the conformational order of the polymer matrix and partly disrupted the hydrogen bond network of the polyamide.

  • 173.
    Corradini, M.
    et al.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Hayano, R.
    Department of Physics, University of Tokyo.
    Hori, M.
    Department of Physics, University of Tokyo.
    Leali, M.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Rizzini, E. Lodi
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Mascagna, V.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Mozzanica, A.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Prest, M.
    Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari.
    Todoroki, K.
    Department of Physics, University of Tokyo.
    Vallazza, E.
    Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari.
    Venturelli, L.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Zurlo, N.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Baratto, C.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Ferroni, M.
    Dipartimento di Ingegneria dell’Informazione, Università di Padova.
    Vomiero, Alberto
    CNR IDASC SENSOR Lab.
    Experimental apparatus for annihilation cross-section measurements of low energy antiprotons2013Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 711, s. 12-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 174.
    Costantini, H.
    et al.
    Università di Genova.
    Angulo, C.
    Centre de Recherches du Cyclotron, Universit¶e Catholique de Louvain, Louvain-la-Neuve.
    Bemmerer, D.
    Institut für Atomare Physik und Fachdidaktik, Technische Universität Berlin.
    Bonetti, R.
    Università Degli Studi di Milano and INFN.
    Broggini, C.
    INFN.
    Confortola, F.
    Università di Genova.
    Corvisiero, P.
    Università di Genova.
    Cruz, J.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Descouvemont, P.
    Physique Nucléaire Théorique et Physique Mathématique, Université Libre de Bruxelles.
    Formicola, A.
    Laboratori Nazionali del Gran Sasso.
    Fülop, Z.
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Gervino, G.
    Dipertemento di Fisica Teoria, Universita di Torino and INFS.
    Guglielmetti, A.
    Università Degli Studi di Milano and INFN.
    Gustavino, C.
    Laboratori Nazionali del Gran Sasso.
    Gyürky, G.
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Imbriani, G.
    Osservatorio Astronomico di Collurania Vincenzo Cerulli.
    Jesus, A. P.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Junker, M.
    Laboratori Nazionali del Gran Sasso.
    Lemut, A.
    Università di Genova.
    Menegazzo, R.
    INFN.
    Prati, P.
    Università di Genova.
    Roca, V.
    Seconda Università di Napoli.
    Rolfs, C.
    Institut Für Experimentalphysik III.
    Romano, M.
    Seconda Università di Napoli.
    Alvarez, C. Rossi
    INFN.
    Vomiero, Alberto
    Dipartimento di Fisica, Università di Padova.
    Zavatarelli, S.
    Università di Genova.
    Recent results of the 14N(p,γ)15O measurement at LUNA2005Inngår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 758, nr 1-4 SPEC. ISS., s. 383C-386CArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The 14N(p, γ)15O reaction has been investigated by LUNA at the National Laboratory of Gran Sasso (LNGS) using two different techniques. The first study has been performed using a solid target and detecting the γ-rays coming from the single transitions with a HPGe detector in very close geometry to the target. In a second phase a windowless gas target sorrounded by a nearly 4π BGO summing crystal has been used and the total S-factor has been measured down to Eb = 80 keV. © 2005 Elsevier B.V. All rights reserved.

  • 175.
    Coutinho, Jose
    et al.
    Univ Aveiro, Dept Phys, Campus Santiago, P-3810193 Aveiro, Portugal..
    Torres, Viktor J.B.
    Univ Aveiro, Dept Phys, Campus Santiago, P-3810193 Aveiro, Portugal..
    Demmouche, Kamel
    Ctr Univ Belhadj Bouchaib Ain Temouchent, Inst Sci, Route Sidi Bel Abbes,BP 284, Ain Temouchent 46000, Algeria.
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Theory of the carbon vacancy in 4H-SiC: Crystal field and pseudo-Jahn-Teller effects2017Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 17, artikkel-id 174105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The carbon vacancy in 4H-SiC is a powerful minority carrier recombination center in as-grown material and a major cause of degradation of SiC-based devices. Despite the extensiveness and maturity of the literature regarding the characterization and modeling of the defect, many fundamental questions persist. Among them, we have the shaky connection of the EPR data to the electrical measurements lacking sublattice site resolution, the physical origin of the pseudo-Jahn-Teller effect, the reasoning for the observed sublattice dependence of the paramagnetic states, and the severe temperature dependence of some hyperfine signals, which cannot be accounted for by a thermally activated dynamic averaging between equivalent Jahn-Teller distorted structures. In this work, we address these problems by means of semilocal and hybrid density functional calculations. We start by inventorying a total of four different vacancy structures from the analysis of relative energies. Diamagnetic states have well defined low-energy structures, whereas paramagnetic states display metastability. The reasoning for the rich structural variety is traced back to the filling of electronic states which are shaped by a crystal-field-dependent (and therefore site-dependent) pseudo-Jahn-Teller effect. From calculated minimum energy paths for defect rotation and transformation mechanisms, combined with the calculated formation energies and electrical levels, we arrived at a configuration-coordinate diagram of the defect. The diagram provides us with a detailed first-principles picture of the defect when subject to thermal excitations. The calculated acceptor and donor transitions agree well with the binding energies of electrons emitted from the Z(1/2) and EH6/7 traps, respectively. From the comparison of calculated and measured U-values, and correlating the site-dependent formation energies with the relative intensity of the DLTS peaks in as-grown material, we assign Z(1) (EH6) and Z(2) (EH7) signals to acceptor (donor) transitions of carbon vacancies located on the h and k sublattice sites, respectively.

  • 176.
    Cruzata, O.
    et al.
    Universidad de La Habana, Technological Laser Laboratory, La Habana, Cuba.
    Concina, Isabella
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Universita degli Studi di Brescia, Department of Information Engineering, Brescia, Italy.
    Vaillant, Lídice
    Universidad de La Habana, División ENERMAT, La Habana, Cuba.
    Rotary sample holder design for the optimization of the nanostructures seeding [Diseñ o de porta-muestra rotatorio para la optimizació n del proceso de sedimentació n de nanoestructuras]2017Inngår i: Revista Cubana de Fisica, ISSN 0253-9268, E-ISSN 2224-7939, Vol. 34, nr 2, s. 140-142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A cylinder-plug device capable of holding a sample and rotating at 2000 turns per second in a stable fashion was designed and constructed. It reproduces the working principle of a commercial spin-coating system to grow films. The device was successfully used in the activation by nucleation centers of ZnO on glass for the hydrothermal obtainment of ZnO nanorods, of potential use in nanostructured solar cells.

  • 177.
    Czerwinski, Bartlomiej
    et al.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Delcorte, Arnaud
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Molecular dynamics study of fullerite cross-linking under keV C 60 and Arn cluster bombardment2013Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, nr 7, s. 3595-3604Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular dynamics computer simulations are used to elucidate the cross-linking processes induced by 0.6-50 keV C60 and Arn cluster bombardment in a C60 fullerite solid sample. The obtained results indicate the presence of a "chemical effect" when C 60 projectile is used. Namely, the bombarding C60 delivers additional, highly reactive, radicals which interact with the atoms of the fullerite sample, increasing the efficiency of the cross-linking process. The omission of those interactions in the analysis makes the C60 very similar to the case of the Ar18 bombardment. For Arn cluster bombardment, the initial energy per atom in the projectile is the parameter which has the predominant influence on the cross-linking process. Furthermore, a relationship between the energy thresholds for fragmentation of the target molecules and cross-linking initiation and the size of the Ar clusters is observed. Both of these thresholds decrease with increasing size of the projectile.

  • 178.
    Czerwinski, Bartlomiej
    et al.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Postawa, Zbigniew
    Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow.
    Garrison, Barbara J.
    Department of Chemistry, Pennsylvania State University.
    Delcorte, Arnaud
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Molecular dynamics study of polystyrene bond-breaking and crosslinking under C60 and Arn cluster bombardment2013Inngår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, s. 22-26Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular dynamics computer simulations are used to elucidate the bond-breaking and crosslinking processes induced by 2.5 keV C60 and Arn cluster bombardment in an amorphous sec-butyl-terminated polystyrene sample. The obtained results indicate that replacement of C 60 by Ar18 or Ar60 projectiles leads to the decrease of the number of broken bonds and, hence, to the decrease of formation of new intra- and intermolecular (crosslinking) bonds. When the number of atoms in the Arn cluster is increased from 60 to 250 or more, the total number of broken bonds and the total number of newly created bonds reach a zero value. Additional comparison to the case of a fullerite crystal reveals that the change of material properties leads to almost 7.5-fold reduction of the efficiency of the crosslinking process.

  • 179.
    De Melo, C.
    et al.
    Université de Lorraine, CNRS, IJL, Nancy, France. Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Jullien, M.
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Ghanbaja, J.
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Montaigne, F.
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Pierson, J.-F.
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Soldera, F.
    Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Rigoni, Federica
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mücklich, F.
    Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Horwat, D.
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Local Structure and Point-Defect-Dependent Area-Selective Atomic Layer Deposition Approach for Facile Synthesis of p-Cu2O/n-ZnO Segmented Nanojunctions2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 43, s. 37671-37678Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Area-selective atomic layer deposition (AS-ALD) has attracted much attention in recent years due to the possibility of achieving accurate patterns in nanoscale features, which render this technique compatible with the continuous downscaling in nanoelectronic devices. The growth selectivity is achieved by starting from different materials and results (ideally) in localized growth of a single material. We propose here a new concept, more subtle and general, in which a property of the substrate is modulated to achieve localized growth of different materials. This concept is demonstrated by selective growth of high-quality metallic Cu and semiconducting Cu2O thin films, achieved by changing the type of majority point defects in the ZnO underneath film exposed to the reactive species using a patterned bilayer structure composed of highly conductive and highly resistive areas, as confirmed by transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The selective growth of these materials in a patterned ZnO/Al-doped ZnO substrate allows the fabrication of p-Cu2O/n-ZnO nanojunctions showing a nonlinear rectifying behavior typical of a p-n junction, as confirmed by conductive atomic force microscopy (C-AFM). This process expands the spectra of materials that can be grown in a selective manner by ALD and opens up the possibility of fabricating different architectures, taking advantage of the area-selective deposition. This offers a variety of opportunities in the field of transparent electronics, catalysis, and photovoltaics.

  • 180.
    de Melo, Claudia
    et al.
    Université de Lorraine, CNRS, IJL, F-54000 Nancy, France. Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Jullien, Maud
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Battie, Yann
    LCP-A2MC, Institut Jean Barriol, Université de Lorraine, Metz, France.
    En Naciri, Aotmane
    LCP-A2MC, Institut Jean Barriol, Université de Lorraine, Metz, France.
    Ghanbaja, Jaafar
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Montaigne, François
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Pierson, Jean-François
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Rigoni, Federica
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Migot, Sylvie
    Department of Materials Science and Engineering, Saarland University, D-66123 Saarbrücken, Germany.
    Mücklich, Frank
    Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Horwat, David
    Université de Lorraine, CNRS, IJL, Nancy, France.
    Tunable Localized Surface Plasmon Resonance and Broadband Visible Photoresponse of Cu Nanoparticles/ZnO Surfaces2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 47, s. 40958-40965Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plasmonic Cu nanoparticles (NP) were successfully deposited on ZnO substrates by atomic layer deposition (ALD) owing to the Volmer–Weber island growth mode. An evolution from Cu NP to continuous Cu films was observed with an increasing number of ALD cycles. Real and imaginary parts of the NP dielectric functions, determined by spectroscopic ellipsometry using an effective medium approach, evidence a localized surface plasmon resonance that can be tuned between the visible and near-infrared ranges by controlling the interparticle spacing and size of the NP. The resulting Cu NP/ZnO device shows an enhanced photoresponse under white light illumination with good responsivity values, fast response times, and stability under dark/light cycles. The significant photocurrent detected for this device is related to the hot-electron generation at the NP surface and injection into the conduction band of ZnO. The possibility of tuning the plasmon resonance together with the photoresponsivity of the device is promising in many applications related to photodetection, photonics, and photovoltaics.

  • 181.
    de Melo, Claudia
    et al.
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Jullien, Maud
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Battie, Yann
    LCP-A2MC, Institut Jean Barriol, Universitéde Lorraine, Metz, France.
    Naciri, Aotmane En
    LCP-A2MC, Institut Jean Barriol, Universitéde Lorraine, Metz, France.
    Ghanbaja, Jaafar
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Montaigne, Francois
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Pierson, Jean-Francois
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Rigoni, Federica
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Migot, Sylvie
    Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Mücklich, Frank
    Department of Materials Science and Engineering, Saarland University, Saarbrücken, Germany.
    Horwat, David
    Universitéde Lorraine, CNRS, IJL, Nancy, France.
    Semi-Transparent p‑Cu2O/n-ZnO Nanoscale-Film Heterojunctions for Photodetection and Photovoltaic Applications2019Inngår i: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 2, nr 7, s. 4358-4366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transparent nanoscale-film heterojunctions based on Cu2O and ZnO were fabricated by atomic layer deposition and reactive magnetron sputtering. The constitutive layers exhibit high crystalline quality and a local epitaxial relation between Cu2O and ZnO was achieved with [110] Cu2O || [001] ZnO and [001] Cu2O || [010] ZnO as evidenced by high resolution transmission electron microscopy and. Cu2O films show very low resistivity and high mobility values of 9–150 Ω cm and 19 cm2/V s, respectively. The Cu2O/ZnO heterojunctions exhibit a nonlinear rectifying behavior characteristic of a p–n junction, self-powered photoresponse under 1 Sun illumination and an average transmittance of 73% in the visible region of the electromagnetic spectrum. These results are promising for all-oxide transparent electronics, photodetection and photovoltaic applications.

  • 182.
    Delcorte, Arnaud
    et al.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Cristaudo, Vanina
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Lebec, V.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Czerwinski, Bartlomiej
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Sputtering of polymers by keV clusters: Microscopic views of the molecular dynamics2014Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 370, s. 29-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article reviews the results of molecular dynamics simulations of cluster sputtering of hydrocarbon polymers obtained in the last few years and expand them with unpublished data of Ar cluster bombardment. The targets are molecular solids of linear hydrocarbons, polyethylene and polystyrene, including a polyethylene substrate decorated with adsorbed globular macromolecules. The projectiles are (hydro)carbon and Arn clusters, from small to massive, as well as Bin and Au400 clusters. The study focuses on the dynamics of cratering and sputtering, using a coarse-grained representation of the samples, on the study of molecular fragmentation, crosslinking and free H formation, using a fully atomistic model, and on the conditions of desorption of macromolecules by massive clusters. The results explain the similarities and differences between several cluster types and sizes and, to a large extent, the sputtering yields of Arn clusters and their 'universal' dependence on the scaled cluster energy, as observed in the experiments. They also demonstrate the reduction of sample fragmentation and crosslinking when going to larger clusters and the incidence angle dependence of intact macromolecule emission. Recent experimental validations obtained in our laboratory are also introduced and comparisons with data obtained by other groups are discussed in order to present a more complete picture of the physics of cluster bombardment of organic solids and polymers.

  • 183.
    Delcorte, Arnaud
    et al.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Czerwinski, Bartlomiej
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Cristaudo, Vanina
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Lebec, V.
    Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Louvain-la-Neuve.
    Re-print of "Sputtering of polymers by keV clusters: Microscopic views of the molecular dynamics"2015Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 377, nr 1, s. 580-590Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article reviews the results of molecular dynamics simulations of cluster sputtering of hydrocarbon polymers obtained in the last few years and expand them with unpublished data of Ar cluster bombardment. The targets are molecular solids of linear hydrocarbons, polyethylene and polystyrene, includingapolyethylene substrate decorated with adsorbed globular macromolecules. The projectiles are (hydro)carbon and Arn clusters, from small tomassive, as well as Bin and Au400 clusters. The study focuses on the dynamics of cratering and sputtering, using a coarse-grained representation of the samples, on the study ofmolecular fragmentation, crosslinking and freeHformation, usingafully atomistic model, and on the conditions of desorption of macromolecules by massive clusters. The results explain the similarities and differences between several cluster types and sizes and, to a large extent, the sputtering yields of Arn clusters and their 'universal' dependence on the scaled cluster energy, as observed in the experiments. They also demonstrate the reduction of sample fragmentation and crosslinking when going to larger clusters and the incidence angle dependence of intact macromolecule emission. Recent experimental validations obtained in our laboratory are also introduced and comparisons with data obtained by other groups are discussed in order to present a more complete picture of the physics of cluster bombardment of organic solids and polymers.

  • 184.
    Dembele, K. T.
    et al.
    Institut National de la Recherche Scientifique.
    Nechache, R.
    Institut National de la Recherche Scientifique.
    Nikolova, L.
    Institut National de la Recherche Scientifique.
    Vomiero, Alberto
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Santato, C.
    Département de Génie Physique, École Polytechnique de Montréal.
    Licoccia, S.
    Department of Chemical Sciences and INSTM Padova, Padova University.
    Rosei, F.
    Institut National de la Recherche Scientifique.
    Effect of multi-walled carbon nanotubes on the stability of dye sensitized solar cells2013Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 233, s. 93-97Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the improvement of the operational stability of dye-sensitized solar cells (DSSCs) by incorporating multi-wall carbon nanotubes (MWCNTs) in conventional nanostructured semiconducting TiO2 photoanodes. DSSCs were prepared by adding various concentrations of MWCNTs (up to 1.0% wt.) to TiO2 anatase nanoparticles. Optimization of MWCNT concentration leads to photoconversion efficiency as high as 4.1% as opposed to 3.7% for pure TiO2 photoanodes. The performance of the solar cells was measured for 10 consecutive days of continuous ambient light exposure. MWCNT addition results in the decrease of efficiency from 4.1% to 3.7%, while a decrease from 3.7% to 2.4% was recorded in pure TiO2 photoanodes. These results are encouraging toward the commercial exploitation of DSSCs.© 2013 Elsevier B.V. All rights reserved.

  • 185.
    Dembele, Kadiatou Therese
    et al.
    INRS-EMT.
    Selopal, Gurpreet Singh
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Milan, Riccardo
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Trudeau, Charles
    Département de Génie Électrique, École de Technologie Supérieure, Montréal.
    Benetti, Daniele
    INRS-EMT.
    Soudi, Afsoon
    INRS-EMT.
    Natile, Marta Maria
    CNR-IENI.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Cloutier, Sylvain
    Département de Génie Électrique, École de Technologie Supérieure, Montréal.
    Concina, Isabella
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Rosei, Federico
    INRS-EMT.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Graphene below the percolation threshold in TiO2 for dye-sensitized solar cells2015Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, nr 6, s. 2580-2588Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate a fast and large area-scalable methodology for the fabrication of efficient dye sensitized solar cells (DSSCs) by simple addition of graphene micro-platelets to TiO2 nanoparticulate paste (graphene concentration in the range of 0 to 1.5 wt%). Two dimensional (2D) Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirm the presence of graphene after 500°C annealing for 30 minutes. Graphene addition increases the photocurrent density from 12.4 mA cm-2 in bare TiO2 to 17.1 mA cm-2 in an optimized photoanode (0.01 wt% graphene, much lower than those reported in previous studies), boosting the photoconversion efficiency (PCE) from 6.3 up to 8.8%. The investigation of the 2D graphene distribution showed that an optimized concentration is far below the percolation threshold, indicating that the increased PCE does not rely on the formation of an interconnected network, as inferred by prior investigations, but rather, on increased charge injection from TiO2 to the front electrode. These results give insights into the role of graphene in improving the functional properties of DSSCs and identifying a straightforward methodology for the synthesis of new photoanodes.

  • 186.
    Dembele, Kadiatou Therese
    et al.
    Institut National de la Recherche Scientifique.
    Selopal, Gurpreet Singh
    CNR IDASC SENSOR Lab.
    Soldano, Caterina
    CNR IDASC SENSOR Lab.
    Nechache, Riad
    Institut National de la Recherche Scientifique.
    Rimada, Julio Cesar
    Solar Cells Laboratory, Institute of Materials Science and Technology (IMRE), University of Havana.
    Concina, Isabella
    CNR IDASC SENSOR Lab.
    Sberveglieri, Giorgio
    CNR IDASC SENSOR Lab.
    Rosei, Federico
    Institut National de la Recherche Scientifique.
    Vomiero, Alberto
    CNR IDASC SENSOR Lab.
    Hybrid carbon nanotubes-TiO2 photoanodes for high efficiency dye-sensitized solar cells2013Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, nr 28, s. 14510-14517Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a fast and effective procedure for the preparation of high efficiency hybrid photoanodes for dye-sensitized solar cells (DSCs), based on nanocrystalline TiO2 with limited addition of multiwall carbon nanotubes (CNTs). The mixing process between CNTs and TiO2 nanoparticles is almost instantaneous, which makes it feasible for large-scale fabrication. Enhanced electron lifetime and reduced charge recombination lead to highly increased short circuit current density and overall photoconversion efficiency (from 13.6 mA cm-2 to 16.0 mA cm-2 and from 7.0% to 9.0%, respectively, considering the bare TiO2 and the optimum CNTs concentration, which is 0.010 wt %), while the small reduction in open circuit photovoltage does not significantly affect cell performances. This result is remarkable since a standard dye molecule (N719) was used and no chemical treatments of the photoanodes prior to cell fabrication were applied (i.e., soaking in TiCl4 to boost open circuit photovoltage). © 2013 American Chemical Society.

  • 187. Demirel, B.
    et al.
    Paul, Jan
    Analyses of products from autoclave reactions: derivations of reaction parameters1996Inngår i: Vol. 41, nr 4, s. 1157-1160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents energetics for high pressure hydroprocessing reactions derived from post analyses of liquid and gaseous products. Specifically, GC and GC/MS were used to follow the product distribution fram the hydrocracking of methyldecalins over zeohte supported palladium and platinum catalysts as a function of temperature. Plain Arrhenius plots summarize key results and reveal possible connections in terms of`activation energies between hydrogen consumption and the amounts of different products. The total cycloalkane production and the consumption ofhydrogen both show a simple temperature dependence with the same{open_quote}activation{close_quote} energies. Methane production varies more rapidly with temperature but can still be described by a single exponential term. The final example, conversion to aromatics, displays a more complicated dependence with an accelerated yield at high temperature. This form of data analyses connects to a new routine for mass balance evaluations and it is now applied to model catalyst performance and to understand optimum reaction conditions. Other branches of this project include surface spectroscopic measurements of fresh, sulfided and used catalysts, characterization of partially hydrogenated naphthalenes and modeling of hydrogen activity at metal sulfides.

  • 188.
    Devaux, Xavier
    et al.
    Institut Jean Lamour, Department P2M, UMR 7198 CNRS–Université de Lorraine, Ecole des Mines, 54042 Nancy.
    Vigolo, Brigitte
    Institut Jean Lamour, CNRS – Nancy Université, Laboratoire de Chimie du Solide Minéral, Nancy Université.
    McRae, Edward
    Institut Jean Lamour, CNRS – Nancy Université, Laboratoire de Chimie du Solide Minéral, Nancy Université.
    Valsaque, Fabrice
    Institut Jean Lamour, Nancy Universite.
    Allali, Naoual
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mamane, Victor
    Laboratoire de Synthèse Organométallique et Réactivité, Université Henri Poincaré - Nancy, Laboratoire de Structure et Réactivité des Systèmes Moléculaires Complexes, Nancy Université.
    Fort, Yves
    Laboratoire de Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 CNRS–Université de Lorraine, 54506 Vandoeuvre-les-Nancy, Laboratoire de Synthèse Organométallique et Réactivité, Université Henri Poincaré - Nancy.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Dossot, Manuel
    Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564, CNRS–University of Lorraine.
    Tsareva, Svetlana Yu.
    Institut Jean Lamour, Nancy Universite.
    Covalent Functionalization of HiPco Single-Walled Carbon Nanotubes: Differences in the Oxidizing Action of H2SO4 and HNO3 during a Soft Oxidation Process2015Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 16, nr 12, s. 2692-2701Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The results of a study on the evolution of HiPco single-walled carbon nanotubes during the oxidizing action of H2SO4 and HNO3 are presented. The process conditions used have been chosen so as to avoid any significant damage to the nanotube structure. The type and level of functionalization, the location of the grafted functions on the surface of the nanotube and the changes in morphological characteristics of the samples were examined by using a wide and complementary range of analytical techniques. We propose an explanation for the differences in the oxidizing action of sulfuric and nitric acids. The combined results allow us to suggest possible reaction mechanisms that occur on the surface of the nanotube.

  • 189.
    Di Maria, Francesca
    et al.
    Istituto per la Sintesi Organica e Fotoreattivita' (ISOF), Consiglio Nazionale delle Ricerche.
    Zangoli, Mattia G.
    Istituto per la Sintesi Organica e Fotoreattivita' (ISOF), Consiglio Nazionale delle Ricerche.
    Gazzano, Massimo
    Istituto per la Sintesi Organica e Fotoreattivita' (ISOF), Consiglio Nazionale delle Ricerche.
    Fabiano, Eduardo
    Institute for Microelectronics and Microsystems (CNR-IMM).
    Gentili, Denis
    Istituto per lo studio dei Materiali, Nanostrutturati (ISMN), Consiglio Nazionale delle Ricerche.
    Zanelli, Alberto
    Istituto per la Sintesi Organica e Fotoreattivita' (ISOF), Consiglio Nazionale delle Ricerche.
    Fermi, Andrea
    School of Chemistry, Cardiff University.
    Bergamini, Giacomo
    Department of Chemistry Giacomo Ciamician, University of Bologna.
    Bonifazi, Davide
    School of Chemistry, Cardiff University.
    Perinot, Andrea
    Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia.
    Caironi, Mario
    Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia.
    Mazzaro, Raffaello
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Istituto per la Microelettronica e i Microsistemi (IMM), Consiglio Nazionale delle Ricerche.
    Morandi, Vittorio
    Istituto per la Microelettronica e i Microsistemi (IMM), Consiglio Nazionale delle Ricerche.
    Gigli, Giuseppe
    Department of Mathematics and Physics, Ennio De Giorgi University of Salento, Lecce.
    Liscio, Andrea
    Institute for Microelectronics and Microsystems (CNR-IMM).
    Barbarella, Giovanna
    Istituto per la Sintesi Organica e Fotoreattivita' (ISOF), Consiglio Nazionale delle Ricerche.
    Controlling the Functional Properties of Oligothiophene Crystalline Nano/Microfibers via Tailoring of the Self-Assembling Molecular Precursors2018Inngår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, nr 32, artikkel-id 1801946Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oligothiophenes are π-conjugated semiconducting and fluorescent molecules whose self-assembly properties are widely investigated for application in organic electronics, optoelectronics, biophotonics, and sensing. Here an approach to the preparation of crystalline oligothiophene nano/microfibers is reported based on the use of a “sulfur overrich” quaterthiophene building block, T4S4 , containing in its covalent network all the information needed to promote the directional, π–π stacking-driven, self-assembly of Y-T4S4-Y oligomers into fibers with hierarchical supramolecular arrangement from nano- to microscale. It is shown that when Y varies from unsubstituted thiophene to thiophene substituted with electron-withdrawing groups, a wide redistribution of the molecular electronic charge takes place without substantially affecting the aggregation modalities of the oligomer. In this way, a structurally comparable series of fibers is obtained having progressively varying optical properties, redox potentials, photoconductivity, and type of prevailing charge carriers (from p- to n-type). With the aid of density functional theory (DFT) calculations, combined with powder X-ray diffraction data, a model accounting for the growth of the fibers from molecular to nano- and microscale is proposed

  • 190.
    Di Mauro, Alessandro
    et al.
    Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via S. Sofia 64, 95123 Catania.
    Landström, Anton
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Concina, Isabella
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Impellizzeri, Giuliana
    Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via Monteroni, 73100 Lecce.
    Privitera, Vittorio
    Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via S. Sofia 64, 95123 Catania, Italy.
    Epifani, Mauro
    Istituto per la Microelettronica e i Microsistemi, IMM-CNR, Via Monteroni, 73100 Lecce, Italy.
    Surface Modification by Vanadium Pentoxide Turns Oxide Nanocrystals into Powerful Adsorbents of Methylene Blue2019Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 533, s. 369-374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hypothesis: If nanocrystals of such semiconductor as SnO2 and TiO2, which are not known as powerful adsorbents, have their surface modified by layer of V2O5, how will the adsorption properties be affected? Answering this question would provide a new set of surface properties to be designed by surface engineering of oxide nanocrystals.

    Experiments: SnO2 and TiO2 colloidal nanocrystals were prepared by coupling sol-gel and solvothermal synthesis. By co-processing with V chloroalkoxide and subsequent heat-treatment at 400-500 °C, surface deposition of V2O5 layers was obtained. The methylene blue adsorption onto the prepared materials was tested and compared with the pure oxide supports. Cycling of the materials and analysis of the adsorption process was also investigated.

    Findings: The V-modified nanocrystals extracted ∼ 80% methylene blue from 1.5 x 10-5 M aqueous solution after 15 min only, contrarily to pure materials, which took up only 30% of the dye even after 120 min. Comparison with pure commercial V2O5 showed that the peculiar adsorption properties were imparted by the surface deposition of the V2O5-like layers. This report demonstrates that new classes of adsorbing materials can be conceived by suitably coupling different metal oxides.

  • 191.
    Dobryden, Illia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Scanning probe microscopy studies of interaction forces between particles: emphasis on magnetite, bentonite and silica.2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Scanning probe microscopy (SPM), such as the atomic force microscope (AFM), using colloidal probes is a highly suitable technique to probe single particle-particle interactions in aqueous solution. The interaction force between a colloidal probe on the AFM cantilever and sample surface is measured. Ultrasmall intermolecular and surface forces, down to the piconewton level, can reliably be measured under controlled experimental conditions with AFM. The interaction between magnetite, bentonite and silica particles plays an important role in many different applications. One important application is in the steel production process where high-quality iron ore pellets are used. Moreover, the interaction between magnetite nanoparticles with Ca2+ ions and with silica particles has high importance in several medical applications and for nanoelectronics. It is known and widely studied that particle surface properties significantly affect the particle dispersion and aggregation. Also, the particles are often treated in aqueous suspensions or in moist conditions prior to the final aggregation, for instance in a pelletizing processes. Thus, different dissolved chemical species may modify the magnetite, bentonite and silica surfaces, which causes the surface properties to change. However, the exact mechanism how the dissolved chemical species influence the direct particle-particle interaction and particle adhesion is not well known.The main focus of this thesis was the study of magnetite particle force interaction with natural and synthetic magnetite, silica and bentonite particles in aqueous solution with SPM. In addition, complimentary methods, such as scanning electron microscopy (SEM), vertical scanning interferometry (VSI), energy dispersive spectroscopy (SEM-EDS), x-ray diffraction (XRD) and electrophoresis techniques were used for surface morphology investigation, chemical characterization, determination of atomic structure and measurements of zeta-potential. The particle interaction forces were examined in solutions with various Ca2+ ion concentrations and in NaCl solution to determine the effect of Ca2+ ions on the surface properties. Also, the effect of pH at various concentrations was studied. The colloidal probes in the studies were natural magnetite and bentonite particles, micrometer-sized spherical silica particles. Sample surfaces were natural magnetite particles, smooth layers of synthetic magnetite nanoparticles and bentonite flakes.Qualitative changes in adhesion forces, i.e. interaction trends, and forces on approach for magnetite-magnetite, magnetite-silica, magnetite-bentonite and bentonite-silica interaction systems with an increase of Ca2+ ion concentration and pH were measured and evaluated. The interaction trends were consistent in most cases with zeta-potential measurements. Possible surface modification and formation of calcium silicates and calcium carbonates at pH 10 on the magnetite surfaces was discussed. The long-range repulsive interaction, similar to a steric-like interaction, was observed in the interactions for bentonite-silica and magnetite-silica systems, likely due to the swelling of bentonite layers and rising of bentonite flakes from the surface. The rising of bentonite flakes in water was verified with cryo-scanning electron microcopy investigation. Furthermore, the measured adhesion forces were compared with calculated adhesion forces, which were evaluated with the use of a few contact mechanics models. The comparison revealed discrepancies, which could be explained by the particle surface roughness. Additionally, a comparison of VSI and AFM techniques for surface characterization was performed on samples possessing sharp periodic surface structures and three stage plateaux honed cast iron surface. This comparison is of high relevance to the accurate calculation of tribological surface roughness parameters. Moreover, force measurements on biological samples and between magnetic particles are also briefly discussed in the thesis.The work within this thesis shows that SPM methods can be successfully applied to measure and predict forces between natural particles, such as magnetite and bentonite, in solution. The obtained and presented results are new and of high interest in applications where the knowledge of the dispersion and aggregation of studied particle interaction is important.

  • 192.
    Dobryden, Illia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Surface characterization and force measurements applied to industrial materials with atomic force microscopy2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The thesis focuses on the application of force measurements with atomic force microscopy (AFM) on materials with a few surface contacts/asperities and chemically modified surfaces. The technique allows measurements of ultra-small intermolecular and surface forces, down to the piconewton level. The force measurements between surfaces of well-defined geometry are often used to measure and model the interaction between different systems of charged and neutral surfaces in various environments. However, detailed knowledge of the contacting surface profile geometry and surface properties is required to model the fundamental forces involved in the interaction. The preparation of such well-defined and idealized surfaces is often time consuming and the surfaces may not possess the behavior and properties of a source material in real processes, such as in industry. Moreover, external factors such as magnetic fields, ionic strengths and pH-values in a solution, may further complicate the evaluation. Hence, it is desirable to explore and develop techniques for trustable measurements of forces between “real” surfaces. These are often a complex composition of various force interactions and multiple surface contacts.The AFM probe technique was explored to measure force interactions between “real” particle surfaces. The work shows the applicability of the AFM technique to study the interaction forces despite the forecasted difficulties with the roughness of the particles.A technique to measure the adhesion and work of adhesion from AFM force curves was implemented and used. The thermal tune method was implemented in our commercial NT-MDT microscope to determine cantilever spring constants. The force interactions between natural microsize (m-s) magnetite particles and synthetic nanosize (n-s) magnetite particles were studied in calcium solution with concentrations of 1, 10, 100 mM and at pH values 4, 6 and 10. The changes in force interactions, due to variations in calcium concentration and pH were investigated. The adhesion force change with the concentration and pH was similar for m-s/m-s and m-s/n-s systems, and the adhesion force increased with the concentration at pH 6, except for the highest calcium concentration of 100 mM at pH 10. It was found that the magnetite surface modification could appear at the highest calcium concentration at pH 10. Moreover, the thesis contains preliminary results of the force interaction study between natural and synthetic bentonite-magnetite particles in calcium solution with concentrations of 1, 10 and 100 mM at pH 6.The influence of roughness on the calculation of contact mechanics parameters were studied with AFM and Vertical Scanning Interferometry (VSI). This is important for future development of a model to describe and characterize the force interaction between samples with multiple surface contacts. It was found that the optical artifacts, induced by VSI, have a large influence on all the roughness parameters calculated on the calibration grids, which represent extreme surface topographies.

  • 193.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Yang, Xiaofang
    Scanning probe microscopy study of magnetite particle force interactions in a solution2011Konferansepaper (Annet vitenskapelig)
  • 194.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Potapova, Elisaveta
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Application of AFM to probe micro- and nano-sized magnetite particle interaction in Ca2+ solution2014Inngår i: Proceedings of the International Summer School on Application of Scanning Probe Microscopy in Life Sciences, Soft Matter and Nanofabrication", Aalborg: River Publishers, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Natural magnetite is used for producing iron ore pellets, one of the raw materials in steel production. The quality of produced pellets depends on many factors, including the properties of the magnetite concentrate fed to pelletization. To be able to minimize the effect of the variations in feed properties on pellets quality, investigation of magnetite particle interaction with a focus on the surface properties is required. Atomic force microscopy (AFM), using the colloidal probe technique, is a suitable tool for measuring such particle-particle interaction in-situ. Natural particles are usually of micro-sizes (m-s) and have different sizes and shapes, which complicates an accurate investigation of particle interaction with AFM. To overcome such difficulties, synthetic nanoparticles are used instead. Process water chemistry is one of the factors affecting magnetite surface properties. Partial dissolution of calcite and apatite minerals, present in iron ore, results in high Ca2+ concentrations in the process water, which has been shown to have a major effect on the charge of the magnetite particles [1, 2]. The aim of this study was therefore to investigate forces and aggregation between magnetite particles, of micro- and nano-size (n-s), in Ca2+ solutions at various pH values. The spherical monodispersed magnetite nano-sized particles, with a diameter of approx. 10 nm, were synthesized by the precipitation technique [3]. Measurements were performed for m-s probe/m-s layer and m-s probe/n-s layer systems. Natural magnetite particles of 10-30 µm size were glued to NP-S cantilevers (Digital Instruments/Bruker, Santa Barbara, CA) with a measured spring constant of 0.12 N/m. Nano-sized particles were deposited on the glass slides by dip-coating. Roughness (Ra) of the n-s layers was measured with AFM and was about 10 nm for areas 1×1µm2, a representative high-resolution image is shown in Figure 1. Particle interaction was similar for m-s and n-s magnetite particles at pH 4 and 6. At pH 10, the interaction behavior was different due to probable surface modification of natural magnetite particles by ions from process water. The adhesion force for both interacting systems was measured, see ref. [4] for a detailed description of the results. To verify that ϛ-potential measurements could be used to predict the interaction between charged particles (in this case silica and magnetite) in solutions containing inorganic ions, force measurements between n-s magnetite layer and a SiO2 spherical probe (3.5 µm in diameter) were performed and correlated with the ϛ-potential results for these particles in the same solutions. Also, a DLVO simulation was performed to theoretically confirm the experimental interaction based on surface charge trends. An example of the simulated force curves is shown in Figure 2. The interaction between the probe and the magnetite surface was attractive at pH 4 and 6 but became repulsive at pH 8 and 10, which is in agreement with what could be expected from the ϛ-potential results for these particles.

  • 195.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Potapova, Elisaveta
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Force interactions between magnetite, silica, and bentonite studied with atomic force microscopy2015Inngår i: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 42, nr 4, s. 319-326Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iron ore pellets consist of variety of mineral particles and are an important refined product used in steel manufacturing. Production of high-quality pellets requires good understanding of interactions between different constituents, such as magnetite, gangue residues, bentonite, and additives. Much research has been reported on magnetite, silica, and bentonite surface properties and their effect on pellet strength but more scant with a focus on a fundamental particle–particle interaction. To probe such particle interaction, atomic force microscopy (AFM) using colloidal probe technique has proven to be a suitable tool. In this work, the measurements were performed between magnetite–magnetite, bentonite–magnetite, silica–bentonite, and silica–magnetite particles in 1 mM CaCl2 solution at various pH values. The interaction character, i.e., repulsion or attraction, was determined by measuring and analyzing AFM force curves. The observed quantitative changes in interaction forces were in good agreement with the measured zeta-potentials for the particles at the same experimental conditions. Particle aggregation was studied by measuring the adhesion force. Absolute values of adhesion forces for different systems could not be compared due to the difference in particle size and contact geometry. Therefore, the relative change of adhesion force between pH 6 and 10 was used for comparison. The adhesion force decreased for the magnetite–magnetite and bentonite–silica systems and slightly increased for the magnetite–bentonite system at pH 10 as compared to pH 6, whereas a pronounced decrease in adhesion force was observed in the magnetite–silica system. Thus, the presence of silica particles on the magnetite surface could have a negative impact on the interaction between magnetite and bentonite in balling due to the reduction of the adhesion force.

  • 196.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden.
    Touati, Baligh
    Physics Condensed Matter Laboratory, Faculty of Science of Tunis, University of Tunis El-Manar.
    Gassoumi, Abdelaziz
    Physics Condensed Matter Laboratory, Faculty of Science of Tunis, University of Tunis El-Manar.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Kamoun, Najoua
    Physics Condensed Matter Laboratory, Faculty of Science of Tunis, University of Tunis El-Manar.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Morphological and electrical characterization of Cu-doped PbS thin films with AFM2017Inngår i: Advanced Materials Letters, ISSN 0976-3961, E-ISSN 0976-397X, Vol. 8, nr 11, s. 1029-1037Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lead sulphide (PbS) is a direct band gap IV–VI intrinsic p-type semiconductor with good potential for application in solar cells, sensors, etc. Doping the films with Cu2+ ions may improve the electrical properties. Here, Cu-doped PbS films were deposited on conducting glass substrates. The morphology, topography and thickness of the doped PbS films were examined using atomic force microscopy (AFM) and high-resolution SEM. AFM analysis showed decreasing surface roughness and grain size with the increase of Cu2+ concentration from 0.5 to 2.0 at%. Local surface electrical measurements using conducting AFM and Kelvin probe force microscopy showed the possibility to probe semi-quantitatively the changes in surface potential, work function, and Fermi level upon doping of the films. The estimated apparent work function for the un-doped PbS grains in the film was slightly above 4.5 eV, while it decreased to a minimum value of 4.43-4.45 eV at 1–1.5 at% Cu-doping. Conducting AFM measurements showed that local resistance of the doped samples is lower than on pure PbS films. These results indicate Cu doping as an effective strategy to tune the electrical properties of PbS thin films toward the development of suitable optically active materials for application in photovoltaics.

  • 197.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Yang, Xiaofang
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    An atomic force microscopy study of the interaction between magnetite particles: the effect of Ca2 + ions and pH2013Inngår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 233, s. 116-122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Force interactions between a microsize (m-s) magnetite probe and thin layers of synthesized magnetite particles as well as microsize (m-s) magnetite particles from magnetite concentrate were investigated using atomic force microscopy (AFM). Of special interest was the influence of Ca2 + ions and pH on the interaction between the probe and the two different magnetite particle surfaces. The probe and the magnetite surfaces were immersed in aqueous Ca2 + solutions (100, 10, and 1 mM) at various pH values (4, 6, and 10). The colloidal probe technique and a self-made computer program for automatic evaluation of adhesion forces were used. The analysis revealed an increase in adhesion force with increased calcium concentration at pH 6 for both the systems investigated. However, the adhesion behavior between the probe and the m-s and n-s magnetite particle surfaces is different at pH 10. The possible appearance of calcium carbonate precipitated onto the magnetite surfaces as well as the possible influence of already adsorbed silicate on magnetite particles from the concentrate is discussed. In addition to Ca, Cl and Na atoms, added to the working solutions, and the Fe and O detected signals, the SEM-EDS analysis also detected Si atoms on the surface of the m-s particles.

  • 198.
    Dobryden, Illia
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Yang, Xiaofang
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Interaction forces between surface modified magnetite particles in aqueous solution2011Konferansepaper (Annet vitenskapelig)
  • 199.
    Donarelli, Maurizio
    et al.
    SENSOR Lab., Department of Information Engineering, University of Brescia.
    Milan, Riccardo
    SENSOR Lab., Department of Information Engineering, University of Brescia.
    Rigoni, Federica
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. SENSOR Lab., Department of Information Engineering, University of Brescia.
    Drera, Giovanni
    Department of Mathematics and Physics, Catholic University of Sacred Heart.
    Sangaletti, Luigi
    Department of Mathematics and Physics, Catholic University of Sacred Heart.
    Ponzoni, Andrea
    National Institute of Optics, National Research Council (CNR-INO), Unit of Brescia.
    Baratto, Camilla
    SENSOR Lab., Department of Information Engineering, University of Brescia.
    Sberveglier, Giorgio
    SENSOR Lab., Department of Information Engineering, University of Brescia.
    Comini, Elisabetta
    SENSOR Lab., Department of Information Engineering, University of Brescia.
    Anomalous gas sensing behaviors to reducing agents of hydrothermally grown α-Fe2O3 nanorods2018Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 273, s. 1237-1245Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    α-Fe2O3 nanorods have been grown by hydrothermal method, dispersed in ethanol and drop casted on a pre-patterned alumina substrate with Pt electrodes. Their morphology, crystalline and electronic properties have been investigated by Scanning Electron Microscopy, Raman and X-ray Photoelectron Spectroscopies and X-ray Diffraction. The so-fabricated devices have been used for hydrogen gas sensing, showing their ability to detect H2 at operating temperatures > 200 °C, at relative humidity values comprised from 0% to 50%. The sensing behavior of α-Fe2O3 nanorods is compatible with an n to p conductivity transition when the operating temperature is increased up to 300 °C. Outstanding p-type hydrogen sensing performances of α-Fe2O3 have been observed and reported. Besides H2 detection, the α-Fe2O3 nanorods-based device is a good humidity sensor, at room temperature (n-type) and at 400 °C (p-type). CO and ethanol sensing performances have been investigated at different operating temperatures and relative humidity values. CO and ethanol anomalous acceptor-like behaviors at 200 °C in humid air has been explained by the interactions of these target gases with the water molecules adsorbed on the metal oxide surfaces. An explanation of the n–p behavior transition at T > 200 °C in terms of band bending is reported.

  • 200.
    Drab, Mitja
    et al.
    Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia.Laboratory of Clinical Biophysics, Chair of Orthopaedic Surgery, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
    Mesarec, Luka
    Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia.
    Imani, Roghayeh
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Jeran, Marko
    Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia. Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia.
    Junkar, Ita
    Department of Surface Engineering and Optoelectronics, “Jožef Stefan” Institute, Ljubljana, Slovenia.
    Kralj-Iglič, Veronika
    Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia. Institute of Biosciences and BioResources, National Research Council of Italy, Italy.
    Kralj, Samo
    Condensed Matter Physics Department, “Jožef Stefan” Institute, Ljubljana, Slovenia. Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia.
    Iglič, Aleš
    Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia. Laboratory of Clinical Biophysics, Chair of Orthopaedic Surgery, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia. Institute of Biosciences and BioResources, National Research Council of Italy, Italy.
    Chapter Six - The role of membrane vesiculation and encapsulation in cancer diagnosis and therapy2019Inngår i: Advances in Biomembranes and Lipid Self-Assembly, ISSN 2451-9634, Vol. 29, s. 159-199Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We summarize recent findings and advances in cancer diagnostics in relation to extracellular vesicles (EVs) and emerging therapeutic options of nanomaterials. We revise the common mechanism for EV inception, vesiculation, through a physical model of the liquid mosaic membrane with laterally mobile membrane rafts that determine local spontaneous curvature. If such in-plane orientational ordering is present, we show that spatial non-homogeneities may trigger energetically favourable membrane vesiculation. In addition, we revise a novel technique of cancer therapy using multifunctional titanium nanobeads (NBs) that form a fully biocompatible system used for optical imaging, magnetic resonance imaging and selective reactive oxygen species photo-generation. We study the encapsulation of these functional NBs theoretically with Monte Carlo (MC) simulations and find that the wrapping transition depends on the strength of mobile charges, giving insight into future functional optimization for maximum therapeutic benefit.

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