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Physics of Condensed Matter, Atoms and Molecules

The research activity carried out by the members of the Physics of Condensed Matter, Atoms and Molecules group deals with fundamental issues related to physical properties of condensed matter and of advanced knowledge-based materials. Research is fully integrated in the national and international scenario and it is funded by national (PRIN, FIRB) and international (H2020, large scale infrastructures) projects.

The focus is mainly on systems possessing physical properties with high technological potential and social relevance (e.g. nanostructured materials for electronic, biosensing and energy applications) and development of advanced methods in the field of synchrotron radiation and laser spectroscopy.

The group constitutes the main nucleus of the Bologna Research Unit of the Consorzio Nazionale per le Scienze Fisiche della Materia (CNISM)

The attention devoted to applicative developments of fundamental research results has triggered the constitution of two academic Start Ups targeted to the industrial exploitation of technologically valuable know-how. Some members of the group are active in the Technology Transfer activity of the Department and are affiliated to the CIRI-MaM center through consultancy and contract collaboration with Italian SMEs. This activity has brought about the approval of various international patents.

 

X-ray and Synchrotron radiation physics

F.Boscherini (Full Prof.), L.Pasquini (Assoc. Prof.), G. Rossi (PhD student), N. Patelli (PhD student)

New and highly refined methods for investigation of the physical properties of condensed matter have been developed thanks to the great recent advances in synchrotron radiation and free electron laser sources. In this context, we focus on the use of x-ray spectroscopic methods such as X-ray Absorption Fine Structure (XAFS) and Resonant Inelastic X-ray Scattering (RIXS) as tools to investigate the static and dynamic properties of advanced materials and nanostructures. Current emphasis is on the study of processes accompanying visible light absorption by means of differential and time resolved methods, especially in materials relevant for energy conversion.

This research is funded by a PRIN 2015 project (NEWLI: NEW LIght on transient states in condensed matter by advanced photon - electron spectroscopies, PI Boscherini), University of Bologna RFO funds and access to large scale facilities.

This research is carried out in collaboration with several Institutes of CNR - “Istituto Officina dei Materiali” www.iom.cnr.it, NANO (www.nano.cnr.it) and “Istituto Struttura della Materia” (www.ism.cnr.it) and ESRF and Elettra synchrotron radiation laboratories (www.esrf.eu and www.elettra.eu).

 

Organic semiconductors and nanostructured this films for advanced electronic devices

B. Fraboni (Assoc. Prof.), D. Cavalcoli (Assoc. Prof.), T. Cramer (Assist. Prof.), L. Basiricò (Post Doc.), M.Tessarolo (Post Doc.), A. Ciavatti (Post Doc.), D.Cavedale (Post Doc), F.Decataldo (PhD student).

Organic (carbon-based) semiconductors possess peculiar properties that make them ideal candidates to develop innovative flexible, transparent or wearable electronics (e.g., plastic, rollable large area active matrices for computer screens, smart textiles, photo-detectors and molecular sensors). Moreover, the possibility to use synthetic chemistry and inexpensive solution-based or printing fabrication techniques makes organic semiconductors and high mobility oxides extremely viable novel materials for future technologies. Our research activity is focused on the fundamental aspects of charge transport processes within organic materials (e.g. charge carrier generation, transport and collection) and on radiation-matter interaction effects, phenomena that are still far from being understood, despite the thriving performance of organic based devices. We carry out experimental electrical, spectroscopic and structural characterization on the following main areas:

a. Organic semiconducting single crystals. We recently showed how effective, direct ionizing radiation detectors (e.g. X-rays and alpha particles) can be realized based on solution-grown organic semiconducting single crystals. This research is carried out in the framework of FP7 –iFLEXIS (www.iflexis.eu) project, cooodinated by the Bologna group in collaboration with nine partners (University of Lisbon, CEA France, University of Trieste, University of Cagliari, Eurorad-France, Nanograde-Switzerland, Tagsys-France, Bioage-Italia). Other active collaborations include Max-Planck Institut Mainz-Germania, University of Kentucky (USA), University of Surrey (UK), University of Cambridge (UK), University of Linz (Austria) and Elettra synchrotron radiation laboratory, Italia (www.elettra.eu).

b. Nanostructured polymers for smart textiles and organic bioelectronics: Wearable electronics offers many prospective applications such as sensing/monitoring of body functions. We developed a novel nanoscale modification process, based on thin layers of the conductive polymer poly(3,4-ethylenedioxithiophene) (PEDOT) to fabricate passive and active devices such as organic electrochemical transistors (OECTs) directly onto fabric yarns. This research is partly funded by the Regional project “MATRICS”, carried out in collaboration with the Politecnico di Milano (2016-2018) and by the MISE project “LET’S” for innovative Research (2017-2019). Other active collaborations include Ecole Normale Des Mines EMSE (France), Ludwig-Maximillian Universitat Monaco (Germania), Max Planck institute Mainz (Germania)  and University of Wollongong (Australia)

c. High mobility oxides for flexible and transparent electronic devices: High mobility oxide semiconductors such as Zinc Tin Oxide (ZTO) and Gallium Indium Zinc Oxide (GIZO) combine unique electrical performance as active materials in thin-film transistors (TFTs). Flexible and transparent devices can be realized on unconventional light-weight substrates, with field-effect mobility above 10 cm2/Vs and operating voltage below 10V. This research is carried out in collaboration with the New University of Lisbon and with Los Alamos National Laboratory (USA)

 

Semiconductors and nanostructures for photovoltaics and photonic applications

D. Cavalcoli (Assoc. Prof.), B. Fraboni (Assoc. Prof.), G. Piacentini (Post Doc), M.A.Fazio (PhD student)

  1. Semiconductor thin films and nanostructures for photovoltaics:Silicon is a material widely employed in the field of nano- and micro-electronics, as well as in photovoltaics. Si can have different phases, such as amorphous, crystalline, nano-crystalline and nanostructured. Even though silicon is widely spread and studied in the last 60 years, the physical properties of Si nanostructures are still debated and under investigation. Si based oxides, mixed amorphous- nanocrystalline Si based thin films show intriguing electrical and optical properties that can lead to interesting applications in high efficiency heterojunction Si solar cells, thin film solar cells. The goal of the research is to study transport, optical, structural and microscopical properties of thin films for photovoltaic applications. In addition to Si, also Germanium nanostructures and compounds containing Cu, In, Zn, S are investigated. Advanced materials like inorganic perovskites, which could replace organic perovskites in advanced solar cell technology, are also investigated.
  2. III-Nitrides for photonics and power electronics: III-Nitrides compounds (III-N, GaN, InN, AlN), Ga oxides, and their alloys have wide band gaps ranging from blue to near UV. Even though III-N are now widely diffused in the market (solid state illumination, LED and LASER, high frequency electronics), their fundamental properties, in particular the role of defects, are still unclear. The goal of the research is to study quantum confinement, transport properties, defects and degradation mechanisms through the employment of electrical, spectroscopic and microscopic characterizations tools. Electronic properties are investigated by charge collection spectroscopy methods. Funding: UniBo, UE FP-7 (ITN-RAINBOW e IRRESISTIBLE), Regione Emilia Romagna (Spinner Project).

Collaborations: University of Konstanz, Physics Department and Forschungszentrum, Institute of Energy and Climate Research Jülich, Germany; MACEPV Group, CNRS, Strasbourg, France; Energy research Centre of the Netherlands (ECN); University of Milan Bicocca, Materials Science Department; CNR-MATIS and Physics Department, Catania; IMEM-CNR Parma.

 

Nanostructured materials for energy conversion and storage

L. Pasquini (Assoc. Prof.), F. Boscherini (Full Prof.), S. Sanna (Researcher), M.Calizzi (PhD student), N. Patelli (PhD student)

The conversion and storage of energy represent a key issue to promote an efficient management of energy resources. Development in this field requires real breakthroughs in materials physics. We are working since several years on the subject of hydrogen in advanced nanostructured materials. In particular, we have developed magnesium-based nanomaterials with outstanding hydrogen sorption kinetics and storage properties at low temperature. Furthermore, we study the potentiality of carbon-based nanostructures, mainly graphene and intercalated fullerene, as hydrogen storage materials and ionic conductors. In parallel, we are investigating semiconductor oxides for photocatalytic applications. In this framework, in addition to the growth of nanostructures by means of physical deposition techniques under high vacuum, we carry out structural analysis by electron microscopy, X-ray diffraction and absorption, and characterize the thermodynamic and kinetic properties. Our activity benefits from several scientific collaborations with European centers of excellence, also within the network created by the recently completed COST Action “Nanostructured materials for solid-state hydrogen storage”: http://www.cost-mp1103.eu.

 

Cold atom interferometry

M. Prevedelli (Assoc. Prof.)

Laser-cooled atoms are, by now, a standard tool for precision measurements. Both time and frequency standards and inertial sensors can be implemented starting from clouds of 104 - 107 atoms cooled down to few mK. Presently, high sensitivity interferometers that can measure the local value of the gravitational field g with more than 11 digits are under construction. Apart from the obvious applications in geological prospection, these instruments will allow extremely sensitive tests of the equivalence principle ("All bodies fall with the same acceleration") or of the Newton's law of gravitation at small distances (d < 1 mm) (Magia experiment, INFN and Univ. of Firenze). A mixed, optical and atomic, interferometer for gravitational wave detection is also under development (MIGA experiment, Univ. of Bordeaux). A very special test of the equivalence principle aims at measuring the free fall acceleration of antihydrogen atoms (Aegis experiment at CERN). The group is involved in all the experiments previously mentioned.

 

Technology transfer

E. Campari (Assoc. Prof.)

This activity is carried out in collaboration with SMEs, mainly from Emilia Romagna region. It regards items as different as coffee machines and joints for oil industry, realization of spectral hypercameras and magnetostrictive sensors, cork stoppers and rubber o-ring characterization. Common to all activities is the need for enterprises to gain access to University know-how and instrumentation, especially with regard to those regarding Condensed Matter Physics. This activity has resulted in filing and approval of several patents.

 

Magnetism and superconductivity

S.Sanna (Researcher)

New magnetic and superconducting materials offer spectacular quantum phenomena as well as many technological perspectives. The research is focused on the study of magnetism, unconventional superconductivity and related electronic phenomena of new compounds, in bulk form (powder/ single crystals), as well as thin films and nanoparticles. The principle experimental approach is the use of powerful microscopic probes of condensed matter, such as nuclei and muons, to reveal information that cannot be obtained by other methods. In addition macroscopic characterization such as x-rays and neutron diffraction, transport and magnetization measurement are used to complement the experimental investigation. The main compounds under investigation are superconducting and magnetic iron pnictides, heavy fermions, nanomagnets, magnetic nanoparticles and pyrochlores.

Experiments of Muon Spectroscopy are regularly performed at the Paul Sherrer Institute in Switzerland (https://www.psi.ch/lmu/) and Rutherford Appleton Labs in United Kingdom (http://www.stfc.ac.uk/). Nuclear Magnetic Resonance measurements are carried out in collaboration with the Physics Department of Parma (http://smfi.unipr.it/it) and Pavia (http://nmrphysics.unipv.it/). The characterization of the macroscopic properties is performed at the Department of Physics and Astronomy of Bologna and also in collaboration with the SPIN-CNR Institute of Genoa (http://www.ge.spin.cnr.it/).

Contacts

Federico Boscherini

Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5805

fax: +39 051 20 9 5113

Daniela Cavalcoli

Associate Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5116

Enrico Gianfranco Campari

Associate Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5148

Tobias Cramer

Senior assistant professor (fixed-term)

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5131

Beatrice Fraboni

Associate Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5806

Luca Pasquini

Associate Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5149

fax: +39 051 20 9 5153

Marco Prevedelli

Associate Professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 1122

Samuele Sanna

Assistant professor

Dipartimento di Fisica e Astronomia - DIFA

Viale Berti Pichat 6/2

Bologna (BO)

tel: +39 051 20 9 5068