I followed the Master of Science in Physics at the University of Rome Tor Vergata.
The work of my thesis, entitled "Measurements of Anisotropy in Surface Reflectance Infrared (IR-RAS) on the optical-transition of dangling bonds in Si (111) electron-phonon interaction and 2x1 as a function of temperature", was held under the supervision of Prof. G. Chiarotti. Always at the University of Tor Vergata, I obtained my PhD thesis with a study on the optical properties of organic films ("Thin and ultra-thin organic layers investigated by Reflectance Anisotropy Spectroscopy"). The results and their applications in the field of solid state devices (namely gas sensors), have allowed me to win the Giulotto prize and to be called by the Institute des Nanosciences de Paris (Paris-INSP-France) and the J. Kepler University of Linz (Austria).
Currently I am working on the physica-chemical properties of the liquid/solid interface by means of an electrochemical scanning probe microscopy (EC-SPM).
We present a multitechnique investigation of the structural and electronic properties of the prot... more We present a multitechnique investigation of the structural and electronic properties of the prototypical system composed by ultra-thin films of magnetic molecules [Co-tetraphenyl-porphyrins (Co-TPP)] grown on a ferromagnetic substrate [oxygen passivated Fe(0 0 1), namely the Fe(0 0 1)-p(1 × 1)O surface]. Low Energy electron diffraction (LEED) and scanning tunneling microscopy (STM), coupled with first-principles calculations, reveal the formation of a commensurate superstructure at monolayer coverage, made by a square array of flat-lying TPP molecules. UV–photoemission and inverse photoemission spectroscopies (UPS and IPES) are used to investigate their electronic structure. Similar to our previous results on the Zn–TPP growth on Fe(0 0 1)–p(1 × 1)O, the passivation of the metallic surface is able to preserve the photoemission features characteristic of quasi-free molecules, opening the route towards an exploitation of single oxide layers as protective films in organic/inorganic junctions. X-ray photoemission (XPS) and near edge X-ray adsorption fine structure spectroscopies (NEXAFS), are used to reveal the details of the Co–TPP interaction with the substrate.
We propose a method to grow metal tetraphenyl porphyrin (MTPP) molecular layers where a long-rang... more We propose a method to grow metal tetraphenyl porphyrin (MTPP) molecular layers where a long-range structural and magnetic order can be achieved simultaneously and at room temperature by a proper treatment of the ferromagnetic substrate. We focus in particular on the oxygen-passivated Fe(001)-p(1 × 1)O surface, where MTPP molecules (with M=Co and Ni) arrange by forming square commensurate overlayers. Spin-resolved photoemission detects a clear spin-splitting of CoTPP electronic states, while no magnetic response is obtained from NiTPP, as expected from the electronic configuration of the respective free molecules. We link these observations to the decoupling action of oxygen at the interface, whose effect is to enhance the molecular diffusivity and tune the electronic interaction with the substrate electronic structure.
The development of novel protocols and techniques for waste treatment represents the state of the... more The development of novel protocols and techniques for waste treatment represents the state of the art in the so‐called “green conversion”. Chemical wastes deriving from industrial and power‐station processes, which involve organic crystals, can be very hazardous for the environment. Studying their dissolution mechanism, both theoretically and experimentally, represents a mandatory step in the critical task of their disposal. Surprisingly, most of the studies are focused on millimeter scale length, from which one could estimate the crystal dissolution rate. In these studies, where no information about the dissolution mechanism on a molecular scale is provided, etch‐pit formation is recognized as the ultimate mechanism of crystal dissolution.
In this work, we show the morphological evolution of organic nanocrystals on the sub‐micrometer scale range in a reactive dissolution process controlled by pH. This approach allows us to explore ranges of high undersaturation, whereby crystal dissolution occurs even though etch‐pit formation is suppressed. Adopting different surface and bulk‐sensitive techniques (atomic force microscopy, time‐of‐flight secondary ion mass spectroscopy and X‐ray/electron diffraction, Raman spectroscopy, respectively), we investigate the dissolution process of porphyrin thin films deposited on the basal plane of highly oriented pyrolytic graphite, proving that such films constitute a model system to unveil the dissolution mechanism of organic nanocrystals.
ABSTRACT Nickel-iron interfacial intermixing, resulting from annealing ultrathin Ni films grown o... more ABSTRACT Nickel-iron interfacial intermixing, resulting from annealing ultrathin Ni films grown on Fe(001), has been investigated by low-energy electron diffraction, Auger electron spectroscopy and scanning tunnelling microscopy. The Ni/Fe interface has been found to be highly unstable at relatively low annealing temperatures, with dramatic thermal effects on the surface morphology of the Ni/Fe(001) epitaxial films.
The growth process of thin films and multilayers of quaterthiophene and sexithiophene onto molecu... more The growth process of thin films and multilayers of quaterthiophene and sexithiophene onto molecular single crystals has been monitored in situ and in real time during deposition by organic molecular beam epitaxy, measuring the anisotropy of the optical reflectivity. The evolution of the spectra with thickness provides the signature of an epitaxial growth of the films.
ABSTRACT We have recently measured for the first time–by using Reflectance Anisotropy spectroscop... more ABSTRACT We have recently measured for the first time–by using Reflectance Anisotropy spectroscopy- the optical gap between dangling-bond states on a single-domain diamond C(111)-2 × 1 surface. The experimental result we have obtained (1.47±0.02 eV ) represents the conclusion of the long-standing effort to determine if this surface is metallic or semiconducting. The large surface gap (even larger for possible excitonic effects) opens a new scientific question: at the moment neither state-of-the-art band calculations have succeeded in obtaining it, nor has its physical origin been explained.
The growth process of molecular thin films deposited on an interacting crystalline substrate by o... more The growth process of molecular thin films deposited on an interacting crystalline substrate by organic molecular-beam epitaxy is monitored in situ by reflectance anisotropy spectroscopy (RAS). From the RAS signal evolution measured during the early stages of deposition, evidence is found of two opposite growth modes, namely layer-by-layer and island modes, obtained when changing the supersaturation of the vapor phase on the substrate.
Ordered films of porphyrins are routinely obtained by Langmuir-Blodgett technique, with a thickne... more Ordered films of porphyrins are routinely obtained by Langmuir-Blodgett technique, with a thickness control at the level of a single monolayer. The study of their optical anisotropy by reflectance anisotropy spectroscopy (RAS) has evidenced an interesting modification of the spectral line shape around the Soret band of the porphyrin layer after a certain critical thickness has been deposited onto the
Spontaneous deposition of aggregates of a tetraphenylporphyrin derivative, possessing a cationic ... more Spontaneous deposition of aggregates of a tetraphenylporphyrin derivative, possessing a cationic appended functionality, straightforwardly occurs from aqueous solutions. Combined spectroscopic studies and AFM morphological characterisation reveal that these layered films feature a ...
We present a multitechnique investigation of the structural and electronic properties of the prot... more We present a multitechnique investigation of the structural and electronic properties of the prototypical system composed by ultra-thin films of magnetic molecules [Co-tetraphenyl-porphyrins (Co-TPP)] grown on a ferromagnetic substrate [oxygen passivated Fe(0 0 1), namely the Fe(0 0 1)-p(1 × 1)O surface]. Low Energy electron diffraction (LEED) and scanning tunneling microscopy (STM), coupled with first-principles calculations, reveal the formation of a commensurate superstructure at monolayer coverage, made by a square array of flat-lying TPP molecules. UV–photoemission and inverse photoemission spectroscopies (UPS and IPES) are used to investigate their electronic structure. Similar to our previous results on the Zn–TPP growth on Fe(0 0 1)–p(1 × 1)O, the passivation of the metallic surface is able to preserve the photoemission features characteristic of quasi-free molecules, opening the route towards an exploitation of single oxide layers as protective films in organic/inorganic junctions. X-ray photoemission (XPS) and near edge X-ray adsorption fine structure spectroscopies (NEXAFS), are used to reveal the details of the Co–TPP interaction with the substrate.
We propose a method to grow metal tetraphenyl porphyrin (MTPP) molecular layers where a long-rang... more We propose a method to grow metal tetraphenyl porphyrin (MTPP) molecular layers where a long-range structural and magnetic order can be achieved simultaneously and at room temperature by a proper treatment of the ferromagnetic substrate. We focus in particular on the oxygen-passivated Fe(001)-p(1 × 1)O surface, where MTPP molecules (with M=Co and Ni) arrange by forming square commensurate overlayers. Spin-resolved photoemission detects a clear spin-splitting of CoTPP electronic states, while no magnetic response is obtained from NiTPP, as expected from the electronic configuration of the respective free molecules. We link these observations to the decoupling action of oxygen at the interface, whose effect is to enhance the molecular diffusivity and tune the electronic interaction with the substrate electronic structure.
The development of novel protocols and techniques for waste treatment represents the state of the... more The development of novel protocols and techniques for waste treatment represents the state of the art in the so‐called “green conversion”. Chemical wastes deriving from industrial and power‐station processes, which involve organic crystals, can be very hazardous for the environment. Studying their dissolution mechanism, both theoretically and experimentally, represents a mandatory step in the critical task of their disposal. Surprisingly, most of the studies are focused on millimeter scale length, from which one could estimate the crystal dissolution rate. In these studies, where no information about the dissolution mechanism on a molecular scale is provided, etch‐pit formation is recognized as the ultimate mechanism of crystal dissolution.
In this work, we show the morphological evolution of organic nanocrystals on the sub‐micrometer scale range in a reactive dissolution process controlled by pH. This approach allows us to explore ranges of high undersaturation, whereby crystal dissolution occurs even though etch‐pit formation is suppressed. Adopting different surface and bulk‐sensitive techniques (atomic force microscopy, time‐of‐flight secondary ion mass spectroscopy and X‐ray/electron diffraction, Raman spectroscopy, respectively), we investigate the dissolution process of porphyrin thin films deposited on the basal plane of highly oriented pyrolytic graphite, proving that such films constitute a model system to unveil the dissolution mechanism of organic nanocrystals.
ABSTRACT Nickel-iron interfacial intermixing, resulting from annealing ultrathin Ni films grown o... more ABSTRACT Nickel-iron interfacial intermixing, resulting from annealing ultrathin Ni films grown on Fe(001), has been investigated by low-energy electron diffraction, Auger electron spectroscopy and scanning tunnelling microscopy. The Ni/Fe interface has been found to be highly unstable at relatively low annealing temperatures, with dramatic thermal effects on the surface morphology of the Ni/Fe(001) epitaxial films.
The growth process of thin films and multilayers of quaterthiophene and sexithiophene onto molecu... more The growth process of thin films and multilayers of quaterthiophene and sexithiophene onto molecular single crystals has been monitored in situ and in real time during deposition by organic molecular beam epitaxy, measuring the anisotropy of the optical reflectivity. The evolution of the spectra with thickness provides the signature of an epitaxial growth of the films.
ABSTRACT We have recently measured for the first time–by using Reflectance Anisotropy spectroscop... more ABSTRACT We have recently measured for the first time–by using Reflectance Anisotropy spectroscopy- the optical gap between dangling-bond states on a single-domain diamond C(111)-2 × 1 surface. The experimental result we have obtained (1.47±0.02 eV ) represents the conclusion of the long-standing effort to determine if this surface is metallic or semiconducting. The large surface gap (even larger for possible excitonic effects) opens a new scientific question: at the moment neither state-of-the-art band calculations have succeeded in obtaining it, nor has its physical origin been explained.
The growth process of molecular thin films deposited on an interacting crystalline substrate by o... more The growth process of molecular thin films deposited on an interacting crystalline substrate by organic molecular-beam epitaxy is monitored in situ by reflectance anisotropy spectroscopy (RAS). From the RAS signal evolution measured during the early stages of deposition, evidence is found of two opposite growth modes, namely layer-by-layer and island modes, obtained when changing the supersaturation of the vapor phase on the substrate.
Ordered films of porphyrins are routinely obtained by Langmuir-Blodgett technique, with a thickne... more Ordered films of porphyrins are routinely obtained by Langmuir-Blodgett technique, with a thickness control at the level of a single monolayer. The study of their optical anisotropy by reflectance anisotropy spectroscopy (RAS) has evidenced an interesting modification of the spectral line shape around the Soret band of the porphyrin layer after a certain critical thickness has been deposited onto the
Spontaneous deposition of aggregates of a tetraphenylporphyrin derivative, possessing a cationic ... more Spontaneous deposition of aggregates of a tetraphenylporphyrin derivative, possessing a cationic appended functionality, straightforwardly occurs from aqueous solutions. Combined spectroscopic studies and AFM morphological characterisation reveal that these layered films feature a ...
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Papers by G. Bussetti
In this work, we show the morphological evolution of organic nanocrystals on the sub‐micrometer scale range in a reactive dissolution process controlled by pH. This approach allows us to explore ranges of high undersaturation, whereby crystal dissolution occurs even though etch‐pit formation is suppressed. Adopting different surface and bulk‐sensitive techniques (atomic force microscopy, time‐of‐flight secondary ion mass spectroscopy and X‐ray/electron diffraction, Raman spectroscopy, respectively), we investigate the dissolution process of porphyrin thin films deposited on the basal plane of highly oriented pyrolytic graphite, proving that such films constitute a model system to unveil the dissolution mechanism of organic nanocrystals.
In this work, we show the morphological evolution of organic nanocrystals on the sub‐micrometer scale range in a reactive dissolution process controlled by pH. This approach allows us to explore ranges of high undersaturation, whereby crystal dissolution occurs even though etch‐pit formation is suppressed. Adopting different surface and bulk‐sensitive techniques (atomic force microscopy, time‐of‐flight secondary ion mass spectroscopy and X‐ray/electron diffraction, Raman spectroscopy, respectively), we investigate the dissolution process of porphyrin thin films deposited on the basal plane of highly oriented pyrolytic graphite, proving that such films constitute a model system to unveil the dissolution mechanism of organic nanocrystals.