Eleonora Bolli - Academia.edu (original) (raw)

Papers by Eleonora Bolli

The Cambridge Structural Database, 2023

Nano-micro letters, Apr 26, 2024

ACS applied energy materials, Jan 30, 2024

Surfaces and interfaces, Mar 1, 2024

Zeitschrift für Kristallographie, Aug 31, 2023

Surface and Interface Analysis, Jan 24, 2023

Internal prosthesis and grafts are currently made of Ti alloys, stainless steels and Co–Cr alloys... more Internal prosthesis and grafts are currently made of Ti alloys, stainless steels and Co–Cr alloys. In spite of excellent biocompatibility, they show some drawbacks that concern their mechanical properties (e.g. elastic modulus) and the need of secondary surgery for removing the implant. For this reason, a growing attention has been focused on biodegradable materials that can be absorbed into the body after tissue remodelling. In particular, Mg alloys are promising candidates for temporary implants thanks to their high biocompatibility, biodegradability and good mechanical properties that match those of human bone. In this work, the surface modifications of biodegradable AZ31 alloy were analysed after immersion for 15 days in a physiological solution (NaCl 0.09%) by using X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. XPS analysis of the surface of as‐supplied AZ31 alloy showed the presence of MgO, whereas after immersion in the physiological solution, only Mg (OH)2 was detected. The result has been discussed with reference to literature data. From the photoemission spectra and quantitative analysis, a small amount of Ca (about 2 wt%) was also detected.

Surface and Interface Analysis, Dec 22, 2022

Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work fu... more Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work function of photovoltaic (PV) anodes in hybrid thermionic devices for the conversion of thermal‐to‐electrical energy. Because PV anodes integrated in thermionic converters can operate at temperatures higher than room temperature, in this study, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the temperature dependence up to 300°C of the chemical and physical properties of BaFx thin‐films, deposited on gallium arsenide and silicon, that represent possible candidates for PV anodes. A correlation between chemical composition and work function reduction by 0.5 ± 0.1 eV for the thin films on both GaAs and Si has been found as a function of temperature from room temperature to 300°C. According to XPS analyses, this effect can be ascribable to the thermal desorption of the first contaminated layers of BaFx coatings.

Nanomaterials

Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate th... more Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) measurements were performed on the films deposited by electron-beam evaporation with different nominal thicknesses (in the range of 2–50 nm) and in multi-layered mixed structures with barium fluoride (BaF2) films. The obtained results indicate that non-continuous films are required to minimize the work function (down to 2.7 eV at room temperature), thanks to the formation of surface dipole effects between crystalline islands and substrates, even if the stoichiometry is far from the ideal one (Sc/O = 0.38). Finally, the presence of BaF2 in multi-layered films is not beneficial for a further reduction in the work function.

Surface and Interface Analysis

Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work fu... more Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work function of photovoltaic (PV) anodes in hybrid thermionic devices for the conversion of thermal‐to‐electrical energy. Because PV anodes integrated in thermionic converters can operate at temperatures higher than room temperature, in this study, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the temperature dependence up to 300°C of the chemical and physical properties of BaFx thin‐films, deposited on gallium arsenide and silicon, that represent possible candidates for PV anodes. A correlation between chemical composition and work function reduction by 0.5 ± 0.1 eV for the thin films on both GaAs and Si has been found as a function of temperature from room temperature to 300°C. According to XPS analyses, this effect can be ascribable to the thermal desorption of the first contaminated layers of BaFx coatings.

Micromachines

Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed l... more Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed laser irradiation (100 fs duration, 800 nm wavelength, 1.44 J cm−2 single pulse fluence) to analyse the evolution of induced alterations on the surface morphology and structural properties. The aim was to identify the occurrence of laser-induced periodic surface structures (LIPSS) as a function of the number of pulses released on the unit area. Micro-Raman spectroscopy pointed out an increase in the graphite surface content of the films following the laser irradiation due to the formation of ordered carbon sites with respect to the pristine sample. SEM and AFM surface morphology studies allowed the determination of two different types of surface patterning: narrow but highly irregular ripples without a definite spatial periodicity or long-range order for irradiations with relatively low accumulated fluences (<14.4 J cm−2) and coarse but highly regular LIPSS with a spatial periodicity o...

Nanomaterials

A recent innovation in diamond technology has been the development of the “black diamond” (BD), a... more A recent innovation in diamond technology has been the development of the “black diamond” (BD), a material with very high optical absorption generated by processing the diamond surface with a femtosecond laser. In this work, we investigate the optical behavior of the BD samples to prove a near to zero dielectric permittivity in the high electric field condition, where the Frenkel-Poole (FP) effect takes place. Zero-epsilon materials (ENZ), which represent a singularity in optical materials, are expected to lead to remarkable developments in the fields of integrated photonic devices and optical interconnections. Such a result opens the route to the development of BD-based, novel, functional photonic devices.

Micromachines, Feb 4, 2023

Advanced Materials Technologies

Materials

Surfaces of commercial molybdenum (Mo) plates have been textured by fs-laser treatments with the ... more Surfaces of commercial molybdenum (Mo) plates have been textured by fs-laser treatments with the aim to form low-cost and efficient solar absorbers and substrates for thermionic cathodes in Concentrated Solar Power conversion devices. Morphological (SEM and AFM), optical (spectrophotometry), and structural (Raman spectroscopy) properties of the samples treated at different laser fluences (from 1.8 to 14 J/cm2) have been characterized after the laser treatments and also following long thermal annealing for simulating the operating conditions of thermionic converters. A significant improvement of the solar absorptance and selectivity, with a maximum value of about four times higher than the pristine sample at a temperature of 800 K, has been detected for sample surfaces treated at intermediate fluences. The effects observed have been related to the light trapping capability of the laser-induced nanotexturing, whereas a low selectivity, together with a high absorptance, could be reveal...

Dalton Transactions

The optoelectronic features of 3-hydroxyflavone (3HF) self-assembled on the surface of an n-type ... more The optoelectronic features of 3-hydroxyflavone (3HF) self-assembled on the surface of an n-type semiconducting metal oxide (TiO2) and an insulator (Al2O3) are herein investigated.

ACS Applied Materials & Interfaces

Surface and Interface Analysis

The Cambridge Structural Database, 2023

Nano-micro letters, Apr 26, 2024

ACS applied energy materials, Jan 30, 2024

Surfaces and interfaces, Mar 1, 2024

Zeitschrift für Kristallographie, Aug 31, 2023

Surface and Interface Analysis, Jan 24, 2023

Internal prosthesis and grafts are currently made of Ti alloys, stainless steels and Co–Cr alloys... more Internal prosthesis and grafts are currently made of Ti alloys, stainless steels and Co–Cr alloys. In spite of excellent biocompatibility, they show some drawbacks that concern their mechanical properties (e.g. elastic modulus) and the need of secondary surgery for removing the implant. For this reason, a growing attention has been focused on biodegradable materials that can be absorbed into the body after tissue remodelling. In particular, Mg alloys are promising candidates for temporary implants thanks to their high biocompatibility, biodegradability and good mechanical properties that match those of human bone. In this work, the surface modifications of biodegradable AZ31 alloy were analysed after immersion for 15 days in a physiological solution (NaCl 0.09%) by using X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. XPS analysis of the surface of as‐supplied AZ31 alloy showed the presence of MgO, whereas after immersion in the physiological solution, only Mg (OH)2 was detected. The result has been discussed with reference to literature data. From the photoemission spectra and quantitative analysis, a small amount of Ca (about 2 wt%) was also detected.

Surface and Interface Analysis, Dec 22, 2022

Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work fu... more Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work function of photovoltaic (PV) anodes in hybrid thermionic devices for the conversion of thermal‐to‐electrical energy. Because PV anodes integrated in thermionic converters can operate at temperatures higher than room temperature, in this study, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the temperature dependence up to 300°C of the chemical and physical properties of BaFx thin‐films, deposited on gallium arsenide and silicon, that represent possible candidates for PV anodes. A correlation between chemical composition and work function reduction by 0.5 ± 0.1 eV for the thin films on both GaAs and Si has been found as a function of temperature from room temperature to 300°C. According to XPS analyses, this effect can be ascribable to the thermal desorption of the first contaminated layers of BaFx coatings.

Nanomaterials

Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate th... more Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) measurements were performed on the films deposited by electron-beam evaporation with different nominal thicknesses (in the range of 2–50 nm) and in multi-layered mixed structures with barium fluoride (BaF2) films. The obtained results indicate that non-continuous films are required to minimize the work function (down to 2.7 eV at room temperature), thanks to the formation of surface dipole effects between crystalline islands and substrates, even if the stoichiometry is far from the ideal one (Sc/O = 0.38). Finally, the presence of BaF2 in multi-layered films is not beneficial for a further reduction in the work function.

Surface and Interface Analysis

Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work fu... more Thin films based on barium fluoride (BaFx) have demonstrated the capability to reduce the work function of photovoltaic (PV) anodes in hybrid thermionic devices for the conversion of thermal‐to‐electrical energy. Because PV anodes integrated in thermionic converters can operate at temperatures higher than room temperature, in this study, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the temperature dependence up to 300°C of the chemical and physical properties of BaFx thin‐films, deposited on gallium arsenide and silicon, that represent possible candidates for PV anodes. A correlation between chemical composition and work function reduction by 0.5 ± 0.1 eV for the thin films on both GaAs and Si has been found as a function of temperature from room temperature to 300°C. According to XPS analyses, this effect can be ascribable to the thermal desorption of the first contaminated layers of BaFx coatings.

Micromachines

Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed l... more Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed laser irradiation (100 fs duration, 800 nm wavelength, 1.44 J cm−2 single pulse fluence) to analyse the evolution of induced alterations on the surface morphology and structural properties. The aim was to identify the occurrence of laser-induced periodic surface structures (LIPSS) as a function of the number of pulses released on the unit area. Micro-Raman spectroscopy pointed out an increase in the graphite surface content of the films following the laser irradiation due to the formation of ordered carbon sites with respect to the pristine sample. SEM and AFM surface morphology studies allowed the determination of two different types of surface patterning: narrow but highly irregular ripples without a definite spatial periodicity or long-range order for irradiations with relatively low accumulated fluences (<14.4 J cm−2) and coarse but highly regular LIPSS with a spatial periodicity o...

Nanomaterials

A recent innovation in diamond technology has been the development of the “black diamond” (BD), a... more A recent innovation in diamond technology has been the development of the “black diamond” (BD), a material with very high optical absorption generated by processing the diamond surface with a femtosecond laser. In this work, we investigate the optical behavior of the BD samples to prove a near to zero dielectric permittivity in the high electric field condition, where the Frenkel-Poole (FP) effect takes place. Zero-epsilon materials (ENZ), which represent a singularity in optical materials, are expected to lead to remarkable developments in the fields of integrated photonic devices and optical interconnections. Such a result opens the route to the development of BD-based, novel, functional photonic devices.

Micromachines, Feb 4, 2023

Advanced Materials Technologies

Materials

Surfaces of commercial molybdenum (Mo) plates have been textured by fs-laser treatments with the ... more Surfaces of commercial molybdenum (Mo) plates have been textured by fs-laser treatments with the aim to form low-cost and efficient solar absorbers and substrates for thermionic cathodes in Concentrated Solar Power conversion devices. Morphological (SEM and AFM), optical (spectrophotometry), and structural (Raman spectroscopy) properties of the samples treated at different laser fluences (from 1.8 to 14 J/cm2) have been characterized after the laser treatments and also following long thermal annealing for simulating the operating conditions of thermionic converters. A significant improvement of the solar absorptance and selectivity, with a maximum value of about four times higher than the pristine sample at a temperature of 800 K, has been detected for sample surfaces treated at intermediate fluences. The effects observed have been related to the light trapping capability of the laser-induced nanotexturing, whereas a low selectivity, together with a high absorptance, could be reveal...

Dalton Transactions

The optoelectronic features of 3-hydroxyflavone (3HF) self-assembled on the surface of an n-type ... more The optoelectronic features of 3-hydroxyflavone (3HF) self-assembled on the surface of an n-type semiconducting metal oxide (TiO2) and an insulator (Al2O3) are herein investigated.

ACS Applied Materials & Interfaces

Surface and Interface Analysis