The electrochemical synthesis of ammonia through the nitrogen reduction reaction (NRR) is receivi... more The electrochemical synthesis of ammonia through the nitrogen reduction reaction (NRR) is receiving much attention, since it is considered a promising alternative to the Haber–Bosch process. In NRR experiments, a Nafion membrane is generally adopted as a separator. However, its use is controversial since ammonia can be trapped in the membrane, to some extent, or even pass through it. We systematically investigate the interaction of a Nafion membrane with ammonia and with an electrolyte and compare it with Zirfon as a possible alternative separator. We show that Nafion containing ammonia can easily release it when immersed in a 0.1 M Na2SO4 ammonia-free electrolyte, due to the cation exchange mechanism (Na+-NH4+). Since Na2SO4 is a commonly adopted electrolyte for NRR experiments, this may cause serious measurement errors and non-reproducible results. The same experiments performed using the polysulfone Zirfon separator clearly show that it is immune to interactions with ammonia, bec...
Bifacial photovoltaics (BPVs) are emerging with large momentum as promising solutions to improve ... more Bifacial photovoltaics (BPVs) are emerging with large momentum as promising solutions to improve energy yield and cost of PV systems. To reach its full potential, an accurate understanding of the physical characteristics of BPV technology is required. For this reason, we collected experimental data to refine a physical model of BPV. In particular, we simultaneously measured the module temperature, short circuit current (Isc), open-circuit voltage (Voc), power at the maximum power point (Pmpp), and the energy yield of a bifacial and a monofacial minimodule. Such minimodules, realised with the same geometry, cell technology, and module lamination, were tested under the same clear sky outdoor conditions, from morning to afternoon, for three days. The bifacial system experimentally shows higher module temperatures under operation, about 10 °C on a daily average of about 40 °C. Nevertheless, its energy yield is about 15% larger than the monofacial one. We propose a physical quantitative ...
IEEE Journal of Selected Topics in Quantum Electronics, 2016
In this paper, silicon photomultipliers (SiPM) are proposed as optical detectors for bio sensing.... more In this paper, silicon photomultipliers (SiPM) are proposed as optical detectors for bio sensing. Optical transduction is the most used detection mechanism in many biosensor applications, such as DNA microarray and real-time polymerase chain reaction. The performances of a 25 pixels device used for both applications are studied. The results confirm that the SiPM is more sensitive than the traditionally employed detectors. In fact, it is able to experimentally detect 1 nM and 100 fM of fluorophore concentrations in dried samples and solutions, respectively. We present and discuss in details the detector configuration and its characterization as fluorescence detector for bio sensing.
The effects of geometrical arrangement of MOSFETs on breakdown (BD) evolution in ultrathin gate o... more The effects of geometrical arrangement of MOSFETs on breakdown (BD) evolution in ultrathin gate oxide have been studied. Specific attention was paid to the impact of heat confinement in narrow MOSFETs on the BD evolution from soft BD to hard BD. It is found that, based on a numerical simulation, the thermal effect, which is the main driving force of catastrophic BD, is more severe in narrow MOSFETs than wide MOSFETs, which is in agreement with the degradation rate measured from their respective BD transients.
Increasing attention is now paid to bifacial PV devices since these, compared to monofacial modul... more Increasing attention is now paid to bifacial PV devices since these, compared to monofacial modules, allow increased electricity production thanks to their additional radiation collection from the back side. Since accurate performance predictions are of crucial importance for PV devices to maximize the electricity production, several efforts have been made for bifacial PV modeling and related optimization [1]–[6]. In this work, we present a new analytical model, usable to any geographical position, for the performance prediction of bifacial PV modules. We compare the model predictions to experiments in which module height, ground albedo, and tilt are varied and we observe good agreement.
Si nanocrystals have been deposited onto oxidized Si substrates by chemical vapor deposition of S... more Si nanocrystals have been deposited onto oxidized Si substrates by chemical vapor deposition of SiH4. The dots have been completely embedded into SiO2 and used as floating gate of MOS memory devices. The tunneling of electrons through the gate stack, their trapping in the Si dots and detrapping, and their storage have been experimentally investigated. The results are shown and discussed.
Platinum thin films are deposited on open-cell nickel foam with porosity of 95% via spontaneous g... more Platinum thin films are deposited on open-cell nickel foam with porosity of 95% via spontaneous galvanic displacement. Ni foams with different morphologies and pore size are compared and characterized by electrochemical and structural analysis techniques. The effect of Pt coating on the electrochemical activity is studied by using the Pt coated foam as electrode material for hydrogen evolution reaction in an aqueous alkaline electrolyte. The electrocatalytic activity of the electrodes is evaluated using linear sweep voltammetry curves and Tafel plots as a function of deposition time. The comparison with scanning electron microscopy analyses demonstrates that the catalytic activity has a maximum when the platinum film completely covers the Ni surface. The further increase of the Pt thickness leads to mechanical instability with crack formation and delamination. The effect of the foam morphology on the Pt deposition rate has been evaluated and discussed, determining the minimum Pt amo...
There is an increasing interest to use silicon photomultipliers (SiPMs) in medical applications l... more There is an increasing interest to use silicon photomultipliers (SiPMs) in medical applications like Photoplethysmography or Functional Near Infrared Spectroscopy, allowing the monitoring of physiological signs through non-invasive equipment. The use of large area SiPMs with embedded color filters for environmental light rejection could bring relevant advantages in these applications in terms of higher signal-to-noise ratio of the measurements. Here, we report on the first electro-optical characterization results obtained on n-on-p SiPMs with green interference bandpass filters glued on the top side of the detector SMD package. We will show how the use of the filter considerably increases, especially for large overvoltage values, the SiPM dark noise rate, due to the significant amplification of optical cross-talk effects (up to 150% of dark current increase at 50%-OV). This makes necessary a careful evaluation of the SiPMs performances in order to define the best operating conditions and layout characteristics of the detectors that will be used in the final applications.
The electrochemical synthesis of ammonia through the nitrogen reduction reaction (NRR) is receivi... more The electrochemical synthesis of ammonia through the nitrogen reduction reaction (NRR) is receiving much attention, since it is considered a promising alternative to the Haber–Bosch process. In NRR experiments, a Nafion membrane is generally adopted as a separator. However, its use is controversial since ammonia can be trapped in the membrane, to some extent, or even pass through it. We systematically investigate the interaction of a Nafion membrane with ammonia and with an electrolyte and compare it with Zirfon as a possible alternative separator. We show that Nafion containing ammonia can easily release it when immersed in a 0.1 M Na2SO4 ammonia-free electrolyte, due to the cation exchange mechanism (Na+-NH4+). Since Na2SO4 is a commonly adopted electrolyte for NRR experiments, this may cause serious measurement errors and non-reproducible results. The same experiments performed using the polysulfone Zirfon separator clearly show that it is immune to interactions with ammonia, bec...
Bifacial photovoltaics (BPVs) are emerging with large momentum as promising solutions to improve ... more Bifacial photovoltaics (BPVs) are emerging with large momentum as promising solutions to improve energy yield and cost of PV systems. To reach its full potential, an accurate understanding of the physical characteristics of BPV technology is required. For this reason, we collected experimental data to refine a physical model of BPV. In particular, we simultaneously measured the module temperature, short circuit current (Isc), open-circuit voltage (Voc), power at the maximum power point (Pmpp), and the energy yield of a bifacial and a monofacial minimodule. Such minimodules, realised with the same geometry, cell technology, and module lamination, were tested under the same clear sky outdoor conditions, from morning to afternoon, for three days. The bifacial system experimentally shows higher module temperatures under operation, about 10 °C on a daily average of about 40 °C. Nevertheless, its energy yield is about 15% larger than the monofacial one. We propose a physical quantitative ...
IEEE Journal of Selected Topics in Quantum Electronics, 2016
In this paper, silicon photomultipliers (SiPM) are proposed as optical detectors for bio sensing.... more In this paper, silicon photomultipliers (SiPM) are proposed as optical detectors for bio sensing. Optical transduction is the most used detection mechanism in many biosensor applications, such as DNA microarray and real-time polymerase chain reaction. The performances of a 25 pixels device used for both applications are studied. The results confirm that the SiPM is more sensitive than the traditionally employed detectors. In fact, it is able to experimentally detect 1 nM and 100 fM of fluorophore concentrations in dried samples and solutions, respectively. We present and discuss in details the detector configuration and its characterization as fluorescence detector for bio sensing.
The effects of geometrical arrangement of MOSFETs on breakdown (BD) evolution in ultrathin gate o... more The effects of geometrical arrangement of MOSFETs on breakdown (BD) evolution in ultrathin gate oxide have been studied. Specific attention was paid to the impact of heat confinement in narrow MOSFETs on the BD evolution from soft BD to hard BD. It is found that, based on a numerical simulation, the thermal effect, which is the main driving force of catastrophic BD, is more severe in narrow MOSFETs than wide MOSFETs, which is in agreement with the degradation rate measured from their respective BD transients.
Increasing attention is now paid to bifacial PV devices since these, compared to monofacial modul... more Increasing attention is now paid to bifacial PV devices since these, compared to monofacial modules, allow increased electricity production thanks to their additional radiation collection from the back side. Since accurate performance predictions are of crucial importance for PV devices to maximize the electricity production, several efforts have been made for bifacial PV modeling and related optimization [1]–[6]. In this work, we present a new analytical model, usable to any geographical position, for the performance prediction of bifacial PV modules. We compare the model predictions to experiments in which module height, ground albedo, and tilt are varied and we observe good agreement.
Si nanocrystals have been deposited onto oxidized Si substrates by chemical vapor deposition of S... more Si nanocrystals have been deposited onto oxidized Si substrates by chemical vapor deposition of SiH4. The dots have been completely embedded into SiO2 and used as floating gate of MOS memory devices. The tunneling of electrons through the gate stack, their trapping in the Si dots and detrapping, and their storage have been experimentally investigated. The results are shown and discussed.
Platinum thin films are deposited on open-cell nickel foam with porosity of 95% via spontaneous g... more Platinum thin films are deposited on open-cell nickel foam with porosity of 95% via spontaneous galvanic displacement. Ni foams with different morphologies and pore size are compared and characterized by electrochemical and structural analysis techniques. The effect of Pt coating on the electrochemical activity is studied by using the Pt coated foam as electrode material for hydrogen evolution reaction in an aqueous alkaline electrolyte. The electrocatalytic activity of the electrodes is evaluated using linear sweep voltammetry curves and Tafel plots as a function of deposition time. The comparison with scanning electron microscopy analyses demonstrates that the catalytic activity has a maximum when the platinum film completely covers the Ni surface. The further increase of the Pt thickness leads to mechanical instability with crack formation and delamination. The effect of the foam morphology on the Pt deposition rate has been evaluated and discussed, determining the minimum Pt amo...
There is an increasing interest to use silicon photomultipliers (SiPMs) in medical applications l... more There is an increasing interest to use silicon photomultipliers (SiPMs) in medical applications like Photoplethysmography or Functional Near Infrared Spectroscopy, allowing the monitoring of physiological signs through non-invasive equipment. The use of large area SiPMs with embedded color filters for environmental light rejection could bring relevant advantages in these applications in terms of higher signal-to-noise ratio of the measurements. Here, we report on the first electro-optical characterization results obtained on n-on-p SiPMs with green interference bandpass filters glued on the top side of the detector SMD package. We will show how the use of the filter considerably increases, especially for large overvoltage values, the SiPM dark noise rate, due to the significant amplification of optical cross-talk effects (up to 150% of dark current increase at 50%-OV). This makes necessary a careful evaluation of the SiPMs performances in order to define the best operating conditions and layout characteristics of the detectors that will be used in the final applications.
Uploads