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7 results on '"Di Palma, V."'

1. Plasma-Assisted Atomic Layer Deposition of IrO2 for Neuroelectronics

Author

Di Palma, V, Pianalto, A, Perego, M, Tallarida, G, Codegoni, D, Fanciulli, M, Di Palma, Valerio, Pianalto, Andrea, Perego, Michele, Tallarida, Graziella, Codegoni, Davide, Fanciulli, Marco, Di Palma, V, Pianalto, A, Perego, M, Tallarida, G, Codegoni, D, Fanciulli, M, Di Palma, Valerio, Pianalto, Andrea, Perego, Michele, Tallarida, Graziella, Codegoni, Davide, and Fanciulli, Marco

Abstract

In vitro and in vivo stimulation and recording of neuron action potential is currently achieved with microelectrode arrays, either in planar or 3D geometries, adopting different materials and strategies. IrO2 is a conductive oxide known for its excellent biocompatibility, good adhesion on different substrates, and charge injection capabilities higher than noble metals. Atomic layer deposition (ALD) allows excellent conformal growth, which can be exploited on 3D nanoelectrode arrays. In this work, we disclose the growth of nanocrystalline rutile IrO2 at T = 150 °C adopting a new plasma-assisted ALD (PA-ALD) process. The morphological, structural, physical, chemical, and electrochemical properties of the IrO2 thin films are reported. To the best of our knowledge, the electrochemical characterization of the electrode/electrolyte interface in terms of charge injection capacity, charge storage capacity, and double-layer capacitance for IrO2 grown by PA-ALD was not reported yet. IrO2 grown on PtSi reveals a double-layer capacitance (Cdl) above 300 µF∙cm−2, and a charge injection capacity of 0.22 ± 0.01 mC∙cm−2 for an electrode of 1.0 cm2, confirming IrO2 grown by PA-ALD as an excellent material for neuroelectronic applications.

Published
2023

2. Effect of the ZnSnO/AZO Interface on the Charge Extraction in Cd-Free Kesterite Solar Cells

Author

Gobbo, C, Di Palma, V, Trifiletti, V, Malerba, C, Valentini, M, Matacena, I, Daliento, S, Binetti, S, Acciarri, M, Tseberlidis, G, Gobbo, C, Di Palma, V, Trifiletti, V, Malerba, C, Valentini, M, Matacena, I, Daliento, S, Binetti, S, Acciarri, M, and Tseberlidis, G

Abstract

Cu2ZnSnS4 (CZTS) is a promising absorber material to produce thin film solar cells thanks to its high absorption coefficient, low cost and low toxicity. CdS is commonly used as a buffer layer for CZTS solar cells but, beyond its toxicity, it has a nonoptimal band alignment with CZTS. ZnxSn1−xO (ZTO), based on earth-abundant and nontoxic elements and with a large and tunable band gap, is a suitable alternative buffer layer. In this paper, the atomic layer deposition (ALD) of ZTO was employed by testing different compositions and thicknesses. ALD not only leads to very compact and homogenous ZTO layers (enabling tuning the stoichiometry of the ZTO so prepared) but also makes the i-ZnO layer (usually sandwiched between the buffer layer and the transparent contact) redundant and detrimental. Through SCAPS simulation and impedance measurements, the ZnSnO/AZO interface impact on the Cd-free kesterite solar cells’ performances has been investigated, highlighting its leading role in achieving an effective charge extraction and the detrimental effect of the i-ZnO layer. With this approach, a solar cell based on an architecture simpler and more eco-friendly than the conventional one has been produced with comparable efficiencies.

Published
2023

3. Effect of the ZnSnO/AZO Interface on the Charge Extraction in Cd-Free Kesterite Solar Cells

Author

Carla Gobbo, Valerio Di Palma, Vanira Trifiletti, Claudia Malerba, Matteo Valentini, Ilaria Matacena, Santolo Daliento, Simona Binetti, Maurizio Acciarri, Giorgio Tseberlidis, Gobbo, C, Di Palma, V, Trifiletti, V, Malerba, C, Valentini, M, Matacena, I, Daliento, S, Binetti, S, Acciarri, M, and Tseberlidis, G

Subjects
kesterite, Control and Optimization, buffer layer, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, ZTO, Building and Construction, Cd-free, charge extraction, atomic layer deposition, Electrical and Electronic Engineering, Engineering (miscellaneous), Energy (miscellaneous)
Abstract

Cu2ZnSnS4 (CZTS) is a promising absorber material to produce thin film solar cells thanks to its high absorption coefficient, low cost and low toxicity. CdS is commonly used as a buffer layer for CZTS solar cells but, beyond its toxicity, it has a nonoptimal band alignment with CZTS. ZnxSn1−xO (ZTO), based on earth-abundant and nontoxic elements and with a large and tunable band gap, is a suitable alternative buffer layer. In this paper, the atomic layer deposition (ALD) of ZTO was employed by testing different compositions and thicknesses. ALD not only leads to very compact and homogenous ZTO layers (enabling tuning the stoichiometry of the ZTO so prepared) but also makes the i-ZnO layer (usually sandwiched between the buffer layer and the transparent contact) redundant and detrimental. Through SCAPS simulation and impedance measurements, the ZnSnO/AZO interface impact on the Cd-free kesterite solar cells’ performances has been investigated, highlighting its leading role in achieving an effective charge extraction and the detrimental effect of the i-ZnO layer. With this approach, a solar cell based on an architecture simpler and more eco-friendly than the conventional one has been produced with comparable efficiencies.

Published
2023

4. Plasma-Assisted Atomic Layer Deposition of IrO2 for Neuroelectronics

Author

Valerio Di Palma, Andrea Pianalto, Michele Perego, Graziella Tallarida, Davide Codegoni, Marco Fanciulli, Di Palma, V, Pianalto, A, Perego, M, Tallarida, G, Codegoni, D, and Fanciulli, M

Subjects
Atomic Layer deposition, IrO2, Neuroelectronics, Microelectrode arrays, IrO2, pseudocapacitive, atomic layer deposition, neuroelectronics, General Chemical Engineering, General Materials Science, neuroelectronic, FIS/03 - FISICA DELLA MATERIA
Abstract

In vitro and in vivo stimulation and recording of neuron action potential is currently achieved with microelectrode arrays, either in planar or 3D geometries, adopting different materials and strategies. IrO2 is a conductive oxide known for its excellent biocompatibility, good adhesion on different substrates, and charge injection capabilities higher than noble metals. Atomic layer deposition (ALD) allows excellent conformal growth, which can be exploited on 3D nanoelectrode arrays. In this work, we disclose the growth of nanocrystalline rutile IrO2 at T = 150 °C adopting a new plasma-assisted ALD (PA-ALD) process. The morphological, structural, physical, chemical, and electrochemical properties of the IrO2 thin films are reported. To the best of our knowledge, the electrochemical characterization of the electrode/electrolyte interface in terms of charge injection capacity, charge storage capacity, and double-layer capacitance for IrO2 grown by PA-ALD was not reported yet. IrO2 grown on PtSi reveals a double-layer capacitance (Cdl) above 300 µF∙cm−2, and a charge injection capacity of 0.22 ± 0.01 mC∙cm−2 for an electrode of 1.0 cm2, confirming IrO2 grown by PA-ALD as an excellent material for neuroelectronic applications.

Published
2023

5. INSPEX: Optimize Range Sensors for Environment Perception as a Portable System.

Author

Foucault J, Lesecq S, Dudnik G, Correvon M, O'Keeffe R, Di Palma V, Passoni M, Quaglia F, Ouvry L, Buckley S, Herveg J, di Matteo A, Rakotovao T, Debicki O, Mareau N, Barrett J, Rea S, McGibney A, Birot F, de Chaumont H, Banach R, Razavi J, and Ó'Murchú C

Abstract

Environment perception is crucial for the safe navigation of vehicles and robots to detect obstacles in their surroundings. It is also of paramount interest for navigation of human beings in reduced visibility conditions. Obstacle avoidance systems typically combine multiple sensing technologies (i.e., LiDAR, radar, ultrasound and visual) to detect various types of obstacles under different lighting and weather conditions, with the drawbacks of a given technology being offset by others. These systems require powerful computational capability to fuse the mass of data, which limits their use to high-end vehicles and robots. INSPEX delivers a low-power, small-size and lightweight environment perception system that is compatible with portable and/or wearable applications. This requires miniaturizing and optimizing existing range sensors of different technologies to meet the user's requirements in terms of obstacle detection capabilities. These sensors consist of a LiDAR, a time-of-flight sensor, an ultrasound and an ultra-wideband radar with measurement ranges respectively of 10 m, 4 m, 2 m and 10 m. Integration of a data fusion technique is also required to build a model of the user's surroundings and provide feedback about the localization of harmful obstacles. As primary demonstrator, the INSPEX device will be fixed on a white cane.

Published
2019
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6. Discontinuous and Continuous Indoor Air Quality Monitoring in Homes with Fireplaces or Wood Stoves as Heating System.

Author

de Gennaro G, Dambruoso PR, Di Gilio A, Di Palma V, Marzocca A, and Tutino M

Subjects
Cooking, Environmental Monitoring, Heating, Air Pollutants analysis, Air Pollution, Indoor analysis, Hazardous Substances analysis, Particulate Matter analysis, Volatile Organic Compounds analysis, Wood
Abstract

Around 50% of the world's population, particularly in developing countries, uses biomass as one of the most common fuels. Biomass combustion releases a considerable amount of various incomplete combustion products, including particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs). The paper presents the results of Indoor Air Quality (IAQ) measurements in six houses equipped with wood burning stoves or fireplaces as heating systems. The houses were monitored for 48-h periods in order to collect PM10 samples and measure PAH concentrations. The average, the maximum and the lowest values of the 12-h PM10 concentration were 68.6 μg/m³, 350.7 μg/m³ and 16.8 μg/m³ respectively. The average benzo[a]pyrene 12-h concentration was 9.4 ng/m³, while the maximum and the minimum values were 24.0 ng/m³ and 1.5 ng/m³, respectively. Continuous monitoring of PM10, PAHs, Ultra Fine Particle (UFP) and Total Volatile Organic Compounds (TVOC) was performed in order to study the progress of pollution phenomena due to biomass burning, their trends and contributions to IAQ. The results show a great heterogeneity of impacts on IAQ in terms of magnitude and behavior of the considered pollutants' concentrations. This variability is determined by not only different combustion technologies or biomass quality, but overall by different ignition mode, feeding and flame management, which can also be different for the same house. Moreover, room dimensions and ventilation were significant factors for pollution dispersion. The increase of PM10, UFP and PAH concentrations, during lighting, was always detected and relevant. Continuous monitoring allowed singling out contributions of other domestic sources of considered pollutants such as cooking and cigarettes. Cooking contribution produced an impact on IAQ in same cases higher than that of the biomass heating system.

Published
2015
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7. A Photolithographic Approach to Polymeric Microneedles Array Fabrication.

Author

Dardano P, Caliò A, Di Palma V, Bevilacqua MF, Di Matteo A, and De Stefano L

Abstract

In this work, two procedures for fabrication of polymeric microneedles based on direct photolithography, without any etching or molding process, are reported. Polyethylene glycol (average molecular weight 250 Da), casted into a silicone vessel and exposed to ultraviolet light (365 nm) through a mask, cross-links when added by a commercial photocatalyzer. By changing the position of the microneedles support with respect to the vessel, different shapes and lengths can be achieved. Microneedles from a hundred microns up to two millimeters have been obtained just tuning the radiation dose, by changing the exposure time (5-15 s) and/or the power density (9-18 mW/cm²) during photolithography. Different microneedle shapes, such as cylindrical, conic or lancet-like, for specific applications such as micro-indentation or drug delivery, are demonstrated.

Published
2015
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