Papers by Alessandro Martucci
Procedia Engineering, 2015
Communications physics, Sep 23, 2021
Ceramics International, Sep 1, 2021
Abstract In this paper we report on the combined visible-light (red λ = 630 nm; green λ = 570 nm;... more Abstract In this paper we report on the combined visible-light (red λ = 630 nm; green λ = 570 nm; purple-blue λ = 430 nm) and mild thermal-activation modes (25 °C–100 °C) towards ppb-level NO2 detection of ZnO nanocrystalline film containing trivalent (Al-Ga) and tetravalent (Si-Ge) ions. Both trivalent and tetravalent doping trigger visible light fast response/recovery behavior as respect to dark conditions. Remarkably Purple-blue light (λ = 430 nm) combined with thermal activation at 75 °C OT results in best performances in terms of variation of sensor resistance as compared to that in dry air, topping maximum gas relative response RR= RGas/RAir ≈ 20 for the 5% Si doped ZnO at 400 ppb NO2. Aliovalent doping of ZnO is obtained using a colloidal heat-up synthesis yielding highly transparent in the visible range degenerately doped n-type ZnO semiconductors films which were characterized by SEM, XRD, XPS techniques to assess morphology, crystal phases and concentration of surface oxygen vacancies, respectively. Optical characterization of the doped films showed a distinctive localized surface plasmon resonance (LSPR) peak in the near infrared region, deriving from the free charge carrier. Aluminum doping is the most effective to narrow the band gap of the doped ZnO films down to 3.22 eV. The influence of the relative humidity (RH) on the gas sensing performances is investigated and for 40% RH a slight decrease of the NO2 relative response was observed. A consistent model explaining the gas sensing mechanism under dark and light conditions and the influence of RH is presented.
Procedia Engineering, 2014
Materials, Feb 15, 2020
We developed hybrid organic-inorganic sol-gel silica coatings with good durability in harsh envir... more We developed hybrid organic-inorganic sol-gel silica coatings with good durability in harsh environment (high temperatures, high vapor velocities) and with slightly hydrophobic behavior, sufficient to promote dropwise condensation (DWC) of pure steam. DWC is a very promising mechanism in new trends of thermal management and power generation systems to enhance the heat transfer during condensation as compared to film-wise condensation (FWC). The sol-gel coatings have been prepared from methyl triethoxy silane (MTES) and tetraethyl-orthosilicate (TEOS) and deposited on an aluminum substrate. The coatings were optimized in terms of precursor ratio and annealing temperature highlighting potentials and limits of such mixtures. A comprehensive surface characterization before and after saturated steam condensation tests has been performed and related to the thermal measurements for evaluating the heat transfer augmentation as compared to FWC obtained on untreated aluminum surfaces. The results showed that the developed hybrid organic-inorganic sol-gel silica coatings are promising DWC promoters.
Sensors
Tungsten oxide thin films with different thicknesses, crystallinity and morphology were synthesiz... more Tungsten oxide thin films with different thicknesses, crystallinity and morphology were synthesized by e-beam deposition followed by thermal treatment and acid boiling. The films with different surface morphologies were coated with gold nanoparticles and tested as optical sensing materials towards hydrogen. X-ray diffraction, scanning electron microscopy, ellipsometry and UV-VIS spectroscopy were employed to characterize the structural, morphological and optical properties of the film. We demonstrated a good response towards hydrogen in air, reaching a good selectivity among other common reducing gases, such as ammonia and carbon monoxide. The sensitivity has been proven to be highly dependent on the thickness and crystallinity of the samples.
Ecotoxicology and Environmental Safety
Fullerene C 60 (FC 60), with its unique physical properties, has been used in many applications i... more Fullerene C 60 (FC 60), with its unique physical properties, has been used in many applications in recent decades. The increased likelihood of direct release into the environment has raised interest in understanding the biological effects of FC 60 to aquatic organisms. Nowadays, only few studies have analysed FC 60 effects and bioaccumulation in marine organisms following in vivo exposure. To provide new data about FC 60 toxicity, Ruditapes philippinarum was selected as target species to assess potential adverse effects of the contaminant. Clams were exposed for 1, 3 and 7 days to predicted environmental concentrations of FC 60 (1 and 10 μg/L) and cellular and biochemical responses were evaluated in clams' gills, digestive gland and haemolymph. The FC 60 content in gills and digestive gland was determined in all experimental conditions after 7 days of exposure. Results showed an increase in oxidative stress. In particular, a significant modulation in antioxidant enzyme activities, and changes in glutathione S-transferase activity were observed in gills. Moreover, damage to lipids and proteins was detected in FC 60-treated (10 µg/L) clams. In digestive gland, slighter variations in antioxidant enzyme activities and damage to molecules were detected. CAT activity was significantly affected throughout the exposure, whereas damage to lipids was evident only at the end of exposure. FC 60 accumulation was revealed in both gills and digestive gland, with values up to twelve-fold higher in the latter. Interestingly, haemolymph parameters were slightly affected by FC 60 compared to the other tissues investigated. Indeed, only Single Cell Gel Electrophoresis and Neutral Red uptake assays showed increased values in FC 60-exposed clams. Moreover, volume and diameter of haemocytes, haemocyte proliferation, and micronucleus assay highlighted significant variations in treated clams, but only in the first phases of exposure, and no changes were detected after 7 days. Our results suggested clam gills as the target tissue for FC 60 toxicity under the exposure conditions tested: the high damage detected to lipids and proteins could contribute to long-term problems for the organism.
Journal of Sol-Gel Science and Technology, 2022
In this paper, we report silk fibroin (SF) and carbon quantum dots (CQDs) nanocomposites obtained... more In this paper, we report silk fibroin (SF) and carbon quantum dots (CQDs) nanocomposites obtained through a facile solution casting approach. The optical properties of the nanocomposites have been characterised by UV–vis absorption and photoluminescence spectroscopy. Crosslinking of SF and chemical interactions with the CQDs have been investigated by FTIR spectroscopy. In addition, water stability and degradability of the prepared composites have been investigated in terms of mass loss, important for applications in a real scenario. We observed that for a concentration of CQDs above 1%wt aggregation of nanoparticles occurs, affecting the photoluminescence of the material. The results show that the best composition in terms of photoluminescence intensity and water stability is 0.5%wt CQDs.
Photochemical & Photobiological Sciences, 2021
Dye-sensitized photoelectrochemical cells represent an appealing solution for artificial photosyn... more Dye-sensitized photoelectrochemical cells represent an appealing solution for artificial photosynthesis, aimed at the conversion of solar light into fuels or commodity chemicals. Extensive efforts have been directed towards the development of photoelectrodes combining semiconductor materials and organic dyes; the use of molecular components allows to tune the absorption and redox properties of the material. Recently, we have reported the use of a class of pentacyclic quinoid organic dyes (KuQuinone) chemisorbed onto semiconducting tin oxide as photoanodes for water oxidation. In this work, we investigate the effect of the SnO2 semiconductor thickness and morphology and of the dye-anchoring group on the photoelectrochemical performance of the electrodes. The optimized materials are mesoporous SnO2 layers with 2.5 μm film thickness combined with a KuQuinone dye with a 3-carboxylpropyl-anchoring chain: these electrodes achieve light-harvesting efficiency of 93% at the maximum absorptio...
Marine Environmental Research, 2018
Chemistry of Materials, 2016
Communications Physics, 2021
The out-of-plane optical constants of monolayer two-dimensional materials have proven to be exper... more The out-of-plane optical constants of monolayer two-dimensional materials have proven to be experimentally elusive. Owing to their reduced dimensionality, optical measurements have limited sensitivity to these properties which are hidden by the optical response of the substrate. Therefore, there remains an absence of scientific consensus on how to correctly model these crystals. Here we perform an experiment on the optical response of a single-layer two-dimensional crystal that addresses these problems. We successfully remove the substrate contribution to its optical response by a step deposition of a monolayer crystal inside a thick polydimethylsiloxane prism. This allows for a reliable determination of both the in-plane and the out-of-plane components of its surface susceptibility tensor. Our results prescribe one clear theoretical model for these crystals. This precise characterization of their optical properties will be relevant to future progresses in photonics and optoelectron...
Journal of Physical Chemistry C, Apr 16, 2015
Tribology International, Jun 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Physics D: Applied Physics, 2018
A series of high quality zinc oxide (ZnO) nanocrystal films doped with Ge at different Ge/Zn mola... more A series of high quality zinc oxide (ZnO) nanocrystal films doped with Ge at different Ge/Zn molar ratios were synthesized by the sol-gel method, and structural and compositional changes induced by Ge doping in the ZnO films were analyzed by x-ray diffraction, x-ray photoelectron spectroscopy and cathodoluminescence spectroscopy. Heavy Ge doping in ZnO was found to effectively reduce intrinsic defects in the films and suppress free exciton emission and defect-related emissions in the visible green-red region, by the substitution of Ge at Zn sites and the formation of non-radiative deep-level traps (GeZn)+. The generation of such non-radiative traps was found to be suppressed with respect to the dopant increase, because of a reduction in carrier concentration along with a formation of stable defect complex GeZn–VZn at high doping content. The clarification of defect alterations in Ge-doped ZnO lays the foundation of quantitative evaluation of defect effects on the electrical and optical properties for improving the quality of GeZnO devices.
International Journal of Thermal Sciences, 2019
Dropwise condensation (DWC) is a promising heat transfer mechanism in new trends of thermal manag... more Dropwise condensation (DWC) is a promising heat transfer mechanism in new trends of thermal management and power generation systems to enhance the heat transfer during condensation. Creation of surfaces which can promote dropwise condensation is one of the main issues. For this purpose, a heat transfer surface that can maintain stable dropwise condensation, using hybrid organic-inorganic sol-gel silica coatings functionalized with methyl groups over an aluminum substrate, is developed and tested. This coating displays mildly hydrophilic behavior. Condensation of steam flowing on this surface occurs in dropwise mode with heat transfer coefficient values equal to 150-180 kW m −2 K −1 in the heat flux range between 150 and 510 kW m −2. The importance of the coating thermal resistance is discussed in the paper. The measured heat transfer coefficient is high compared to previous studies of DWC on metallic-and in particular aluminum-substrates. This type of surfaces paves the way to a cheap and green route to promote stable DWC on aluminum substrates without using fluorocarbons or controlled roughness patterns. 100 kW m −2) and produces very high HTC on superhydrophobic surfaces [21,26-28]. Normally a surface with still low surface tension but only nanometric roughness may be preferable to achieve high HTC and high heat flux. The present paper reports a study of DWC on a smooth metallic
Electrochimica Acta, 2019
Abstract Direct ethanol fuel cells are highly promising energy conversion devices, but the comple... more Abstract Direct ethanol fuel cells are highly promising energy conversion devices, but the complete oxidation of ethanol to CO2 at low temperatures is still one of the main challenges. Titanium oxycarbide (TiO1-xCx) powder is investigated as stable and synergistic support for Pt nanoparticles during the ethanol oxidation reaction (EOR) in acidic electrolytes. EOR products are quantitatively detected online with differential electrochemical mass spectrometry. At room temperature, Pt/TiO1-xCx has a CO2 efficiency maximum of 8.9%, while only 1.7% are measured for Pt nanoparticles on Vulcan carbon (Pt/C). The reaction pathway is channeled towards the formation of C1 products, while C2 product formation is suppressed. This effect is expected to be much enhanced at elevated temperatures which makes TiO1-xCx a highly interesting catalyst support material in general.
Advanced Materials Interfaces, 2018
A simple and efficient method is developed to introduce plasmonic and luminescence functionalitie... more A simple and efficient method is developed to introduce plasmonic and luminescence functionalities in titanate nanosheets (TNSs)–silk nanocomposites by direct cation‐exchange process. First, the cation exchange properties such as exchange kinetic and capacity are studied to verify the behavior of the material and determine the best condition of exchange. In particular, the effect of the valence on the kinetic is investigated through elemental analysis, focusing on three target cations (Ag+, Cu2+, and Eu3+) in water. It is demonstrated that the cation exchange capability of the composite is strictly dependent of the amount of TNSs. By acting on the time of ion exchange or by changing the TNSs concentration in the silk fibroin matrix it is possible to tune the metal ions doping. The process is applicable both on flexible free‐standing membranes and thin films deposited on an appropriate substrate. By exposing the material to UV radiation, it is possible to synthesize in situ metallic ...
Ceramics International, 2016
TiO x C y powders with tunable composition and high specific surface areas have been synthesized ... more TiO x C y powders with tunable composition and high specific surface areas have been synthesized by impregnation of porous carbon black with titanium isopropoxide and firing in argon at 1400 1C. The compositional ratio of the individual ions can be controlled over a broad compositional range by tuning the stoichiometric ratio of the initial reactants. The resultant powders show no detectable oxide or carbonaceous impurity phases. The powders retain artefacts of the porosity of the templating carbon and yield specific surface areas as high as 108 m 2 g À 1 , which makes them useful in catalytic/electrocatalytic applications.
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Papers by Alessandro Martucci