The role of porphyrins and phthalocyanines in thin films form in sensor application has been rece... more The role of porphyrins and phthalocyanines in thin films form in sensor application has been receiving an increasing interest in recent years and various synthetic methodologies can provide the opportunities to explore the influence of chemical modifications on their physico-chemical properties. In this context we report on the synthesis and film preparation of a new bis-substituted Cu-phthalocyanine by using Langmuir-Blodgett deposition technique. Dynamic response characteristics of the electrical conductance to different NO2 concentrations in dry air are presented.
ABSTRACT Zinc oxide (ZnO), particularly in its nanostructured forms, is one of the materials exte... more ABSTRACT Zinc oxide (ZnO), particularly in its nanostructured forms, is one of the materials extensively studied in the last years due to the great number of its possible applications. Several growth techniques can be used to realize this kind of material and, among them, the Pulsed Laser Deposition (PLD) technique has been demonstrated to be a very versatile method to easily control the properties of the grown material.In this regard, this book aims to presents a review about the growth of zinc oxide (ZnO) nanostructured films by Pulsed Laser Deposition (PLD), and in particular by means of excimer laser ablation.
A theoretical comparison of the optical and electronic properties of metallic nanostructures char... more A theoretical comparison of the optical and electronic properties of metallic nanostructures characterized by complementary geometries is proposed in this work. Periodic array of nanoparticles on glass substrate and nano-holes on metal substrate have been analysed performing finite element analysis with the RF Module of COMSOL Multiphysics. Single and array of gold nanostructures have been studied, exploring several key parameters responsible for sensitivity enhancement of LSPR sensors. The analysed structures show a minimum in their spectral transmittance, confirming that regular arrays of nano-holes in thin metal films as well as nano-disk arrays may support localized surface plasmon resonance.
ABSTRACT The behaviour of an alternating co-polymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-th... more ABSTRACT The behaviour of an alternating co-polymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-thienylene), has been first investigated at the air-water interface. The floating has been analysed by monitoring Langmuir curves and Brewster angle microscopy. The floating films were deposited by the Langmuir- Schafer (horizontal lifting) technique onto various substrates. It is evident from experimental data that a strong co-planarity and interchain association originates above all in the floating film on the water surface and in the transferred multilayers. Such films were used as the active layers in resistive chemical gas sensor device, thus revealing excellent sensitivity towards NO2, reversibility and time stability of the response.
ABSTRACT Optical absorption measurements on CNx thin films produced by reactive pulsed laser abla... more ABSTRACT Optical absorption measurements on CNx thin films produced by reactive pulsed laser ablation (RPLA) at different pressures of nitrogen in the growth chamber were performed. The influence of growth regime on optical properties (n,k) of the CNx films has been examined with IR and UV-VIS spectroscopy. The dependence of the absorption coefficient α on the photon energy ℏω at the edge of the absorption band is well described by the relation αℏω=B(ℏω−Eopt)2 indicating the presence of allowed indirect transitions in the 0.8–3.0 eV photon energy range. Furthermore, we observed a decrease in the optical gap values with increasing N concentration in the deposited films. Fourier transform infrared (FTIR) spectra were also employed to analyse the chemical bonding state between the different species present in the films.
Zn(II) tetra-4-(2,4-di-t-amylphenoxy)-phthalocyanine (1a), Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-... more Zn(II) tetra-4-(2,4-di-t-amylphenoxy)-phthalocyanine (1a), Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-(4-mercapto-phenylimino-methyl)-phenoxy] (1b) and Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-(4-formyl)-phenoxy] (1c) phthalocyanine were synthesized. The molecular structures were confirmed by LC–MS, 1H NMR, FT-IR and UV–vis spectra. Spin coated layers of these phthalocyanines have been used as optochemically interactive materials for the detection of volatile organic compounds (VOCs) in the UV–vis spectral range. An optical characterization in controlled atmosphere have been carried out by acquiring the absorption spectra of the phthalocyanine complexes both in dry-air and in the presence of different volatile organic compounds in order to study the optical sensing properties of these thin organic layers towards specific volatile organic compounds. The optical absorption spectra have been analyzed by using a deconvolution analysis centered on the Q and Soret bands. The results of the optical VOCs sensing tests showed interesting differentiation in the optical responses depending on the peripheral substituents of the macromolecules. Morphologic analyses were performed by atomic force microscopy (AFM). The VOC/surface absorption processes were also analyzed in order to understand the VOC-detection mechanisms.
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 ...
Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable sub... more Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable substrates by Langmuir-Blodgett deposition technique in order to realize optical-sensitive active layers using Surface Plasmon Resonance (SPR) technique as transduction methodology. Analysis of the morphology of the sensing layers was performed by Atomic Force Microscopy. In particular, such coatings were tested for the detection of alcohol vapors such as ethanol, methanol and isopropanol. This resulted in a reversible shift in the resonance depth and angular position of the SPR curves, depending on the interactions between the sensing layers and the alcohol vapor molecules. Different sensitivity and rate of response for different alcohol molecules were found and analyzed. Measurements of the sensing response towards successive expositions of the sensing layers to methanol, ethanol and isopropanol vapors were performed in order to analyze the discrimination properties of the active layers t...
... Lett. 71 22 [6] Liu WL, Lee PF, Dai JY ... Proc. 617 (Laser–Solid Interactions for Materials ... more ... Lett. 71 22 [6] Liu WL, Lee PF, Dai JY ... Proc. 617 (Laser–Solid Interactions for Materials Processing) article J2.3.1 [14] Caricato AP, Catalano M, Ciccarella G, Martino M, Rella R, Romano F, Spadavecchia J, Taurino A, Tunno T and Valerini D 2006 Digest J. Nanomater. Biostruct. ...
Titanium oxide thin films have been deposited by thermal evaporation in vacuum and then have been... more Titanium oxide thin films have been deposited by thermal evaporation in vacuum and then have been analyzed before and after a suitable thermal annealing in order to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and conductivity measurements have been performed in order to determine the optical and electrical properties of titanium oxide thin films. The structure and the morphology of such material have been investigated by high resolution electron microscopy and small area electron diffraction.
The role of porphyrins and phthalocyanines in thin films form in sensor application has been rece... more The role of porphyrins and phthalocyanines in thin films form in sensor application has been receiving an increasing interest in recent years and various synthetic methodologies can provide the opportunities to explore the influence of chemical modifications on their physico-chemical properties. In this context we report on the synthesis and film preparation of a new bis-substituted Cu-phthalocyanine by using Langmuir-Blodgett deposition technique. Dynamic response characteristics of the electrical conductance to different NO2 concentrations in dry air are presented.
ABSTRACT Zinc oxide (ZnO), particularly in its nanostructured forms, is one of the materials exte... more ABSTRACT Zinc oxide (ZnO), particularly in its nanostructured forms, is one of the materials extensively studied in the last years due to the great number of its possible applications. Several growth techniques can be used to realize this kind of material and, among them, the Pulsed Laser Deposition (PLD) technique has been demonstrated to be a very versatile method to easily control the properties of the grown material.In this regard, this book aims to presents a review about the growth of zinc oxide (ZnO) nanostructured films by Pulsed Laser Deposition (PLD), and in particular by means of excimer laser ablation.
A theoretical comparison of the optical and electronic properties of metallic nanostructures char... more A theoretical comparison of the optical and electronic properties of metallic nanostructures characterized by complementary geometries is proposed in this work. Periodic array of nanoparticles on glass substrate and nano-holes on metal substrate have been analysed performing finite element analysis with the RF Module of COMSOL Multiphysics. Single and array of gold nanostructures have been studied, exploring several key parameters responsible for sensitivity enhancement of LSPR sensors. The analysed structures show a minimum in their spectral transmittance, confirming that regular arrays of nano-holes in thin metal films as well as nano-disk arrays may support localized surface plasmon resonance.
ABSTRACT The behaviour of an alternating co-polymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-th... more ABSTRACT The behaviour of an alternating co-polymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-thienylene), has been first investigated at the air-water interface. The floating has been analysed by monitoring Langmuir curves and Brewster angle microscopy. The floating films were deposited by the Langmuir- Schafer (horizontal lifting) technique onto various substrates. It is evident from experimental data that a strong co-planarity and interchain association originates above all in the floating film on the water surface and in the transferred multilayers. Such films were used as the active layers in resistive chemical gas sensor device, thus revealing excellent sensitivity towards NO2, reversibility and time stability of the response.
ABSTRACT Optical absorption measurements on CNx thin films produced by reactive pulsed laser abla... more ABSTRACT Optical absorption measurements on CNx thin films produced by reactive pulsed laser ablation (RPLA) at different pressures of nitrogen in the growth chamber were performed. The influence of growth regime on optical properties (n,k) of the CNx films has been examined with IR and UV-VIS spectroscopy. The dependence of the absorption coefficient α on the photon energy ℏω at the edge of the absorption band is well described by the relation αℏω=B(ℏω−Eopt)2 indicating the presence of allowed indirect transitions in the 0.8–3.0 eV photon energy range. Furthermore, we observed a decrease in the optical gap values with increasing N concentration in the deposited films. Fourier transform infrared (FTIR) spectra were also employed to analyse the chemical bonding state between the different species present in the films.
Zn(II) tetra-4-(2,4-di-t-amylphenoxy)-phthalocyanine (1a), Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-... more Zn(II) tetra-4-(2,4-di-t-amylphenoxy)-phthalocyanine (1a), Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-(4-mercapto-phenylimino-methyl)-phenoxy] (1b) and Zn(II) tris-(2,4-di-t-amylphenoxy)-[4-(4-formyl)-phenoxy] (1c) phthalocyanine were synthesized. The molecular structures were confirmed by LC–MS, 1H NMR, FT-IR and UV–vis spectra. Spin coated layers of these phthalocyanines have been used as optochemically interactive materials for the detection of volatile organic compounds (VOCs) in the UV–vis spectral range. An optical characterization in controlled atmosphere have been carried out by acquiring the absorption spectra of the phthalocyanine complexes both in dry-air and in the presence of different volatile organic compounds in order to study the optical sensing properties of these thin organic layers towards specific volatile organic compounds. The optical absorption spectra have been analyzed by using a deconvolution analysis centered on the Q and Soret bands. The results of the optical VOCs sensing tests showed interesting differentiation in the optical responses depending on the peripheral substituents of the macromolecules. Morphologic analyses were performed by atomic force microscopy (AFM). The VOC/surface absorption processes were also analyzed in order to understand the VOC-detection mechanisms.
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 ...
Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable sub... more Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable substrates by Langmuir-Blodgett deposition technique in order to realize optical-sensitive active layers using Surface Plasmon Resonance (SPR) technique as transduction methodology. Analysis of the morphology of the sensing layers was performed by Atomic Force Microscopy. In particular, such coatings were tested for the detection of alcohol vapors such as ethanol, methanol and isopropanol. This resulted in a reversible shift in the resonance depth and angular position of the SPR curves, depending on the interactions between the sensing layers and the alcohol vapor molecules. Different sensitivity and rate of response for different alcohol molecules were found and analyzed. Measurements of the sensing response towards successive expositions of the sensing layers to methanol, ethanol and isopropanol vapors were performed in order to analyze the discrimination properties of the active layers t...
... Lett. 71 22 [6] Liu WL, Lee PF, Dai JY ... Proc. 617 (Laser–Solid Interactions for Materials ... more ... Lett. 71 22 [6] Liu WL, Lee PF, Dai JY ... Proc. 617 (Laser–Solid Interactions for Materials Processing) article J2.3.1 [14] Caricato AP, Catalano M, Ciccarella G, Martino M, Rella R, Romano F, Spadavecchia J, Taurino A, Tunno T and Valerini D 2006 Digest J. Nanomater. Biostruct. ...
Titanium oxide thin films have been deposited by thermal evaporation in vacuum and then have been... more Titanium oxide thin films have been deposited by thermal evaporation in vacuum and then have been analyzed before and after a suitable thermal annealing in order to test their application in NH3 gas-sensing technology. In particular, spectrophotometric and conductivity measurements have been performed in order to determine the optical and electrical properties of titanium oxide thin films. The structure and the morphology of such material have been investigated by high resolution electron microscopy and small area electron diffraction.
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Papers by Roberto Rella