Michele Tonezzer

Production of novel microporous porphyrin materials with superior sensing capabilities

New robust microporous cobalt 5,10,15,20-meso-tetraphenyl porphyrin (CoTPP) thin films for sensing applications have been produced by a novel plasma-based deposition technique named Glow Discharge Induced Sublimation (GDS). CoTPP films have been also produced by conventional vacuum evaporation (VE) and spin coating (SPIN) methods for comparison. The chemical properties of the films were assessed by FT-IR and ESI-MS analyses demonstrating the integrity and the purity of the GDS films. The physical properties of the samples were thoroughly analysed: thickness measurements coupled with surface density analyses showed the impressive free volume of the GDS samples (30 times higher than that of VE ones), SEM images show the extremely rough morphology of GDS samples, and physisorption measurements indicate both the extremely high specific surface area (184 m2 g−1) and the microporosity of the GDS porphyrin films. The sensing capabilities of the samples were investigated by exposing them to low concentrations of NO2 and by monitoring their optical absorption changes. These measurements clearly demonstrate that the GDS process leads to superior sensing materials as a result of the distinctive attainable molecular architectures. GDS-grown CoTPP sensors exhibit very high intense and sensitive responses as well as faster responses and much lower detection limits (<1 ppm) than conventionally deposited ones. Finally, the repeatability and reproducibility of sorption–desorption processes demonstrate the robustness of these assemblies. The GDS method can be extended to several other organic receptors, opening the way for the production of new improved sensing materials.

Deposition and Characterization of Luminescent Eu(tta)3phen‐Doped Parylene‐Based Thin‐Film Materials

Herein, novel host-guest films produced by coarse vacuum cosublimation of the parylene C dimer and Eu(tta)3phen are prepared and studied. Eu(tta)3phen sublimation at different temperatures allows films with different concentrations of the Eu complex to be obtained. The films are characterized by Rutherford backscattering spectrometry (RBS), FTIR spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), and UV/Vis absorption and emission spectroscopy. RBS, FTIR, and XRD reveal the incorporation of Eu(tta)3phen into the parylene matrix. AFM evidences the very flat film surface, which is particularly advantageous for optical applications. UV/Vis absorption and emission analyses confirm that the optical properties of Eu(tta)3phen are preserved in the deposited films. Fluorescence measurements evidence the occurrence of an energy-transfer process between parylene and Eu(tta)3phen, and this results in an increase in the light emitted by the Eu complex that is as much as five times higher than that emitted by Eu(tta)3phen alone.

Analysis of art objects by means of ion beam induced luminescence

The impact of energetic ions on solid samples gives rise to the emission of visible light owing to the electronic excitation of intrinsic defects or extrinsic impurities. The intensity and position of the emission features provide information on the nature of the luminescence centers and on their chemical environments. This makes ion beam induced luminescence (IBIL) a useful complement to other ion beam analyses, like PIXE, in the cultural heritage field in characterizing the composition and the provenience of art objects. In the present paper, IBIL measurements have been performed on inorganic pigments for underlying the complementary role played by IBIL in the analysis of artistic works. Some blue and red pigment has been presented as case study.

Optical Vapors Sensing Capabilities of Polymers of Intrinsic Microporosity

Polymers of Intrinsic Microporosity (PIMs) represent a novel class of polymer–based organic microporous materials that offer unrivaled scope for membrane separations, heterogeneous catalysis and hydrogen storage. In this work, we have explored for the first time the vapors sensing capability of PIMs. The solubility of the polymer in aprotic polar solvents allowed the incorporation of a strongly fluorescent dye (Nile Red). The materials, synthesized by a chemical route, were analyzed by absorption and emission spectroscopy, FT–IR spectroscopy, nitrogen physisorption measurements and X–ray diffraction. In particular the sensing capabilities of the hybrids toward ethanol vapors were tested and the kinetic profiles highlighted the optimal behavior of the films as related to sensitivity, response and recovery speed and reproducibility.

Luminescent Cavitands as Novel Optically Active Materials

In this work optically active cavitand – based thin films purposely produced for detecting aromatic compounds at very low concentrations (ppb) has beeen used as optical sensing materials for benzene monitoring.

Physical Vapour Deposition Techniques for Producing Advanced Organic Chemical Sensors

In the organic chemical sensors field, the main focus to date has been on the molecular design of the receptor as a function of the analyte to be detected. Nevertheless chemical sensing requires an integrated approach, where both the molecular and the material properties of the sensing layer must be finely tuned to achieve the desired properties. Despite its great influence on the ultimate performances of the sensors, the material side has been largely neglected.

Optical Sensing Properties Towards Ethanol Vapors of Au-Polyimide Nanocomposite Films Synthesized by Different Chemical Routes

Nanocomposite films containing Au nanoparticles embedded in a fluorinated polyimide (BPDA–3F) were prepared by two different chemical routes and the synthesis was followed by the estimation of the optical sensing capability of the samples in ethanol vapors. This work arises from the well–known ascertainment that optochemical sensing of volatile organic compounds (VOCs) using MNP (metal nanoparticles) characteristic surface plasmon resonance (SPR) absorption peak as the sensing probe is an attractive technique for its simplicity, high stability and sensitivity [1, 2].

Novel Vacuum Evaporated Cavitand Sensors for Detecting Very Low Alcohol Concentrations

High vacuum evaporation (VE) is used for the first time to grow thin films of novel tetraphosphonate, Tiiii[H, CH3, Ph], and tetrathiophosphonate, TSiiii[H, CH3, Ph], cavitands for gas sensing applications. The sensing capabilities of the samples were investigated by exposing Tiiii- and TSiiii-coated QCMs to very low concentrations of ethyl alcohol. The sensitivity, the speed (t50 = 5 s for both the samples) and the detection limit (0.4 ppm for Tiiii and 2.5 ppm for TSiiii) of the samples were determined, indicating highly competitive sensing capabilities.

The SPES Direct Target Project at the Laboratori Nazionali di Legnaro

The construction of the Radioactive Ion Beam (RIB) Facility SPES‐DT, within the framework of the new European RIB panorama is under study at the Laboratori Nazionali di Legnaro. The present project will be devoted to the production of neutron rich exotic nuclei, by using the fission process induced by a 40 MeV proton beam, 200 μA current, on a multi‐sliced Uranium Carbide (UCx) target. The UCx multiple thin disks target, developed at LNL is designed so that the power released by the proton beam is mainly dissipated by irradiation. Following the idea of the existing HRIBF facility at Oak Ridge National Laboratory (USA) where a proton primary beam of 40 MeV is also used, our target configuration is an evolution which permits to sustain a higher power on target. A high number of fission products (up to 1013 fission/s) will be obtained, still keeping a low power density deposition inside the target. The whole facility, together with the details on the Direct Target configuration, will be described. Thermo‐mec...

The SiC Direct Target Prototype for SPES

A R&D study for the realization of a Direct Target is in progress within the SPES project for RIBs production at the Laboratori Nazionali of Legnaro. A proton beam (40 MeV energy, 0.2 mA current) is supposed to impinge directly on a UCx multiple thin disks target, the power released by the proton beam is dissipated mainly through irradiation. A SiC target prototype with a 1:5 scale has been developed and tested. Thermal, mechanical and release calculations have been performed to fully characterize the prototype. An online test has been performed at the HRIBF facility of the Oak Ridge National Laboratory (ORNL), showing that our SiC target can sustain a proton beam current considerably higher than the maximum beam current used with the standard HRIBF target configuration.