4 research outputs found

    Novel phenoxazine-benzonitrile and phenothiazine-benzonitrile donor-acceptor molecules with thermally activated delayed fluorescence (TADF)

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    ABSTRACT: Four novel TADF emitters, containing phenothiazine and phenoxazine as electron-donors and benzonitrile derivatives as electron-acceptors were synthesized and fully characterized. Their photophysical (absorption and emission spectra, molar extinction coefficients, fluorescence quantum yields and lifetimes) and electrochemical properties (HOMO and LUMO energy levels) were measured, and drop-cast solid films of the four compounds were obtained to perform TADF studies. The obtained values for Delta E-ST indicate that these compounds are candidates for OLED applications.info:eu-repo/semantics/publishedVersio

    Fabrication of new polypyrrole/silicon nitride hybrid materials for potential applications in electrochemical sensors: Synthesis and characterization

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    International audienceIn this research, an efficient fabrication process of conducting polypyrrole (PPy)/silicon nitride (Si3N4) hybrid materials were developed in order to be employed as transducers in electrochemical sensors used in various environmental and biomedical applications. The fabrication process was assisted by oxidative polymerization of pyrrole (Py) monomer on the surface of Si/SiO2/Si3N4 substrate in presence of FeCl3 as oxidant. To improve the adhesion of PPy layer to Si3N4 surface, a pyrrole-silane (SPy) was chemically bonded through silanization process onto the Si3N4 surface before deposition of PPy layer. After Py polymerization, Si/SiO2/Si3N4-(SPy-PPy) substrate was formed. The influence of SPy concentration and temperature of silanization process on chemical composition and surface morphology of the prepared Si/SiO2/Si3N4-(SPy-PPy) substrates was studied by FTIR and SEM. In addition, the electrical properties of the prepared substrates were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the best silanization reaction conditions to get Si/SiO2/Si3N4-(SPy-PPy) substrate with high PPy adhesion and good electrical conductivity were obtained by using SPy at low concentration (4.3 mM) at 90°C. These promising findings open the way for fabrication of new hybrid materials which can be used as transducers in miniaturized sensing devices for various environmental and biomedical applications
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