Browsing by Author "Bernede, JC"

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    Evaporated thin films of insulating poly-(tetrabromo-p-phenylenediselenide)
    (PERGAMON-ELSEVIER SCIENCE LTD, 2002) D'Almeida, K; Bernede, JC; Godoy, A; Diaz, FR; Mevellec, JY; Molinie, P
    It has been shown that thin insulating film at the interface transparent conductive oxide/organic electroluminescent film could improve the performance of organic electroluminescent diodes (OLED). Such insulating film can be inorganic or organic. Poly-(tetrabromo-p-phenylenediselenide) (FBrPDSe) has been proved to be an efficient insulating film in OLED. The properties of these evaporated PBrPDSe thin films have been systematically studied by IR absorption, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, electron spin resonance and optical transmission measurements. It is shown that, when the deposition temperature is kept below the decomposition temperature of the polymer, tetrabromo-p-phenylenediselenide molecule is preserved during the deposition process. However the polymer, which is insoluble in powder form, becomes soluble after deposition. It can be concluded that films are mainly composed of oligomers of tetrabromo-p-phenylenediselenide.
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    Synthesis and characterization of polyarylureas. I. Potentially semiconducting polymers
    (WILEY-BLACKWELL, 2001) Diaz, FR; Godoy, A; Moreno, J; Bernede, JC; Sanchez, CO; Opazo, A; Gargallo, L
    Polyarylureas were synthesized from the reaction between phosgene with aromatic diamines. Depending on the pH, the polyarylureas presented different colors when the solvent used was pyridine. The polyarylureas were characterized by IR spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy (XPS). To study the thermal stability of the polymers, a thermal degradation was performed between 35 and 700 degreesC. The polyarylureas decomposed above 350 degreesC. Without doping, polyarylureas are considered as semiconductors [sigma = 10(-9) (Omega cm)(-) (1)]; after doping with I-2, their electrical conductivity increases by several orders of magnitude. (C) 2001 John Wiley & Sons, Inc.