RESUMO
Polymer electrolytes are nanostructured materials which are very attractive components for batteries and opto-electronic devices. (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCI2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering simultaneously recorded with wide-angle X-ray diffraction and differential scanning calorimetry at the synchrotron ELETTRA (Trieste, Italy). These three measurement methods yielded insight into the temperature-dependent changes of the grains of the electrolyte. The heating and cooling rate was 0.5 degrees C/min. Environment friendly galvanic cells as well as solar cells of the second generation are to be constructed with such nanocomposite polymer as electrolyte.
Assuntos
Varredura Diferencial de Calorimetria/métodos , Cristalização/métodos , Eletrólitos/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Polímeros/química , Difração de Raios X/métodos , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície , TemperaturaRESUMO
Thin film structures consisting of nano-crystalline and amorphous silicon layers deposited on glass by plasma enhanced chemical vapour deposition have been studied by optical spectroscopy methods (transmittance, photo-thermal deflection spectroscopy and photo-current spectroscopy) while structure was examined by Raman spectroscopy. The nano-crystalline layers were grown on the same amorphous layers, using different radio-frequency (RF) discharge powers, leading to different structural and optical properties. The energy dependence of the absorption coefficient above the band gap agrees well to the bimodal size distribution of crystals and crystal fraction estimated by Raman spectroscopy. For energies below the band gap, the comparison of the absorption of the bi-layer systems with respect to single amorphous layer reveals that the samples produced at higher RF discharge present a higher disorder degree (Urbach edge increases) and higher number of structural defects (absorption related to the defects increases).
