Poli(tiofeno) (PT) foi estudado através de técnicas de dessorção estimulada por elétrons (ESID) e fótons (PSID) acopladas à espectrometria de massas por tempo-de-voo (TOF-MS), a fim de investigar a resposta desse polímero, quando submetido a feixes de elétrons e fótons. Íons atômicos de enxofre e suas contribuições isotópicas foram claramente identificados. A intensidade máxima das curvas de rendimento iônico de ESID foi medida para todos os íons em cerca de 900 eV, estão relacionadas com o processo de ionização do carbono 1s e explicadas em termos do processo Auger. O estudo da influência de elétrons secundários no processo de desorção foi também realizado, o que é altamente importante, uma vez que envolvem níveis mais baixos de energia, afetando as propriedades de interesse de materiais fotovoltaicos. A análise de TOF-PSID de filmes de PT com diferentes espessuras mostrou um aumento na eficiência da dessorção de espécies mais pesadas, como C3HS+. Este resultado foi atribuído aos elétrons secundários originados nas camadas internas do material.

Poly(thiophene) (PT) was studied by the electron (ESID) and photon (PSID) stimulated ion desorption techniques coupled with time-of-flight mass spectrometry (TOF-MS) in order to investigate the response from this semiconducting polymer when submitted to electron and photon beams. Atomic sulfur ions and its isotopic contributions could be clearly identified. Maximum intensity in the ESID ion yield curves was measured for all ions around 900 eV, which may be related to carbon 1s ionization and explained in terms of the Auger stimulated ion desorption process. The study of the influence of secondary electrons for the desorption process was also investigated, which is highly important, since they involve lower energy levels, affecting the properties of interest of photovoltaic materials. TOF-PSID analysis on PT films with different thicknesses showed an increase in the efficiency to desorb higher mass species, like C3HS+. This result was attributed to the role of secondary electrons originated in the inner layers of the material.

We have investigated the photovoltaic properties of polymer devices based on a blend of two polymers, (poly(3-(2'-methoxy-5'-octylphenyl) thiophene) (POMeOPT) and poly(2,5,2',5'-tetrahexyloxy-7,8'-dicyanodi- p-phenylenevinylene) (CN-PPV), where photo induced charge transfer takes place at the interfaces formed by the interpenetrating network of the donor and the acceptor. The polymer blend films resulting from the spin coating were phase separated and the photo response of the devices depended on the morphology of the segregation. We have studied different blend ratios by photoluminescence quenching, scanning force microscopy and photovoltaic measurements. External quantum efficiencies of 4.5% at 500nm were achieved for the less segregated polymer blend.

Thermal diffusivity and optical absorption have been investigated for porous silicon, at room temperature, using photoacoustic spectroscopy. The experimental results obtained conform well with the existing studies recently published. The value obtained for thermal diffusivity is 0.045 ± 0.002 cm²/s.The absorption onsets show energy structures, differing from the ordinary semiconductor of bulk type.