A strict control of the properties of organic conducting polymeric films is still lacking to fabricate reliable practical devices based on these materials. In particular, the direct correlation of the material type and the conduction mechanisms is not immediate and usually controversial. The study of the electrical transport in these materials must include the charge injection across the electrodes and the bulk transport. For the latter case, the more accepted models consider that the current is limited by the space charge and by capture of carriers in traps, which in the case of the films could be associated to the nanoparticles. The aim of this project is to study theoretically the effects of a temperature-dependent mobility on the dominant transport mechanism in chitosan films containing gold nanoparticles. For this, continuity-Poisson equations within the drift-diffusion approximation must be solved using proper boundary conditions that take into account the injection mechanisms from the electrodes into the film. It is expected to contribute with a project that is being currently carried out at the Nanotechnology, Biosensors and Devices Laboratory - FZEA/USP, which aims to explain a hysteresis phenomenon observed in the current-voltage curves of these materials. This study envisages exploring, through numerical simulations and comparison with experimental results, the effects on the current-voltage curves of several parameters such as mobility, film thickness and nanoparticle concentration, among others. These films could be used in organic memories or as a matrix for bio-receptor incorporation for biosensors.
News published in Agência FAPESP Newsletter about the scholarship: