Propriedades eletrônicas e estruturais de nanoestruturas de carbono funcionalizadas para aplicação em sensores

Abstract

This work presents a study of properties of functionalized carbon nanotubes and graphene nanoribbons. We studied, by first principles simulations, the structural and electronic properties of functionalized nanotubes and interacting with molecules of biological interest. Furthermore, we analyzed the properties of these systems under the action of applied electric fields, noting changes on their behavior due the external perturbation. In the case of nanotubes interacting with anti-inflammatory nimesulide, the interaction is repulsive, resulting in energetically unstable systems, but which may have their behavior controlled by the external field. We noted that when the carbon nanotube interacts with the antimalarial primaquine, a strong bond between the systems occurs, where the presence of primaquine can modify the electronic properties of nanotubes. In the other hand, for the case of carbon nanostructures interacting with vitamins, the interaction is weak. We also evaluated the structural, electronic and magnetic properties of Ti and Mn doped carbon nanoribbons (or graphene nanoribbons) and properties of defective nanoribbons, by first principles simulations (code SIESTA), and analyzed the electronic transport properties of some of these systems, by tight-binding methods associated with Green s functions. We noted that there is an edge and sublattice effect in zigzag edged nanoribbons, where the properties of the systems can be modified depending on the defect location with respect to the edge. We demonstrate that carbon nanostructures can act as selective sensors of atoms or adsorbed molecules, besides representing a route to drug delivery.