Simulation of the electric transport in nanostructured organic films

• Grant number: 12/02644-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2012
• Effective date (End): March 31, 2014
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Andrés Vercik
• Grantee: Marcello Vinícius da Silva Ferreira
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

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 between 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 the capture of carriers in traps, which in the case of the films could be associated with the nanoparticles. The aim of this project is to study theoretically the effects of 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 to 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.(AU)