Design and development of a self-powered electrochromic biosensor

Resumen

Current trends in analytical chemistry aim at developing simpler and more affordable sensing devices. Electrochromic materials enable the fabrication of electrochemical sensors that exploit colour changes as a means to reduce instrumentation requirements. Although many chemical compounds used in electroanalysis exhibit electrochromic properties, the inclusion of these materials in the construction of electrochromic analytical sensors has begun to emerge only recently. This thesis focuses on the development of a new type of analytical devices relying on the use of electrochromic materials, reducing to a minimum the required components, and removing the need for silicon-based electronics. First, the working principle of self-powered electrochromic sensors is presented, demonstrating how with the appropriate geometry it is possible to obtain a sensing platform capable of providing a quantitative readout of the analyte concentration. The experimental data obtained are combined with the use of numerical simulations to develop a mathematical model that helps to have a further understanding of the behaviour of the device. Moreover, these simulations were used as a design tool to improve the performance of future electrochromic devices. New materials in the form of screen-printing pastes have also been formulated to substitute certain components of the device such as the electrochromic material or the electrolyte. These materials were used in the last part of the thesis to manufacture a fully printed electrochromic sensor able to provide quantitative results without the aid of an external signaling device.