(Invited) Electrochemically Synthesized High Density Chemical Sensor Arrays

Abstract

Electronic detection of molecules is rapidly emerging as an alternative to the tranditional optical and electrochemical methods because of the small size, low-power consumption, improved sensing performance and most of all possibility of developing high density arrays for simulatenous analyses of multiple species in small sample volumes. Recently, one-dimensional nanostructures (e.g., carbon nanotubes (CNTs), inorganic, and organic nanowires) as conduction channels of field effect transistors (FETs) have been developed for detection of a variety of gaseous molecules with excellent low detection limit, sensitivity, and selectivity. These features are a consequence of dramatic decrease in characteristic length and increase in the ratio of surface to volume atoms, allowing for rapid diffusion into the bulk and for a more significant fraction of the atoms to participate in surface processes such as chemical and biochemical binding interactions. One-dimensional geometries also enhance response times by virtue of their two-dimensional mass transfer profile. Furthermore, nanowires are heralded for device miniaturization and sensor arrays, enabling duplicate elements to reduce false positives/negatives and pattern recognition systems termed electronic noses where each sensor in the array has a unique response to every analyte creating a fingerprint type response that increases sensitivity and selectivity. Finally, sensors are also attractive for their proven commercial viability, as this approach uses a single material behaving as both the sensitive layer and transducer to directly covert chemical information into an electronic signal without the need for labels, allowing for real-time, continuous monitoring. In this presentation, synthesis, functionalization, and assembly of various nanoengineered materials including CNTs and conducting polymer nanowires will be discussed to create “true” high density gaseous sensor arrays with superior sensing performance in cost-effective manner. Finally, Android based smartphone integratable sensor will be demonstrated.