Polythiophene-Based Chemical Sensors: Toward On-Site Supramolecular Analytical Devices

Abstract

Abstract Polythiophene (PT) derivatives are in the spotlight as functional materials with their conductivity and optical properties, which depend on the distortion of coplanarity of the flexible backbone. The PT derivatives can be applied to chemical sensors owing to their tunable chemical and physical properties, while on-site sensing in aqueous media using PT-based solid-state devices is still challenging. In this Account, we describe a strategy for on-site supramolecular analytical devices. To maximize the applicability of PTs, we designed two types of PT-based chemical sensors. In the optical sensors, microarrays made of a hydrogel containing PTs on portable glass chips can simultaneously analyze multi-analytes combined with pattern recognition techniques. The various optical responses by adding analytes on the microarray chips can be recorded by easy-to-handle methods such as a digital camera, achieving on-site and high-throughput analysis without large spectrophotometers. Next, water-gated polythiophene transistors can offer highly sensitive detection due to a synergy effect of field-effect doping and interfacial charge modulation. Moreover, the electrical device with a microfluidic chamber allows real-time monitoring. We believe that our approaches would be a guideline to pave the way for the realization of supramolecular analytical devices.