Detecting Minute Chemical Vapors via Chemical Interactions between Analyte and Fluorinated Thiophene–Isoindigo Conjugated Polymer Transistor

Detecting and discriminating chemical vapors are essential for environmental monitoring and medical diagnostics. In this study, highly sensitive chemical vapor sensors fabricated from fluorinated thiophene–isoindigo donor–acceptor conjugated polymers are realized through understanding the interaction of the fluorine functional group and different chemical vapors. The polymers possess the merits of facile synthesis for high quality materials, good field-effect transistor performance, and stability in air and humid environments. The transistor exhibits extremely high detecting capability for minute chemical vapor down to the ppb range. The detecting sensitivity of the transistor depends on the chemical structure of the polymer and the nature of analytes. Polar molecules such as amines with potential hydrogen bond donor can adsorb in close vicinity to conducting channels due to the formation of a hydrogen bond with fluorine atoms, enhancing the sensitivity significantly. Chemical vapors such as acetone and xylene interacting with the polymers via dipolar and van der Waals forces, respectively, have to accumulate sufficient amounts in the polymer films or at the dielectric interface. Through understanding functional group–analyte interactions, polymers can be designed for multiparameter sensing, paving ways toward ultrasensitive sensors and accurate discrimination of different kinds of chemical vapors.