NO2 gas sensing based on ordered ultrathin films of conducting polymer and its nanocomposite

The metal oxides films are widely used for CO, aromatic hydrocarbon and NO2, gas-sensing applications, but such sensors mostly lack selectivity and operate at high temperatures (300-500 °C). We focused on the use of organized ultrathin films of conducting polymers and their nanocomposites, which recognize selectively the NO2 gases with a very high sensitivity (≤ppb). Polyhexylthiophene (PHTh), poly(ethylene dioxythiophene) (PEDT), PHTh-PEDT copolymer, sulfonated polyaniline, polyaniline (PANI)-SnO2, polypyrrole (PPy)-SnO2, PEDT-SnO2, PHTh-SnO2 and copolymer (HTh-EDT)-SnO2 conducting polymer and nanocomposite thin films were fabricated and used for gas sensing applications. The physical properties (UV and FTIR) such films were investigated before and after the NO2 gas treatment. Regioregular PHTh, its copolymer P(HTh-PEDT), and their metal oxide nanocomposites films detected NO2 gas with a high sensitivity.