The preparation and gas sensitivity study of polythiophene/SnO2 composites

Nanocomposites of SnO₂ and polythiophene (PTP) were synthesized by the in situ chemical oxidative polymerization method. These nanocomposites were characterized by FTIR, transmission electron microscope (TEM), X-ray diffraction (XRD) and thermogravimetric and differential thermal analysis (TG–DTA) techniques, which proved the polymerization of thiophene monomer and the strong interaction between polythiophene and SnO₂. The composites were used for gas sensing to methanol (MeOH), ethanol (EtOH), acetone, and NO_x at different working temperature. It was found that PTP/SnO₂ materials with different PTP mass percent (1%, 5%, 10%, 20% and 30%) could detect NO_x with very higher selectivity and sensitivity at much lower working temperature than the reported SnO₂. The PTP/SnO₂ nanocomposites responded to NO_x at concentration as low as 10 ppm. PTP/SnO₂ composite containing 5 mass% PTP showed the highest sensitivity at room temperature. The sensing mechanism of PTP/SnO₂ nanocomposites to NO_x was presumed to be the effects of p–n heterojunction between PTP and SnO₂.