Fabrication and performance of polypyrrole (Ppy)/TiO2 heterojunction for room temperature operated LPG sensor

Abstract In this paper, we report on the fabrication and performance of room temperature operated liquefied petroleum gas (LPG) sensor based on polypyrrole/TiO 2 (Ppy/TiO 2 ) heterojunction. Ppy/TiO 2 heterojunction was prepared by sequencial depositing TiO 2 film by chemical bath deposition and Ppy film by electrodeposition method. Ppy and TiO 2 films were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), FTIR and thermo-emf techniques. The XRD study revealed amorphous and nanocrystalline natures for Ppy and TiO 2 films, respectively. The SEMs of Ppy and TiO 2 films showed cauliflower-like and densely compact morphologies respectively. Maximum gas response of 55% was observed for Ppy/TiO 2 heterojunction at 1040 ppm of LPG. Relative humidity affected the gas sensing performance of heterojunction. Good stability, fast response and recovery times indicate that Ppy/TiO 2 heterojunction is a one of the candidate for room temperature LPG detection.

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