Room temperature liquefied petroleum gas (LPG) sensor based on p-polyaniline/n-TiO2 heterojunction

In the present work, we report on the performance of a room temperature (300 K) liquefied petroleum gas (LPG) sensor based on a p-polyaniline/n-TiO2 heterojunction. The heterojunction was fabricated using electrochemically deposited polyaniline on chemically deposited TiO2 on a stainless steel substrate. Both the methods (chemical bath deposition and electrodeposition) are simple, inexpensive and suitable for large-scale production. TiO2 and polyaniline films were characterized for their structural as well as surface morphologies and LPG response was studied. The XRD analysis showed formation of polycrystalline TiO2 while polyaniline exhibited amorphous nature. Morphological analysis using scanning electron microscopy (SEM) of the junction cross-section revealed formation of a diffusion free interface. The heterojunction showed the maximum response of 63% upon exposure to 0.1 vol% LPG at room temperature.