Development of WO₃-PEDOT: PSS hybrid nanocomposites based devices for liquefied petroleum gas (LPG) sensor

Hybrid nanocomposite device (Glass/WO₃-PEDOT: PSS/Ag) was developed by chemical mixing and casting technique on a glass substrate. The properties of various hybrid nanocomposite materials were studied by dispersing 1 wt%, 3 wt% and 5 wt% of WO₃ nanomaterial in PEDOT: PSS conducting polymer. The structural, morphological and optical properties of the composite films were studied by X-ray diffraction (XRD), UV–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscope (AFM). The crystallite size was calculated to be 62 nm, 65 nm and 69 nm for 1 wt%, 3 wt% and 5 wt% of WO₃ in PEDOT: PSS polymer. The energy band gap and Urbach energy value were calculated from absorption spectra. Chemical structure and modes of vibration in composite films were analyzed by FTIR and Raman spectroscopy, respectively. Grain size and surface roughness were investigated using AFM technique and Nanoscope analysis software. The grain size found to vary between 54 and 93 nm for pure polymer and composite films. The Liquefied Petroleum Gas (LPG) sensing response of 5 wt% WO₃-PEDOT: PSS composite thin film was tested at room temperature. The variation in response resistance of the composite film was measured as a function of time with exposure to LPG. The response and recovery time were observed to be 29.4 s and 54.0 s, respectively at 500 ppm concentration of LPG. The sensor response significantly increased with increase in concentration (ppm) of LPG. The structural properties and gas sensing response of the synthesized hybrid composite makes it a promising device for gas sensing applications at room temperature.