Optical, vibrational and fiber optic gas-sensing properties of hematite microparticles

We report the fiber optic gas-sensing application of hematite microparticles (HMPs) with an average crystallite size of 35 ± 2 nm, which has been synthesized by co-precipitation method. Structure and morphology of the prepared HMPs have been carried out using x-ray diffraction technique (XRD) and scanning electron microscopic techniques, respectively. The XRD pattern reveals that the prepared HMPs exhibit rhombohedral structure and rhomb-centered lattice. Vibrational properties of prepared microparticles have been studied using the Raman and Fourier-transform infrared spectroscopic analysis. The direct–indirect bandgaps and refractive index of the material have been deduced from the UV–Vis absorption spectroscopic analysis. The calculated refractive index indicates that the proposed gas sensor works under leaky mode and has been used for sensing the presence of acetone, ethanol, ammonia and methanol.