Detection of liquefied petroleum gas below lowest explosion limit (LEL) using nanostructured hexagonal strontium ferrite thin film

• Published in: Sensors and actuators. B, Chemical Chemical, 2017-10, Vol.249, p.96-104
• Main Authors: Singh, Monika, Yadav, B.C., Ranjan, Ashok, Sonker, Rakesh K., Kaur, Manmeet
• Format: Article
• Language: English
• Subjects: Co-precipitation method; LPG sensor; Macroporous; Strontium ferrite
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.04.075

[Display omitted] •SEM shows that the film is macro porous and TEM confirms the hexagonal structure of strontium ferrite with minimum particle size as 20nm.•The optical band gap of material was found to be 3.2eV and FTIR confirms the characteristic absorption peaks at 443cm−1 and 592.7cm−1.•The LPG sensing of nanostructured strontium ferrite thin film was carried out for the first time at room temperature.•The value of maximum sensitivity was found 7 and percentage sensor response was 602 for 5vol.% LPG.•Minimum response time was found 20s and recovery time was found 40s for 0.5vol.% LPG which is below LEL. The nano crystalline hexagonal strontium ferrite nanoparticles SrFe12O19 were synthesized successfully by chemical co-precipitation method. Thin films of strontium ferrite were prepared on glass substrate and characterized by various techniques such as XRD, SEM, TEM, EDS, UV-spectroscopy and FTIR. XRD pattern revealed the phase transformation of M-type hexa-ferrite with the minimum crystallite size of 18nm. Uniform macroporous surface structure of the film was exposed by SEM images. Existence of iron, strontium and oxygen in the material was confirmed by EDX. Optical characterization of the material was done by UV-Spectroscopy and band gap was found as 3.2eV. The liquefied petroleum gas (LPG) sensing behavior of strontium ferrite film was investigated at room temperature. The variations in electrical resistance of the film were measured with the exposure of LPG with respect to time as a function of concentration (0.5–5vol.%) of LPG. The maximum value of sensitivity for these films was found 7 and maximum sensor response was 602.23.