IOT Enabled Printed LP Gas Sensor using Reduced Graphene Oxide / Tin(IV) Oxide Nanocomposite on Flexible Substrate

Liquified Petroleum Gas (LPG) is a composition of propane and butane, which is widely used in industrial and domestic applications as a fuel. Being a highly flammable and asphyxiant gas, LPG also poses severe safety hazards from manufacture to utilization. Thus, global demand for LPG sensors is surging as they ensure protection against leaks while elevating worker safety in industries. In this study, a novel method to sense LPG using reduced-Graphene Oxide / Tin(IV) oxide (r-GO / SnO₂) nanocomposite was developed. A simple Wheatstone bridge circuit with interdigitated electrodes for resistors was printed using Silver nanoparticle ink on a flexible polyethylene terephthalate (PET) substrate. The sensing material was coated on the electrodes. The FTIR results proved the presence of r-GO and SnO₂, and the SEM analysis further verified the proper formation of sphere-shaped nanoparticles in the sensing material. The strongest adhesion of 5B was obtained from the Cross-Hatch Adhesion Test (ASTM D3359 - method B) for the sensing material on PET. An ESP 32 System on a Chip (SoC) was utilized for remote sensing via a cloud server. Enhanced sensitivity was observed with great response and recovery times with the implementation of the bridge circuit.