Preparation of ZnO Thin Films by Spin Coating Technique for LPG Detection

In the present study, zinc oxide (ZnO) thin films were successfully synthesized using the spin coating technique, a simple and cost-effective method suitable for producing uniform and adherent films. The primary objective of this work was to investigate the gas sensing properties of the prepared ZnO thin films, with particular emphasis on their response to liquefied petroleum gas (LPG). The gas sensing characteristics were evaluated using a static gas sensing system. Among the various target gases tested including ethanol, methanol, compressed natural gas (CNG), and ammonia the ZnO thin films exhibited the highest sensitivity towards LPG. A maximum sensitivity of 85.59% was recorded at an optimal operating temperature of 100 °C for an LPG concentration of 1000 ppm, demonstrating the film's excellent gas sensing performance at relatively low temperatures. The films showed high selectivity towards LPG over other interfering gases, indicating their potential utility in practical applications where gas discrimination is essential. In addition to high sensitivity and selectivity, the ZnO films displayed fast dynamic response characteristics, with a response time of 23 seconds and a recovery time of 55 seconds. These results suggest that ZnO thin films prepared via spin coating are promising candidates for efficient and reliable LPG gas sensor devices.