Boosting the chemi-resistive performance of rGO/Co2SnO4 hybrid films for ultra-sensitive and rapid low-ppm-level dimethylamine gas sensing under ambient conditions

Volatile organic compounds (VOCs) are extensively used across numerous industrial and domestic sectors, have raised a growing environmental and health concerns. Among them, dimethylamine (DMA) is a highly toxic and readily volatile compound widely utilized in pharmaceutical and agrochemical industries, necessitating efficient detection and monitoring due to its significant ecological and health risks. Chemi-resistive based binary metal oxide semiconductor as a sensing layer have been widely studied. However, their performance hindered by the requirement of elevated operating temperatures, poor selectivity, and interference from other target analytes. Achieving the superior gas sensing performance under ambient condition remains a major bottleneck, primarily due to limited available active sites and sluggish charge-transfer dynamics. In this research, we designed a rGO/Co 2 SnO 4 hybrid sensor film using spray pyrolysis followed by spin coating techniques to boosting their DMA gas sensing behaviour at room temperature. Subsequently, the developed sensor films were scrutinized using structural, optical, morphological, and elemental analyses to affirm their physicochemical properties and the creation of Schottky barriers at the interfaces. The optimized rGO/Co 2 SnO 4 hybrid sensor (CTR1.0) shows an enhanced sensor response of S = 12,548 towards 5 ppm DMA gas at room temperature, alongside with the rapid response (117 s) and recovery time (19 s), respectively. These results demonstrate that the effective rGO/Co 2 SnO 4 interfacial coupling markedly enhances charge transport and target gas adsorption, outlining a promising roadmap for developing scalable, advanced and low-power DMA sensors with superior performance.