Studying the Performance of SnS-Based Zn (0%, 2% and 4%)-Doped Methanol Sensors Under the Optimal Temperature of 240 °C.

Addressing the critical limitation of high operating temperatures plaguing conventional resistive gas sensors, this work reports the synthesis of Zn-doped SnS gas-sensing materials with doping concentrations of 0%, 2%, and 4% via a one-step hydrothermal route-an approach that enables precise regulation of dopant distribution and material microstructure. Systematic gas-sensing tests demonstrate that all as-prepared sensors exhibit remarkable responsiveness to methanol at a reduced optimal operating temperature of 240 °C, with the response values increasing significantly with Zn doping content: 22.1% for pristine SnS, 48.9% for 2% Zn-doped SnS, and 65.2% for 4% Zn-doped SnS when exposed to 50 ppm methanol. Beyond enhanced response, the Zn-doped SnS sensors maintain excellent methanol selectivity against interfering gases (e.g., ethanol, formaldehyde, acetone) and achieve a low detection limit of 5 ppm, which meets the practical requirements for trace methanol monitoring. The superior performance of 4% Zn-doped SnS-exhibiting a 195% response enhancement compared to pristine SnS-originates from the synergistic effects of Zn-induced defect engineering and improved charge carrier mobility, as supported by structural and electrical characterizations. This study not only provides a facile strategy for developing low-temperature-operating methanol sensors but also highlights the potential of Zn-doped SnS as a promising candidate for high-performance gas-sensing applications in environmental monitoring, industrial safety, and biomedical detection.