Ultrahigh triethylamine sensitivity of WO₃-MoO₃ n-n heterojunction sensor operating at low-temperature

Real-time monitoring of triethylamine (TEA) is essential for environmental safety and various applications in daily life. However, TEA gas sensors still encounter specific technical challenges, such as high operating temperatures and insufficient sensitivity. In this study, in order to reduce the operating temperature and improve sensitivity, WO₃-MoO₃ (WMo) n-n heterojunctions were synthesized via calcination and subsequent solvothermal method, in which WO₃ tightly bound to the MoO₃ nanobelt surface. The resulting heterojunction demonstrated excellent TEA sensing performance. The optimized gas sensor achieved a high response of 627.28 to 20 ppm TEA at a low operating temperature (100 °C). In addition, the device exhibited strong selectivity and stability. These improvements in gas sensing performance were attributed to the formation of n-n heterojunction between MoO₃ and WO₃, as well as the surface gas sensing reaction of oxygen species facilitated by oxygen vacancies at the heterojunction interface. This study can be applied to the design of novel n-n type metal oxide heterojunction materials for the application of low-temperature high-sensitivity TEA sensors.