Tunable Charge Carrier Properties in Phosphotungstic Acid-Derived P-WO3/SnO2 for Enhanced Triethylamine Detection.

Regulating the efficient carrier transport characteristics at the interface of composite materials is the key to developing high-performance metal oxide semiconductor gas sensors. The P-WO3/SnO2 heterojunction composite material was prepared through the phosphotungstic acid derivative method in this work. The optimized 3% P-WO3/SnO2 sensor exhibits outstanding capabilities at 263 °C, including a high response value (19.26 to 20 ppm TEA, a 2.4-fold enhancement over pristine SnO2), an ultralow detection limit (30 ppb), and long-term stability (30 days). These improvements are attributed to the synergistic effects of heterojunction formation and P doping, which optimize the electronic structure, facilitate charge carrier transport, and refine the band alignment at the heterojunction interface. This work demonstrates a synergistic interface-defect modulation strategy via polyoxometalate-mediated heterojunction construction and P doping, offering new insights for designing advanced gas-sensitive materials with superior performance.