Sm³⁺-Doped Sm/ZnIn₂S₄ for Selective Triethylamine Sensing

Semiconductor gas sensors are an efficient technological means for real-time detection of triethylamine (TEA) gas, with sensitivity, detection limit, good selectivity, and response speed being the core indicators for evaluating their performance. In this paper, Sm3+ doping was used to regulate the structure and electronic properties of ZnIn2S4, resulting in the construction of a nanomaterial (Sm/ZnIn2S4) that exhibits excellent comprehensive response performance toward TEA. Experiments show that Sm doping significantly enhances the material's response performance to TEA: the response time is significantly reduced from 95 s for pure ZnIn2S4 to 15 s; at 150 °C, the response value to 50 ppm TEA increases to 36.0, approximately 5.4 times that of the undoped sample (6.6). The Sm/ZnIn2S4 material exhibits a selectivity coefficient of up to 78% for TEA, with a detection limit (LOD) as low as 0.2 ppm. Combining electrochemical impedance spectroscopy and work function analysis, the underlying mechanisms behind the enhanced response performance were elucidated. From three perspectives─pore structure regulation, TEA molecular property matching, and crystal face response activity─the structural advantages of Sm/ZnIn2S4 in the molecular recognition process were systematically explored, providing theoretical support and experimental evidence for the design and development of high-performance gas-sensitive materials.