W-doped ZnO nanofibers for enhanced triethylamine sensing via electronic structure modulation

Sensitive and reliable detection of triethylamine (TEA) is essential due to its toxicity and widespread presence in industrial processes and food spoilage. However, traditional metal oxide semiconductor sensors suffer from low response, poor selectivity, and limited understanding of the electronic mechanism underlying gas-sensing performance. In this work, W-doped ZnO nanofibers with different W contents were successfully fabricated by electrospinning followed by calcination, and their TEA sensing performances were systematically investigated. Among all samples, the 3.0 at% W-ZnO sensor exhibited the best performance at 235 °C, delivering a response of 35.8 toward 20 ppm TEA, which was 3.3 times that of pure ZnO, together with a fast response time of 7 s, good selectivity, and excellent sensing stability. Moreover, the optimized sensor was successfully applied to monitor TEA released during shrimp storage, indicating its potential for freshness evaluation. Experimental characterization revealed that W incorporation promotes oxygen vacancy formation and increases the concentration of surface chemisorbed oxygen species. Density functional theory calculations further indicated that W doping alters the local charge distribution and electronic structure of ZnO, thereby facilitating oxygen adsorption, oxygen activation, and charge transfer during the sensing process. Such electronic modulation effectively accelerates the surface oxidation reaction toward TEA and enhances the sensing response. This work provides new insight into how electronic structure modulation influences gas-sensing behavior and offers an effective strategy for designing high-performance TEA sensors.