Heterostructuring via oxidative transformation of transition metal dichalcogenides unveils new horizons for improving key sensor performance parameters, including sensitivity, selectivity, and stability, by leveraging the synergistic interplay of charge carrier dynamics and surface interactions at the interfaces. Herein, the NH3 sensing characteristics of VS2 are significantly enhanced by forming VOx/VS2 heterostructures through a facile oxidative modification, wherein VOx induces strong interfacial coupling with the hierarchical, flower-like VS2. Detailed material characterization and electrical analysis reveal significant structural reconfiguration and electronic modulation within the VOx/VS2 architecture, both of which are pivotal to the superior NH3 sensing performance. The optimized VOx/VS2 sensor showcases ultralow NH3 detection down to 280 ppb across a wide dynamic range of 0.4-200 ppm at room temperature. The designed sensor exhibits remarkable stability, long-term reliability (>10 weeks), exceptional selectivity, and consistent response and recovery properties. Further investigation into the sensing mechanism discloses that chemical sensitization by VOx promotes selective NH3 adsorption, while electronic sensitization at the VOx/VS2 heterointerface modulates charge transfer dynamics. By employing the VOx/VS2 sensor, this study proposes three innovative sensor prototypes: (i) an autonomous self-triggered sensing switch, (ii) a piezoelectric nanogenerator-driven self-powered gas detector, and (iii) flexible wearable sensors, demonstrating the potential of the developed devices for diverse application scenarios.
Nath et al. (2026) studied this question.