Photovoltaic Gas Sensor Based on Double-Heterojunction Synergy for Self-Powered Trimethylamine Detection.

Trimethylamine (TMA), a representative volatile organic amine, is crucial for the precise and rapid evaluation of food freshness and environmental safety. However, existing gas sensors face challenges, such as low system integration and limited operational lifetime, which restrict their practical application in the Internet of Things (IoT). In this work, we fabricated a photovoltaic gas sensor by constructing a PANI:PSS/MoO3 multifunctional layer on silicon nanowire arrays. Through precise energy-band engineering and dual-heterojunction structure, we optimized the separation, transport, and transfer of photogenerated carriers, enabling self-powered TMA detection with excellent performance for the first time. Systematic characterization and electrical testing confirmed that the sensor exhibited stable photovoltaic properties. Under these conditions, the sensor achieved a detection limit for TMA as low as 10 ppb with a response time of only 19 s, placing its overall performance among the best of similar devices. Additionally, cycling tests and lifetime verification confirmed its reliable long-term operational capability. This research fills a gap in self-powered TMA detection, significantly extending the lifespan of sensing systems and broadening their application prospects, providing a potential technological reference for the development of self-sustaining IoT smart terminals.