Exploration of versatile metal oxide and chalcogenide-based materials for room temperature NO2 sensing: A comprehensive review

초록

With rising concerns over air pollution and climate change, real-time detection of nitrogen dioxide (NO2) has become crucial for environmental monitoring and human health protection. Conventional metal oxide semiconductor sensors, though widely used, typically require high operating temperatures (200-400 degrees C), resulting in high energy consumption and limited applicability in portable or wearable systems. Recent research has therefore focused on developing room-temperature NO2 sensors based on metal oxides and metal chalcogenides, which offer tunable electronic structures, high surface reactivity, and potential for low-power operation. This review comprehensively summarizes the development, mechanisms, and performance of room-temperature NO2 sensors based on these materials. Particular emphasis is placed on the role of heterojunctions (p-n, n-n, p-p) in enhancing charge transfer and modulating interfacial potential barriers, as well as insights from density functional theory (DFT) and in situ characterization techniques such as ultraviolet photoelectron spectroscopy (UPS) and scanning kelvin probe microscopy (SKPM). Key performance metrics, including sensitivity, selectivity, response/recovery times, and long-term stability, are discussed in detail. Finally, the review outlines current challenges and future directions for translating laboratory-scale advances in metal oxide-and chalcogenidebased sensors into scalable, market-ready technologies for practical environmental applications.

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