Chemiresistive Gas Sensors: Materials, Mechanisms, and Applications on the Road to Intelligence and Multifunctionality

Why It Matters

Enhanced CGSs promise real‑time, low‑cost detection across critical sectors, accelerating the shift toward smart, IoT‑connected sensing ecosystems.

Key Takeaways

• MOSs dominate due to high sensitivity and stability
• Heterojunctions boost selectivity and lower detection limits
• ML integration enables real‑time pattern recognition
• Wearable CGSs support continuous health monitoring
• Humidity mitigation remains critical for reliable operation

Pulse Analysis

Chemiresistive gas sensors have moved from laboratory curiosities to practical components of the Internet of Things, driven by a diverse material toolbox. Metal‑oxide semiconductors still lead the market because of their robust response to a wide range of gases, yet carbon nanomaterials, conducting polymers, MXenes, and emerging two‑dimensional transition‑metal dichalcogenides add flexibility in selectivity and operating temperature. By tailoring nanostructure morphology, creating heterojunction interfaces, and applying targeted doping or surface functionalization, researchers can dramatically improve detection limits, response times, and resistance to humidity—key hurdles that previously limited field deployment.

Beyond raw performance, the integration of advanced data analytics and power solutions is reshaping CGS capabilities. Machine‑learning algorithms now decode complex resistance patterns, enabling multi‑gas discrimination and predictive maintenance without extensive calibration. Simultaneously, self‑powered designs leveraging energy harvesting and low‑power wireless modules allow sensors to operate autonomously on wearable patches or distributed industrial nodes. These intelligent features reduce infrastructure costs and open new use cases in personal health monitoring, where continuous breath analysis can flag early disease markers, and in food safety, where real‑time spoilage detection extends shelf life.

The review also flags persistent challenges that will define the next research wave. Achieving consistent performance under variable humidity, scaling fabrication for mass production, and ensuring long‑term stability remain open problems. Addressing them will require interdisciplinary collaboration across materials science, circuit engineering, and AI development. As these obstacles are overcome, chemiresistive gas sensors are poised to become ubiquitous, delivering low‑cost, high‑fidelity environmental and biomedical data that underpin smarter cities and healthier societies.