Materials Engineering for Light-Activated Gas Sensors: Insights, Advances, and Future Perspectives

Light activation stands out as one of the most promising strategies for improving the energy efficiency of chemiresistive gas sensors, a crucial step toward their commercialization and integration with smart devices. Current designs of light-activated gas sensors have primarily focused on catalyst decoration and doping in various photoreactive substrates (e.g., semiconducting metal oxides, conductive metal-organic frameworks, or transition metal dichalcogenides). These approaches aim to induce surface activation to varying extents rather than optimizing the material itself for efficient light-energy utilization. Consequently, advancing light-activated gas sensor technology requires a dual focus on enhancing gas response characteristics and maximizing the utilization of incident light energy. To this end, this review provides an in-depth analysis of the photochemical mechanisms governing light-activated gas sensing, highlights key factors for performance optimization, and discusses the recent advancement in design strategies such as band structure tuning through doping, plasmonic nanoparticle incorporation, and heterojunction engineering. This review concludes with insights on future research directions in material development, signal processing, and device integration, offering a comprehensive perspective on the practical advancements of light-activated gas sensing technology.