The Advanced Application of Halide Perovskite Materials for Gas Sensor.

The demand for highly functional chemical gas sensors has surged in response to critical needs such as health monitoring, protection against harmful gases, and assessment of food freshness. Over the past few decades, various chemiresistive gas sensors have been developed, exhibiting considerable sensitivity to a range of gases. However, their performance remains constrained by notable drawbacks, including elevated operating temperatures, inadequate sensitivity, and poor selectivity. In recent years, perovskite materials have garnered substantial attention due to their exceptional chemical and physical properties-such as a high absorption coefficient, low ionic binding energy, tunable bandgap, and high carrier mobility. Concurrently, significant strides have been made in leveraging both organic and inorganic perovskite-based sensors for detecting environmental gases. This review provides a comprehensive overview of the recent advancements in perovskite-based gas sensors, systematically analyzing the field from material design and engineering to device applications. We dissect the critical influence of perovskite crystal structures and micro/nano-architectures on key performance metrics such as sensitivity, selectivity, response/recovery time, and stability. The applications of these materials in detecting a wide array of hazardous gases-including H2S, NH3, NOx, CO/CO2, and various volatile organic compounds (VOCs)-are thoroughly examined, with representative examples and underlying sensing mechanisms discussed in detail. However, the path to commercialization is obstructed by persistent challenges of instability, selectivity, and the severe environmental and health risks of lead. This has catalyzed a major research thrust towards non-toxic, lead-free perovskites. Consequently, the field is pivoting towards lead-free perovskites. This analysis underscores that synergistic innovation in lead-free material science and device engineering is critical to overcoming current barriers, paving the way for the development of robust, high-performance, and commercially viable gas sensors that align with global sustainability goals.