Wearable Inorganic\nOxide Chemiresistor Based on Flexible\nAl<sub>2</sub>O<sub>3</sub>‑Stabilized ZrO<sub>2</sub> Ceramic\nSponge Substrate for NO<sub>2</sub> Sensing

Wearable\ngas sensors, possessing the advantages of high sensitivity,\nexcellent flexibility, high permeability, low weight, and workability\nat ambient conditions, hold great promise for real-time health monitoring\nand early warnings of poisonous gases. However, obtaining high-performance\nwearable gas sensors utilizing the current well-developed inorganic\nsemiconductor oxide sensing materials is still very limited due to\ntheir fragile and rigid nature. Herein, a newly designed wearable\ngas sensor based on an all-inorganic ASZ (Al<sub>2</sub>O<sub>3</sub>-stabilized ZrO<sub>2</sub>)/ZnO/SnO<sub>2</sub> nanofibers is introduced\nfor the first time. The flexible ASZ ceramic sponge substrate (with\na Young’s modulus of 4.15 MPa) and ultrathin ZnO/SnO<sub>2</sub> sensing layer endow the wearable gas sensor with promising properties\nsuch as super flexibility (with a bending radius of 5 mm), high gas\npermeability, and low weight. Furthermore, driven by UV light irradiation,\nthis all-inorganic wearable sensor also demonstrates a stable NO<sub>2</sub> sensing response under different bending states at room temperature,\nwhich enables the gas sensor to be more compatible with wearable sensing\napplications. This work offers a general method to achieve a high-performance\nwearable gas sensor based on inorganic materials and provides new\ninsights into their potential in wearable gas-sensing applications.