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Abstract The accurate, continuous analysis of healthcare-relevant gases such as nitrogen oxides (NO x ) in a humid environment remains elusive for low-cost, stretchable gas sensing devices. This study presents the design and demonstration of a moisture-resistant, stretchable NO x gas sensor based on laser-induced graphene (LIG). Sandwiched between a soft elastomeric substrate and a moisture-resistant semipermeable encapsulant, the LIG sensing and electrode layer is first optimized by tuning laser processing parameters such as power, image density, and defocus distance. The gas sensor, using a needlelike LIG prepared with optimal laser processing parameters, exhibits a large response of 4.18‰ ppm −1 to NO and 6.66‰ ppm −1 to NO 2 , an ultralow detection limit of 8.3 ppb to NO and 4.0 ppb to NO 2 , fast response/recovery, and excellent selectivity. The design of a stretchable serpentine structure in the LIG electrode and strain isolation from the stiff island allows the gas sensor to be stretched by 30%. Combined with a moisture-resistant property against a relative humidity of 90%, the reported gas sensor has further been demonstrated to monitor the personal local environment during different times of the day and analyze human breath samples to classify patients with respiratory diseases from healthy volunteers. Moisture-resistant, stretchable NO x gas sensors can expand the capability of wearable devices to detect biomarkers from humans and exposed environments for early disease diagnostics. 

Monitoring nitrogen utilization efficiency and soil temperature in agricultural systems for timely intervention is essential for crop health with reduced environmental pollution. Herein, this work presents a high‐performance multi‐parameter sensor based on vanadium oxide (VO_X)‐doped laser‐induced graphene (LIG) foam to completely decouple nitrogen oxides (NO_X) and temperature. The highly porous 3D VO_X‐doped LIG foam composite is readily obtained by laser scribing vanadium sulfide (V₅S₈)‐doped block copolymer and phenolic resin self‐assembled films. The heterojunction formed at the LIG/VO_Xinterface provides the sensor with enhanced response to NO_Xand an ultralow limit of detection of 3 ppb (theoretical estimate of 451 ppt) at room temperature. The sensor also exhibits a wide detection range, fast response/recovery, good selectivity, and stability over 16 days. Meanwhile, the sensor can accurately detect temperature over a wide linear range of 10–110 °C. The encapsulation of the sensor with a soft membrane further allows for temperature sensing without being affected by NO_X. The unencapsulated sensor operated at elevated temperature removes the influences of relative humidity and temperature variations for accurate NO_Xmeasurements. The capability to decouple nitrogen loss and soil temperature paves the way for the development of future multimodal decoupled electronics for precision agriculture and health monitoring.