A self-heating gas sensor for online monitoring of endogenous ethylene of post-harvest cut chrysanthemums

The decay of post-harvest cut chrysanthemums (PHCCs) during storage and shipment results in enormous loss, and the accumulated endogenous ethylene is one of the main reasons. However, it is challenging for current technologies to onsite monitoring of endogenous ethylene of PHCCs whose concentration is very low. Here, we propose a ethylene sensor with high performances enabled by self-heating capability. Specifically, laser-induced graphene (LIG) patterns are in-situ fabricated on the upper and lower sides of a polyimide substrate. The upper LIG is coated with chemo-resistive SnO2 for ethylene sensing and the lower LIG serves as heater for self-heating. The working temperature is well tuned by the heater and effectively transferred to SnO2. Owing to the self-heating capability, the sensor displays outstanding ethylene detection performances, such as ultra-low limit of detection (1.654 ppb), wide detection range (0.05-100 ppm), high sensitivity (0.2249 ppm−1), high detection linearity (0.9925), and long-term stability (>14 days). Moreover, the sensor is integrated with a data acquisition circuit and connected to a mobile application, realizing online monitoring of endogenous ethylene of PHCCs. The results demonstrate that the decay of PHCCs is accelerated as the endogenous ethylene accumulates. This work would promote the online monitoring of endogenous ethylene of plants.