ZnO/LIG nanocomposites to detect acetone gas at room temperature with high sensitivity and low detection limit

While the low-cost noninvasive measurements of diabetes based on exhalation diagnosis is of high interest, it is still difficult for the needed gas sensors to achieve high sensitivity, low detection limit, and low power consumption. This study presents a highly sensitive acetone gas sensor with ultralow detection limit based on zinc oxide (ZnO)/laser-induced graphene (LIG) composite with heterostructures on interdigitated electrodes prepared by one-step laser direct writing and simple drop casting. The resulting ZnO/LIG-based acetone gas sensor exhibits a large response of −24 % to 1 ppm acetone, a fast response recovery time of 21/23 s, and an ultralow experimentally demonstrated (or theoretical) detection limit of 4 ppb (or 334 ppt). Further combined with a molecular sieve coating layer, the acetone gas sensor can accurately detect acetone in the highly humid environments such as the exhaled breath and differentiate diabetic patients from healthy individuals for early diagnostics and treatment evaluations.