Development of a Cloud‐Based Epidermal MoSe2 Device for Hazardous Gas Sensing

Abstract Toxic gases such as NO 2 and irritant gases such as NH 3 are two of the harshest aspects that trigger the exacerbation of the respiratory system for asthma patients. Monitoring and recording high‐risk gases are very important for tracking disease and alerting patients because humans can be exposed to a vulnerable environment with inconspicuous gases. Current detectors suffer from lack of portability and cannot provide daily real‐time detection. This work develops a light, inexpensive epidermal gas sensor based on ultralarge MoSe 2 nanosheets. MoSe 2 nanosheets are obtained using a gold‐assisted exfoliation method and the electrical and optical properties of the film are characterized. A high‐performance gas sensor for NO 2 and NH 3 , which can be integrated onto human skin, is fabricated and shows great stability with up to 30% tensile strain. In particular, the device is able to detect down to 1 part per million with fast response (<200 s). The system is effective in providing timely warnings and the sensing data are uploaded to a cloud‐based terminal so that a medical institute can easily access them and provide a more accurate diagnosis.