Flexible, Disposable Cellulose-Paper-Based MoS 2 /Cu 2 S Hybrid for Wireless Environmental Monitoring and Multifunctional Sensing of Chemical Stimuli.

Multifunctional sensors responding to different chemical stimuli fabricated using functional nanomaterials still remain a challenge because of the usage of the same sensor multiple times for different sensing applications and unreliable front-end processing of the sensing data. This challenge is intensified by the lack of suitable techniques for fabricating disposable sensors, which can be integrated into smartphones with a dedicated application developed for each sensing application. A novel MoS2 /Cu2 S hybrid grown on disposable cellulose paper by the hydrothermal method is reported for its utilization in sensing humidity, temperature, breath, and ethanol adulteration, wherein the data can be wirelessly transmitted to a smartphone with the dedicated application module for each sensing application. The sensor can be utilized for a particular sensing application and then can be disposed, avoiding the need for utilizing the same sensor for different sensing applications, thereby increasing the accuracy of the sensing data. The sensing mechanism of the fabricated sensor is explained for each stimulus in terms of change in the transport properties of the MoS2 /Cu2 S hybrid. The development of such unique hybrid materials for wireless disposable multifunctional sensors is a great step ahead in flexible and wearable electronics having potential applications in medical, security, Internet of things, etc.