Stretchable, ultrasensitive, and low-temperature NO2 sensors based on MoS2@rGO nanocomposites

The recent development of 3D highly porous laser-induced graphene (LIG) has drawn significant attention for numerous sensing applications. In particular, novel gas sensing platforms based on stretchable LIG patterns with self-heating capabilities have been demonstrated as a simple alternative to interdigitated electrodes (IDEs) for integrating gas-sensitive nanomaterials. However, their direct performance comparison with the IDEs is unclear. In this paper, the sensing performance of nanomaterials with various specific surface areas between the LIG patterns and IDEs are compared directly. Molybdenum disulfide (MoS2) @ reduced graphene oxide (rGO) was synthesized with controllable size and morphology for nitrogen dioxide (NO2) sensing. When dispersing MoS2@rGO on an IDE integrated on a soft silicone polymeric substrate, the stretchable gas sensor exhibited mechanical robustness upon stretching and a significantly large signal-to-noise ratio (SNR) for rapid detection of 10 ppb NO2. The MoS2@rGO nanocomposite was integrated on a stretchable 3D porous LIG pattern yielding an extraordinarily high SNR of 1026.9 to NO2 of 2 ppm. Considering the high SNR of over 60 to NO2 of 10 ppb, the novel LIG gas sensing platform with a simple fabrication process shows a great promise to test nanomaterials and enable stretchable bio-integrated gas sensors for monitoring of the health and environment.