Nature-inspired structure and electronic structure regulation enable polyacrylonitrile nanofiber/cobalt-doping SnS2 nanosheets to integrate flexible room-temperature gas sensor

Flexible room-temperature (RT) gas sensors are highly desirable due to their low power consumption and wearability. However, it is very challenging to integrate excellent mechanical flexibility and superior gas sensing properties. Here, polyacrylonitrile (PAN) nanofiber/cobalt-doping SnS2 nanosheets with nature-inspired "branch-leaf" structure was well tailored by directly grown Co-SnS2 ultrathin nanosheets on PAN nanofiber for the first time. With the interfacial bonding interaction between PAN substrate and SnS2 nanosheets, the geometrical deformability of composite structure, the interfacial bonding force, stress distribution, transfer and dissipation will be enhanced. Moreover, the electronic structure and S vacancy are regulated by Co-doping, then improve the gas transmission/diffusion, gas sensitive reactivity and carrier transfer/transport properties. The integrated RT NO2 gas sensor exhibits excellent flexibility (minimum radius of curvature is 3.9 µm), high response, fast response/recovery speed (6.2 and 27.5/60 s). Meanwhile, it possesses a low detection limit and long-term stability. This comprehensive strategy for the integration of mechanical and gas sensitive properties unlocks the inherent bottlenecks of conventional film-based gas sensors and open a new design avenue for the development of flexible electronics.