Interface engineered WS2/ZnS heterostructures for sensitive and reversible NO2 room temperature sensing

Abstract

The inherent high surface areas and unique semiconducting properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) make them attractive for the sensing applications. However, the challenges of sensitivity, recoverability and stability still need to be overcome for the rapidly developing fields of TMD based gas sensors. With the general advantages of 2D nanomaterials, construction of 2D TMD based heterostructure is an effective approach for improving their sensing performance by the synergistic effects of hybridization. Herein, we design a novel tungsten disulfide (WS2)/zinc sulfide (ZnS) based TMD heterostructure to realize quick and reversible nitrogen dioxide (NO2) detection at room temperature (25 °C). Specifically, the engineered 2D/0D WS2/ZnS p–n heterostructure gives a desired response of 32.5 to 5 ppm NO2 with a fast response speed of 4 s, which is dramatically enhanced compared with that of pure WS2 nanosheets. More importantly, WS2/ZnS heterostructure based gas sensor can achieve full recovery state after each sensing cycle without using external energies, showing an excellent recyclability at room temperature. The optimal sensor also exhibits low detection concentration of 10 ppb, high selectivity as well as outstanding long-term stability. Such impressive features originating from the synergistic effects of WS2/ZnS heterostructure have been discussed in detail from the geometrical, electronic and chemical effects. These outstanding sensing properties of WS2/ZnS heterostructure sensor imply the possibility of using this novel nanostructure in highly efficient NO2 room temperature sensing applications.