2D/2D SnS2/SnSe2 van der Waals heterostructure for highly sensitive room-temperature NO2 sensor: Key role of interface contact

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-06, Vol.466, p.143369, Article 143369
• Main Authors: Wu, Ruozhen, Yan, Kangkai, Zhao, Jinyun, Cai, Zhenghan, Jian, Shaoju, Qiu, Liqing
• Format: Article
• Language: English
• Subjects: Heterointerface; NO2; Sensor; SnS2; SnSe2; van der Waals heterostructure
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.143369

•Two sets of 2D/2D SnS2/SnSe2 vdW heterostructures are fabricated for room-temperature high-sensitive NO2 sensors.•The key role of the distance of interface contact in vdW heterostructure is revealed by DFT calculation and XPS analysis.•Increasing heterojunction and improving interface contact enhance the sensing properties of SnS2/SnSe2 vdW heterostructure.•High response value and sensitivity for NO2 gas are achieved in 2D/2D vdW heterostructure at room temperature. 2D/2D van der Waals (vdW) heterostructure is an effective strategy for improving the functions of 2D layered nanomaterials due to the high-quality heterointerfaces with the lacked dangling bonds at the interfaces. However, little attention was paid to investigating the effect of heterointerface amount and quality on gas-sensing performance. Here, two sets of 2D/2D SnS2/SnSe2 vdW heterostructures with tunable SnSe2 content are fabricated by physical mixing and solvothermal growth methods for room-temperature NO2 gas sensors. Compared to pure SnS2 and SnSe2 layers, the creation of 2D/2D vdW heterostructure shows a great improvement in sensing performance at room temperature. Moreover, the response and sensitivity are further enhanced by increasing the amount of heterointerface. More importantly, the SSSe-1.0 vdW heterostructures with improved interface contact by solvothermal growth exhibit a much higher response and sensitivity than that of MSSe-1.4 prepared by physical mixing, showing the highest response (1274.1% for 2 ppm) with the sensitivity of 598.2 % ppm−1 to NO2 gas. The mechanism of enhanced response and sensitivity for the SSSe-1.0 sensor is investigated by DFT calculation and XPS analysis, revealing that the strengthening of the interface contact improves the charge transfer and NO2 adsorption in 2D/2D SnS2/SnSe2 vdW heterostructure. Such effect of heterojunction number and interface contact on sensing performance paves a solid step toward the development of 2D layered crystals-based NO2 sensors and extends to applications in other fields.