Flexible, 3D SnS2/Reduced graphene oxide heterostructured NO2 sensor

• Published in: Sensors and actuators. B, Chemical Chemical, 2020-02, Vol.305, p.127445, Article 127445
• Main Authors: Wu, Jin, Wu, Zixuan, Ding, Haojun, Wei, Yaoming, Huang, Wenxi, Yang, Xing, Li, Zhenyi, Qiu, Lin, Wang, Xiaotian
• Format: Article
• Language: English
• Subjects: 3D structure; Adsorption; Charge transfer; Charge transport; Detection; Displays; Electronic properties; Endurance; Flexible gas sensor; Gas sensors; Graphene; Heterojunctions; High temperature; Linearity; Liquid crystal polymer (LCP); Liquid crystal polymers; Liquid crystals; Nitrogen dioxide; NO2 sensor; Reduced graphene oxide; Room temperature; Selectivity; Sensitivity; SnS2; Substrates; Tin disulfide
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.127445

[Display omitted] •3D structured SnS2/Reduced graphene oxide (RGO) heterojunction is synthesized via a facile hydrothermal route.•The 3D SnS2/RGO heterojunction exhibits an order of magnitude higher response to NO2 gas than the pristine RGO.•A liquid crystal polymer substrate was used to fabricate flexible NO2 sensor with endurance to mechanical deformation and humidity variation.•A charge transfer mechanism mediated by a depletion layer is proposed for the NO2 sensing mechanism.•The elevated temperature improves the response and recovery kinetics. Graphene (Gr) has been recognized as a promising candidate for room temperature (RT), high-performance gas sensing due to its unique structure and electronic properties. However, the poor selectivity of pristine Gr hinders its practical application in NO2 detection. SnS2 displays a strong physical affinity to NO2, while the ultrahigh resistance and low sensitivity at RT limit its utility. Here, 3D structured SnS2/reduced graphene oxide (RGO) heterojunction, a novel gas responsive material merging the merits of RGO and SnS2, is synthesized through a facile hydrothermal route. The 3D SnS2/RGO displays impressive NO2 sensing performance, including high sensitivity (6.1 ppm−1), excellent selectivity, low theoretical limit of detection (8.7 ppb), linearity and reversibility. The SnS2/RGO heterojunction exhibits 22.6 times higher response to NO2 than the pristine RGO, indicating the remarkable role of surface decoration in enhancing the gas sensing performance of RGO. The high sensitivity originates from the formation of heterojunction and 3D porous structures, which promote NO2 adsorption, diffusion and charge transfer by providing alternative adsorption sites and charge transport paths. Notably, a liquid crystal polymer substrate is employed to fabricate a flexible NO2 sensor with endurance to mechanical deformation. The elevated temperature improves the response and recovery kinetics.