Enhanced flexoelectric and piezoelectric pairing of bent polyvinylidene fluoride (PVDF) membrane with two-dimensional (2D) stannic sulfide-bismuth oxychloride (SnS2-BiOCl) heterojunction.

In this study, n-type stannic sulfide (SnS 2) nanosheets and p-type bismuth oxychloride (BiOCl) nanosheets prepared by hydrothermal method are utilized to construct the heterostructure SnS 2 -BiOCl composite through ultrasonication and grinding procedures. The piezoelectric SnS 2 -BiOCl heterojunction nanosheets are incorporated into the ferroelectric polyvinylidene fluoride (PVDF) membrane to fabricate the PVDF-based SnS 2 -BiOCl (PVDF-SnS 2 -BiOCl) flexoelectric strain sensor. The optimal amount of SnS 2 -BiOCl heterojunction in the PVDF-SnS 2 -BiOCl membrane is determined. A thorough analysis is conducted on the impact of bending curvature, frequency of bending, the size and thickness of the membrane, water flapping, underwater bending, resistance to fatigue from repeated bending, and resistance to corrosions from acid and alkali on the membrane's output current and voltage. The experimental and density functional theory (DFT) calculation results indicate that the PVDF-SnS 2 -BiOCl(2:1)-10 % membrane, functioning as a smart strain sensor, has the ability to monitor human joint movements and water fluctuations in different situations. Additionally, it can be used as a coating for polyester and linen fabrics and can be connected in series or in parallel. The experimental findings align closely with the results obtained from DFT calculations. The outcomes demonstrate that the PVDF-SnS 2 -BiOCl membrane strain sensor, which is highly flexible, sensitive, and attachable, is well-suited for smart wearable electronic materials. [Display omitted] • 2D SnS 2 -BiOCl heterojunction can improve the electrical field of PVDF film. • 2D SnS 2 -BiOCl heterojunction can enhance the polarization value of PVDF. • The polarizability of PVDF-SnS 2 -BiOCl membrane increases upon bending stress. • The increased polarization value of PVDF-SnS 2 -BiOCl is due to the charged ions. • PVDF-SnS 2 -BiOCl strain sensor can detect body motion and water fluctuation. [ABSTRACT FROM AUTHOR]