PVDF-HFP encapsulated WS2 nanosheets in droplet-based triboelectric nanogenerators for possible detection of human Na+/ K+ ion concentration.

Here we report the liquid-solid interaction in droplet-based triboelectric nanogenerators (TENG) for estimation of human Na+/K+ levels. The exploitation of PVDF-HFP encapsulated WS2 as active layer in the DTENG leads to the generation of electrical signal during the impact of water droplet. Comparison over the control devices indicates that surface quality and dielectric nature of the PVDF-HFP/WS2 composite largely dictates the performance of the DTENG. The demonstration of excellent sensitivity of the DTENG towards water quality indicates its promising application towards water testing. In addition, the alteration in output signal with slightest variation in ionic concentration (Na+ or K+) in water has been witnessed and is interpreted with charge transfer and ion transfer processes during liquid-solid interaction. The study reveals that the ion mobility largely affects the ion adsorption process on the active layer of PVDF-HFP/WS2 and thus generates distinct output profiles for diverse ions like Na+ and K+. Following that, the DTENG characteristics have been exploited to artificial urine where the varying output signals have been recorded for variation in urinary Na+ ion concentration. Therefore, the deployment of PVDF-HFP/WS2 in DTENG holds promising application towards the analyse of ionic characteristics of body fluids.