Development of novel MoS2 hydrovoltaic nanogenerators for electricity generation from moving NaCl droplet

•Successful demonstration of>7 V output voltage generation using MoS2 nanogenerator.•High voltage generation mechanism for fabricated device has been explained using equivalent circuit model.•Effect of underlying substrate and number of MoS2 layers on output voltage has been studied in detail.•A practical nanogenerator has been demonstrated utilizing the simulated sea waves (0.6 M NaCl). [Display omitted] Competence of two-dimensional (2D) material e.g. MoS2 for developing efficient seawater energy harvester has been investigated as sea water stores huge amount of clean energy in its dynamic form. Hydrovoltaic nanogenerators has been fabricated using MoS2 monolayer grown by pulsed laser deposition (PLD) technique. Fabricated MoS2 nanogenerators are found to generate voltage>7 V by the dynamic flow of NaCl electrolyte over MoS2 monolayer. Good quality large area growth of MoS2 monolayer using PLD technique was confirmed by Raman spectroscopy, Photoluminescence (PL), in-situ RHEED and XPS. Obtained high voltage from MoS2 hydrovoltaic nanogenerators has been explained using equivalent circuit model considering dynamic charging and discharging process in formed electric double layer with successive movement of NaCl droplet. Substrate dependent nanogenerator performance was investigated and it was concluded that unintentional doping of MoS2 provided by underlying substrates is crucial for enhancing the power generation. Present work opens the possibility of using MoS2 monolayer as practical nanogenerator for energy harvesting from sea water (0.6 M NaCl) as demonstrated.