Enhanced Energy Harvesting Performance of Flexible PVDF Piezoelectric Nanogenerators using SnS₂/SnSe₂ Heterostructure as Nanofillers

Abstract

The effect of 2D transition metal dichalcogenides (TMDCs) including SnS2, SnSe2, their heterostructure (SnS2/SnSe2) and Polyvinylidene fluoride (PVDF) based composite films for improved performance of piezoelectric nanogenerators (PENG) is reported. SnS2, SnSe2 and SnS2/SnSe2 heterostructure were synthesized using hydrothermal method. These TMDC materials were incorporated within a PVDF matrix to create flexible thin films using the solution-casting method in order to investigate their outcome as nanofillers within the PVDF polymer framework. X-ray diffraction (XRD) confirmed the phase purity of SnS2, SnSe2 and their heterostructure, while the Raman spectra verified vibrational modes indicating high crystallinity and interfacial coupling. The enhancement of piezoelectric behaviour was revealed by Fourier transform infrared spectroscopy (FTIR), which showed an increment in the β-phase of PVDF post adding the TMDC nanofillers. PVDF/SnS2/SnSe2 heterostructure based nanogenerator exhibited the maximum open circuit voltage (peak-to-peak) (Voc) of 13.2 V and short circuit current (Isc) of 0.87 µA. This improvement is linked to the synergistic effect of the formation of a heterointerface, facilitating charge separation, enhanced stress transfer and polarization due to asymmetric charge distribution at the interface. The generated voltage from the PENG device was used to power an LED. Therefore, our work highlights the application of 2D heterostructure engineering for improving piezoelectric performance and next-generation flexible energy harvesting devices.