2D borophene–MoS2 nanosheet heterostructure as a flexible piezoelectric nanogenerator for self-powered piezotronic sensing

Van-der Waals interlayer interactions between 2D nanosheets open new avenues to construct the desired arrangement of heterostructures with new and exciting properties. Here, we report the synthesis of molybdenum disulphide (MoS2)-borophene nanosheet-based heterostructures via hydrothermal method followed by ultrasonication. Microscopy analysis shows the formation of a few-layered nanosheet-based heterostructure with a high piezoelectric charge coefficient. We fabricate a high-performance flexible piezoelectric nanogenerator based on as-grown borophene–MoS2 nanosheet heterostructures. Surprisingly, the borophene–MoS2 nanosheet heterostructure-based nanogenerator exhibits a high output voltage of 22 V and current density of 34 µA cm−2 with an energy conversion efficiency of 37%, outperforming their pristine components by almost ten times. We also detect band gap shrinkage for the heterostructure nanosheets. Utilising the n-type and p-type semiconductor properties MoS2 and borophene nanosheets, we develop a 2D p–n junction for piezotronics devices. The heterostructure shows high output voltage under UV light and mechanical strain, showing their applications for 2D-based self-powered UV sensor devices. Van-der Waals interlayer interactions between differing 2D nanosheets give rise to unique properties. Here, a molybdenum disulphide-borophene nanosheet-based heterostructure was demonstrated as a high-performance flexible piezoelectric nanogenerator.