Integrated nanospheres occupancy-removal and thermoforming into bulk piezoelectric and triboelectric hybrid nanogenerators with inverse opal nanostructure

Abstract

Traditional processing methods (such as thermoforming and injection moulding) limit the fabrication of nanostructure and make it hard to be directly applied to the assembly of piezoelectric nanogenerators or triboelectric nanogenerators, whose electrical conversion properties have a strong reliance on nanostructure and porosity. Here we report an innovative strategy combining both traditional processing and nanofabrication to develop poly (vinylidene fluoride) (PVDF)–based piezoelectric and triboelectric hybrid nanogenerators (PTNGs), demonstrating promising potential in developing low-cost and scalable PTNGs with a wide material applicability and convenient operation. We showed that periodically ordered and interconnected nanoporous PVDF bulks, as hearts of PTNGs converted mechanical energy into electric energy, were quickly and simply constructed by thermoforming and template removal using monodisperse silicon dioxide (SiO2) nanospheres as placeholder, whereas the pore shape, aperture and porosity of materials could be effectively controlled. Under the simulated periodic vibration, the optimal PVDF bulk with inverse opal structure exhibited a high output voltage of 242 V, which can be applied to light a processed LED bulb (220 V, 3 W) directly. This innovative method opens a new route for the rapid and simple fabrication of nanoporous structure which can be used as various functional devices and directly promote the industrialization, such as optical and electrochemical sensors, wireless charging equipment and capacitors.