Progress in Piezoelectric Nanogenerators Based on PVDF Composite Films.

In recent years, great progress has been made in the field of energy harvesting to satisfy increasing needs for portable, sustainable, and renewable energy. Among piezoelectric materials, poly(vinylidene fluoride) (PVDF) and its copolymers are the most promising materials for piezoelectric nanogenerators (PENGs) due to their unique electroactivity, high flexibility, good machinability, and long-term stability. So far, PVDF-based PENGs have made remarkable progress. In this paper, the effects of the existence of various nanofillers, including organic-inorganic lead halide perovskites, inorganic lead halide perovskites, perovskite-type oxides, semiconductor piezoelectric materials, two-dimensional layered materials, and ions, in PVDF and its copolymer structure on their piezoelectric response and energy-harvesting properties are reviewed. This review will enable researchers to understand the piezoelectric mechanisms of the PVDF-based composite-film PENGs, so as to effectively convert environmental mechanical stimulus into electrical energy, and finally realize self-powered sensors or high-performance power sources for electronic devices.