Enhancement of the Piezoelectric Property of Polyvinylidene Fluoride through Electroactive Phase Enrichment and the Application in Piezoelectric Generators

Polyvinylidene fluoride (PVDF) films have a great potential in soft flexible piezoelectric device development due to the organic nature and high piezoelectric response. To further improve PVDF’s piezoelectric properties, it is necessary to enrich the content of the electroactive phase. In this study, a method to achieve such goal is developed, which is composed of solvent casting, vacuum baking, and a homemade simplified corona poling platform. The experimental results show that the content of the electroactive phase of the PVDF film can be enriched up to 86.1% by optimizing the vacuum baking temperature and poling parameters. In addition, the piezoelectric coefficient (d33) of the poled PVDF film with an absolute value of 16.4 pC·N–1 is achieved. Furthermore, the output piezoelectric voltage and current density of the PVDF film generator can reach ∼2.1 V and ∼240 nA·cm–2, respectively. To further enhance the output performance, 0.5 wt % TiO2 nanoparticles is doped into the PVDF solution, and the output voltage and current density of the generator based on a PVDF-TiO2 composite film are ∼3.5 V and ∼400 nA·cm–2, respectively, which can light up a red LED. Therefore, the method developed in this study made it possible to fabricate a PVDF-based generator in a large scale and has a potential application in a self-powered system.