Carbon quantum dots inducing formation of β phase in PVDF-HFP to improve the piezoelectric performance

Flexible piezoelectric sensors (FPS) have been widely applied to intelligent robot, human/machine interaction and human health measurement system, etc. To improve the piezoelectric performance of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), carbon quantum dots (CQDs) were introduced to form PVDF-HFP/CQDs piezoelectric film. Owing to their large specific surface area (96.3 m(2)/g) and abundant surface defects, CQDs provide mass potential induced active points for the formation of p, phase in PVDF-HFP, and rich surface functional groups (-COOH, -OH and -NH2, etc) which could promote chemical bond with PVDF-HFP. The content of beta, phase in the PVDF-HFP/CQDs film is increased by 14.4 % compared with that in the PVDF-HFP film. Thereby, PVDF-HFP/CQDs based FPS exhibit better sensitivity (36.6 mV/g) than PVDF-HFP based FPS (25.7 mV/g) with good linearity (R-2 > 99 %). Besides, the FPS show excellent mechanical stability under repeated dynamic loading. On this basis, some potential applications of the PVDF-HFP/CQDs based self-powered FPS were explored, including anti-touch alarm system, finger bending detection, voice recognition and vibration monitoring. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

PVDF-HFP/CQDs-based FPS exhibit better sensitivity and linearity, excellent mechanical stability, and various potential applications.