Light-Sensitive PVDF-TrFE:PDI Hybrid Nanofibers-Based Flexible Bimodal Piezoelectric Nanogenerator

Abstract

The progress in smart wearable electronic devices and systems demands portable and environment-friendly power sources. Recently, piezoelectric polymers have shown huge potential in the development of feasible energy sources for smart wearable, implantable biomedical devices and autonomous applications to replace hefty batteries, owing to their inherent polarization emanating from crystal structures or molecular rearrangements of materials. Herein, we fabricated a flexible and light-sensitive piezoelectric nanogenerator (PENG) based on electrospun hybrid nanofibers of polyvinylidene fluoride-trifluoroethylene and N, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{N}^\prime $ </tex-math></inline-formula> -bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (PVDF-TrFE:PDI) that can efficiently convert mechanical energy into the electrical domain. The incorporation of PDI molecules significantly improved the crystallinity and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -phase content in PVDF-TrFE:PDI hybrid nanofibers and induced a higher piezoelectric response. Moreover, the optoelectronic investigations confirm that PVDF-TrFE:PDI hybrid nanofibers can absorb/emit light in the visible regime. The effect of doping dye in PVDF-TrFE was thoroughly investigated both in dark and white light illumination. Piezoelectric properties of nanofibers were evaluated by using a piezoresponse force microscope (PFM) and a piezometer. Hybrid nanofibers exhibited <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 41$ </tex-math></inline-formula> % improvement in the piezoelectric coefficient ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$d_{33}$ </tex-math></inline-formula> ) and a significant rise of ~9.75% in the current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 4$ </tex-math></inline-formula> nA) and voltage (~1.14 V) for an optimum concentration of PDI (0.2 wt%). The experimental results of this study might have significant ramifications for various applications in biomedical and self-powered wearable sensor devices and systems.