| Summary: | Flexible piezoelectric energy harvesters have been regarded as an overarching
candidate for achieving self-powered electronic systems for environmental sensors and
biomedical devices
using the self-sufficient electrical energy. In this research, we realize a flexible
high-output and lead-free piezoelectric energy harvester by using the aerosol deposition method
and the laser lift-off process. We also investigated the comprehensive biocompatibility of the
lead-free piezoceramic device using ex-vivo ionic elusion and in
vivo bioimplantation, as well as in vitro
cell proliferation
and histologic inspection. The fabricated LiNbO3-doped (K,Na)NbO3
(KNN) thin film-based flexible energy harvester exhibited an outstanding piezoresponse,
and average output performance of an open-circuit voltage of ∼130 V and a short-circuit
current of ∼1.3
μ
A
under normal bending and release deformation, which is the
best record among previously reported flexible lead-free piezoelectric energy
harvesters. Although both the KNN and Pb(Zr,Ti)O3
(PZT)
devices showed
short-term biocompatibility in cellular and histological studies, excessive
Pb toxic ions
were eluted from the PZT in human serum and tap water. Moreover, the KNN-based flexible
energy harvester was implanted into a porcine chest and generated up to ∼5 V and 700 nA
from the heartbeat motion, comparable to the output of previously reported lead-based
flexible energy harvesters. This work can compellingly serve to advance the development of
piezoelectric energy harvesting for actual and practical biocompatible self-powered
biomedical applications beyond restrictions of lead-based materials in long-term
physiological and clinical aspects.
|
|---|
