Flexible Lead-Free BCT/PDMS-Based Nanogenerator as Piezoelectric Energy Harvester

Nowadays, there is a great demand to develop lead-free piezoelectric materials for wearable energy harvesters. Among the numerous piezoelectric materials, Calcium Barium Titanate Ba
1-x
Ca
x
TiO
3
(BCT) has been extensively used because of it has approximately similar as lead Titanate Zirconate (PZT). In this study, BCT (with
$\mathbf{x}=\mathbf{0}.\mathbf{2}$
nanoparticles were synthesized using sol-gel method in order to be used to fabricate flexible and biocompatible nanogenerators (NGs). These NGs are made out of composites containing polydimethylsiloxane (PDMS) polymer and different percentages of BCT ranging from 10 to 20 wt. %. Piezoelectric performance of NGs were examined using artificial vibration source as well under tapping finger. The performance of the NGs were correlated to their electrical properties measured by impedance spectroscopy. The results illustrate that the nanogenerator with 15
$w$
t. % of BCT nanopowders achieves high piezoelectric performance with a maximum output voltage of 1.56 V under electrodynamic vibration shaker and 15.34 V under tapping finger. The impedance measurements affirms that PENG (15wt. %) is the most suitable nanogenerator.