Flexible PET/Al/PZT/Al/PET multi-layered composite for low frequency energy harvesting
Résumé
Flexible piezoelectric device has been realized by depositing lead zirconate titanate (PZT) thin films by Chemical Solution Deposition (CSD) onto very thin aluminium foil (16 µm) and using polyethylene terephthalate (PET) laminated film (150 µm) as encapsulation. A ruthenium dioxide layer has been used in order to enhance the quality of the PZT/Al interface, improving the dielectric, ferroelectric and piezoelectric properties of the PZT film. The obtained piezoelectric generators have been subjected to large bending motions at low frequencies ranging from 0.1 to 8 Hz and the experimental values of the output voltage, output current and harvested power have been compared to theoretical values (derived from the electrokinetic model of the piezoelectric material) with a very good agreement. Due to the increase of the permittivity of the PZT film by the use of RuO2 interlayer, moderate decrease of the harvested power at the optimal load resistance is found (from 185 nW to 143 nW at 4.4 Hz), despite the enhancement of the piezoelectric properties. This type of very flexible film able to withstand small radius of curvature (1 cm) may yield promising avenue in the field of low frequency mechanical energy harvesting.