Piezoelectric energy conversion by lead-free perovskite BaTiO3 nanotube arrays fabricated using electrochemical anodization

Abstract

Synthesis approaches for diverse morphologies of 1D piezoelectric ceramic nanomaterials are still challenging to investigate nanoscale properties and applications. In this work, we demonstrated a vertically grown barium titanate (BaTiO3; BT) nanotube (BT NT) arrays fabricated using optimized electrochemical anodization and hydrothermal reaction. The centimeter-scale synthesized BT NT arrays with a high aspect ratio of up to 300 showed the complete perovskite crystal structure and the notable piezoelectric coefficient of ~180 pm·V−1. A single BT NT-based piezoelectric device was fabricated on a flexible plastic substrate using a highly controlled focused ion beam-assisted method. The single BT NT device produced a piezoelectric voltage of ~150 mV and a current of ~3 nA when the NT was mechanically stimulated by bending and releasing, which are higher than previously reported values for 1D piezoelectric nanoscale materials. Finally, a flexible piezoelectric energy harvester (f-PEH) was achieved using vertically grown BT NT arrays with an elastomer as a vertically aligned nanocomposite; its generated maximum open-circuit voltage and short-circuit current were ~1.0 V and ~20 nA, respectively. The approach in this study can propose the vision for more advanced 1D piezoceramic nanomaterials and future piezoelectric nanodevices.