High performance flexible two dimensional vertical aligned ZnO nanodiscs based piezoelectric nanogenerator via surface passivation.
Herein, we present the growth of pristine vertical aligned flexible two dimensional (2D) pure ZnO nanodiscs via simple seed assisted solution route and their fabrication of piezoelectric nanogenerator. The preferred growth direction and morphology of wurtzite ZnO nanodiscs were investigated using X-Ray diffraction and field emission scanning electron microscopy (FESEM) studies. Flexible piezoelectric nanogenerator was fabricated using vertical aligned ZnO nanodiscs as active piezoelectric materials and carbon nanotubes-polydimethylsiloxane (CNT: PDMS) film as top electrode. This unique 2D-type ZnO nanodiscs-based nanogenerator generated a direct current (DC) type output voltage and current density about 2.5 V and 30 nA/cm2 under compressive vertical strain, respectively. Significant enhancement of piezoelectric output voltage from a flexible nanogenerator based on a vertical aligned two dimensional (2D) zinc oxide (ZnO) nanodiscs was achieved via thermal annealing. An output voltage and current density of 17 V and 150 nA/cm2 were detected from thermal annealed 2D ZnO nanodiscs based nanogenerators which is approximately 8 times higher (voltage) than that from the pristine nanogenerator. It is proposed that the output performance of the vertical aligned ZnO nanodiscs based nanogenerators increases due to surface passivation and reduction of oxygen vacancy.