Flexible ZnO nanorod-based piezoelectric nanogenerators on carbon papers.

We report on the fabrication of ZnO nanorod (NR)-based flexible piezoelectric nanogenerators (PENGs) on carbon paper (CP). Structural investigations indicate that the ZnO NRs grew well along the porous CP surface. Optical investigation shows that the crystal quality of the ZnO NRs on the CP was comparable to that of NRs grown on Si substrate. As the molar concentration increased from 10-70 mM, the output voltage and current increased consistently from 3.6-6.8 V and 0.79-1.45 μA, respectively. The enhancements of the voltage and current were attributed to the enhanced accumulation of the potentials generated by the increased number of ZnO NRs in the PENG devices. Therefore, the porous CP enhanced the PENG performance due to the higher surface area, and provided a super-flexible self-powering platform.