Zno nanorods-based piezoelectric nanogenerators on double-sided conducting paper

We report on the voltage output enhancement from ZnO nanorod (NR)-based bendable piezoelectric nanogenerators (PENGs) with a conducting paper. Double-sided carbon paper (DSCP) was used as a conducting substrate. Structural investigations by scanning electron microscope and X-ray diffraction results showed that ZnO NRs were successfully grown via a two-step hydrothermal process on both sides of the CP. Photoluminescence peak intensity ratio of the band-edge to the deep level emissions from the ZnO NRs on both sides of the CP substrate was similar values in the range of 1.8 to 2, which indicating a similar crystalline quality of the ZnO NRs on the front and back sides. The output characteristics from the two PENG devices on the CP substrate showed identical piezoelectric output. The output voltage from the DSCP-based PENG was 2.56-and 1.86-fold greater than that from the single-sided PENG devices on only the front and back of the CP substrate, respectively. This enhancement was attributed to the synergetic effect between the PENGs on the front and back of CP and to the modification of the CP’s electrical properties under an electric field generated by the PENGs on the opposite side of the CP substrate.