Improving the Performance of ZnO Nanorod Piezoelectric Nanogenerators by Tuning the PEDOT: PSS as an Intermediate Layer

Abstract The coating design of a piezoelectric nanogenerator (PENG) was optimised to enhance the performance of ZnO nanorod-based PENGs by fine-tuning the PEDOT: PSS intermediate layer. ZnO nanorods were synthesised using the hydrothermal method at 90°C for 5 hours. The PEDOT: PSS layer was deposited via spin coating at rotation speeds (2000-5000 rpm). Furthermore, PDMS and Cu material layers were deposited using spin coating and magnetron sputtering, respectively, ensuring optimal layer characteristics for improved energy harvesting efficiency. The PENGs were fabricated with a material structure of ITO-PET/ZnO/PEDOT: PSS/PDMS/Cu. Various characterization tools including XRD, SEM, UV-Vis, and voltage-current (I-V) measurements were used to determine the materials’ structural, surface morphological, optical properties and their impact on PENG performance. The XRD diffraction patterns of ZnO nanorods coated with PEDOT: PSS revealed a hexagonal wurtzite crystal structure and amorphous phase with a lattice fringe of ~0.52 nm and a crystal size of ~67.91 nm. SEM analysis determined that the average diameter of ZnO nanorod was 67.2 ± 0.48 nm with a thickness of 1297 ± 29.22 nm. The absorption spectra of ZnO/PEDOT: PSS layers were observed in the range of 260-380 nm with an energy bandgap of 3.28 to 3.13 nm, indicating that a thicker PEDOT: PSS layer, resulted in a smaller bandgap with higher PENG conductivity at 8.97 Watt.