Nanopillar- and Nanocone-Structured SrTiO₃/PDMS Films for Triboelectric Nanogenerators

The triboelectric nanogenerator (TENG) is an emerging technology to convert energy for powering electrical devices. Extensive strategies have been studied to enhance the output performance of TENG. Herein, nanopillar- and nanocone-structured SrTiO 3 (STO)/PDMS composite films with different STO concentrations were fabricated as the dielectric layer. The effects of the morphologies of nanostructured composite films produced by the anodic aluminum oxide (AAO) template method on the dielectric and electric properties of the TENG were investigated. The dielectric constant of the structured composite film increased with the concentration of STO nanoparticles and is negligible depending on the frequency from 10 2 to 10 6 Hz. The 9 wt % STO/PDMS composite film with a nanocone structure (aspect ratio = 3) shows the highest dielectric constant value at 4.85. The dielectric loss of nanostructured composite films is steady at 0.01 from 1 × 10 3 to 1 × 10 6 Hz. In addition, the electrical performance of TENG with the nanocone-structured composite films is greater than the nanopillar structure based, and the electric properties are promoted with the nanostructure aspect ratio. Meanwhile, the increased STO concentrations of the composite film significantly enhanced the electric properties of TENG as well. The Voc and Isc of TENG reached about 130 V and 1.4 μA with 9 wt % STO/PDMS nanocone-structured (aspect ratio = 3) composite film. Furthermore, the output voltage and charge density of various nanostructured films were numerically calculated using the Finite Element Method (FEM) in COMSOL Multiphysics, which shows good agreement with the experimental results. Finally, the fabricated TENG device was utilized to power the commercial LEDs and electric devices successfully. As the ideal self-powered sensing device, the portable and functional TENG shows attractive potential of application in the field of self-powered sensing systems and flexible devices.