In this work, the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene (PTFE) triboelectric nanogenerator (TENG). Enhancing surface area by a powerful O₂ and Ar bipolar pulse plasma etching without the use of CF₄ gas has been demonstrated for the first time. TENG with modified surface PTFE using a sequential two-step O₂/Ar plasma has a superior power density of 9.9 Wm⁻², which is almost thirty times higher than that of a pristine PTFE TENG. The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O₂/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG. The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The correlation of surface morphology, chemical structure, and TENG performance was elucidated. In addition, the applications of mechanical energy harvesting for lighting, charging capacitors, keyboard sensing and operating a portable calculator were demonstrated.

In this research, natural rubber (NR)-TiO₂ nanocomposites were developed for triboelectric nanogenerator (TENG) application to harvest mechanical energy into electrical energy. Rutile TiO₂ nanoparticles were used as fillers in NR material to improve dielectric properties so as to enhance the energy conversion performance of the NR composite TENG. The effect of filler concentration on TENG performance of the NR-TiO₂ composites was investigated. In addition, ball-milling method was employed to reduce the agglomeration of TiO₂ nanoparticles in order to improve their dispersion in the NR film. It was found that the TENG performance was significantly enhanced due to the increased dielectric constant of the NR-TiO₂ composite films fabricated from the ball-milled TiO₂. The TENG, fabricated from the NR-TiO₂ composite using 24 h ball-milled TiO₂ at 0.5%wt, delivered the highest power density of 237 mW/m², which was almost four times higher than that of pristine NR TENG. Furthermore, the applications of the fabricated NR-TiO₂ TENG as a power source to operate portable electronics devices were also demonstrated.