Improving the surface charge density of a contact-separation-based triboelectric nanogenerator by modifying the surface morphology

• Effect of nano patterns on charge generation in TENG surfaces was investigated.
• Surface charge densities increased with the modification of contacting areas.
• Hexagonal cone shaped nano pattern produced higher output power than line and pillar pattern.
• Smaller width pillar patterns generated higher output voltage, current and power levels compared to those with larger widths.
• Experimental results will aid for the development of high-efficiency and cost-effective self-powered nano devices.

A triboelectric nanogenerator (TENG) based on the contact-separation mode can be used as a portable power source to harvest the triboelectrification which arises between contacting films. However, a general challenge is that the charge generation is usually limited. The performance of a TENG can be enhanced by modifying the surface morphologies of the triboelectric materials. In this study, we demonstrate morphologies with line, pillar and hexagonal cone shapes on the surfaces of PDMS and PMMA to enhance the charge production in a TENG. A contact and subsequent separation operation between the two surfaces of triboelectric materials is then carried out to generate the charge. Experiments reveal that the maximum output power, voltage and current density of a TENG with 300-nm hexagonal cone patterns on the contacting surfaces are nearly 22, three and six times greater than a TENG without any patterns, respectively. In addition, the results showed that pillar patterns with a smaller width generate higher output voltage, current and power levels compared to those with larger widths. As a result, the generation of the surface charge density in a TENG is augmented by the creation of nanopatterns on its contacting elements. This result will be applicable to the fabrication of a self-powered nanosystem with high efficiency at a low cost.

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