Surface structural analysis of a friction layer for a triboelectric nanogenerator

A triboelectric nanogenerator (TENG) is a promising type of energy harvester which converts ambient mechanical energy into electrical energy efficiently as part of the effort to overcome the energy depletion issue. To enhance the electrical output of the TENGs, the surface morphology is intentionally created on the surface of a friction layer of these harvesters. In this work, the shape dependency of the geometric morphology of a TENG, in terms of the electrical output, force sensitivity, and durability, is investigated by measurements and simulations with the aid of ANSYS. A well-ordered pillar-shaped and dome-shaped nanostructure was created on polydimethylsiloxane (PDMS), which is commonly used as a friction layer in TENGs. It was found here that the TENG with dome-shaped PDMS (DP-TENG) showed greater force sensitivity than the TENG with pillar-shaped PDMS (PP-TENG). However, the PP-TENG was found to be more durable than the DP-TENG. These results stem from the fact that the dome-shaped nanostructure will deform more easily than the pillar-shaped nanostructure. This study suggests a guideline for the structural engineering of the surface morphology of the friction layer with the consideration of the geometric shape to maximize the important properties of the TENGs.