Elevating Outputs of Droplet Triboelectric Nanogenerator through Strategic Surface Molecular Engineering

The droplet triboelectric nanogenerator (D-TENG) converts mechanical energy into electricity through contact electrification and electrostatic induction at the liquid–solid interface. The device's efficiency is significantly influenced by the surface molecular structure of its triboelectric layer. By applying a fluorosilane surface modification, we enhanced the contact electrification sites and improved electron transfer between water molecules and the triboelectric layer, leading to a high-performance D-TENG. This modification allowed the surface potential of modified PTFE to reach 85% of its maximum with just five droplets, generating maximum charges of 80 and 500 nC with deionized and tap water droplets, respectively. These results surpass those of similar energy harvesting devices. The successful electron transfer mechanism was confirmed through first-principles and molecular dynamics, suggesting our approach could be broadly applicable to improving other triboelectric nanogenerators.