Antibacterial flexible triboelectric nanogenerator via capillary force lithography

Increasing the surface contact area (SCA) between active materials of triboelectric nanogenerator (TENG) can effectively enhance energy harvesting performance. In the meantime, owing to potential intimate contacts between skin and wearables, hygienic aspects of TENG devices with high SCA become important. Herein, we present a robust route to fabricate flexible TENGs with antimicrobial capability realized by nano-patterning thermoplastic polyurethane (TPU) thin films. Without involving sophisticated equipment and time-consuming technique, simply tuning curing conditions of capillary force lithography could precisely control the nanostructure geometry. Our topographically designed TENGs could promote higher power generation while preventing biofilm formation without adding any chemical additives. Analysis of pattern amplitude and wavelength correlation to output power is uniquely provided for a deeper understanding of how patterns enable peak performance of TENGs. Furthermore, a prototype TENG was innovatively applied to a smart device as a transparent screen sensor. Specific finger trajectories could be recognized by different electric responses, and as-generated electricity can be directly charged into comercial capacitors. Our proposed TENGs with critical hygienic advancements are expected to open avenues for TENG-incorporated wearables in the post-pandemic era.