A Robust Droplet Triboelectric Nanogenerator with Self-Cleaning Ability Achieved by Femtosecond Laser.

A droplet triboelectric nanogenerator (TENG) has great potential for harvesting the high entropy energy in water. Despite extensive research, it still suffers from low average power density, poor long-term stability, and insufficient flexibility. Here, a porous micronanostructured polytetrafluoroethylene (PTFE) with superhydrophobicity and self-cleaning ability, is generated by femtosecond laser direct processing. The droplet TENG with laser treated PTFE (LT-PTFE) dielectric layer (L-DTENG) can reach a higher output compared with the droplet TENG with a PTFE dielectric layer (P-DTENG). L-DTENG also demonstrated good long-term stability, self-cleaning ability, and flexibility, making it suitable for various applications, including those involving dust and sewage pollution, as well as bending and pressing conditions. Furthermore, a simulation of finite element method (FEM) and an equivalent circuit model are established to understand the working mechanism of L-DTENG. This multifunctional device and theoretical research provide a smart strategy to generate electricity in a complex environment and lay a solid foundation for droplet TENG applications on a large scale.