Film-Sponge-Coupled Triboelectric Nanogenerator with Enhanced Contact Area Based on Direct Ultraviolet Laser Ablation

Triboelectric nanogenerators (TENGs) recently have emerged as applicable and eco-friendly harvesting devices. Numerous studies have been actively conducted to fabricate a flexible and robust TENG with high-output performance. Herein, a film-sponge-coupled TENG (FS-TENG) is proposed using direct ultraviolet laser ablation, as a method for surface modification of a polyimide (PI) film. This state-of-the-art method has advantages of accuracy as well as time efficiency in creating the pattern on the surface; thus, the pre-designed patterns can be precisely constructed within only a minute. In the laser-ablated PI film, the structural design and chemical modification on the surface are investigated related to the triboelectric output performance. Thereafter, a sponge is fabricated based on non-woven polyamide and silicone rubber, which can fully contact with the micro-/nano-scaled structure on the surface of the PI film. After an optimization, the FS-TENG exhibits 48.19 V of open-circuit voltage and 1.243 μA of short-circuit current, which shows approximately 3 times enhanced electric performance compared to the FS-TENG using a pristine PI film. The FS-TENG device demonstrates its robustness through both mechanical stress and flexible stress by showing less than 5% degradation after 50,000 cycles. On the basis of the high flexibility and stability of the FS-TENG, a self-powered scoreboard is successfully developed for lighting a scoreboard in a soccer field. This feasible lighting system can be operated by harvesting the kinetic energy of a soccer player without an additional power source. The novel FS-TENG, thus, provides remarkable potential for a self-powered indoor harvesting system.