Film-Sponge-Coupled Triboelectric Nanogenerator with Enhanced Contact Area Based on Direct Ultraviolet Laser Ablation
Hyunwoo Cho, Seungju Jo, Inkyum Kim, Daewon Kim
Abstract
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.