commercial polyimide (PI) films with infrared lasers in a protective atmosphere; while subsequent studies showed that LIG can also be processed with a variety of lasers, including infrared and ultraviolet lasers, [6,7] and using both synthetic materials and natural materials (e.g., cork and fruit shells [1,8] ) as the precursor of graphene. The microscopic mechanisms governing the LIG process have been investigated in recent years through reactive molecular dynamics models, [7,9,10] providing a theoretical base for understanding the graphene formation process during LIG.Various applications of LIG have been demonstrated, including supercapacitor, [11] gas sensor, [12] Joule heater, [13,14] and solid-state triboelectric nanogenerator (TENG). [15][16][17] Among these devices, TENG, which exploits the coupling effect of triboelectricity and electrostatic induction [18][19][20] to generate energy, has found applications in many areas. The device can not only collect small-scale environmental mechanical energy, such as kinetic energy of human movement, [21,22] mechanical vibration energy, [23][24][25][26] rotational kinetic energy, [27,28] wind energy, [29][30][31] etc., but also be used as a self-powered sensor for monitoring mechanical motion. [32,33] Laser-induced graphene (LIG) has emerged as a promising and versatile method for high-throughput graphene patterning; however, its full potential in creating complex structures and devices for practical applications is yet to be explored. In this study, an in-situ growing LIG process that enables to pattern superhydrophobic fluorine-doped graphene on fluorinated ethylene propylene (FEP)-coated polyimide (PI) is demonstrated. This method leverages on distinct spectral responses of FEP and PI during laser excitation to generate the environment preferentially for LIG formation, eliminating the need for multistep processes and specific atmospheres. The structured and water-repellant structures rendered by the spectral-tuned interfacial LIG process are suitable as the electrode for the construction of a flexible dropletbased electricity generator (DEG), which exhibits high power conversion efficiency, generating a peak power density of 47.5 W m −2 from the impact of a water droplet 105 µL from a height of 25 cm. Importantly, the device exhibits superior cyclability and operational stability under high humidity and various pH conditions. The facile process developed can be extended to realize various functional devices.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202104290.
