Electrically Assisted Thermal Stamping of Tunable Carbon‐Based Nanofilms for Direct Fabrication of Hydrophobic, Energy Harvesting, and Sensing Devices

The demand for multifunctional thin-film devices has accelerated the development of scalable fabrication techniques capable of precisely controlling composition, structure, and patterning. However, conventional approaches rely on complex, multi-step processing and harsh conditions, limiting their applicability. Herein, we report a single-step, electrically assisted thermal stamping (EATS) method for the direct and scalable fabrication of carbon-based nanofilms, including reduced graphene oxide (rGO), polytetrafluoroethylene (PTFE), and their nanocomposite films. By applying localized Joule heating to PTFE-embedded carbon paper under ambient conditions, EATS induces graphite exfoliation, GO reduction, and PTFE incorporation, thereby eliminating the need for multi-step processing or harsh environments. The resulting films exhibit tunable thickness, morphology, and composition, governed by EATS power density and duration. EATS enables spatially selective patterning without the need for complex lithographic techniques. The versatility of EATS is demonstrated through the direct fabrication of functional devices: (i) hydrophobic coatings with contact angles tunable from 44.3° to 109.8°, (ii) triboelectric nanogenerators achieving 10.11 mW cm^-3 power density with <2.8% variation over 10 000 cycles, and (iii) humidity sensors exhibiting a 3.56% sensing error across 50-100% relative humidity. These results establish EATS as a powerful, lithography-free fabrication platform for multifunctional thin-film devices, offering a generalizable strategy for next-generation electronics.