Ultrafast Transparent Defogger Based on High-Quality Graphene Film Directly Grown via Copper Vapor-Assisted Method

Graphene has been a significant candidate to achieve high-performance transparent defoggers as conductive thermogenic layers due to its high transmittance and conductivity. However, the low-temperature synthesis of high-quality graphene defoggers remains challenging due to incomplete carbon precursor decomposition and weak interfacial adhesion. Herein, we report a transparent defogger based on graphene film directly grown on oxide substrates (e.g., SiO₂, Al₂O₃) via a copper-assisted plasma-enhanced chemical vapor deposition method at 800 °C. This strategy enhances catalytic activity and minimizes defects without requiring post-transfer processes, and the as-prepared graphene exhibits excellent homogeneity and high quality at a large scale. The defogger based on graphene film represents a lower heat transfer coefficient (h = 14.4 W m^-2 °C^-1), which means excellent electrothermal properties, and achieves ultrafast defogging within 17.6 s at 30 V with a 3 × 3 cm² defogger. Finite element analysis revealed efficient heat distribution and utilization, demonstrating the superior electrothermal performance of this defogging system. This work highlights the potential of graphene-based defoggers for applications such as rearview mirror defogging, smart windows, and other future technologies.