Ceramic Composite Thin Films

Conducting and Transparent Graphene-Containing Thin Silica Films NU 2007-057 Inventors Dmitry Dikin SonBinh Nguyen* Rodney Ruoff Sasha Stankovich Abstract Northwestern researchers have developed new glass technology that is electrically conducive and may be used in a range of applications including solar reflecting glass, self-cleaning windows, electrostatic charge-dissipating coatings, solar cells and sensor devices. Conductive glasses are typically prepared by metal oxide film coating using complex and expensive operations, such as magnetron sputtering or chemical vapor deposition. The investigators have identified a simple solution-based route to fabricate stable electrically conductive thin films. By incorporating graphene into a silica matrix, they create a conductive inorganic thin film on silicon substrates. Graphite oxide (GO), exfoliated in aqueous medium, is suspended in a silicon sol-gel, spin-coated on glass or hydrophilic SiOx/silicon substrates, chemically reduced and dried to a stable conductive and transparent thin film. With 11 wt% loading, the thin film exhibits ~20 nm thickness and ~12Å roughness after 400 °C curing and comparable conductivity to graphene loading. While the incorporation of graphene produces a slight reduction in transparency, it still maintains high transparency (~0.95) between 380-1000 nm wavelengths. Applications o Solar reflecting glass o Self-cleaning windows o Electrostatic charge-dissipating coatings o Solar cells o Sensor devices Advantages o Simple process o Conductive o Highly transparent o Uniform o Scalable o Resistant to ion diffusion deterioration o Use on a variety of substrates Publication Watcharotone S, Dikin D, Stankovich S, Piner R, Jung I, Dommett G, Evmenenko G, Wu S, Chen S, Liu C, Nguyen B, Ruoff R (2007) Graphene-Silica Composite Thin Films as Transparent Conductors. NANO Letters. 7: 1888-1892. IP Status Issued US Patent No. 8,574,681 Marketing Contact Allan Nader, PhD Invention Manager (e) [email protected] (p) 847-491-4456