Thermal transport on composite thin films using graphene nanodots and polymeric binder

Abstract

Series of composite thin films consisted of graphene nanodots (GNDs) and water-based binder (i.e., polyvinylpyrrolidone and polyvinyl alcohol) are designed and fabricated for nano-engineering devices with enhanced thermal and electrical conductivities. A thermal pyrolysis of citric acid and urea is adopted to synthesize crystalline GNDs under IR irradiation. The as-prepared GNDs are uniformly coated over three types of substrates including Cu foil, cotton cloth and filter paper. The GND thin films emit tunable fluorescence upon thermal treatment of GNDs at 400 °C in helium atmosphere. The thermally treated GND-based thin film exhibits excellent thermal as well as electrical conductivity compared to bare GNDs and reduced graphene oxide sheets. The enhanced conductivity is due to the reduced oxidation level induced by the thermal treatment on GNDs samples which subsequently decreases the photon scattering. With increasing weight loading, GNDs can serve not only as connective point but also as stuff, offering a well-developed conductive path for the heat dissipation. Accordingly, the design of GND thin film is promising for enhanced thermal management for electronic and photonic applications since it enables engineering the fluorescence emission with substantially increased thermal and electrical conductivities.