Synthesis and characterization of graphene based thermoacoustic devices

Thermoacoustic devices were fabricated on flexible plastic substrates with few layer graphene films. The graphene films were grown by chemical vapor deposition on nickel and copper foil substrates, then transferred to the plastic substrates. A simple and reliable technique for electrical contact formation to the graphene was developed, using material from the nickel or copper growth substrate. The thermal and thermoacoustic behavior of the graphene thermophones was characterized as a function of the input electrical signal voltage and frequency, at frequencies up to 10 kHz. The average surface temperature of the device was measured under the same conditions using an infrared pyrometer. Accurate sound reproduction was demonstrated with graphene based thermoacoustic devices, including voice and music. The efficiency of the device is limited by the thermal quenching effect of the substrate.