High-Performance Sound Detection of Nanoscale-Thick and Large-Area Graphene Oxide Films in Liquids

This article presents nanoscale-thick and large-area graphene oxide (GO) films manufactured by a facile method to enable high-performance sound detection in liquids. A Fabry–Perot (F–P) cavity consisting of a GO film, whose vibration diameter is ≈4.4 mm, and a single-mode fiber (SMF) is used as the sensing core for sound detection in liquids. A sound-transparent cap, consisting of a support sleeve and a sound-transparent sleeve, is used to protect the GO-sensing diaphragm to resist liquid pressure to enable long-term stability. The sensing probes with GO diaphragms of ≈100 and 200 nm thickness are placed in ultra-pure water for performance testing. Test results show that they maintain a linear sound pressure response, a flat frequency response, and a uniform directional response from 1 to 100 kHz. They have sensitivities of ≈630 mV Pa⁻¹ and about 84 mV Pa⁻¹, respectively, in the range of 1–100 kHz in all directions in different liquids. These results demonstrate the suitability of the nanoscale-thick and large-area GO films for sound detection in liquids with high performance.