Highly Sensitive Low‐Frequency Acoustic Sensor Based on Functionalized Graphene Oxide

Developing miniaturized low-frequency acoustic sensors with high sensitivity is crucial for diverse applications, including geological monitoring and aerospace exploration. However, the performance of low-frequency acoustic sensor is constrained by the limited mechanical robustness of traditional sensing films at nanoscale thickness. Here, a functionalized graphene oxide (GO)-based Fabry-Perot (FP) low-frequency sensor is proposed, with characteristics of compact size, resistance to electromagnetic interference high-sensitivity low minimum detectable pressure (MDP), and a high signal-to-noise ratio (SNR). The functionalized GO is synthesized through the reaction of GO with dodecylamine and the uniform film is prepared by a self-assembly method. This sensor exhibits a sensitivity of -91.92 dB re 1 rad/µPa at 10-200 Hz with a fluctuation of 0.4 dB, ≈5.6 times higher than that of non-functionalized GO-based sensors prepared by a direct evaporation method. The MDP of this sensor is determined to be 0.333 µPa/Hz^1/2 @20 Hz with a SNR of 136.34 dB, which outperforms previously reported low-frequency sensors using conventional metals or polymers as sensing films.