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

Abstract 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.