天津大学《Small》：基于功能化石墨烯的高灵敏度低频声学传感器

1成果简介

开发具有高灵敏度的微型低频声学传感器对于地质监测和航空航天探测等多种应用至关重要。然而，传统传感薄膜在纳米级厚度上的机械坚固性有限，制约了低频声学传感器的性能。本文，天津大学侯丽丽 教授、Xiaoyan Zhang等研究人员在《Small》期刊发表名为“Highly Sensitive Low-Frequency Acoustic Sensor Based on Functionalized Graphene Oxide”的论文，研究提出了一种基于功能化氧化石墨烯（GO）的法布里珀罗（FP）低频传感器，它具有体积小、抗电磁干扰、高灵敏度、低最小可探测压力（MDP）和高信噪比（SNR）等特点。功能化GO是通过GO与十二胺反应合成的，并通过自组装方法制备了均匀的薄膜。这种传感器在10-200Hz频率范围内的灵敏度为-91.92dB re 1rad/µPa，波动范围为0.4dB，是直接蒸发法制备的非功能化GO传感器的5.6倍。该传感器的MDP值为0.333µPa/Hz1/2 @20Hz，信噪比为136.34dB，优于之前报道的使用传统金属或聚合物作为传感薄膜的低频传感器。

2图文导读

图1、a) Scheme of the architecture of GO and dodecylamine, and the synthesis process for the functionalized GO. b) Illustration of the vibrating diaphragm with fixed edge for converting acoustic signal into light signal. c) Scheme of the structure and principle of the FP sensor.

图2、a) FTIR spectra of dodecylamine, GO, functionalized GO. b) Raman spectra of GO and functionalized GO. c,d) XPS spectra of GO (C1s, N1s). e,f) XPS spectra of functionalized GO (C1s, N1s).

图3、a) Scheme of preparing functionalized GO films using the self-assembly method. b) Scheme of the multi-layer functionalized GO film. c) Procedures of the preparation of multi-layer functionalized GO films and their subsequent transfer to the sensor probe. d) Microscopic image of the film on a silicon substrate. e) SEM image of the functionalized GO film.

图4、a) Scheme of the dual-wavelength phase demodulation system. b) Comparison of FP sensor and standard microphone at 20 Hz. c) Power spectrum of the demodulated phase signal. d) Sensitivity of the functionalized GO and GO-based FP sensors. e) Output of both the GO-based and functionalized GO sensors under 20 Hz acoustic signals. f) Sensor response to varying sound pressures at 10, 20, and 50 Hz. g) Linear correlation between phase signal output and sound pressure at 10, 20, and 50 Hz acoustic signals. h) Power spectra of 10, 20, and 50 Hz acoustic signals at sound pressures of 1.63, 1.84, and 1.66 Pa, respectively.

图5、a) Sensor response over 60 s. b) Power spectrum output with no signal. c) Power spectrum output with acoustic signal at 20 Hz. d) Typical frequency of demodulated phase signals in the range of 0.05–200 Hz (including 0.05, 0.1, 0.5, 1, 5, 10, 20, 50, 100, and 200 Hz), and e) The power spectrum of demodulated phase signals.

3小结

总之，通过提高机械性能和引入官能化GO的疏水特性，我们制备出了与 FP 传感器兼容的均匀、大面积薄膜，实现了高性能低频声学传感。为了解决自组装薄膜的粗糙度和均匀性问题，可以进一步研究薄膜的制备方法以及将薄膜转移到悬浮平膜中的方法。膜片具有很高的机械强度和优异的柔韧性，使其能够自由地悬浮在空气中，并在高声压下振动。我们基于功能化 GO 的声学传感器在 10 至 200 Hz 范围内具有-91.92 dB re 1rad/µPa 的高灵敏度，在 20 Hz 时具有 0.333 µPa/Hz1/2 的低MDP，在低频范围内具有 136.34 dB 的信噪比。值得注意的是，自组装法制备的功能化 GO 膜的低频灵敏度是直接蒸发法制备的GO膜的5.6倍。该传感器还显示出对声压的高度线性响应。这项研究提出了一种可扩展的低频声学传感器制备方法，其灵敏度极高，具有监测自然灾害事件的巨大潜力。

　　文献：
https://doi.org/10.1002/smll.202409043

　　来源：材料分析与应用