A Novel MXene/GO Thermoacoustic Loudspeaker With High Sound Pressure

To realize the high sound pressure level (SPL) of a thermoacoustic (TA) loudspeaker with low driving voltage, a MXene/graphene oxide (GO) TA loudspeaker is proposed with fork-finger structure in this work, in which the mass ratio of MXene is up to 86%. The unique fork-finger structure of the film can afford to boost sound pressure with the thermal expansion of air both vertically and horizontally. Given the unique acoustic synergy between the composites, the MXene/GO composite film is capable of achieving high SPL at low driving voltage. The measured results show that the MXene/GO loudspeaker produces an SPL of 81.4 dB at a lower frequency (3.1 kHz) and a peak of 88.3 dB at 20 kHz with a low driving voltage of 4.5 V, manifesting good frequency response over a wide frequency range. Its TA efficiency is excellent over the entire frequency range from 0.1 to 20 kHz driven by 4.5 V, peaking at as high as $42.46\times 10^{-{4}}$ % (at a measuring distance of 0.5 cm). Additionally, the TA loudspeaker exhibits reliable repeatability (the maximum error is only 0.22%), which shows a great potential in the field of wearable electronics applications. In the application of artificial larynx, the issues of compatibility and stability regarding the MXene/GO TA loudspeaker can be addressed through encapsulation technology. In industrial sensing applications, the reliability and response speed of the system can be enhanced by integrating it with existing sensor networks, which enables remote monitoring and alarming.