Suspended Reduced Graphene Oxide/MXene-Based Thermoacoustic Loudspeaker

Thermoacoustic loudspeakers are regarded as promising candidates for lightweight and miniaturized acoustic devices owing to their magnet-free operation, low driving voltage, simple structural configuration, and the absence of mechanical resonance. Achieving a high sound pressure level (SPL), the key metric for acoustic performance, requires the simultaneous reduction of heat capacity per unit area (HCPUA) and thermal effusivity. Two-dimensional (2D) materials such as MXenes (Ti 3 C 2 T x ) exhibit low HCPUA. However, the limited mechanical strength necessitates substrate support, which introduces thermal leakage and degrades thermoacoustic performance. Here, we report a suspended rGO/MXene-based thermoacoustic loudspeaker that effectively overcomes these limitations. MXenes as the active thermoacoustic layer to reduce HCPUA, while an ultrathin reduced graphene oxide (rGO) layer provides mechanical support with low HCPUA. The suspended device exhibits a low HCPUA of 0.08 J m –2 K –1, achieving an SPL of 85 dB (@15 kHz, 0.6 W) and a high thermoacoustic efficiency (TAE) of 146 × 10 –4 %, surpassing the typical performance of previously reported devices. Moreover, the rGO/MXene loudspeaker demonstrates low harmonic distortion. This work is expected to provide a promising design strategy for high-performance thermoacoustic devices.