Novel graphene thermoacoustic speakers bend and stretch while retaining acoustic performance

Researchers from the Korea Research Institute of Chemical Technology have demonstrated a new class of shape‑configurable thermoacoustic loudspeakers that defy the traditional tradeoff between film thickness, flexibility, and acoustic output. Instead of relying on vibrating membranes, these devices use vertical graphene microstructures to convert electrical signals into sound through rapid heating and cooling, enabling loud, robust, and stretchable audio elements that can be integrated directly onto curved or deformable surfaces.

A core challenge in thermoacoustic speakers is that high sound pressure levels (SPLs) typically require ultrathin conductive films, which are mechanically fragile, difficult to process at scale, and limited in power handling. Thicker films are more durable and easier to manufacture, but they trap heat within their bulk, suppressing thermoacoustic efficiency and causing SPL to collapse as thickness increases. This thickness–performance tradeoff has restricted most previous flexible TA speakers, such as MXene‑based devices, to tens of nanometers thickness, SPLs below 75 dB, and moderate strains around 50%.

Fabrication, morphology, and structural features of patterned VrGO films using dual-laser patterning. (a) Schematic illustration of the dual-laser processing strategy for fabricating patterned VrGO TA loudspeakers and their working mechanism. (b,c) SEM images of CO2 -laser and pulsed-laser-irradiated GO films (scale bar: 500 μm). (d) SEM image showing vertically aligned rGO sheets in the VrGO structure (scale bar: 10 μm). (e) 100% stretched kirigami and (f) 3D-structured VrGO films fabricated via pulsed laser-based patterning. Image from: Advanced ScienceA core challenge in thermoacoustic speakers is that high sound pressure levels (SPLs) typically require ultrathin conductive films, which are mechanically fragile, difficult to process at scale, and limited in power handling. Thicker films are more durable and easier to manufacture, but they trap heat within their bulk, suppressing thermoacoustic efficiency and causing SPL to collapse as thickness increases. This thickness–performance tradeoff has restricted most previous flexible TA speakers, such as MXene‑based devices, to tens of nanometers thickness, SPLs below 75 dB, and moderate strains around 50%.

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