A thin-film photoacoustic speaker based on carbon nanocoils

Miniature speaker devices based on the thermoelastic principle with nanomaterials are regarded as promising alternatives to conventional speakers. Most prominently, photoacoustic speakers have attracted increasing attention in recent years owing to their favorable frequency response and uniform thermal distribution. Herein, by considering carbon nanocoils (CNCs) as an excellent photoacoustic wave-producing material due to their exceptionally low specific heat capacity, we designed a thin-film CNC-PDMS photoacoustic speaker. When illuminated by a 4 W LED optical beam, the speaker achieves a 70 dB audible pressure at a measuring distance of 10 cm. Moreover, the speaker enables the high-quality reproduction of arbitrary audio waveforms, including both speech and music, thereby demonstrating its potential to be developed for a specific advanced speaker. • An efficient photoacoustic speaker was fabricated using CNCs and PDMS as the base materials. • The CNC-PDMS prepared with 90%-pure CNCs produced sound waves reaching up to 73 dB under 6200 Hz modulated light irradiation. • The 90% pure CNC-PDMS demonstrated a conversion efficiency of 1.849 × 10 −4 . • We generated audio-modulated waves using a function generator and evaluated the signal reproduction quality.