Paper-Thin Nanotube Speakers Can Turn Up the Volume

Next-generation loudspeakers could be as thin as paper, as clear as glass, and as stretchable as rubber. Chinese researchers have discovered that sheets of carbon nanotubes can amplify sound as loud as conventional speakers can. These nanotube speakers could eventually be used to add audio capabilities to windows, video screens, and clothing. “It is so wonderfully simple, that it brings up a strong wave of ‘Duh, why didn’t I think of that!’,” says physical chemist Howard Schmidt at Rice University [Nature News].

The researchers made the speaker by aligning carbon nanotubes, each about 10 nanometers in diameters, into thin flexible sheets. When they applied an electric current with an audio frequency to the sheets, the sheets broadcast the sounds loud and clear. The researcher describe their device in Nano Letters. The physics behind the nanotube speakers is different from that of conventional speakers. Unlike standard loudspeakers that generate sound by vibrations in the surrounding air molecules, the nanotube speaker doesn’t emit vibrations. The team used a laser vibrometer to detect vibrations in the sheet, but found nothing [Physorg.com].

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