Paper-thin loudspeakers harness nanotech power
Sheet-like ferroelectret nanogenerator can act as both loudspeaker and microphone. Angus Bezzina reports.
The world is about to get much more interesting for audiophiles, thanks to the development of a paper-thin, flexible device able to turn anything from newspapers to clothing into microphones and loudspeakers.
The device, known as a ferroelectret nanogenerator, or FENG, can convert mechanical energy into electrical energy and vice versa. It was constructed using nanotechnology by Nelson Sepulveda and his colleagues at Michigan State University in the US.
First showcased in 2016, the FENG was initially used to power a keyboard, LED lights and an LCD touch-screen with the mechanical energy provided by a finger swipe or light pressing motion.
Now the FENG can do even more.
Sepulveda and his team have harnessed the FENG’s ability to receive and transmit sound – a form of mechanical energy – in the same way as a microphone and loudspeaker.
To demonstrate these functions, Sepulveda and colleagues embedded the FENG material into a flag and made it operate like a loudspeaker, piping music into it with an iPad connected to an amplifier.
The FENG technology is created through a process in which a silicon wafer is formed from multiple layers of eco-friendly materials including silver, polyimide and polypropylene ferroelectret.
Ions are also inserted into each of these layers so there are charged particles throughout the device. When the FENG is compressed by human motion or mechanical energy, electrical energy is created.
Sepulveda says that while many scientists are preoccupied with the visual and tangible properties of nanotechnology, FENG proves that the speaking and listening aspects of this technology could lead to equally amazing innovations in the future.
“Imagine a newspaper where the sheets are microphones and loudspeakers. You could essentially have a voice-activated newspaper that talks back to you,” he says.