[Image above] Thin, flexible speaker made from graphene that doesn’t create sound vibrations. Instead, it makes sound by rapidly heating and cooling the air around it, which negates the need for a stiff, boxy housing structure. Credit: American Chemical Society; YouTube
Graphene—the material that will revolutionize next-generation electronics. It’s graphene’s single-layer thickness, toughness, and supreme mechanical and thermal properties that make it ideal for developing electronic, optoelectronic, and electromechanical devices and sensors.
But manufacturing graphene in large quantities isn’t necessarily easy. Historically, it’s been an expensive, labor-intensive material to produce for commercial applications—so researchers continue to uncover new and innovative solutions for producing this high-potential material in a way that’s scalable.
Some researchers are even investigating graphene’s acoustic potential.
When it comes to devices like speakers and microphones, graphene surpasses traditional technology with broader ultrasonic reach. Last year, researchers at the University of Belgrade, Serbia, developed a graphene-based microphone that’s nearly 32 times more sensitive than microphones of standard nickel-based construction.
This week, researchers at the Korea Advanced Institute of Science and Technology (KAIST) report a simple way to fabricate thermo-acoustic speakers using ultra-thin graphene.
According to a video produced by the American Chemical Society, even today’s smallest portable speakers come in some kind of rigid, boxlike acoustic cavity. But the speaker developed by the KAIST team is made out of ultrathin graphene.
“The team developed a two-step process that creates an aerogel by first freeze-drying a solution of graphene oxide flakes,” the video explains. “Then they reduce the oxidized graphene to improve its electrical properties.”
Unlike traditional speakers, the graphene thermo-acoustic speaker doesn’t create sound vibrations. Instead, it makes sound by rapidly heating and cooling the air around it, which negates the need for a stiff, boxy housing structure.
And that means these thin, flexible, non-vibrating speakers could be fit snugly against walls or curved surfaces like mobile devices.
The research, published in ACS Applied Materials & Interfaces, is “Application of n-doped three-dimensional reduced graphene oxide aerogel to thin film loudspeaker” (DOI: 10.1021/acsami.6b03618).
Check out the video to see the graphene speaker in action!
Credit: American Chemical Society; YouTube