Researchers at the University of California-Berkeley have developed the world’s first audio speakers with a diaphragm made of layers of graphene. The electrostatic speakers are earphone-sized and the diaphragm is 5 millimeters in diameter and only 30 nanometers thick. It is sandwiched between electrodes that create an electrical field, and when that field vibrates, the diaphragm does too, generating sound. In its unoptimized state, the team says the quality of that sound is “comparable or superior to performance of conventional-design commercial counterparts” across the entire audible spectrum.
What’s the Big Idea?
A speaker works by using a vibrating diaphragm to create sound pressure waves. To make more sounds audible to humans, they often need to be damped, a process that can become complex and inefficient. Thinner diaphragms can get around the damping requirement, and a graphene diaphragm has the advantage of being not only thin, but strong and exceptionally good at conducting electricity. It’s also more energy-efficient, which is good news for mobile devices. As of now there’s no word on if or when these earphones will be commercially available.