Transparent graphene speakers printed with inkjets, lo-fi musical windows are on their way

Transparent Graphene Speaker
Add that magical material known as graphene to the list of things you can make with inkjet printers alongside OLEDs, solar panels, and light-bending metamaterials. Scientists at the Seoul National University used printers and a technique known as vapor deposition to leave a thin film of the graphite-based conductor on sheets of PVDF (poly vinylidene fluoride). By sandwiching the the PVDF between graphene electrodes and applying a current from a sound source researchers were able to create a flat and transparent loudspeaker that could be integrated into windows or screens. Don't expect this low-power sound source to replace your hi-fi though -- since it relies on the distortion-prone piezoelectric effect, it probably won't sound much better than the earpiece on your cellphone.