Researchers and experts always try to think out of the box. They have once again leveraged such extraordinary thinking by making use of background sounds such as the noise of traffic, restaurants, our voices and even music for materializing a fantastic idea. The energy-harvesting prototype (a nanogenerator) created by scientists from the Queen Mary University of London (QMUL) in association with Microsoft is a gadget that can be charged by using the ubiquitous sounds mentioned earlier.
The team used zinc oxide for the manufacture of nanorod – an essential component of this device. Zinc oxide is a piezoelectric substance that creates a voltage by converting energy from motion or mechanical energy into electrical energy when it is squashed or stretched. The piezoelectric substance has this ability because they are crystalline in structure. The energy-harvesting can be made adaptable by coating zinc oxide on different surfaces at different locations. The nanorods can generate a high voltage when their surface is squashed or stretched in response to the vibrations and movements created by the sound. They use the electrical contacts between them so that they can harvest the voltage to charge a mobile.
Gold is generally used as an electrical contact. But, the team has found an innovative way of using cheap aluminum foil instead of gold. The researchers have developed a process of spraying a layer of zinc oxide onto a plastic sheet and then putting the plastic sheet into a mixture of chemicals. The mixture is then heated to 90 °C. The heating causes the nanorods to grow on the surface of the sheet. The above two innovative methods of using aluminum foil and coating zinc oxide onto a plastic sheet makes it possible to cut costs in the production process.
Finally, the device generates 5V which is enough to charge a phone.