Piezoelectric Power - Sci Fi Coming True

What if your cell phone could charge itself from the sound waves passing through it? What if you didn't have to carry spare batteries for portable devices? It's not so far away as you might think.

The science of piezoelectrics has been around since 1880 when it was first described. Piezoelectric is a big word simply meaning that some materials are able to generate an electric current when mechanical pressure or stress is applied. The materials which exhibit these properties are mostly ceramics and crystals.

Piezolectrics were first used in sonar devices during World War I. Yes, your quartz crystal watch that you never wind is powered by piezoelectricity, as is the clock in your computer that is magically correct even when you've turned off the CPU. The technology is also used in some microphones, and automobile cigarette lighters.

There are even night clubs in Europe whose dance floors absorb the energy from footsteps to help power the lights.

But a significant new discovery has just emerged. Tahir Cagin, of Texas A&M University working with a group from the University of Houston has learned that a 100% improvement in efficiency is possible when the piezoelectric materials are manufactured at a specific size. That's a very small size, 21 nanometers thick, to be exact. (That's 21 billionths of a meter, and a human hair is about 100,000 nanometers wide.) Anything larger or smaller doesn't work as well.

The application of this finding could affect the way we power everything from laptop computers, cell phones, mp3 players, remote controls and any number of computer-related devices. Law enforcement and the military are especially interested in the concept.

Cagin says that the work at the scale of his research compared to previous study into piezoelectric properties is similar to switching from working with telephone poles to a human hair. Everything changes when the scale is so different.

"Even the disturbances in the form of sound waves such as pressure waves in gases, liquids and solids may be harvested for powering nano- and micro devices of the future if these materials are processed and manufactured appropriately for this purpose," Cagin said.