Coming soon, self-powered devices that don't require batteries

Washington, Dec 2 : Hate charging your cell phone every now and then? Well, then get ready for a self-powering handset that never needs to be charged - all thanks to the efforts of a researcher who has developed a new technology that could make self-powered devices a reality.

The self-powering cellphone won't require any battery charging because it will convert sound waves produced by the user into the energy it needs to keep running.

Tahir Cagin, a professor in the Artie McFerrin Department of Chemical Engineering at Texas A and M University has used materials called "piezoelectrics" to develop self-powered devices that do not require replaceable power supplies, such as batteries.

To be precise, Cagin and his partners from the University of Houston have found that a certain type of piezoelectric material can covert energy at a 100 percent increase when manufactured at a very small size - in this case, around 21 nanometers in thickness.

In fact, he said that when materials are constructed bigger or smaller than this specific size they show a significant decrease in their energy-converting capacity.

And it is believed that his findings could have potentially profound effects for low-powered electronic devices such as cell phones, laptops, personal communicators and a host of other computer-related devices used by everyone from the average consumer to law enforcement officers and even soldiers in the battlefield.

Cagin's discovery stands to advance an area of study that has grown increasingly popular due to consumer demand for compact portable and wireless devices with extended lifespans.

Other than consumer convenience, self-powering devices are of major interest to several federal agencies.

The Defense Advanced Research Projects Agency has investigated methods for soldiers in the field to generate power for their portable equipment through the energy harvested from simply walking.

And sensors - such as those used to detect explosives - could greatly benefit from a self-powering technology that would reduce the need for the testing and replacing of batteries.

"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," said Cagin.

Piezoelectrics are materials (usually crystals or ceramics) that generate voltage when a form of mechanical stress is applied. Conversely, they demonstrate a change in their physical properties when an electric field is applied.

Cagin said that piezoelectric work at the nanoscale is a relatively new endeavour with different and complex aspects to consider.

He added: "When materials are brought down to the nanoscale dimension, their properties for some performance characteristics dramatically change. One such example is with piezoelectric materials. We have demonstrated that when you go to a particular length scale - between 20 and 23 nanometers - you actually improve the energy-harvesting capacity by 100 percent.

"We're studying basic laws of nature such as physics and we're trying to apply that in terms of developing better engineering materials, better performing engineering materials. We're looking at chemical constitutions and physical compositions. And then we're looking at how to manipulate these structures so that we can improve the performance of these materials."

The findings of the study are detailed in an article published this fall in "Physical Review B," the scientific journal of the American Physical Society.

ANI