Nanogenerators For Implantable Biomedical Devices

ABSTRACT:

Materials Science research is now entered a new phase where the structure and properties of materials are investigated, characterized and controlled at the nanoscale. Though as sophisticated as their larger counterparts, these devices are still burdened because they rely on an outside power. The size of the entire device is determined by the size of the power source. Batteries and other traditional sources are too large, and tend to negate the size advantages of nano devices. Also, batteries being used at present require toxic chemicals and have to be replaced periodically. To overcome these challenges; researchers are finding alternative ways to power nano devices. One promising development is the nano generator. In this talk, we specially emphasized application of nano generators, importance of nanowires in building a nano generator. Nanogenerator allows us to harvest or recycle energy from many sources to power these devices. The nanogenerators take advantage of the unique coupled piezoelectric and semiconducting properties of zinc oxide nanostructures, which produce small electrical charges when they are flexed.

KEYWORDS:

Nano wire, Low power miniature sensors, Piezoelectric effect, Electric power, VIBES (Vibration Energy Scavenging)

INTRODUCTION:

An array of zinc-oxide nanowires that generates current when vibrated with ultrasonic waves could provide a new way to power biological sensors and nano devices. Using ultrasonic waves to vibrate an array of zinc-oxide nanowires, researchers at Georgia Tech have made a tiny generator that can produce direct current. By taking advantage of the fact that zinc-oxide nanowires are piezoelectric, they converted mechanical energy into electricity and by finding a way to collect electricity from multiple nano wires, the researchers took a big step toward a practical nano-scale power generator.

NANOWIRE:

Nanowires and other nano materials have shown great promise in creating future generations of electronic devices. New work from researchers at NIST, George Mason University, and Kwangwoon University in Seoul has generated a hybrid memory device that uses both conventional techniques and exploits the properties of silicon nanowires.

Electron micrograph shows the gallium nitride wires growing on a silicon substrate (colour added for contrast) The hybrid structure exhibited by these devices means that they are more reliable than other nanowire approaches, and they should be easier to integrate into modern components. The hybrid device that the team built is a non-volatile memory device similar to a flash device, which retains its memory even when power is turned off.The wires are generally between 30 and 500 nanometers (nm) in diameter and up to 12 micrometers long. When excited with a laser or electric current, the wires emit an intense glow in the ultraviolet or visible parts of the spectrum, depending on the alloy composition. The nanowires are grown onto an oxide nitride- oxide zinc substrate. When positive voltage is applied, electrons tunnel down into the substrate; when negative voltage is applied, the electrons tunnel back into the wires. When no voltage is present, the device can be read, and the position of the electrons will represent a “1″ or a”0″.

WHAT IS A NANO GENERATOR?

Generation of electricity is necessary for some extremely small devices (nano devices) like medical devices, sensors and portable electronics without the need for bulky batteries or other energy sources. Instead of batteries, electricity for such devices would come, for instance, from muscle contraction or other body movements. Nano generator is one such device. Zinc oxide nanowires in nano generator produce electricity via a long-known phenomenon termed the piezoelectric effect. It occurs in certain materials, which change mechanical energy — from flexing or twisting, for instance — into electricit

To know more about the nanogenerator, how it works, future scope, mail me at muthuvignesh88@gmail.com