Power crisis is one of the most important problem faced by each and every country inorder to overcome this problem researchers are finding an alternative way among them nanogenerator is the promising one.

nanogenerator is nothing but an application of nano technology.

Nano generator help to recharge ipods,cellpohone through our body movements

Although nanodevices fabricated

using nanomaterials such as

nanotubes or nanowires offer low

power consumption,

Adding a battery could sufficiently increase

their size to inhibit their application. Developing

miniature power packages and self-powering

methods will be key to their use in a variety of

applications, including those for wireless sensing;

in-vivo, real-time, and implantable biological

devices; environmental monitoring; and personal

electronics. Consequently, researchers are

developing innovative nanotechnologies

to convert various

forms of energy (such as solar

energy4) into electric energy for

low-power nanodevices.

In our own work, we’ve

used piezoelectric zinc-oxide

nanowire (ZnO NW) arrays

to demonstrate a novel approach for converting

nanoscale mechanical energy into electric

energy.5–7 Here, we review the fundamental

principle behind the nanogenerator, present an

approach for improving its performance, and

discuss some of the challenges we face in pushing

this technology to reach its potential.

The nanowire nanogenerator

The nanogenerator relies on some external

disturbance, such as a vibration or sonic wave,

bending aligned NW arrays. In theory, a voltage

drop occurs in the NW’s cross section when the

NW bends laterally, resulting in positive voltage

on the tensile side and negative voltage on the

compressive side.

Using small-deflection approximation, we

applied the perturbation theory to calculate the

potential piezoelectricity distribution in a NW

when a lateral force pushes its tip.

Advantages

and potential applications

The piezoelectric nanogenerator

could potentially convert the following

into electric energy for self-powering

nanodevices and nanosystems:

mechanicalenergy-movement energy, such

as body or muscle movement or

blood pressure;

vibration energy- from acoustic or

ultrasonic waves; 

hydraulic energy-such as from the

flow of body fluids or blood, the contraction

of blood vessels, or dynamic

fluid in nature.

The microelectromechanical systems

microgenerator, which is mostly built

on a piezoelectric thin-film cantilever,11

can also convert such energy into electric

energy. 

Advantages:

Because NWs can grow on any substrate

at a low temperature, you can

integrate NW-based nanogenerators

with inorganic and organic materials

for flexible electronics.

NW-based nanogenerators work in

a wide frequency range, from a few

hertz to multiple megahertz. Also,

the NW’s mechanical resonance isn’t

required to generate electricity.

ZnO is biocompatible and environmentally

friendly.

NWs have superelasticity and are

very resistive to fatigue, owing to

their small diameter, so we expect the

nanogenerators to be long-lasting.

With a large surface area, NW

functionality might provide additional

advantages, such as surface

modification.

Consequently, the NW-based nanogenerator

could support important applications

in a variety of fields.

For example, it could help wireless

self-powered nanodevices harvest

energy from the environment. It could

also provide a method for indirectly

charging a battery. For biomedical sciences,

self-powered nanodevices could

offer real-time monitoring of blood pressure

and blood-sugar levels. They might

also perform in-vivo detection of cancer

cells or wirelessly measure fluid pressure

in the brain. For environmental science,

the nanogenerator could remotely sense