But, before exploring the advantages of nano-wire technology, one must understand the working principleof existing solar panels.
Working of solar panel:
Solar panel converts Sun’s energy into electricity. A solar panel is made up of solar modules and that in turn is made up of solar cells. A solar cell is made up of silicon which is a semiconductor.
A solar cell is a sandwich of two different layers of silicon that have been specially treated or doped so they will let electricity flow through them in a particular way. The lower layer is doped so it has slightly too few electrons. It’s called p-type or positive-type silicon. The upper layer is doped the opposite way to give it slightly too many electrons. It’s called n-type or negative-type silicon.
When we place a layer of n-type silicon on a layer of p-type silicon, a barrier is created at the junction of the two materials. No electrons can cross the barrier. We can think of the light as a stream of energetic “light particles” called photons. As photons enter our sandwich, they give up their energy to the atoms in the silicon. The incoming energy knocks electrons out of the lower, p-type layer so they jump across the barrier to the n-type layer above and flow out around the circuit. The more light that shines, the more electrons jump up and the more current flows.
Now, that the working of solar panel is clear… working of nano-wire based cells can be understood.
Use of nano-wire based cell:
Instead of using a planar material, like in most semiconductors, using a periodic nano-wire array produces the same amount of current but with significantly less material. Sol Voltaics and a group of scientists from Lund University produced gallium-arsenide nano-wires using their Aerotaxy system which will be able to offer a module efficiency of larger than 27% which is a 50% improvement than current solar panels.
An aerosol generator is used to produce catalytic seed particles where growth reactor is added to promote growth of nano-wires. Extremely high growth rates are achieved without the need for a substrate. The team were the first to prove that p-n junctions with excellent diode characteristics could be created in this way.
The given technique has alot of benefits such as: is low-cost and can be used to mass-produce solar cells. Their work was published in the latest issue of Nano Letters.
Nano-wires are perfect for solar cells as they guide the light onto the solar cells without the need for optical or mechanical aid. Nano-wires could become the next big thing for solar power harvesting.