Nanowire Solar Cell
Nanowire Solar cell
What is a Nanowire
According to wikipedia a nanowire is a structure with a diameter of approximately a nano meter (10 to the power of -9 meters). It can also be defined as the ratio of length to width being more than a thousand. Nanowires can also be defined as a structure with a thickness of approximately a nano meter with an unconstrained length.
(How thin is a nano meter. A very fine human hair is about about 60 micro meters thick. A micro meter is a 1000 nano meters. You would have to divide the human hair 60 000 times lengthwise to be approximately a nano meter thick. Incredible!!!)
Various types of nanowires can exist, e.g. semiconductors, superconductors, insulators, etc, that could be made of a variety of materials.
Nanowire Solar Cell
Why would one wish to make a nanowire solar cell? The short answer will be to improve the efficiency of the solar cell.
According to the Shockley-Queisser limit only 33.7% of the solar energy hitting the cell will be converted into electricity.
The theoretical limit for the nanowire solar cell is however at 46%. As stated this is the theoretical limit, the best achieved thus far is a conversion efficiency of 17.8%, which is an improvement of the previous record of 15.3%. This record was set by a Dutch team from the Technical University of Eindhoven. The research team however believes that this efficiency will soon be improved dramatically, as the nanowire solar cells technology is still fairly new.
The improved efficiency is achieved by the nanowire's ability to concentrate light intensity to 15 times more than normal. Due to the characteristics of the nanowire resonances occur that concentrate the light on the solar cells where the electricity is generated. The nanowire solar cell work the same as a normal solar cell, the outer layer of the solar cell is however replaced by the nanowires that concentrate the light.
The link is an interesting read on Nanowire technology
As a shortage of electricity becomes bigger and bigger and the use of fossil fueled power stations increase pollution world wide, I hope they succeed to improve this sustainable solution to our energy crisis.
Photo of normal solar cell
Image Credit
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