How Do Solar Cells Make Electricity?

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SOLAR (PHOTOVOLTAIC) ENERGY EXPLAINED.


The video is perfect to visually assist with the concept, however if video isn’t an option, here is the breakdown in good old plain English…

Question: How do solar cells make electricity?

Simple Answer: With Phosphorus Diffusion (and a few other things).

There are of course many elements which contribute to a solar cells ability to generate electricity however phosphorus diffusion is a major ingredient in transforming a silicon wafer to become an electric component capable of generating electricity for use in solar panels.


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THE OVEN


Silicon solar cells enter a tube furnace which is heated to over 800 degrees celsius and diffused with phosphorus gas. The phosphorus gas condenses on the open surfaces of the solar cells, penetrating the solar cells and causing two layers with differing electronic characteristics based on their respective atomic structures.

THE BASE


The base material is silicon which previously was mixed with Boron atoms during crystallisation. Boron is used because it has three outer electrons, one less than silicon. A positively charged hole is thus created within the atomic bond.

THE TOPPING


Diffused phosphorus atoms are slightly different. They have five outer electrons which means one more negatively charged electron than silicon. The result, two different charge carriers, negative electrons and positive holes that strive to achieve an equipotential bond according to the principle of opposites attract.

THE EFFECTS


The fully charged carriers really get going when the sun’s rays hit them. In sunlight, the photons light energy virtually shoots large numbers of charged carriers from their bonds. This effect generates an electric field between a positively charged layer and a negatively charged layer. The charged carriers try to escape from this field, thereby causing the difference in potential to increase even further. If contact are applied the charged carriers will take the path of least resistance. Which in turn generates a flow of electrons, or electrical current illustrating the photovoltaic principal.

The fully charged carriers really get going when the sun’s rays hit them. In sunlight, the photons light energy virtually shoots large numbers of charged carriers from their bonds. This effect generates an electric field between a positively charged layer and a negatively charged layer. The charged carriers try to escape from this field, thereby causing the difference in potential to increase even further. If contact are applied the charged carriers will take the path of least resistance. Which in turn generates a flow of electrons, or electrical current illustrating the photovoltaic principal.

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