First, let’s take a closer look to the structure of a solar cell: The heart of a photovoltaic system are the solar cells. They are composed of a semiconductor substance, mostly it is silicon which is used here. A semiconductor is a substance that is neither an electrical conductor nor an insulator. Also, their behavior can be exactly regulated through the injection of other chemical elements.
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From Sunlight to Energy - How does solar work?
From Sunlight to Energy – How does solar work?
In one hour, more energy from the sun strikes the earth than the entire world could use in a year. But how do we harness this energy? Learn how a solar system converts sunlight into usable electricity. Learn how solar works – from sunlight to energy!
The chemistry of a photovoltaic cell
A solar cell based on silicon consists of two layers. Besides of the main part, which is silicon, the upper layer contains an injection of phosphorous. Phosphorous can form a chemical compound with five electrons, whereas silicon can only build a bond with four electrons. As consequence, for every phosphorous atom there remains one electron that can move freely. Electrons are charged negatively and that is why the upper layer is called n-layer.
The second layer, called p-layer, includes some boron atoms, which can form a chemical bond with only three electrons. That makes it one electron less than silicon atoms can form a compound with. Taken separately these both layers are electrically neutral.
The decisive element here is the junction between those two layers: At the dividing line freely moving electrons from the surplus-layer can fill the electron holes in the p-layer. In this small area the layers are not neutral anymore. A small electrical field emerged.
Sunlight knocks the electrons out
Sunlight consists of tiny light units – so called photons. With the sun shining and photons impinging on the surface of the solar cell, electrons are extracted from the silicon. Those electrons, that are extracted in the area of the junction, migrate towards the p-layer, electron holes migrate towards the n-layer. The voltage grows higher the more sunshine meets the solar cell.
Connected over an electrical circuit, the electron surplus from the n-layer can migrate back to the p-layer. A direct current is generated.
Before we can use this power directly from the power outlet, one essential transformation has yet to happen: A power inverter converts the DC (direct current) into AC (alternating current). With a solar battery installed excess energy can be stored here, if you produce more electricity than required. Excess energy can also be sold back to the power grid. In this case a digital meter helps you to track your energy use and habits. The excess power is measured and calculated by the feed-in tariff. That will show as a credit on your account and help you to lower your electricity bill.
You want to see how it works in practice and watch your electricity bill shrink?
Contact us and go solar now.