How Do Solar Cells Work?

Photo-Voltaic Solar Panels By understanding the answer to how do solar cells work, you will have a better understanding of how solar energy works.

So...You're Wondering, "How Do Solar Cells Work?"

In essence, photons from the light source bump into an electron that's loosely held by an atom, which then translates into a current.

When enough of these reactions get together, you get enough current to do useful work.

"How do solar cells work?" is a fairly common question among many people who are looking to go solar.

Solar cells convert energy from a light source into electricity, using a process called the photoelectric effect.

How A Solar Cell Work - The Crystal Silicon Wafer Example

When talking about how solar cells work, most of the examples used work from single crystal silicon wafers.

These wafers take crystalline silicon and put two different impurities in them.
In the side that faces the sun, the impurity is phosphorous, which creates a bunch of loosely held electrons.
Adjacent to that silicon plate is one that has boron as an impurity.
Boron makes 'gaps' that the extra electron from the phosphorous layer can move into.

How A Solar Cell Work - A Golf Ball Example

If you imagine that the photon is about like a golf ball, and the free electrons are like ping pong balls, with the positive layer of silicon having ping-pong ball sized holes, you'll get a decent idea of what's going on.

These impurities (phosphorous and boron) are called 'doping' and are the reason behind the joke in the title of this article.

Now, we're going to example the analogy a bit deeper.
Imagine that your incoming golf balls are different colors, but only the green ones will actually hit ping pong balls.

I know this seems nonsensical, but it's about how solar cells work in the real world.

Photons (the golf balls) have different wavelengths, which correspond to colors.

The material that solar cells are made out of are transparent to a lot of wavelengths...

And not all of them will be absorbed where they can bounce electrons free to form a current path.

That current path is going to go out through a positive and negative lead, just like on a car battery.

Lots of research has gone into making solar cells that are multi-layer.

The top most layer is (ideally) going to catch photons of a different frequency than the layer underneath it - and is ideally transparent to the color of light that the photovoltaic cell underneath it needs.

In practice, these don't have perfect results, and to date, they've been limited to specialty applications.

When Discussing How Do Solar Cells Work, The Array Is A Critical Element

Each solar cell in a panel has to be wired into an array - this is an important part of how solar cells work.

Each solar panel produces a small fraction of a watt, thus, you need to make sure that all that power is aggregated into a strong enough current to do something useful.
You also need to take some care with your solar array.

The Angle Of Incidence And It's Rolw In How Solar Cells Work

The angle of incidence refers to the angle at which the solar cell faces the sun.

Because of how solar cells work, changing the angle of incidence by a few degrees can reduce the amount of energy collected from sunlight by as much as 40% or more.

This is why a lot of solar cell arrays use motors to keep them tracking the sun directly.