Solar panels are becoming increasingly common. They’re a green energy source, not too expensive and work pretty well for the amount of space they require! But how do they work?
They are made up of smaller units called photovoltaic cells which use various principles of solid state physics to run. Don’t let that scare you off though, it’s really not too hard to understand.
The majority of photovoltaic cells are composed primarily of a silicon semi-conductor
with positively and negatively charged electrical contacts. An electric field exists in this semiconductor because the silicon is doped, a process that adds phosphorous atoms to one side and boron atoms into the silicon on the other side. This allows electron flow with a more negative phosphorus-doped side and a more positive boron-doped side.
When a photon of light hits an electron in the silicon, the electron gains enough energy to break free from it’s normal bonded state and begins to move towards the positive contact because of the pre-existing electric field.
And what does electron movement mean? That’s just an electrical current.
So at this point, we’ve generated an electron flow that can then be used to power electrical devices. And that’s pretty much the entirety of how a single solar cell works. In a whole panel, many of these cells are connected up, and if you’re lucky enough to have a battery system, the energy is stored in that battery.