Continuing from yesterday’s blog where I laid out some electrical basics, I’ll begin with the solar panels themselves.

A solar panel is a photovoltaic module interconnected with multiple photovoltaic cells. The term photovoltaic means that light energy is converted into either current or voltage, depending on the desired outcome. When a light photon hits a photodiode it excites an electron causing it to move…simply put. Most solar cells are created with silicon (crystalline, polycrystalline, and non-crystalline), the reason for this is that silicon has a chemical make-up of 14 positive protons and 14 negative electrons with the possibility of 4 additional electrons being gained on the outer shell. The silicon creates a crystal lattice where every silicon atom is connected to four other silicon atoms and they all share the electrons.

This balance, while naturally impressive, does us no good because there is no incentive for the electrons to move. At this point we see other elements added to the crystal structure (this is called doping), like phosphorus which has 5 electrons in its outer shell and boron which only has 3. Now we have an imbalance, we have extra electrons that need somewhere to go and open spaces for them travel. (Phosphorus-silicon is referred to as n(egative)-type and Boron-silicon is referred to as p(ositive)-type).

There is no net charge with this crystalline structure until the two types are joined together. This then causes an equalized junction where the negative electrons line up on the p-type side and the positive electrons line up on the n-type side. Electrical conducting channels are then crisscrossed between the silicon wafers and allow a path for the electrons to travel. This is the basic solar cell module.

Once a light photon of a certain amount of energy and wavelength hits the p-side it causes the electron to break free. Since the p-side is full of the same force it is attracted by the n-side. Making the move from one side to the other will hopefully cause the electron to jump to the crisscrossed conductors and wallah, we have an electrical circuit.

To be continued…