Operation of a Silicon Monocrystalline PV Panel
The atoms in a pure crystal silicon nucleus contain positive charged protons, around which are layers of negatively charged electrons. The outer layer of the electrons is not completely full, so nearby atoms share these electrons, which bond them together in a lattice within the crystal.
If the crystal is doped with an impurity having more electrons in its outer layer, it will produce more negatively charged electrons which are free to move around. This is known as an N – type silicon.
If the crystal is doped with an impurity having less electrons in its outer layer there will be a shortage of electrons, and the spaces left in the outer layer are called holes. These are also free to move around, and this is known as a P – type silicon.
In a PV cell the two doped silicone crystals are joined and electrons from the N-type silicone are attracted to the P-type silicone and move towards the holes in the P-type silicone. They stop at the junction at which an electric field is created.
So now we have a row of negatively charged electrons facing a row of positive charged holes, separated and preventing further movement by the magnetic field at their junction.
If light is absorbed by the cell, the electrons are shunted across the junction. Now, if joined by an electric circuit, the electrons flowing across the junction from N to P will be returned from where they came from via the circuit in a continuous flow, setting up a DC current.
These separate cells are joined together to form a module, and the number of modules for the required electric output fitted into an aluminum frame, which is bolted securely to the galvanized angle support frame. An isolating gasket should be fitted between the aluminum frame and the galvanized support frame to prevent galvanic corrosion.