Photovoltaic Effect

If the light shines on the solar cell and the light is absorbed in the interface layer, photons with enough energy can excite electrons from covalent bond in P-type silicon and N-type silicon, so as to produce electron hole pairs. Before recombination, electrons and holes near the interface layer will be separated from each other through the electric field effect of space charges. Electrons move towards the positively charged N region and holes towards the negatively charged P region. By separating the charges in the interface layer, an outward testable voltage will be generated between the P and N regions. At this time, electrodes can be added on both sides of the silicon chip and voltmeter can be connected. For crystalline silicon solar cells, the typical value of open circuit voltage is 0.5~0.6V. The more electron hole pairs generated by illumination in the interface layer, the greater the current. The more light energy absorbed by the interface layer, the larger the area of the interface layer, i.e. the battery, and the greater the current formed in the solar cell