A solar cell is a photoelectric semiconductor sheet that uses sunlight to directly generate electricity. As long as it is exposed to light that meets certain illuminance conditions, it can instantly output voltage and generate current when there is a loop. In physics, it is called solar photovoltaic (Photovoltaic, abbreviated as PV), or photovoltaic for short.
 
Solar cells are devices that directly convert light energy into electrical energy through photoelectric effect or photochemical effect. Crystalline silicon solar cells that work with the photovoltaic effect are the mainstream, while the implementation of solar cells with thin-film cells that work with the photochemical effect is still in its infancy.

Principle
 
A solar cell is a photoelectric element that can convert energy, and its basic structure is made by joining P-type and N-type semiconductors. The most basic material of semiconductors is "silicon", which is non-conductive, but if different impurities are added to the semiconductor, it can be made into P-type and N-type semiconductors, and then the P-type semiconductor has a hole (P-type semiconductor is missing a negatively charged electron, which can be regarded as an additional positive charge), and an N-type semiconductor has a free electron potential difference to generate current, therefore, when the sunlight is irradiated, the light energy excites the electrons in the silicon atoms, and the convection of electrons and holes is generated. These electrons and holes are affected by the built-in potential and are attracted by the N-type and P-type semiconductors respectively, and gathered at both ends. At this time, if the external electrodes are connected to form a loop, this is the principle of solar cell power generation.
 
Simply put, the principle of photovoltaic power generation is to use solar cells to absorb sunlight with a wavelength of 0.4 μm to 1.1 μm (for silicon crystals) and directly convert light energy into electrical energy output.
 
Since the electricity generated by solar cells is direct current, if you need to provide electricity to household appliances or various electrical appliances, you need to install a direct/ac converter and replace it with alternating current before it can be supplied to household or industrial electricity.
 
Crystalline silicon solar cells include monocrystalline silicon solar cells and polycrystalline silicon solar cells. At present, the conversion efficiency of monocrystalline silicon cells can reach 19.8%-22.5%, and the conversion efficiency of polycrystalline silicon cells is about 18.6%-19%.