The working principle of crystalline silicon n/p-type solar cells: When p-type semiconductor and n-type semiconductor are closely combined and connected together, a p-n junction is formed at the interface between the two. When the photovoltaic cell is illuminated by sunlight, positive and negative charges accumulate on both sides of the p-n junction, generating a photovoltage and forming a built-in electric field. This is the "photovoltaic effect". Theoretically, at this time, if electrodes are drawn out on both sides of the built-in electric field and connected to an appropriate load, a current will form and power will be obtained on the load. Solar cell modules are solid devices that utilize the electronic properties of semiconductor materials to achieve PV conversion.