A solar cell is a device that uses the photoelectric effect of semiconductor materials to convert solar energy into electrical energy. The basic process of the photovoltaic effect: Assuming that light is irradiated on the solar cell and received at the interface, photons with sufficient energy will excite the covalent bond electrons of P-type and N-type silicon, and the empty pair causes it to be generated. electronic. Before recombination, the electrons and holes adjacent to the interface layer are separated from each other by the space charge electric field. The charge passing through the interface layer forms a voltage that can be tested outwards between the P and N regions. At this point, you can add electrodes on both sides of the silicon wafer and connect them to the voltmeter. For crystalline silicon solar cells, the standard open circuit voltage is 0.5-0.6V. The more electron-hole pairs generated by light on the interface layer, the higher the current. The more light energy the interface layer receives, the larger the interface layer. In other words, the larger the battery area, the greater the current formed in the solar cell.