Solar Batterys generate electricity based on the photoelectric properties of specific materials. Black bodies (like the sun) emit electromagnetic waves of different wavelengths (corresponding to different frequencies), such as infrared, ultraviolet, visible light, and so on. When these rays hit different conductors or semiconductors, the photons interact with free electrons in the conductors or semiconductors to generate an electric current. The shorter the wavelength and the higher the frequency, the more energy the rays have. For example, ultraviolet rays have much higher energy than infrared rays. But not all wavelengths of ray energy can be converted into electricity, it is worth noting that the photovoltaic effect is independent of the intensity of the ray, only when the frequency reaches or exceeds the threshold of photovoltaic effect, the current can be generated. The maximum wavelength of light that can make the semiconductor produce photovoltaic effect is related to the band gap width of the semiconductor. For example, the band gap width of crystalline silicon is about 1.155eV at room temperature, so the wavelength of light less than 1100nm can produce photovoltaic effect of crystalline silicon. Solar cell power generation is a renewable and environmentally friendly way of power generation, which does not produce greenhouse gases such as carbon dioxide and does not pollute the environment. According to the production material is divided into silicon semiconductor battery, CdTe film battery, CIGS film battery, dye sensitized film battery, organic material battery and so on. Silicon cell is divided into single crystal cell, polycrystal cell and amorphous silicon film cell. Conversion efficiency is the most important parameter for solar cells. In silicon-based solar cells developed in the laboratory, the efficiency of monocrystal silicon cells is 25.0%, that of polycrystalline silicon cells is 20.4%, that of CIGS thin film cells is 19.6%, and that of CdTe thin film cells is 16.7%. The efficiency of amorphous silicon (amorphous silicon) film cell is 10.1%
Solar cell is a kind of photoelectric element that can convert energy. Its basic structure is made by combining P-type and N-type semiconductors. The most basic material of semiconductor is "silicon", which is non-conductive. However, if different impurities are added to the semiconductor, P-type semiconductor and N-type semiconductor can be made. Then, P-type semiconductor has a hole (P-type semiconductor lacks a negatively charged electron, but can be seen as having a positive charge), and N-type semiconductor has an extra free electron potential difference to generate current. Therefore, when the sun shines, the light energy will excite the electrons in the silicon atom, and generate the convection of electrons and holes. These electrons and holes will be affected by the built-in potential and attracted by the N-type and P-type semiconductor respectively, and gather at both ends. At this point, if the external electrodes are connected to form a loop, this is the principle of solar cell power generation.
