The three main technical fields using solar energy are: photothermal conversion, photoelectric conversion and photochemical conversion. In addition, there are energy storage technologies. The photochemical transformation of the sun includes photosynthesis, photoelectrochemistry, photosensitivity and photodegradation reactions. At present, this technical field is still in the experimental research stage. Photovoltaic conversion is mainly solar panels and power systems of various specifications and types. Solar cells are devices that directly convert sunlight into electrical energy. The photovoltaic efficiency of solar cells is about 10-14%, and its product types mainly include monocrystalline silicon, polycrystalline silicon and amorphous silicon. The price of Chinese products is about 60-80% of the peak brick. The application range of solar cells is very wide. For example, artificial satellites, unmanned weather stations, communication stations, television relay stations, sun clocks, electric fences, black lights, navigation lights, railway signal lights, etc.