Solar cells were first discovered by the French physicist Alexander Edmund Becquerel (1820-1891) during the study of a phenomenon - photovoltaic phenomenon. Related to the photoelectric effect. Einstein successfully used quantum principles to explain this phenomenon and won a Nobel Prize.

Photovoltaic power generation principle, when the photon irradiates the semiconductor material, colliding with the electron in the atom. If the photon has enough energy, the electron in the outer layer of the atom will absorb energy. If the electron absorbs enough energy, it will escape from the bondage and escape from the metal. It becomes a photoelectron. Photovoltaic panels are made of silicon, which is doped with boron or phosphorus atoms to form P-or n-type semiconductors. The contact surface forms an electric potential difference, which will form a current. The photoelectric effect is a phenomenon in which light causes a potential difference between a non-uniform semiconductor or between a semiconductor and a metal. Firstly, it is the process of converting photons (light waves) into electrons and light energy into electrical energy. Second, is the formation of the voltage process.

According to Planck's law, the energy of an incident photon is inversely proportional to its wavelength. Shorter-wavelength radiation occupies the purple end of the spectrum, including ultraviolet radiation and gamma rays. On the other hand, long-wavelength radiation occupies the red end, including infrared radiation, microwaves, and radio waves. Therefore, solar photovoltaic panels can generate electricity in cloudy and rainy days, but due to current technical reasons, the efficiency of solar energy conversion is still very low, and the power generation efficiency in cloudy and rainy days is not as good as that in the day.

And it's also possible to generate electricity by friction on rainy days, which will be converted to graphene. Because there is sodium, calcium, ammonium plasma in the rain, and the positively charged ion layer will interact with the negative electrons of graphene, resulting in a double-layer structure similar to the quasi-capacitor. The potential difference between the two layers is large enough to generate voltage and current.

There are many factors that affect solar power generation, such as the thickness of solar photovoltaic panels, and the shuttles of photons between photovoltaic panels and other particles, resulting in energy loss. Another factor that affects efficiency is the reflectivity of solar cells. To reduce the loss of reflectivity and improve efficiency, solar cell manufacturers usually coat cells with non-reflective, light-absorbing materials. This is why solar cells are usually black.

With the development of clean energy in recent years, the development of solar energy, wind energy and water conservancy stations can alleviate the pressure caused by current energy sources, and also alleviate the greenhouse effect of the earth.