Summary Bell Labs in the United States discovered in 1954 that doping a certain amount of impurities in silicon would make it more sensitive to light, and produced the first solar panel with practical applica
In 1849, the term "photo-voltaic" (photo-voltaic) appeared, meaning that electromotive force was generated by light. In the 1950s, as people gradually understood the physical properties of semiconductors, Bell Labs in the United States discovered in 1954 that doping a certain amount of impurities in silicon would make it more sensitive to light, and produced the first solar panel with practical application value.
There are more positively charged holes, while N-type silicon has more negatively charged electrons. The relative diffusion and recombination of electrons and holes produces a built-in electric field directed from N-type silicon to P-type silicon on the contact surface of P-type and N-type silicon materials. When the incident sunlight is absorbed, the electrons generated in the built-in electric field will move to the N-type silicon under the action of the electric field, and the holes will move to the P-type silicon and accumulate on both sides. If they are connected by wires, current can be generated.
Light is converted into electricity, but not everything is possible. In fact, when sunlight (solar radiation) passes through the atmosphere and reaches the ground, air molecules, water vapor, dust, etc. in the atmosphere will absorb, reflect, and scatter sunlight. These effects will not only cause sunlight The weakening of the radiation intensity will also change the direction of radiation and the spectral distribution of radiation. In other words, sunlight reaching the ground usually consists of direct solar radiation and scattered solar radiation.
Direct solar radiation refers to radiation that comes directly from the sun without changing its radiation direction. Scattered solar radiation refers to a part of solar radiation that is absorbed, scattered and reflected by air molecules, dust, water vapor, etc. in the atmosphere. The sum of scattered solar radiation and direct solar radiation reaching the ground is called total radiation.
