The solar cell is mainly composed of silicon, gallium arsenide, indium selenium, copper, etc. material, basically the same principle of them to generate electricity. Crystalline silicon, for example, when the sun is irradiated onto the surface of the silicon to the portion of photon of energy by the silicon atom absorption atoms mainland electron generating transitions, so some ground potential difference is formed inside the material, so that light energy is transformed into electrical energy storage up. When the solar collectorwhen the circuit is turned on, the voltage can generate a current flow through an external circuit, a silicon solar led light1. The principle of silicon solar cell works with the structure of the solar cell power generation semiconductor photoelectric effect the general semiconductor structure is as follows: positive charge represents a silicon atom, negative charge around the silicon atoms next four electronic.
When the incorporation of other impurities in the silicon crystal, such as boron, phosphorus, etc., when the boron was doped in the silicon crystal will exist a hole, and it is formed as follows: positive charge represents a silicon atom, a negative charge represented around the silicon atomic next four electrons. The incorporation of boron atoms represented by the yellow, because only three electron around the boron atom, so will produce a hole into shown blue, the hole becomes very unstable because no electron, easily absorbed electrons and formed Ppositive) type semiconductor.
Similarly, after the incorporation of phosphorus atom, because the phosphorus atom has five electrons, so it will have an electronic became very active, the formation of the N (negative)-type semiconductor. Yellow phosphorus nuclei, red excess electrons.
Contains more holes in the P-type semiconductor containing more electrons in the N-type semiconductor, so that, when the P-type and N-type semiconductor when taken together, will be in the contact surface to form an electrical potential difference, which is the PN junction.
When the P-type and N-type semiconductor when taken together, will form in the interface of the two semiconductor regions a special thin layer), the P-type side of the interface is negatively charged, positively charged N-type side. This is due to the P-type semiconductor multi-hole, the N-type semiconductor multi-free electron concentration difference. N area electronics will diffuse into the P region, the P region of the hole will be diffused into the N region, once the diffusion is formed by a N to P "farm", thereby preventing the diffusion. After equilibrium is reached, the formation of such a special thin layer to form an electrical potential difference, which is the PN junction. ????
When wafer photodetecting, PN junction, an N-type semiconductor of the hole is moved to the P-type region, while moving electrons into the N-type region of the P-type region, thereby forming a current from the N-type region to the P-type region. And then in a PN junction to form an electrical potential difference, which formed a power supply.
In the semiconductor is not a good conductor of electricity, electronics through the p-n junction if the flow in the semiconductor, the resistance is very large, the loss will be very large. But if in the upper layer, all coated with metal, and the sun not passed, the current can not produce p-n junction, it is generally covered with a metal grid, in order to increase the area of ​​the incident light.