Illustration of The Principle of Solar Panels
Illustration of The Principle of Solar Panels
Solar energy is the best energy source for mankind, and its inexhaustible and renewable characteristics determine that it will become the cheapest and most practical energy source for mankind. Solar panels are clean energy without any environmental pollution. Dayang Optoelectronics has developed rapidly in recent years, is the most dynamic research field, and is also one of the most high-profile projects.
The method of making solar panels is mainly based on semiconductor materials, and its working principle is to use photoelectric materials to absorb light energy after photoelectric conversion reaction, according to the different materials used, can be divided into: silicon-based solar cells and thin-film solar cells, today mainly to talk to you about silicon-based solar panels.
First, silicon solar panels
Silicon solar cell working principle and structure diagram The principle of solar cell power generation is mainly the photoelectric effect of semiconductors, and the main structure of semiconductors is as follows:
A positive charge represents a silicon atom, and a negative charge represents four electrons orbiting a silicon atom. When the silicon crystal is mixed with other impurities, such as boron, phosphorus, etc., when boron is added, there will be a hole in the silicon crystal, and its formation can refer to the following figure:
A positive charge represents a silicon atom, and a negative charge represents four electrons orbiting a silicon atom. The yellow indicates the incorporated boron atom, because there are only 3 electrons around the boron atom, so it will produce the blue hole shown in the figure, which becomes very unstable because there are no electrons, and it is easy to absorb electrons and neutralize, forming a P (positive) type semiconductor. Similarly, when phosphorus atoms are incorporated, because phosphorus atoms have five electrons, one electron becomes very active, forming N(negative) type semiconductors. The yellow ones are phosphorus nuclei, and the red ones are the excess electrons. As shown in the figure below.
P-type semiconductors contain more holes, while N-type semiconductors contain more electrons, so that when P-type and N-type semiconductors are combined, an electric potential difference will be formed at the contact surface, which is the PN junction.
When P-type and N-type semiconductors are combined, a special thin layer is formed in the interfacial region of the two semiconductors), and the P-type side of the interface is negatively charged and the N-type side is positively charged. This is due to the fact that P-type semiconductors have multiple holes, and N-type semiconductors have many free electrons, and there is a concentration difference. Electrons in the N region diffuse into the P region, and holes in the P region diffuse into the N region, forming an "internal electric field" directed from N to P, thus preventing diffusion from proceeding. After reaching equilibrium, such a special thin layer is formed to form a potential difference, which is the PN junction.
When the wafer is exposed to light, the holes of the N-type semiconductor in the PN junction move to the P-type region, and the electrons in the P-type region move to the N-type region, resulting in a current from the N-type region to the P-type region. Then a potential difference is formed in the PN junction, which forms the power supply.