Solar energy because of its renewable and clean environmental characteristics are widely concerned about, solar cell manufacturers are more and more. Solar cell working principle is the use of photoelectric materials to absorb light after the photoelectric conversion reaction, according to the different materials used, Solar panel structures solar cells can be divided into: silicon-based solar cells and thin film batteries, but because of its uneven conversion efficiency, many battery manufacturers are actively looking for new high-performance battery materials and production technology, Today we mainly talk about silicon-based solar cells.
Because the semiconductor is not a good conductor of electricity, the electron in the n after the junction if the flow in the semiconductor, Solar panel structures the resistance is very large, the loss is very large. However, if the upper layer all coated with metal, the sun can not pass, the current can not be produced, so the general use of metal mesh cover n Junction (such as the figure comb electrode) to increase the area of incident light.
In addition, the silicon surface is very bright, will reflect a large amount of solar light, can not be used by the battery. To this end, the scientists gave it a very small reflective coefficient of protective film (pictured), the actual industrial production is basically the chemical vapor deposition of a layer of silicon nitride film, thickness of about 1000. Reduce the reflection loss to 5% or less. After all, Solar panel structures the current and voltage provided by a battery is limited, so many batteries (usually 36) are used in parallel or in tandem to form solar photovoltaic panels.
The usual crystalline silicon solar cells are made from high quality silicon wafers of 350~450μm thickness, which are sawn and cut from the ingot of a lifting or casting silicon.
Chemical vapor deposition mainly takes Sih2cl2, SiHCl3, SiCl4 or SiH4 as reaction gas, reacts to produce silicon atoms in a certain protective atmosphere and deposits on the heated substrate, and the substrate material is generally selected Si, SiO2, $literal, etc. However, Solar panel structures it is found that it is difficult to form large grains on non-silicon substrates, and it is easy to form voids between grains. The solution to this problem is to first deposit a thin layer of amorphous silicon on the substrate with a lpcvd, the amorphous silicon layer is annealed, the larger grain is obtained, then the thick polycrystalline silicon film is deposited on the seed crystal, Solar panel structures so the recrystallization technology is undoubtedly a very important link, At present, the technology mainly includes solid-phase crystallization method and central melting recrystallization method. Solar panel structures In addition to the recrystallization process, polycrystalline silicon thin film batteries have adopted almost all of the technology to prepare monocrystalline silicon solar cells, so the conversion efficiency of the solar cells is obviously improved.