Polycrystalline Silicon Cells and Amorphous Solar Power Batteries

Monocrystalline silicon solar power batteries are the most efficient conversion of silicon cells, is also the most stable performance of a, Nai its production process energy consumption is high, monocrystalline silicon rods cut and cut also need energy consumption and material loss Great. Therefore, the development of other types of silicon cells to pay attention. At present, solar power batteries and amorphous silicon cells have been put into industrial production and a large number of people into the market. Polysilicon does not have the same crystal structure as monocrystalline silicon, and a large number of fine silicon crystals are disordered in the material. Polycrystalline silicon cell conversion efficiency than single-crystal silicon cells, but its production process consumes less energy.

The crucible growth method is a polysilicon rod obtained by pouring molten silicon into a crucible and controlling the cooling rate thereof so that the cross section thereof may be square. Square silicon rods need to be sawed to get the battery wafer, but to avoid the circular wafer cut into a square process, thereby reducing the production of solar power batteries in the process of energy consumption and material waste solar powered portable generator. This method of production of polycrystalline silicon cell conversion efficiency inch up to 15%. Method is directly from the molten silicon out of a cross-section of octagonal polysilicon, the wall thickness of 3300 and up to 6 to. The octagonal tube can then be cut into individual cell wafers with a laser. It is reported that this method of production of polycrystalline silicon cell conversion efficiency has reached 14%.

Polycrystalline silicon cells still maintain the basic characteristics of the crystal, so it is an indirect band gap of 1.16 of the band gap material, wafer manufacturing follow-up process and monocrystalline silicon cells the same. In order to ensure sufficient light absorption, the wafer also requires a larger thickness. Amorphous silicon does not have a specific crystal structure, the direction of the silicon atoms are arranged in random order and the spacing is different from one another solar powered portable generator, resulting in many covalent bonds in the material is not complete . This incomplete covalent bond produces a large number of defect states in the band gap. Amorphous properties lead to poor mobility of electron holes in the material, while the defect state will capture the carrier. So people are not optimistic about the beginning of this material. It was not until 1975 that the material of the Heart II was obtained that it was found that the dangling bonds were suppressed by hydrogen to greatly reduce defect states in the bandgap.

Early amorphous silicon cells in the light of performance degradation, through the design and production technology development, such as the use of multi-junction technology, making the amorphous solar power batteries performance has been stable. The theoretical maximum conversion efficiency of amorphous silicon is 27%, and the conversion efficiency of commercialized products is about 10%. Because it can be made using deposition technology, and the thickness of the material can be made very thin, amorphous silicon cells can be produced instainless steel and polymer substrates to form flexible flexible products. On the indirect bandgap materials, monocrystalline silicon, there is no certain thickness can not guarantee high conversion efficiency, solar powered portable generator while the advantages of amorphous silicon thin-film battery can save a lot of expensive pure silicon material, so in the production of thin-film battery, the non- Crystalline silicon has its advantages.

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