Classification of photovoltaic glass. Photovoltaic glass substrates for solar cells generally include ultra-thin glass, coated glass, low iron content (ultra-white) glass and other types. According to the use of different properties and manufacturing methods, photovoltaic glass can be divided into 3 products, namely flat-panel solar cell cover, generally calendering glass; Thin-film battery conductive substrates, usually only a few microns thick, are coated on the surface of flat List of semiconductor materials, and lenses or mirrors used in solar photovoltaic systems. The characteristics and functions of these three products are completely different, and their added value is also very different.

The most widely used photovoltaics glass today is high-transmittance glass, which is low in iron content, also known as ultra-white glass. Iron in ordinary glass belongs to impurities (except for endothermic glass) , the presence of iron impurities, on the one hand to color glass, on the other hand, increase the heat absorption of glass, also reduce the transmittance of glass.

Iron in glass is introduced by the raw material itself, Refractory or metal production equipment and can not be completely avoided. The iron content in glass can only be controlled by production to reduce as much as possible. At present, the iron content of solar cell glass is between 0.008% ~ 0.02% , while the iron content of ordinary float glass is above 0.7% . For the 3.2 mm and 4mm thick glasses used in China, the solar visible light transmittance is generally 90% ~ 92% .

As one of the most important components of solar photovoltaics, glass panels must be highly transparent. Therefore, the iron content of silicon materials used in the production of solar glass is very strict, the content of FE2O3 is 140-150 ppm.

Application of photovoltaic glass. According to reports, the world has long used transparent flat glass as a substrate for the development and application of solar cells in Germany. German scientists installed the panel-shaped solar cells as window panes on buildings, which can feed electricity directly to households and the excess energy can also be fed to the grid, the development and utilization of this kind of glass for solar cell was paid attention to by the United States and Japan soon after, so the development and application of low-iron and ultra-thin glass for solar energy was accelerated.