The different types of photovoltaic cells are
In photovoltaic cells, crystalline silicon dominates the market share due to its high photoelectric conversion efficiency, mature manufacturing process, and low cost advantages. As a semiconductor material, pure silicon has low electrical conductivity at room temperature. By doping silicon with other elements, its electrical properties can be adjusted.
By applying doping techniques to a complete silicon wafer, a PN junction is formed near the interface of the two semiconductors, creating a potential difference and an internal electric field. When sunlight strikes the surface of the solar cell, photons with energy exceeding the bandgap of the silicon material are absorbed by silicon through intrinsic absorption, generating electron-hole pairs. The solar cell works by converting light energy into electrical energy. The key to improving the efficiency of the cell’s absorption of sunlight is reducing the reflection of light on the surface of the cell, while improving the conversion efficiency of the solar energy involves reducing internal energy losses.
Crystalline silicon solar cells can be divided into monocrystalline and polycrystalline cells based on the crystalline structure of the substrate material used.
In recent years, the production and manufacturing technology of monocrystalline silicon wafers, solar cells, and modules have continuously advanced. Compared to polycrystalline products, monocrystalline modules have higher conversion efficiency, which helps increase the electricity generation of photovoltaic power plants while effectively lowering the cost per kilowatt-hour, leading to a significant increase in market share.
From small to large sizes: Large-size technology has effectively increased module power, reduced logistics costs, and lowered installation costs in power plants, which in turn reduces the cost of producing, transporting, and installing each watt, ultimately lowering the final cost per kilowatt-hour.
From P-type to N-type: Crystalline silicon solar cells can be divided into P-type cells (silicon doped with gallium) and N-type cells (silicon doped with phosphorus) based on the doping elements of the silicon substrate. The P-type crystalline silicon cell technology route, by adding a passivation layer on the rear side, reduces photoelectric losses and improves conversion efficiency in PERC cells. The minority carriers in N-type silicon wafers are holes, which have relatively low sensitivity to metal impurities. Therefore, compared to P-type silicon wafers, N-type silicon wafers have the advantage of a higher minority carrier lifetime, as well as better resistance to light degradation. N-type cells made from these wafers exhibit higher photoelectric conversion efficiency and long-term stability.
This is an introduction to the different types of photovoltaic cells, as explained by Hengyuan Tai.