subject: Polysilicon Efficient Battery [print this page] The appears of polysilicon solar cell mainly in order to reduce costs, its advantage is to preparation out large size square silicon ingot which suitable for large-scale production directly, the equipment is simple, manufacturing process is simple, save electricity and silicon powder material, the material requirements is also lower. Grain boundary and impurity influence can improve through the battery technology; Due to the material and boundary effect, batterys efficiency is low. Battery technology mainly uses the suction miscellaneous, passivation, back field technology.
In recent years, suction mixed process have been attention again, including phosphorus oxychloride suction miscellaneous and aluminum suction mixed process. Suction mixed process also applied in microelectronics devices process, and we can see its purity reach a certain level of single crystal silicon, wafer also have effect, but the conditions it used do not necessarily apply to solar cell, so you need to study suitable for solar cell special suction mixed process. Some studies proves that, in polysilicon solar cell, different material suction mixed effect is different, especially for high carbon content of the materials could not show the phosphorus suction mixed role. Some scholars proposed phosphorus suction mixed model, that is, absorb sundry rate controlled dry two steps: (1) the metal powder impurity release/diffusion determines the lower limit of temperature suction noise; (2) the segregated model control the suction of sundry optimum temperature. Many other scholars said that in phosphorous diffusion of silicon when clearance current production is the basic factors of complex absorption mechanism .
Conventional aluminum suction hybrid technology is in the back of the battery steamed aluminized film after sintered form, also can form the battery back field at the same time. In recent years in the suction on the complex work proof, it produce certain effect to efficient monocrystalline silicon solar cell and polysilicon solar cell.
Passivation is an effective method to improve the quality of the polysilicon. A kind of method is using hydrogen passivation, passivation silicon in the defects such as suspension key. In the crystal growth by stress in the influence of the defects of the silicon materials, hydrogen passivated, the results is better. Hydrogen passivation can use ion implantation and plasma treatment. In polysilicon solar cell surface using pECVD method coated with silicon nitride minus reflection film, because of silane decomposition generates hydrogen ion, it is good for the polysilicon produce hydrogen passivation.
In high efficiency solar cell is often used on surface oxygen passivation technology to improve the efficiency of the solar cell, in recent years in the photovoltaic levels of crystalline silicon material use also has obvious effect, especially adopts thermal oxidation have apparent effects. Use PECVD method in lower temperature on surface oxidation, in recent years is also used, have certain effect.
In polysilicon solar cell surface due to there are many crystal, not as crystal to single crystal silicon that by corrosion can get ideal suede structure, thus the surface of various processing so as to achieve the effect of minus reflection for a recent study goal, of which more than the knife grinding wheel surface groove, to 10 cm multiply 10cm area of silicon wafer processing time down to 30 seconds, has a certain practical potential.
Porous silicon as polysilicon solar cell has the practical significance for reducing reflection film, its antireflective role can compare with double minus reflection film, the efficiency of the polysilicon batteries can achieve 13. 4%. Beijing of China non-ferrous metal research institute and Chinese academy of sciences and the photosensitive chemical institute jointly developed in screen printing polysilicon solar cell use on porous silicon has been reached close to practical results.
Because of polysilicon material production cost is lower than single crystal silicon cZ materials, so polysilicon components than single crystal silicon components has greater potential to reduce costs, thereby enhancing the efficiency of the polysilicon batteries research work also have received attention. In the past 10 years, the development of polysilicon efficient battery is very fast, of which some representative work is Geogia Tech. Battery, UNSW battery, Kysera battery, etc.
