Preparation And Performance Research Of Phosphorus-Containing Graphene Modified Front Side Silver Paste For Crystalline Silicon Solar Cells

The over-exploitation of traditional fossil energy makes the energy crisis imminent.People pay more and more attention to the research and development of new energy.There are also numerous types of solar cells,and silicon-based solar cells are the most developed and occupy the main position.Silver paste is the most important component in the front electrode of crystalline silicon solar cell,and glass frit is one of the key materials in the metallization process of the front electrode.Through continuous scientific inquiry and technological update,the research team has been able to continuously reduced the cost of solar cells and significantly improved the photoelectric conversion efficiency of cells.This paper investigates the material preparation of rare metal-doped positive silver paste glass frit and phosphorusdoped graphene,applying their materials to the silver paste for the frontal electrode of solar cells.Through a series of test methods,the characterization of the materials was analyzed,and the influence of these properties on the electrical performance of crystalline silicon solar cells was explored.The research details are as follows:(1)Through the study of conventional lead-based glass frits,this paper prepared two rare metal doped glass frits with positive silver paste by melt quenching method.By comparing with the former glass frits,the effects of the glass frits phase transition temperature and each characteristic temperature of the rare metal glass frits on the structure of the contact interface,ohmic contact and electrical properties of solar cells were investigated.The results show that the characteristic temperature points of glass frit doped with rare metal oxides are better than those of traditional glass frit.The front electrode grid line of the solar cell made by this method can help dissolve silver powder,corrode anti-reflection film during sintering,and form a thin glass layer containing a lot of silver crystal and Ag-Pb co-fused gold at the AgSi contact interface,which provides an effective way for electron transmission and promotes the formation of good ohmic contact.Therefore,the monocrystalline silicon solar cell made of glass frit doped with rare metal oxides has lower series resistance and higher photoelectric conversion efficiency(22.62%).(2)Emitter doping has an important impact on the electrical performance of solar cells.In this paper,phosphoric acid is selected as the phosphorus source,and the methods of freeze drying and heat treatment are used to prepare graphene and phosphate-doped graphene.Scanning and transmission electron microscopy showed that both graphene and phosphate-doped graphene had fold morphology.Fourier infrared spectroscopy and X-ray photoelectron spectroscopy showed that phosphoric acid mainly existed in the form of P-C and P-O bonds.The effects of phosphorus-doped graphene on silicon wafer etching,diffusion and bonding were further analyzed.The results show that the contact between graphene and silicon wafer can form a Schotky barrier,thus promoting the one-way flow of electrons.The N-type emitter where phosphorus diffuses below the electrode is a heavily doped deep junction,achieving the role of electron-hole separation.The best electrical performance of the corresponding cell was achieved when the content of phosphorus doped graphene is 2%.