The Design And Sintering Process Of Positive Electrode Of Preparation Of Nano Silver And Copper Powder For Solar Cells

The photocurrent in the silicon solar cell is collected through the silver electrode in front of the cell,which is mostly fabricated by using cheap screen printing and rapid heat treatment.However,with the increase of the price of metallic silver,it has become an important problem of the technical level of the Ag electrode of the Si-based solar cell.The emphasis here is on the mechanism of ohmic contact between the front electrode and the Si-based solar cell during sintering and the preparation of the front electrode with cheaper copper instead of silver.However,the chemical and physical properties of Ag and Cu are different,and in particular,the chemical reactivity is completely different,that makes Cu,which is high in activity,susceptible to oxidation when sintering in an air atmosphere at a high temperature.Therefore,after the solar cell sintered at high temperature,the electrode formed by copper paste has higher sheet resistance and lower efficiency.In order to overcome this challenge,this paper is researching on the crystalline silicon solar cell,in order to improve the electrical contact property between the positive electrode prepared by screen printing and the surface of the silicon wafer,to improve the interface conductivity,and to reduce the cost of the electrode material.The electrode paste is added with a kind of nanometer conductive particles,and then the sintering process of different slurry is studied to prepare the complete solar cell sheet.(1)We prepared silver-copper nano-powder,used screen printing technology to prepare the positive electrode of solar cells,and determined the sintering process.Solar simulator test results shows that adding 10% nano silver-copper particles in the surface of the electrode can increase solar cell efficiency from 6.9856% to 7.0577%.In order to investigate the conductive mechanism,the contact interface between the electrode and the silicon wafer was characterized by XPS.The results show that the conductive phase at the electrode surface is more than that at the interface between the electrode and the silicon.By scanning electron microscopy,the metal particles is precipitated in the interface,thereby enhancing the interface conductivity between the electrode contact and the silicon wafer.(2)We prepared silver-copper core-shell nano-powder and solar simulator test results shows that adding 10% nano silver-copper core-shell particles in the surface of the electrode can increase solar cell efficiency from 6.9856% to 7.4566%.In order to investigate themechanism of conduction,the XPS and XRF were used to characterize the electrode of the electrode.The results show that the conductive phase at the interface of cell is more than that at the electrode surface and the SEM shows that metal particles is precipitated in the interface,thereby enhancing the interface conductivity between the electrode contact and the silicon wafer,and copper particles does not oxidize after sintering.