Research Of Organic Phase Of Ag Paste And Glass Frit Of Al Paste For Silicon Solar Cells

China has a large market of PV industry.Glass frit of Ag paste is one of the most important materials in the production of silicon solar cells and is dependent on import.It is necessary for domestic factories to grasp the technology for production of Ag paste.On the other hand,PERC as a new structure of silicon solar cell has developed rapidly recently.It will be a huge cost to transform conventional production line of BSF cells to PERC.My work is aimed at developing a new kind of organic phase of Ag paste and a new kind of glass frit of Al paste.Rheology behavior of Ag paste depends heavily on the organic phase.Through research of thixotropic agents,thickening agent and solvent,this work successfully finds the key factors of the rheology behavior of Ag paste.As a result,this work proposes a new way to prepare the organic phase and Ag paste,which behave as well as commercial Ag paste Dupont PV19 in printing performance and height width ratio of the silver grid lines.The reduction of electronic recombination losses in silicon solar cells by the passivation of silicon-electrode interfaces is necessary for high efficiency cells.In this work,we successfully fabricate a new glass frit with molybdenum oxide(MoOx,x<3)as the functional material,which can reduce recombination losses and enhance the adhesive force of an aluminum back surface in comparison with traditional glass frits.After adding this glass frit into pristine aluminum paste,whose average efficiency is 17.9%,we gain an average efficiency of 18.3% with a highest efficiency of 18.9%.This glass frit coating on surfaces of aluminum particles can effectively facilitate hole-transfer from the silicon layer to the aluminum electrode,reducing electronic recombination losses.A thermite reaction that occurs during the firing process can help grow a thicker back surface field layer which is also good for reducing electronic recombination.We also find improvement of short circuit current density in silicon solar cells with transition metal doping of Al paste with materials such as molybdenum oxide.These results strongly confirm our previous conclusion that using electron selective materials that can undergo thermite reaction is a promising low-cost way of improving the efficiency of conventional BSF silicon solar cells.