The Preparation Of Crystalline Silicon Solar Cells With Silver Powder And Its Effect On The Properties Of Silver Paste On The Back

With pollution-free, renewable and inexhaustible characteristics, solar is one of the most important energy of our future. Researches and applications of solar energy have been the hotspot of science and engineering circles. The thesis aims at solving technical difficulties of silver electrode material on the back of crystalline silicon solar cell, and thus puts emphasis on conductive silver powder preparation and effects of the silver powder performance on back silver paste of the cell. Spherical silver powder was prepared by the liquid phase chemical reduction, and the role of reductants, dispersion agent types and their concentration, as well as pH value and reaction temperature in controlling the morphology and particle size of silver was researched.Flake silver powder was obtained by the mechanical milling and then effects of types and content of milling dispersant on the morphology, average particle size and bulk density of flake silver,, also milling time on the morphology, average particle size bulk density and specific surface area of the silver, were explored. Effects of silver morphology, dispersion, tap density and the relative value of silver and glass powder content on sinter film and battery photovoltaic performance were analyzed.Applying liquid phase chemical reduction, silver powder with good dispersion and uniform morphology was prepared. The dispersant has a great influence on the silver morphology. Based on reaction of sodium cirate, triethanolamine, tween three, spherical, dendritic and sheet silver forms were obtained, respectively. When m(sodium cirate)/m(AgNO3) mass ratio is0.08, the silver is with good distribution, average particle size is2.52μm. The optimum reductive solution is as follows:the temperature40℃and the PH of6. The speeds of adding and stirring solution are10mL/min and500r/min, respectively. Under this condition, silver is with good dispersion and uniform morphology, and average particle size the silver is2.5μm, the particle size distribution on the2-5μm and tap density3.8g·cm-3.Mechanical milling is the main method of preparing flake silver. Effects of milling dispersant types and concentration on the performance of flake silver were explored. Silver with uniform particle size, good dispersion was synthesized by using the composite dispersant. When the concentration of the dispersant is1.5wt%, the average particle size of the silver is6.32μm, bulk density1.18g·cm-3.Effects of milling time on morphology, average particle size, bulk density and specific surface area of the silver were investigated. When the time is short enough, silver flake is large, and also its bulk density and specific area. While the time is long enough, due to brittle fracture, hardening, powder plastic drop, the bulk density and specific surface area increases, and thus existing an optimun milling time. The results obtained in the milling of15h, morphology of the silver piece shape is sheet-like, and average particle size the silver is5.89μm, bulk density1.12g·cm-3, specific surface area2.85cm2/g.A significant impact of silver morphology, dispersion, tap density and the relative value of silver and glass powder content on sinter film and battery photovoltaic has found out. The paste and solar cell prepared by flake silver have the best adhesion and photoelectric and spherical silver better, dendritic silver the worst. High dispersion and tap density of silver can significantly improve the photoelectric conversion efficiency of solar cell. With the rise of the relative value of silver and glass powder content, the photoelectric conversion efficiency increases followed reducing. When the relative value is16.4, namely the silver content of82%and glass powder5%, the photoelectric conversion efficiency is17.58%, the best result.