DEVELOPMENT OF THE FRONT-SIDE CONDUCTOR OF A LEAD-FREE SILVER PASTE FOR SCREEN-PRINTED SILICON SOLAR CELLS

摘要

In this study, a lead-free Ag paste for front-side conductor was developed with good electrical properties optimizing the lead-free glass compositions. Excellent specific contact resistance in conjunction with high fill factor (FF) of 0.770 were obtained on 55Ω/sq emitters with alkali-textured cell by 780°C spike firing of the lead-free Ag paste in a lamp-heated walking beam furnace. In a 1000-hour damp heat test under 85°C/85 Rh% condition for the lead-free cells, it was found that the Eff/Eff_(initial) value decreased less than 3%. The possibility of increasing efficiency is also shown with improving the Ag gridline aspect-ratio to form narrower gridlines using optimized Ag paste.