Study of the Influences of Aluminum Pastes on Aluminum Back Surface Fields in Crystalline Silicon Solar Cells

Abstract

Authors Different kinds of aluminum pastes have been successfully prepared by adding various additives including the glass powders with different melt-points, the aluminum powders with different sizes, and the inert fillers. We emphatically analyze the influence of aluminum pastes prepared as above on the electrical performance of the as-formed silicon aluminum alloy layer (P+). The optical microscope was used to observe the morphology of aluminum back surface fields (Al-BSF) formed in the rear of silicon wafers. The results show that it could promote the formation of silicon aluminum alloy layer by using the glass binder with lower melt point. The solar cell exhibits the best surface conductivity and appearance when the ratio of coarse and fine aluminum powders is 2:1. In addition, the corresponding photoelectric conversion could reach to a high level of 18.09% when the mass fraction of the inert filler was adjusted to 1.3%.