Study on the Curing Process of Silver Paste of Heterojunction Solar Cells Using Response Surface Methodology

Abstract

Adhesion strength is of great importance for silver paste of heterojunction solar cells (HJT silver paste). It has a close relation with the curing system, as well as the curing process or curing conditions of the paste. The interactions among all the curing conditions such as curing time (t, min), treatment temperature (T, °C), and curing agent dosage (m, wt%) are obviously complex and hard to analyze. Response surface methodology (RSM) is used to research the interactions among t, T, and m and to optimize the curing process. The results of this study indicate that an increase of curing time and treatment temperature both had a positive effect on adhesion strength. The effect of curing time is more obvious under a lower treatment temperature. 41 wt%, 199 °C, and 44 min were determined as the optimum process conditions. The quadratic model predictions fitted well with the experimental data with a deviation less than 3%. The FTIR results indicated that there were both addition and esterification processes in the reaction of E51 and ring-open MeTHPA. Scanning electron microscopy (SEM) images showed that the silver paste formed a dense interconnected network and provided a continuous pathway for current carrier transmission. This research demonstrated the effectiveness of the E51-MeTHPA system for HJT silver paste and the superiority of RSM in studying the curing process of silver paste.