Optimizing the metallization process for high fill factor of n-type crystalline silicon TOPCon solar cells

Abstract

The primary challenge in solar cell manufacture concerning the metallization process is the need to achieve a balance between the electrical and optical performance of the metal contacts as the contribute to shading and the series resistance (Rs) of solar cells. Addressing these challenges with the optimization of the metallization process is crucial for achieving a high fill factor (FF) in solar cells, as FF is a key parameter indicating the quality and efficiency of a solar cell. An impact of different snap-off, distances between mask and cells, of n-type TOPCon (Tunnel Oxide Passivated Contact) solar cells during the screen-printing process was conducted. This experiment employs testing and analysis to determine the most effective snap-off distance that minimizes the Rs variability, resulting in an overall enhancement in cell efficiency. The smaller snap-off distance can lead to better performance in n-TOPCon solar cells due to finer lines, uniform contacts, and lower Rs. The I-V characteristics of 1.4 mm are Jsc of 39.58 mA/cm2, Voc of 684.63 mV, FF of 80.54 %, and power conversion efficiency (PCE) of 21.83 %, respectively. In addition, dark I-V measurement is essential for diagnosing performance issues; we got shunt resistance (Rsh) of 4.97 x 106 Ω which is the highest value that indicates minimal Rs of 0.3 Ω. As a result, it is a potential strategy for n-TOPCon solar cell improvements.