Optimization and Performance Analysis of n-TOPCon Solar Cells Through Investigation of Local Dot Contact Printing Techniques and Their Impact on Efficiency

Advancing photovoltaic technology is crucial for meeting the growing global energy demand sustainably. This study explores the effects of printing conditions, such as dot print type, co-firing belt speed, and paste application method, on the performance of n-type Tunnel Oxide Passivated Contact (n-TOPCon) solar cells. The research systematically investigates combinations of single and double dot printing with high-temperature TOPCon Ag paste and low-temperature HIT paste, processed at co-firing belt speeds of 100, 130, and 160 ipm. Key findings reveal that incorporating low-temperature HIT paste with single dot printing (Dot SP + HIT SP) consistently achieves superior performance, with peak efficiency of 22.57% at 100 ipm and 22.15% at 130 ipm. Optimal thermal processing at 130 ipm ensures a balance between dopant activation and minimal thermal stress, achieving efficiencies up to 22.15%. Loss analyses highlight the critical influence of passivation and contact resistance on metrics such as fill factor (FF), short-circuit current density (Jsc), and open-circuit voltage (Voc). Minority carrier density (MCD) and lifetime (τ) analyses underscore the trade-offs introduced by dot printing, with MCD decreasing from 5.9×10¹⁵ cm⁻<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> to 5.5×10¹⁵ cm⁻<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and τ from 460 µs to 408 µs. This comprehensive study provides valuable insights into optimizing n-TOPCon solar cell fabrication for enhanced efficiency and cost-effectiveness, with potential implications for large-scale photovoltaic production.