Enhancing passivation and reducing absorption losses in TOPCon solar cells via Poly-Si finger structure

Tunnel Oxide Passivated Contact (TOPCon) technology is one of the most influential and industrially feasible solar cell technologies today. Its excellent passivation contact performance has become a hot spot of current research. However, more serious parasitic absorption exists in polysilicon films, and balancing the thickness of polysilicon to solve the absorption coefficient of poly-Si with metallization contact is worthy of further research and discussion. To solve this problem, poly-Si was prepared graphically using laser, and the poly-Si finger TOPCon cell structure was formed by the heat generated by the laser. Various characterization techniques such as scanning electron microscopy (SEM), electrochemical voltammetry (ECV) and spectroscopic ellipsometry (SE) confirmed the validity of the structure. The main results show that the poly-Si finger structure effectively reduces the parasitic absorption loss of polysilicon, improves the current density of the cell and maintains the passivation performance on par with the metal contact. As a result, the average conversion efficiency in the final production stage increased by 0.33 % compared to the baseline set. This study emphasizes the potential of this poly-Si finger structure to drive the fabrication of highly efficient solar cells by emphasizing significant improvements in parasitic absorption losses and overall cell performance. • Preparation of poly-Si masks using lasers. • Preparation of P-doped polysilicon using in situ doping by tube-PECVD. • The initial proposal for a double poly-Si finger passivation structure. • 0.33 % gain in average conversion efficiency relative to baseline.