Optimization of TOPCon Structured Solar Cell Using AFORS-HET

Optimization of TOPCon Structured Solar Cell Using AFORS-HET

The tunnel oxide passivated contact (TOPCon) structured solar cell, improved version of fi rst-generation PERT solar cell, delivers the highest power conversion effi ciency, and is the most commercially available. The first-generation solar cell still suffers from recombination losses, which strongly impacts the conversion efficiency of the cell. To reduce the losses, efforts need to be made to suppress the recombination by passivating the rear junction using a dielectric layer, tunneling layer, along with an excellent field-effect passivation. The tunneling current is strongly dependent on the thickness of the dielectric layer, i.e., an increase in SiO 2 thickness results in the decrease of the tunneling current by more than one magnitude. Although raising the doping in the n + -Si layer enhances the tunneling probability of an electron, which allows for a thicker layer for better passivation. The paper discusses the results of a numerical simulation tool to study the impact of surface recombination on the performance of TOPCon solar cells. The solar cell is simulated at different surface recombination velocity observing typical solar cell parameters with varying tunnel oxide (SiO 2 ) thickness and doping of fi eld-eff ect passivation (n + -Si) to obtain the optimized value. Optimization of SiO 2 /n + -Si backside structure is essential to obtain a structure reaching a high theoretical efficiency.

The tunnel oxide passivated contact (TOPCon) structured solar cell, improved version of fi rst-generation PERT solar cell, delivers the highest power conversion effi ciency, and is the most commercially available. The first-generation solar cell still suffers from recombination losses, which strongly impacts the conversion efficiency of the cell. To reduce the losses, efforts need to be made to suppress the recombination by passivating the rear junction using a dielectric layer, tunneling layer, along with an excellent field-effect passivation. The tunneling current is strongly dependent on the thickness of the dielectric layer, i.e., an increase in SiO 2 thickness results in the decrease of the tunneling current by more than one magnitude. Although raising the doping in the n + -Si layer enhances the tunneling probability of an electron, which allows for a thicker layer for better passivation. The paper discusses the results of a numerical simulation tool to study the impact of surface recombination on the performance of TOPCon solar cells. The solar cell is simulated at different surface recombination velocity observing typical solar cell parameters with varying tunnel oxide (SiO 2 ) thickness and doping of fi eld-eff ect passivation (n + -Si) to obtain the optimized value. Optimization of SiO 2 /n + -Si backside structure is essential to obtain a structure reaching a high theoretical efficiency.