Electrical Performance, Loss Analysis, and Efficiency Potential of Industrial-Type PERC, TOPCon, and SHJ Solar Cells: A Comparative Study

Abstract

Currently, the efficiency of p-type passivated emitter and rear contact (PERC) cells has been growing at an absolute efficiency of 0.5% per year and has reached 23%–23.5% in mass production while getting closer to its theoretical efficiency limit. n-Type tunnel oxide passivated contact (TOPCon) and silicon heterojunction (SHJ) cells with their superior “passivating selective contacts” technology were the most interesting photovoltaics (PV) technology in the industry. The effect of different passivated contact layers with respect to their influence on the J₀, J_0,metal, ρ_c, and the carrier selectivity (S₁₀) and the loss analysis and efficiency potential of industrial-type PERC, TOPCon, and SHJ solar cells were studied and compared. The results showed that TOPCon structure with a high passivation performance and good optical performance is more suitable for bifacial solar cell and the highest theoretical limiting efficiency with metal shading on the n-type Si wafer (η_b,e,h,m,max) can be achieved to 27.62%. Although SHJ structure with the highest passivation performance but the worst optical performance owing to the parasitic absorption of a-Si:H layer and high contact resistivity, the value of η_b,e,h,m,max is 0.7% lower than that of TOPCon solar cells. PERC structure has superior optical performance than SHJ structure, but due to poor passivation performance, the η_b,e,h,m,max is only 26.42%. The next-generation products may be heterojunction back-contact (HBC) and TOPCon back-contact (TBC) cells with high η_b,e,h,m,max of 28.12% and 27.99%, respectively. Exploiting a perfect passivation of the noncontact area, the wide process window and low cost are required and transferring these new concepts to industrial solar cell production will be the next major challenge.