TOPerc Solar Cell: An Integral Approach of Tunnel Oxide Passivated Contact (TOPCon) and Passivated Emitter and Rear Contact (PERC) Architectures for Achieving Efficiency Beyond 25%

Passivated emitter and rear contact (PERC) on p-type mono silicon has a roadmap for achieving >24% efficiency. The decrease of the full-area rear metal contact to partial rear contact (<10%) accounts for the majority of the increase in efficiency of PERC solar cells over Al-BSF solar cellswhich reached its maximum efficiency around 19.5%. P-type tunnel oxide passivated contacts (TOPCon) solar cells have achieved further improvement in efficiency & GE;25% by completely removing the partial rear metal contact and introducing a thin tunneling oxide layer at the rear. Thus passivating the partial rear and front metal contacts using SiOx/poly-Si tunnelling layer stacks and an AlOx/SiNx stack on the entire back surface to passivate the remaining areas might lead to further advancements in PERC solar cells. Therefore, by integrating TOPCon and PERC architectures, as originally proposed by Fraunhofer lab, a modified design known as TOPerc solar cell has been studied in depth in this paper. Using 3D Sentaurus TCAD simulation software, a thorough numerical simulation of a p-TOPerc solar cell has been performed. It is shown that efficiency of 25.2% and 26.0% is obtained for a p-type wafer of bulk lifetime of 400 & mu;s and 5.0 ms, respectively.

Automated summary

The decrease in full-area rear metal contact to partial rear contact contributes to the increase in efficiency of PERC solar cells. P-type tunnel oxide passivated contacts (TOPCon) solar cells further improve efficiency by removing the partial rear metal contact and introducing a thin tunneling oxide layer at the rear. By integrating TOPCon and PERC architectures, a modified design known as TOPerc solar cell achieves efficiencies of 25.2% and 26.0% for different p-type wafer lifetimes.