Optimizing strategy of bifacial TOPCon solar cells with front-side local passivation contact realized by numerical simulation

Abstract

The tunnelling oxide passivation contact (TOPCon) solar cells have been impressive in the global photovoltaic (PV) market originating from their high efficiency and stability. However, it exhibits significant recombination losses due to its boron diffusion, laser damage and metal-semiconductor contact on front side. The bifacial TOPCon structure demonstrates massive potential in the improvement of passivation and contact performance with the premise that it can solve the parasitic absorption of polycrystalline silicon (poly-Si). In this study, the localized poly finger structure with excellent optics and passivation performance is designed in the front side of bifacial solar cells to compare with traditional TOPCon and full-area poly passivation devices. The theoretical efficiency and detailed power loss analysis in our simulation reveal that suppressing the recombination of FSF (front surface field) and the contact area is the crucial strategy to improve device performance, with optimized efficiency of 26.62 % and FF of 85.16 %. These results indicate that the route of BJ (back junction) structure containing localized selective contact and full coverage high-quality passivation holds potential in realizing both high J_sc and V_oc for FBC (front and back contact) solar cells, featuring great instructive significance for future industrialization of PV production.