The meaning of TOPCon solar cells
TOPCon (Tunnel Oxide Passivated Contact) solar cells are based on an N-type silicon substrate with a tunnel oxide passivated contact. Compared to PERC (Passivated Emitter and Rear Contact) solar cells, TOPCon cells use a tunnel oxide layer with excellent charge transport properties on the back of the cell, along with a 20 nm thick doped polysilicon layer, forming a passivated contact structure. This structure effectively reduces surface recombination and metal contact recombination, increasing the open-circuit voltage and improving the energy conversion efficiency.
TOPCon is a solar cell technology based on the principle of selective carrier transport with a tunnel oxide passivated contact, achieving better passivation performance. The TOPCon cell structure uses an N-type silicon substrate, with a thin silicon oxide layer prepared on the back of the cell, followed by the deposition of a doped silicon thin layer. The combination of these layers forms a passivated contact structure that effectively reduces surface and metal contact recombination, providing greater potential for further improving the efficiency of N-PERT (N-type Passivated Emitter and Rear Cell) solar cells.
TOPCon cells maximize the retention and use of existing traditional P-type cell production equipment processes, requiring only additional boron diffusion and thin-film deposition equipment. There is no need for back-side hole drilling or alignment, greatly simplifying the cell production process with low difficulty in mass production. The process equipment and production line are highly compatible and can work with the high-temperature fabrication lines of PERC and N-PERT bifacial cells. TOPCon cells have advantages such as low degradation, high bifaciality, and a low temperature coefficient, which significantly enhance power generation performance in end-use solar power stations.