High efficiency n-PERT solar cells by B/P co-diffusion method

Abstract

In this work, boron paste was coated on the silicon surface by spin-coating method, and the boron-doped emitter and phosphorus-doped back surface field were fabricated in one co-diffusion process, because the boron paste acted as a barrier during phosphorus diffusion. Then, n-PERT (Passivated Emitter Rear Totally-diffused cell) solar cells were successfully prepared by this B/P co-diffusion method with the front efficiency of 20.41% and the back efficiency reaching 18.32%. It was demonstrated that the emitter and back surface field formed a good passivation layer on top by thermal oxidation respectively, which enabled open-circuit voltage to reach 648.7 mV. It should be emphasized that the whole process was effectively simplified compared with the conventional process of n-PERT solar cells. Thus, these first results indicate that B/P co-diffusion might be a promising alternative method for mass production of the n-PERT solar cells.g