Process Study on Selective Emitter of TOPCon Solar Cells

Abstract

Abstract: In order to improve the photoelectric conversion efficiency of tunnel oxide passivated contact (TOPCon) solar cells, the selective emitter structure was prepared by boron diffusion and laser doping. The effects of sheet resistance of boron diffusion, power output ratio of laser and oxidation time on the passivation of the emitter were studied. The experimental results show that when the sheet resistance is 140 Ω/□, the oxidation temperature is 1 020 ℃, and the oxidation time is 30 min, the sheet resistance of light doping region (p⁺) reaches 320 Ω/□, the corresponding implied open circuit voltage reaches 729 mV, and the dark saturation current density is 12 fA/cm². The sheet resistance of heavily doping region (p⁺⁺) reaches 113 Ω/□, the corresponding implied open circuit voltage reaches 710 mV, and the dark saturation current density is 26 fA/cm². Based on the selective emitter process, the highest conversion efficiency of 24.75% was obtained with an open circuit voltage of 720 mV, and a short-circuit current improvement of 30 mA, leading to an absolute efficiency gain of 0.26 percent point for the champion conversion efficiency.

Key words: TOPCon solar cell, selective emitter, boron diffusion, laser, oxidation, photoelectric conversion efficiency

CLC Number:

TM914.4

YANG Lu, SONG Zhicheng, NI Yufeng, ZHANG Ting, WEI Kaifeng, RUAN Miao, SHI Huijun, ZHENG Leijie. Process Study on Selective Emitter of TOPCon Solar Cells[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2024, 53(1): 138-144.

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