Investigating the viability of PERC solar cells fabricated on Ga- instead of B-doped monocrystalline silicon wafer

Abstract

The viability of commercial Ga-doped silicon PERC solar cell is decided by its efficiency, cost and reliability. In this article, the viability of Ga-doped Cz-Si PERC solar cells has been investigated systematically from an industrial perspective. Firstly, the relationship of wafer resistivity, contact fraction and variation of series resistance for PERC solar cell has been established for increasing the usage rate of Ga-doped crystal. Then, based on the relationship, an average efficiency of 22.21% for the PERC cells with five busbars fabricated from the whole Ga-doped CZ crystal has been achieved. The statistical results of electrical parameters show that the PERC cells fabricated on Ga-doped Cz-Si wafers with a wide resistivity variation (0.5–2.0 Ω⋅cm) are highly comparable with that of PERC cells made from B-doped Cz-Si wafers with typical resistivity (0.5–1.0 Ω⋅cm). The obtained results demonstrated that the full range of resistivity values produced from a Ga-doped Cz crystal can be used to fabricate quality, cost-effective PERC solar cells. Meanwhile, a comparative study of initial degradation for optimized Ga-doped PERC solar cells and stabilized B-doped PERC solar cells was carried out in accumulative irradiation of 20 kWh/m2 at 50 °C and 80 °C. The results indicate that Ga-doped PERC cells are more stable than stabilized B-doped PERC cells even though at high temperature. The results obtained in this paper demonstrate the viability of Ga- instead of B-doped Cz-Si wafer as substrate to fabricate cost-effective PERC solar cells.