Efficiency improvement of B/Ga co-doped p-type multicrystalline silicon passivated emitter and rear cells induced by B/Al co-doping

Abstract

In the present work, electrical performance of B/Ga co-doped p-type multicrystalline silicon passivated emitter and rear cell (PERC) was improved by B/Al co-doping. By combining the Al-Si alloying process with the relative high solid solubility of B in Si, high doping concentration in B/Al BSF was realized with the maximum doping concentration of 1.86E19 cm−3, which was almost one magnitude higher than Al doping. Benefiting from the relative high doping concentration, the saturation current density expelled the influence of emitter decreased from 135.1 fA cm−2 to 121.1 fA cm−2. The suppression of saturation current together with the J01 both indicated the electrical improvement of PERC solar cell, with the open-circuit voltage (VOC) enlargement of 1.5 mV and efficiency improvement of 0.02%. After body defect passivation, the electrical parameters of all PERC solar cells increased slightly, while the superiority of the B/Al paste aggravated with the efficiency enlargement of 0.05%. All these efforts will be helpful to deepen the understanding of B/Ga co-doped p-type multicrystalline PERC solar cell as well as B/Al co-doping.