Impurity mechanism of monocrystalline silicon PERC solar cells stimulated by prelight-induced degradation

Abstract

Although the monocrystalline silicon (mono-Si)-passivated emitter and rear contact (PERC) solar cells have achieved incredible efficiency, they still can be further improved by hydrogenation. So the hydrogenation was performed to investigate the improvement of large area (>240 cm2) mono-Si PERC solar cells and estimate the significance of previous light-induced degradation (pre-LID) under a high-intensity infrared (HI-IR) LEDs source platform. Then, the results indicated that the parameters, such as open-circuit voltage (Uoc) and short-circuit current density (Jsc) and fill factor (FF), could be better improved after LED hydrogenation with the execution of the pre-LID. The efficiency of mono-Si PERC solar cells with pre-LID increased by ~0.190 ± 0.005%abs. for 2 min, which was higher than that without pre-LID (0.115 ± 0.005%abs.). Moreover, the results showed that the efficiency of large area mono-Si PERC solar cells with light-induced degradation (LID) treatment after LED hydrogenation only existed a slight degradation of about −0.253 ± 0.005%rel.. Compared with mono-Si PERC solar cells without pre-LID, the efficiency improvement and LID mitigation of mono-Si solar cells with pre-LID was faster and more significant by LED hydrogenation, so that the LED hydrogenation time significantly can shorten from 6 to 2 min. Additionally, the possible presence of a boron-oxygen (BO) model was estimated, and this BO model is susceptible to be activated by the injection of external energy, resulting in more BO defects in the process of pre-LID, so that subsequent hydrogenation rate becomes faster.