Light and elevated temperature induced degradation in B–Ga co-doped cast mono Si PERC solar cells

Abstract

The utilization of boron-doped Si solar cells based on the structure of a passivated emitter and rear cell (PERC) in the solar industry has increased recently. However, this type of high efficiency solar cell is exposed to a so-called light and elevated temperature induced degradation (LeTID). A suppressing of mc-Si LeTID has been studied through a regeneration treatment at high temperature under illumination or in the dark, but most was about the lifetime samples. In this work, to evaluate the applicability of regeneration and annealing at industrial relevant conditions, industrially made B–Ga co-doped cast-mono Si PERC solar cells were treated in a light soaking tool in which the intensity of light and substrate temperature could be adjusted separately and a rapid thermal process (RTP) system. This treatment was evaluated during a subsequent intentional degradation under conditions of 75 °C with an LED white light source at an intensity of 1 kW/m2. The results showed that properly regenerated samples by high intensity illumination at elevated temperatures suffered from the least degradation, while untreated solar cells had most severe degradation. The RTP method could improve the performance of the solar cells but the RTP-treated samples were less stable than the regenerated samples. It demonstrates the application of a fast (around 20 min) regeneration method could be coupled in mass production. Further, RTP treatment combining with an accelerated regeneration step may be a potential method to provide both the improved performance and high anti-LeTID properties in Si PERC solar cells.