6 inch IBC cells with efficiency of 23.5% fabricated with low-cost industrial technologies

The rear contact pattern design of IBC cells plays an important role in achieving high cell efficiency. It necessitates a trade-off between a reduction of the internal recombination losses by using fine geometries of pitch and contact size, and a reduction of the series resistance losses by using large metal coverage and contact area ratio. In this paper, the rear contact pattern is optimized based on characterization and simulation techniques. From this optimization, IBC cells were fabricated on 6 inch pseudo-square n-type wafers with a champion cell demonstrating an efficiency of 23.5%, which is the highest total-area efficiency reported to date for a 6 inch IBC cell. Compared to our previous design, an absolute 0.5% efficiency gain has been achieved.