Optimization of Front Diffusion Profile in Bifacial Interdigitated Back Contact Solar Cell

The diffusion profiles of the front floating emitter (FFE) and front surface field (FSF) in a bifacial interdigitated back contact solar cell are optimized. The optimization results revealed that the FFE and FSF schemes are beneficial for enhancing the cell performance at the front and rear sides, respectively. Lighter doping is particularly better for the FSF scheme, and the FFE scheme requires a large diffusion depth for improving the performance. Increasing the area of the rear emitter boosts the performance of the cell, and an FFE scheme with 90% rear emitter area is found to be the best design. Quantum efficiency mapping demonstrated that the FFE scheme suppresses the loss at the back surface field region, thereby enhancing the performance of the total cell. The FSF scheme improves the quantum efficiency for the entire region by enhancing the carrier transport in the vertical direction. Furthermore, loss analysis revealed that the FFE scheme suppresses the recombination loss at the maximum power point, which is an important advantage over the FSF scheme.