Quantifying edge and peripheral recombination losses in industrial silicon solar cells

A finite-element model is constructed to represent a silicon solar cell as a vast network of diodes with different saturation current densities, with focus on the definition of three recombination parameters to describe the vicinity of the wafer edges. By simulating the voltage distribution across the cell plane, as well as the cell current-voltage characteristics at different illumination intensities, these peripheral and edge recombination parameters are extracted for various cell types and processes by comparison with corresponding measurement data. It is noted that the monocrystalline silicon PERC cells studied have significantly lower peripheral and second diode edge recombination compared with Al-BSF cells. For the Al-BSF cells studied, there can be ~0.25%-0.6% absolute efficiency gain if the peripheral and edge recombination sources are eliminated.