The influence of edge masking on the optoelectronic performance in back contact silicon solar cells

Edge recombination remains a significant bottleneck for crystalline silicon solar cells approaching the theoretical efficiency limit. While edge masking is routinely employed to mitigate this loss and thereby strive for high efficiencies in test, the resulting electrical performance gain is often simplistically attributed to geometric shielding. Here, we elucidate a more fundamental physical origin of this enhancement through carrier dynamics simulations and equivalent circuit modeling. We reveal that masking drives a light-to-dark operating state transition, transforming the masked edge into a highly resistive dark state that acts as a reinforced “resistive barrier”. This barrier impedes lateral carrier diffusion toward the physical edge, effectively suppressing edge recombination. This mechanism underpins our experimental efficiency of 26.85% without any edge passivation. Furthermore, our model predicts that removing metallization in the masked region can completely isolate the dark edge load, reaching a simulated efficiency of 27.39%. This work establishes a theoretical framework for masking test and provides structural guidelines to maximize its potential in solar cell testing.