Simulation Insights Into Enhanced Emitter Contact Passivation via LECO on Industrial TOPCon Solar Cells

ABSTRACT Recent progress in industrial tunneling oxide passivated contact (TOPCon) solar cells has demonstrated that laser‐enhanced contact optimization (LECO) technology substantially reduces the emitter contact recombination current density ( J 0e,metal ), leading to a remarkable enhancement in cell efficiency. However, the physical mechanisms underlying this suppression remain insufficiently explored. This study employs advanced numerical simulations to systematically decode the interactions between firing conditions, LECO treatment, and doping dynamics. A process simulation reveals that the boron profile exhibits negligible deviation after a typical firing step, ruling out thermal redistribution as a contributor to J 0e,metal suppression. Instead, lower peak firing temperatures promote localized, non‐continuous contact morphologies. In a baseline 25.5% TOPCon solar cell, this partial metal contact ratio is quantified at 37.27%, directly correlating with diminished recombination losses. To mitigate contact resistivity ( ρ c ), LECO complementarily rectifies underfired contacts by forming excellent Ag/Si contacts. These insights motivate a dual optimization strategy: (1) dopant engineering via selective emitter technology to maximize contact passivation while minimizing ρ c and (2) partial metal contact ratio reduction by tuning firing parameters, Ag paste composition, LECO energy density, etc., aiming for a 1% partial contact ratio without compromising ρ c . Implementing this approach, the simulated cell efficiency improves from 25.5% to 26.07%, offering actionable guidelines for industrial TOPCon optimization. The strategy also suggests an alternative route for J 0e,metal suppression, paving a viable path to elevate the efficiency of conventional TOPCon solar cells, enabling them to compete with more advanced double‐sided and back‐contact solar cells.