Laser-enhanced contact optimization (LECO), or laser-enhanced contact optimization, patented by Cell Engineering GmbH in 2016, replacing the conveyor furnace (FFO) technology typically used for TOPCon solar cell.

  In principle, the current formed by the laser is transmitted along the path of low contact resistance, causing silver-silicon mutual diffusion, thereby reducing the contact resistance; The duration of the entire sintering process matches the carrier lifetime, and the laser stops rapidly after that, so as to maximize the retention of the original passivation layer and avoid carrier recombination caused by direct contact between metal and silicon matrix.

  Laser-assisted sintering is suitable for all high-temperature sintering silver paste sintering processes, so it has potential for PERC, TOPCon, and even xBC solar cells. For TOPCon solar cells, laser-assisted sintering has a higher efficiency potential than PERC cells due to the use of burn-through slurry on both front and back. It is worth mentioning that because laser-assisted sintering can accurately control the sintering process, the difficulty of thinning the back of the TOPCon solar cell is reduced, and another layer of efficiency improvement space is opened from the perspective of reducing parasitic absorption.

                        Before LSP                                                      After LSP

   Laser-assisted sintering technology not only improves the open-circuit voltage and filling factor of TOPCon solar cell, but also improves the density and mechanical strength of the front grid of the solar cell , and improves the performance of the TOPCon solar cell as a whole.