Laser-enhanced contact optimization in silicon solar cells improves carrier transport by locally activating the metal-silicon interface. The fill factor recovers. Contact resistance drops. The cell performs better.
The same localized activation that improves carrier transport also creates kinetically unstable interface states. The laser energy that frees carriers near the contact simultaneously disrupts the interface structure, generating defects that are initially dormant but degrade the cell over time. The improvement and the degradation share a source.
The predictive framework in this work couples electrothermal modeling with time-dependent degradation assessment to distinguish stable optimization zones from latent damage zones in the laser parameter space. Some laser conditions improve the contact permanently. Others improve it temporarily while creating a degradation pathway that unfolds over the cell's operational lifetime.
Modern fine-line contact designs make this problem worse. Narrower contact fingers concentrate current at the interface, reducing the stability margin. The same geometric optimization that enables higher efficiency also narrows the window between beneficial activation and damaging activation. The cell is simultaneously better and more fragile.
The dual nature of the laser treatment means you can't optimize for initial performance and expect reliability. The contact that measures best on day one may be the contact that fails on year five. The framework's value is in mapping which improvements are real and which are loans against future degradation.