LECO study by Chinese institutes improved UHRS TOPCon cell contact

Researchers from Universites of China, has studied Laser-enhanced contact optimization (LECO) in TOPCon solar cells with UHRS emitters. The standard LECO process has improved passivation but resulted in weaker contact than medium resistance cells due to fewer Ag nanoparticles and a lower interfacial potential gradient. UHRS-based cells also showed higher resistance, reducing overall contact quality. By applying a slightly higher reverse voltage, researchers achieved contact resistivity below 1 mΩ·cm² and cell efficiency of 26.25%. The improvement was linked to Ag spike-like contacts and a wider Ag/glass blend zone, which has enhanced carrier transport. The study clarified LECO contact mechanisms and proposed a method to improve UHRS-based TOPCon performance.