Photonic Curing of Copper Inks: A Pathway to Scalable Copper Metallization for Solar Cells

Copper (Cu) is widely regarded as a desirable alternative to silver (Ag) for photovoltaic (PV) cell metallization because it offers much lower cost and greater abundance while maintaining comparable bulk resistivity. However, the oxidation of Cu remains a major challenge, as it requires inert atmospheric conditions that hinder manufacturability. This study demonstrates a photonic curing approach that uses a continuouswave CO 2 laser (10.6 μm) to sinter micro and nanoscale Cu particles printed as metal grid lines on indium tin oxide (ITO)‐coated crystalline silicon (c‐Si) wafers for silicon heterojunction (SHJ) PV cells. The method enables rapid, localized heating that minimizes both oxidation and thermal stress on temperature‐sensitive layers, while remaining compatible with advanced solar cell technologies, including SHJ and tandem devices. Cu metal fingers are deposited by microdispensing and subsequently sintered with optimized laser parameters. Their microstructural, elemental, thickness, and electrical properties are systematically characterized. Under optimized conditions, the process achieves a bulk resistivity ( ρ b ) of ≈19 μΩ·cm and a contact resistivity ( ρ c ) of ≈35 mΩ cm −2 . The printed Cu fingers exhibit widths of ≈190 μm and heights of ≈20 μm, resulting in aspect ratios of ≈0.1–0.15.