Laser-assisted additive manufacturing for copper nanoparticle metallization in photovoltaics

Copper is increasingly considered for next-generation microarchitectured solar cells due to its unique photovoltaic and cost characteristics. Laser-assisted additive manufacturing enables cost-effective, scalable route for copper metallization with localized energy input, and minimal thermal damage to underlying device layers. In this study, high concentrations of copper nanoparticle suspensions (75–85 wt. %) were prepared and deposited on indium tin oxide-coated silicon heterojunction solar cells, followed by a two-step CO2 laser process consisting of drying and selective sintering. A tailored thermal model, incorporating the thermophysical and optical properties of each material, was used to guide the optimal laser conditions for both steps. Processing and structure property relationships were evaluated through SEM imaging and four-point-probe measurements. Laser-sintered lines showed improved densification and conductivity compared with thermally annealed counterparts, indicating that localized laser energy enables more effective neck growth and reduced lateral spreading. The results highlight a promising pathway toward high-precision, low-thermal damage metallization for advanced solar-cell architectures and provide a foundation for further optimization of laser-based cooper processing.