The advancement of photovoltaic technologies requires cost-effective, scalable, and rapid manufacturing techniques. Additive manufacturing combined with laser sintering offers a maskless approach for copper metallization, enabling precise patterning of conductive tracks to enhance solar cell efficiency.

Our research group has previously explored laser sintering for depositing conductive silver lines and films using the nanoparticle electrospray laser deposition process. This method was also effective for titanium dioxide nanoparticles deposition on borosilicate glass and quartz, achieving transparent TiO2 films (~91% transmittance). While silver has been widely used in solar cell metallization due to its ease of processing, cooper presents a cost-effective alternative. However, its susceptibility to oxidation is mitigated using laser processing.  

This study investigates how laser processing conditions—scanning speed, laser intensity, copper line width, and the feed rate—affect the electrical conductivity and porosity of laser-sintered copper lines. A computational model incorporating radiative transfer equation modeling, volume of fluid method, and user-defined functions optimize processing.

A custom-formulated shear-thinning copper nanoparticle suspension is deposited onto indium tin oxide (ITO)-coated silicon wafers via an auger pump, followed by laser sintering to produce copper lines ranging from 60-80 μm in width with high aspect ratio and electrical conductivity. Post-sintering characterization includes scanning electron microscopy, X-ray diffraction, surface profilometry and four-point probe measurements to assess morphology and electric performance. Model predictions for line width are validated against experimental data.

This study advances laser-assisted additive manufacturing for photovoltaic applications, offering insights into optimizing cooper sintering for scalable, high-precision solar cell fabrication.