R. Shankar, A. Amert, J.J. Kellar, K.W. Whites
South Dakota School of Mines and Technology, US
silver nano-ink, solar cell electrodes, inkjet printing, conductive ink
we have produced silver nanoparticles using the polyol synthesis and have tailored the ink formulation by choosing a solvent mixture to meet the rheological requirement of industrial printhead (XAAR 1001FF). A solvent mixture which can suspend the ligand capped silver nanoparticle was developed while maintaining the target rheology. A desktop R&D printer, the LP50, developed by Pix-Dro has been used for the jetting optimization for the printheads used here. A drop-view camera was used to optimize the inkjet droplets during the jetting process and a print-view camera was used to analyze the printed patterns closely. Statistical analysis of the jetting process was conducted using printer integrated software. Typical printing parameters such as greyscale, DPI variation, substrate heating etc were optimized to achieve high print quality. Test of the dispersion showed that there was no sedimentation for more than a month. After the rheological and printing optimization, solar prototypes were successfully printed on silicon and ITO substrates. We have demonstrated the capability of printing silver electrodes having line width below 100 µm.