Developing the next generation low-cost inks for high efficiency multi crystalline silicon solar cells

In this paper, we report the development of nano-dispersion-technology (NDT) for front silver solar paste manufacturing as opposed to the three-roll-milling (TRM) technology that is commercially available. The NDT showed uniform dispersion of the particles in the paste as revealed by the SEM analysis after printing and drying. Multicrystalline cells were fabricated using paste manufactuctured by NDT and compared to the TRM counterpart. The best efficiency of 17.0% was achieved with the NDT paste compared to the 17.1% for the TRM counterpart. The 0.1% efficiency difference was due to fill factor difference between the two technologies. The slight higher series resistance for the NDT cell, which cause the loss in fill factor was attributed to the finer gridline width, which led to the use of less Ag paste. The overall low fill factor in both cells was due to high ideality factor at 0.1 suns, which was revealed by Suns _ V
_oc
measurements. Such high ideality factor can be caused by recombination in the depletion region resulting from silver proximity to the cell's junction. The quality of the multicrystalline cell could also result in a high ideality factor.