Capitalising on the Precisions of Ion Implantation and Ink Jetted Fine Gridline to Create Low-Cost High Efficiency Silicon Solar Cells

This paper reports ink-jetted gridline, production ready, solar cells with ion implanted homogeneous high sheet resistance emitters having efficiency of >19%. The average efficiency of ∼18.96% on 80 ohm/square ion implanted emitter with highest efficiency of 19.2% demonstrates the potential of combining the two high precision technologies, inkjet printing and ion implantation. The key attributes of the cells include average open circuit voltage (VOC) of 640 mV, fill factor (FF) of 79.14% and short circuit current density (JSC) of 37.8 mA/cm2. Worthy of note is that, the front gridlines width and height of 47.6 μm and 43.9 μm resulting in aspect ratio of 0.92 using only 83 mg total Ag, which is, at least 20% Ag less than today's screen printed cells. However, the reference screen-printed cells showed similar average efficiency with the best gridline widths of ∼70 μm and height of ∼28 μm used >100 mg of Ag. Statistical analysis illustrates that the highest efficiency with the screen-printed contacts is an outlier as the minimum efficiency for the ink-jetted group. This efficiency is very significant because all cells were fabricated on a pilot production line at Shanghai Shengzhou New Energy Co. Ltd, in China.