Improved Electrical Performance of Low-Temperature-Cured Silver Electrode for Silicon Heterojunction Solar Cells

Abstract

To realize the high conversion efficiency potential of silicon heterojunction (SHJ) solar cells, it is crucial to minimize the series resistance by reducing the line resistivity and contact resistance of the Ag gridlines formed via low-temperature (<similar to 240 degrees C) curing. To reduce the resistivity and contact resistance of the screenprinted Ag gridlines on an indium tin oxide (ITO) layer, two strategies are utilized in this study: 1) the addition of Ag nanoparticles (NPs) into a low-temperature-curing polymer-based Ag paste for the resistivity and 2) the insertion of a thin Ag contact layer by inkjet printing between the screenprinted Ag gridline and the ITO layer for contact resistance. The effectiveness of these approaches was examined by curing the Ag gridlines at various temperatures in the range of 160-220 degrees C for 10 min. After curing at 200 degrees C, the low resistivity of 2.2 mu Omega.cm and specific contact resistance of 0.55 m Omega.cm(2) were obtained by adding 20 wt. % of Ag NPs and inserting the inkjet-printed Ag contact layer, respectively. Microstructural analyses were also performed to correlate the outstanding electrical properties of the Ag gridlines.