This report focuses on the overall achievements and successes of the Project, including how key performance limitation of mainstream laser-doped screen printed contacts in industrial PERC solar cells have been addressed. The Project has successfully developed several novel LDSE technologies and contacting technologies to mitigate contact recombination losses in screen-printed solar cells with reduced metal/Si interface areas.
The main focus of the ARENA 2020/RND005 project is to research and develop novel laser-doped selective emitter (LDSE) and screen-printed contacting technologies for industrial silicon solar cells to address the fundamental limitations of highly recombination active metal/Si interfaces on the efficiency of current screen-printed solar cells.
With over 97% of the market share in the current PV industry, screen printing has long been recognized as a robust and cost-effective technique for the metallization of silicon solar cells. Despite significant improvements in the performance of screen-printed contacts in solar cells, one remaining limiting factor to the efficiency of screen-printed industrial PERC and TOPCon solar cells is carrier recombination losses at metal/Si interfaces, which are becoming increasingly detrimental as the silicon bulk and surface passivation quality continuously improve in industrial solar cells. With current finger spacings of approximately 1.3 mm, the traditional contacting pattern design results in more than 5% metal/Si interface areas, limiting open-circuit voltage (VOC) of industrial PERC solar cells to 680-690 mV and therefore efficiency. To allow further improvements in the efficiency of industrial screen-printed solar cells, overcoming such efficiency limitations from carrier recombination at metal/Si interfaces will be a critical requirement for the future developments of screen-printed solar cells in the PV industry.