UC Davis

One of the largest and fastest growing renewable energy technologies is photovoltaics. Crystal silicon solar cells are the dominant commercial photovoltaic technology, holding about 95% of the market share. The next generation of crystal silicon solar cell designs are silicon heterojunction and POLO/TOPCon, both of which utilize a passivating carrier selective contact. These two cell designs are expected to make up ~ 80% of the global market by 2030. Part of their emerging dominance is due to their remarkable efficiencies, which are rapidly approaching the theoretical limit. As such, in the area of energy improvements, there is only limited room to improve. This leaves reducing the lifetime cost as one of the most substantial ways to lower the LCOE. Reducing the lifetime cost can be achieved by either reducing the deployment cost or improving the device lifetime. Reducing the deployment cost concerns not only the materials and manufacturing, but also installation, repair, and end of life requirements of the device. These considerations alone favor improving the device lifetime as one of the most effective ways to lower the lifetime cost, and thus improve the LCOE. To this end, we have carried out a series of comprehensive computational and theoretical efforts to understand the underlying physical mechanisms, model long-timescale dynamics, and develop mitigation strategies for the passivation degradation in silicon heterojunction and POLO/TOPCon solar cells.