Modeling-Free Efficiency Gain Analysis of Passivated Emitter and Rear Silicon Solar Cells

We introduce an approach to analyze and identify the predominant loss mechanisms in silicon solar cells. For this end, we focus on the potential efficiency gains to be acquired by suppressing each loss mechanism. All the losses are scaled to efficiency gains, leading to quantities similar to the derivative of the efficiency with respect to the loss mechanisms. All impacts are directly comparable to one another since the potential gains are quantified in the same units. The approach is solely based on measured data alone and we take injection-dependent lifetimes correctly into account by measuring at maximum power point like conditions. This approach is exemplarily applied to passivated emitter and rear cells (PERC) based on p-type mono- and multicrystalline silicon wafers. For our examined solar cells, we identify as bottlenecks the optical and recombination properties of the front-side metallization in case of the monocrystalline PERC cell and the reflection at the active area in the multicrystalline case with potential efficiency gains of 1.23%(abs) and 1.56%(abs), respectively.