Interface-Dependent Efficiency Tradeoff in Si-Based Carrier-Selective Solar Cells

Carrier-selective (CS) silicon solar cells are of recent research interest, and a variety of different materials have been investigated in this regard. However, the efficiency tradeoff with CS material/interface properties is not yet fully explored. In this context, through detailed analytical and numerical modeling, here we provide several interesting insights on the same. First, we show that perfect band alignment is a desirable feature only if the interface is devoid of any trap states. Otherwise, a band offset of around 0.2-0.4 eV provides sufficient band bending to reduce the effect of interface recombination, thus improving the performance. Surprisingly, the interface passivation quality for the minority carrier extraction layer is found to be far less demanding than that for the majority carrier extraction layer. In addition, doping density and dielectric constant of CS layers have a similar effect as band offset on solar cell performance. Our results have obvious implications toward the selection of appropriate materials as CS layers, and hence, are of broad interest to the community.