Monolithic Perovskite/Si Tandem Solar Cells: Pathways to Over 30% Efficiency

The article commences with a review focusing on three critical aspects of the perovskite/Si tandem technology: the evolution of efficiencies to date, comparisons of Si subcell choices, and the interconnection design strategies. Building on this review, a clear route is provided for minimizing optical losses aided by optical simulations of a recently reported high-efficiency perovskite/Si tandem system, optimizations which result in tandem current densities of ≈20 mAcm⁻² with front-side texture. The primary focus is on electrical modeling on the Si-subcell, in order to understand the efficiency potential of this cell under filtered light in a tandem configuration. The possibility of increasing the Si subcell efficiency by 1% absolute is offered through joint improvements to the bulk lifetime, which exceeds 4 ms, and improves surface passivation quality to saturation current densities below 10 fA cm⁻². Polycrystalline-Si/SiO_x passivating contacts are proposed as a promising alternative to partial-area rear contacts, with the potential for further simplifying cell fabrication and improving device performance. A combination of optical modeling of the complete tandem structure alongside electrical modeling of the Si-subcell, both with state-of-the-art modeling tools, provides the first complete picture of the practical efficiency potential of perovskite/Si tandems.