Energy Yield Modeling of Bifacial All‐Perovskite Two‐Terminal Tandem Photovoltaics

All-perovskite two-terminal tandem photovoltaics offer high power conversion efficiencies (PCEs) that can surpass the limits of single-junction photovoltaics. In this study, energy yield (EY) simulations are performed to assess the performance of bifacial all-perovskite tandem solar cells. Under standard test conditions, in the absence of albedo, bifacial tandems demonstrate a 4.9% relative lower PCE compared to equivalent monofacial tandems due to transparency losses at the semitransparent rear side. However, under realistic irradiation conditions, albedo irradiation leads to an enhancement in EY for bifacial cells. This enhancement enables bifacial cells to produce more energy than monofacial cells, even over relatively low average reflectance (R$_A$) ground such as dark sandstone (R$_A$ = 9%). The EY gain for bifacial cells rises to a maximum of 40–50% for ground modeled as a perfect reflector (R$_A$ = 100%), accompanied by a shift in optimum top subcell bandgap to 1.56 eV. This shift is of particular interest as low-bandgap perovskite semiconductors (with lower bromide concentrations) offer enhanced stability under realistic operation conditions. Finally, this work presents a route to increase the PCE of simulated monofacial and bifacial cells, to 31.9% and 30.8%, respectively, by optimizing the optical and electrical performance of the cells