Direct Silicon/Perovskite Heterojunction Solar Cells Enabled by Interfacial Energetics and Charge-Selective Contact Engineering.

Single-junction crystalline silicon (Si) and perovskite solar cells are approaching their fundamental efficiency limits, while the prevailing Si/perovskite tandem architecture requires complex sub-cell interconnection and current matching. Here, we developed a Si/perovskite heterojunction architecture by integrating semi-transparent perovskite solar cells with both N-type and P-type crystalline Si substrates. By systematically tuning the resistivity of the Si substrates, favorable interfacial energy-level alignment and low-resistivity P-type Si exhibiting the most suitable band configuration for efficient charge transfer were obtained. A 1,4-bis(trifluoromethyl)benzene (C8H4F6) passivation treatment together with a NiOx + self-assembled monolayer (SAM) bilayer hole-transport interface was employed to suppress interfacial recombination and improve charge extraction. A graded SnO2/ITO/NiOx + SAM interface synergistically delivers electron selectivity, low-resistance charge extraction, and defect passivation coupled with energy-level modulation, enabling the direct Si/perovskite heterojunction solar cell to reach a champion power conversion efficiency of 14.23%. This work opens an alternative, structurally simplified pathway for Si/perovskite integration and provides a foundational design framework for this new class of photovoltaics.