Buried‐Interface Engineering of Conformal 2D/3D Perovskite Heterojunction for Efficient Perovskite/Silicon Tandem Solar Cells on Industrially Textured Silicon

Abstract Exploring strategies to control the crystallization and modulate interfacial properties for high‐quality perovskite film on industry‐relevant textured crystalline silicon solar cells is highly valued in the perovskite/silicon tandem photovoltaics community. The formation of a 2D/3D perovskite heterojunction is widely employed to passivate defects and suppress ion migration in the film surface of perovskite solar cells. However, realizing solution‐processed heterostructures at the buried interface faces solvent incompatibilities with the challenge of underlying‐layer disruption, and texture incompatibilities with the challenge of uneven coverage. Here, a hybrid two‐step deposition method is used to prepare robust 2D perovskites with cross‐linkable ligands underneath the 3D perovskite. This structurally coherent interlayer benefits by way of preferred crystal growth of strain‐free and uniform upper perovskite, inhibits interfacial defect‐induced instability and recombination, and promotes charge‐carrier extraction with ideal energy‐level alignment. The broad applicability of the bottom‐contact heterostructure for different textured substrates with conformal coverage and various precursor solutions with intact properties free of erosion are demonstrated. With this buried interface engineering strategy, the resulting perovskite/silicon tandem cells, based on industrially textured Czochralski (CZ) silicon, achieve a certified efficiency of 28.4% (1.0 cm 2 ), while retaining 89% of the initial PCE after over 1000 h operation.