Antimony oxide buffer layer for single- and double-junction perovskite-based solar cells

Abstract Atomic layer-deposited tin oxide serves as an effective buffer layer in perovskite/silicon tandem solar cells due to its efficient charge extraction and sputtering tolerance. Nevertheless, its unavoidable chemical erosion effect of atomic layer-deposited tin oxide on perovskite requires thicker fullerene charge transport layers, leading to increased parasitic optical absorption. Herein, we firstly integrated thermal evaporated antimony oxide into solar cells to effectively replace atomic layer-deposited tin oxide, enabling a thinner fullerene to minimize optical losses and prevent damage to the perovskite. The unique amorphous-nanocrystalline structure of, antimony oxide facilitates ultrafast carrier transport via its embedded nanocrystalline network. The antimony oxide-based tandem solar cells demonstrated a significant improvement in power conversion efficiency compared to tin oxide-based devices, primarily due to an enhanced short-circuit current density of approximately 1 mA/cm² in the perovskite top cell. Remarkably, even at 64.64 cm 2 scale, the antimony oxide-based encapsulated large-area tandem solar cell retains an efficiency of 28.16% (with a certified value of 27.70%), attesting the scalability of this approach.