Hierarchical Dual‐Scaffolds Enhance Charge Separation and Collection for High Efficiency Semitransparent Perovskite Solar Cells

Organometal halide perovskite solar cells (PSCs) have shown much promise to be made semitransparent (ST) for a variety of applications. However, charge separation and collection are still inefficient from the ultrathin absorber layer and thus limit the ST‐PSCs performance. Herein a type of hierarchical dual scaffolds is first reported to tackle this problem consisting of a quasi‐mesoscopic inorganic (TiO2) layer and a percolating organic (phenyl‐C61‐butyric acid methyl ester) manifold throughout the capped or filled perovskite bulk. It is demonstrated that the soft PCBM scaffold affords efficient charge separation due to the formation of a penetrating network intimately interfaced with perovskite crystals, meanwhile the quasi‐mesoporous hard TiO2 scaffold strongly based on the substrate further offers a continuous electron transport. As a result, the ST‐PSCs based on the ultrathin perovskite layer (≈100 nm) with the dual‐scaffolds have achieved an internal quantum efficiency of ≈100%, boosting the device efficiency to 12.32%. Furthermore, the real ST‐PSCs fabricated by replacing the Ag electrode with a PEDOT:PSS transparent electrode have reached an efficiency of 8.21% with an average visible transmittance of 23%, placing among the highest performing devices of the kind reported to date.