Structural Compensation Strategy: Composite NiO _x Hole Transport Layers Enabling High‐Efficiency and Scalable Inverted Perovskite Solar Cells

ABSTRACT

Sputtered nickel oxide (NiO _x ) integrated with a self‐assembled monolayer (SAM) as a hole‐transport layer represents a promising strategy for the scalable application of inverted (p‐i‐n) perovskite solar cells. However, the inherent limitations of sputtered NiO _x , characterized by insufficient surface functionality, hinder the ordered deposition of SAMs, thereby constraining device performance. Here, we demonstrate a method to achieve uniform NiO _x films by controlling the oxygen cooling pressure during the magnetron sputtering process. To further enhance the quality of the interface, we introduce a structural‐compensation strategy comprising a sputtered underlayer complemented by a solution‐processed hydroxyl‐rich overlayer. The magnetron‐sputtered bottom layer provides a compact, low‐defect contact, while the solution‐processed top layer creates a hydroxyl‐rich surface, facilitating effective SAM anchoring and decoupling SAM deposition from charge extraction processes. This interfacial engineering not only enhances hole extraction, but also promotes perovskite crystallization, leading to enlarged grain sizes, reduced strain, and suppressed non‐radiative recombination. Consequently, the resulting inverted devices deliver high performance across bandgaps and scales: 24.86% and 21.78% for small‐area 1.55 and 1.68 eV cells, respectively, and 21.38% for a 12.4 cm ² module based on the 1.55 eV absorber, all with robust operational stability. This work provides a practical and scalable pathway toward high‐performance perovskite photovoltaics.