A P‐Type Organic Dye as Interface Layer for Efficient and Stable Inverted Perovskite Solar Cells

ABSTRACT Nickel oxide (NiO _x ) is a promising hole‐transport material widely used in inverted perovskite solar cells (PSCs) due to its high carrier mobility and good transparency. However, light‐induced degradation of the NiO _x– perovskite heterojunction remains the main factor limiting the long‐term operational lifetime of these solar cells. In this study, a traditional p ‐type organic dye ( TPA‐CN ), commonly used in p ‐type NiO _x dye‐sensitized solar cells, is employed as self‐assembled monolayer (SAM) molecules for interface modification between NiO _x and perovskite in inverted PSCs. In TPA‐CN , carboxyl anchoring groups passivate Ni ^{3 +} defects on NiO _x and enhance hole extraction, while the cyano group passivates undercoordinated Pb ^{2 +} in the buried perovskite layer, lowering trap density. Furthermore, TPA‐CN functions as an interfacial bridge, boosting charge transfer from the perovskite to NiO _x , which improves both the performance and stability of perovskite solar cells (PSCs). As a result, TPA‐CN ‐modified devices achieve a peak power conversion efficiency (PCE) of 25.54%, compared to 21.80% for unmodified control devices. Notably, unencapsulated devices maintain 89.2% of their initial PCE after 1800 h under ambient conditions (ISOS‐D‐1) and 95.3% after 500 h of continuous 1‐sun illumination. This research presents an effective molecular design approach for developing high‐performance inverted PSCs using charge‐selective materials.