Synergistic Halogen‐Bonding Passivation and Carboxylic Acid Anchoring in Carbazole‐Based Hole‐Transport Materials Enhance Performance and Stability of p–i–n Perovskite Solar Cells

Abstract Interfaces pose significant challenges to the performance and stability of perovskite solar cells (PSCs), as defects and weak interactions at these boundaries can lead to energy losses and degradation. To address these issues, it is crucial to functionalize hole transport materials (HTMs) to effectively manage interfacial defects and enhance charge transfer. This study introduces a carbazole‐based hole transport layer (TC‐ICA) that leverages halogen bonding (XB) for enhanced interface passivation with the perovskite layer and carboxylic group anchoring to the indium‐doped tin oxide (ITO). By combining these functionalities, the TC‐ICA material leads to exceptional device stability (99% shelf stability over 320 days of air storage and a T80‐lifetime exceeding 1000 h under light soaking) and enhanced efficiency (15.4%), outperforming single‐function materials like TC‐CA (14.7%) and TC‐I (10.7%). This dual‐function strategy marks a significant advancement in the quest for high‐performance and long‐term stable PSCs.