T-Shaped Linear Organic Semiconducting Interlayer Enables Highly Efficient NiOx-Based Perovskite Solar Cells

Interfacial defects and misaligned energy levels represent critical challenges in NiO_x-based inverted perovskite solar cells (PSCs), which jointly constrain photovoltaic performance and accelerate perovskite degradation. Herein, a novel T-shaped linear semiconductor (WH14) is developed through a rational vertical π-extension strategy and introduced as an interlayer in NiO_x-based PSCs. The fully exposed heteroatoms of WH14 enable effective defect passivation and block the oxidation of Ni^>3+ with perovskite at the interface. Meanwhile, the electron-withdrawing nature of the dithienophenazine (DTPA) central core significantly lowers the highest occupied molecular orbital (HOMO) level, facilitating ideal energy alignment for efficient interfacial hole extraction. Consequently, the WH14 modified NiO_x-based devices achieved a remarkable power conversion efficiency (PCE) of 25.20% along with excellent long-term stability, retaining over 80% of their initial efficiency after being aged for 1200 h in ambient air. This study underscores the potential of molecular engineering in developing linear organic semiconductors to address interfacial challenges and promote the advancement of high-performance NiO_x-based inverted PSCs.