Post-Treated NiO _x with 1-Dodecanethiol for Enhanced Interfaces in Inverted Perovskite Solar Cells

High Resolution Image Download MS PowerPoint Slide Nickel oxide (NiO x ) is widely recognized as an effective hole-transport layer for inverted perovskite solar cells (PeSCs); nevertheless, its performance is often hindered by the transformation of Ni 2+ to Ni 3+, which generates interfacial defect states and accelerates nonradiative recombination. To address this issue, we introduce a thiol-based interfacial passivation strategy using 1-dodecanethiol (DDTH) at the NiO x /perovskite junction. The strong coordination between thiol groups and nickel atoms forms robust Ni–S bonds, effectively passivating interfacial defects and stabilizing the NiO x surface. This interfacial modification suppresses nonradiative recombination, enhances hole extraction, and improves energy-level alignment across the interface. Consequently, DDTH-treated devices exhibit markedly improved charge transport and reduced interfacial losses. An optimized device incorporating 0.5 mg mL –1 DDTH achieves a power conversion efficiency (PCE) of 19.3% and retains 80% of its initial efficiency after 500 h of one-sun illumination at room temperature (≈27 °C), demonstrating markedly enhanced operational stability.