Synergistic Conformation Locking and Terminal Conjugation Engineering of Carbazole-Based Self-Assembled Monolayers for High-Performance Organic Solar Cells

• • PCz-HPA achieves a power conversion efficiency (PCE) of 19.75% in PM6:L8-BO-based organic solar cells, representing a significant improvement over conventional 2PACz-based devices and demonstrating the efficacy of conformational locking. • • The rigid cyclohexane linker in PCz-HPA induces a highly ordered, densely packed monolayer on ITO, leading to enhanced surface coverage and a strengthened interfacial dipole, which are critical for reducing recombination losses and improving charge extraction. • • PCz-HPA-based devices exhibit superior air-processing stability compared to flexible-linker counterparts, addressing a key bottleneck for scalable manufacturing under ambient conditions. • • The design principle of linker rigidification and terminal conjugation extension is validated across multiple active layer systems, indicating its generality for developing high-performance SAM interlayers in organic optoelectronics.