Monolayer MnPS Nanosheet Integration for Extended Exciton Diffusion and Charge Transport in High-Performance Thickness-Insensitive Organic Photovoltaics.

Industrial-scale roll-to-roll processing of organic photovoltaics (OPVs) requires photoactive layers ≥300 nm for manufacturability and mechanical robustness, yet state-of-the-art high-efficiency systems remain confined to 80-120 nm due to intrinsic exciton diffusion and charge transport limitations. To resolve this fundamental thickness-efficiency trade-off, monolayer MnPS nanosheet (1-2 nm) via liquid-phase exfoliation are engineered to extend exciton diffusion lengths and out-of-plane charge mobility, as validated through multimodal characterization. The optimized PM6:Y6:MnPS system achieves record efficiencies of 19.53% (100 nm) and 18.41% (300 nm), demonstrating unprecedented 94.3% thickness tolerance and setting the highest reported retention for thick-film (>300 nm) OPVs. Universal applicability is evidenced through 20.45%/19.70% (D18-Cl:L8-BO system) and 20.41%/19.62% (D18:L8-BO system) efficiencies at 100/300 nm, outperforming state-of-the-art thick-film devices. This monolayer MnPS nanosheet integration paradigm establishes a general design rule for thickness-insensitive organic semiconductors, overcoming the critical photon harvesting-charge extraction dichotomy in industrial-scale OPV manufacturing.