12.1% Record-Efficiency 986 nm Quantum-Cutting Quasi-2D Perovskite Light-Emitting Diodes for Large-Area Dual-Mode Applications.

Ytterbium-ion (Yb3+)-doped quasi-2D layered metal halide perovskites (quasi-2D LMHPs) stand out as a transformative platform for near-infrared (NIR) emissions beyond 950 nm, holding great promise for revolutionizing next-generation photonic systems. Herein, we report a synergistic engineering strategy to simultaneously regulate phase distribution in the emissive layer and carrier transport in the hole-transport layer, enabling record-performance NIR perovskite light-emitting diodes (PeLEDs) emitting at 986 nm. The incorporation of fluorinated aromatic spacers (p-F-PEA+) and partial formamidinium (FA+) substitution strengthens organic-inorganic interactions, affording well-controlled phase distribution and highly efficient exciton-to-Yb3+ energy transfer. Meanwhile, zwitterionic kanamycin is introduced to neutralize the intrinsic acidity of PEDOT:PSS via distinct chemical interactions, leading to balanced carrier injection and suppressed nonradiative recombination. Benefiting from this dual-layer modulation, the optimized Yb3+-doped (PEA1.8p-F-PEA0.2)(Cs1.6FA0.4)Pb3Br10 PeLEDs exhibit a record peak NIR external quantum efficiency (EQE) of 12.1% at 986 nm and an outstanding operational half-life (T50) of 1823 min. More critically, we break the scalability bottleneck of NIR PeLEDs with 300 mm2 large-area devices delivering a state-of-the-art EQE of over 7.5%. We pioneer a visible/NIR dual-mode display and imaging platform via patterned PeLEDs, integrating explicit visible identification and covert NIR high-security anticounterfeiting. This work broadens the application prospects of NIR PeLEDs in high-security anticounterfeiting, nondestructive imaging, and smart photonic systems.