986/1540 nm Quantum Cutting-Based Perovskite Near-Infrared Light-Emitting Diodes: Overcoming Bottlenecks via a Quantum Dot-Matrix Hybrid Strategy

Near-infrared light-emitting diodes are essential for biomedical imaging and short-range telecommunication, but perovskite-based devices face bottlenecks: inherently large optical bandgaps and halide migration-induced phase instability. Quantum cutting offers a key advantage by converting one high-energy photon into two near-infrared photons to boost emission efficiency. Herein, we design a hybrid nanostructure strategy by embedding oleic acid-capped ytterbium (Yb³⁺)-doped CsPbCl_3-xBr_x perovskite quantum dots into a Yb³⁺-doped CsPbCl_3-xBr_x polycrystalline matrix. Comprehensive characterizations reveal that the oleic acid capping layer exerts a synergistic dual effect: passivating uncoordinated Pb²⁺ defects (reducing density by ∼76%) and inducing controlled lattice strain, thus suppressing halide segregation. Yb³⁺ shows quantum cutting -mediated 986 nm emission with rare negative thermal quenching (via phonon-assisted energy transfer), enabling 159% photoluminescence quantum yield. The inverted 986 nm near-infrared light-emitting diode delivers 7.8% external quantum efficiency (EQE) and demonstrates a maximum power density of 951 µW cm⁻². Extending this strategy to Yb³⁺/erbium (Er³⁺) co-doped hybrid films, we further realize electroluminescence at 1540 nm with EQE of 1.67% via sequential energy transfer. This work establishes a versatile platform for perovskite optoelectronics by synergizing defect engineering and energy transfer optimization.