Energy Funnel‐Driven Quantum Cutting in Yb <sup>3+</sup> /Er <sup>3+</sup> ‐Doped Quasi‐2D Perovskites Enables High‐Efficiency Dual‐Band Near‐Infrared Light‐Emitting Diodes
Wei Li, Donglei Zhou, Yuhang Fang, Yanrun Jia, Tianyuan Wang, Yuqi Wang, Yue Wang, Ruixin Song, Enhui Wang, Xue Bai, Wen Xu, Hongwei Song
Abstract
Abstract Quasi‐two‐dimensional (quasi‐2D) perovskites exhibit efficient visible‐light emission, but have remained challenging for near‐infrared (NIR) electroluminescence. Here, a breakthrough is reported in achieving NIR emissions at 986 and 1540 nm through quantum cutting in ytterbium/erbium (Yb 3+ /Er 3+ )‐doped quasi‐2D perovskite films. Atomic‐scale transmission electron microscopy reveals that Yb 3+ ions substitute Pb 2+ sites, establishing robust halide coordination that stabilizes the lattice and enables efficient energy transfer. The synergistic combination of Yb 3+ doping and phosphatidylethanolamine (PE) modulates perovskite domain phase distribution, driving the photoluminescence quantum yield (PLQY) to an exceptional 170%—a notable enhancement for NIR emitters. Transient absorption spectroscopy uncovers a cascaded energy transfer mechanism: photoexcited carriers in low‐n‐phases funnel into the n = ∞ phase, enabling sequential energy transfer to Yb 3+ ions and subsequent NIR emission. NIR light‐emitting diodes are fabricated with record‐high external quantum efficiencies (EQEs) of 9.32% at 986 nm and 1.96% at 1540 nm. This work provides atomic‐scale insights into lanthanide ion integration in perovskites and establishes a universal strategy for quantum‐cutting sensitization in optoelectronic materials, paving the way for next‐generation NIR optoelectronic technologies.