Design of Dual‐Mode Interfacial Domains Enable Efficient and Stable Pure Red Perovskite Quantum Dots LEDs

ABSTRACT Strongly confined CsPbI 3 perovskite quantum dots (QDs) are urgently needed for stable pure‐red perovskite QDs light‐emitting diodes (PeLEDs). However, it's challenging for realization of high performance pure‐red PeLEDs with an intrinsic trade‐off between external quantum efficiency (EQE) and stability with single functional group ligands. In this report, we design an interfacial dynamic‐static matching strategy by designing a dual‐function ligand, Fluorobenzamine (PhFA), to construct dual‐mode interfacial domains that simultaneously suppress nonradiative pathways and stabilize the lattice structure. We find that the ammonium (‐NH 2 ) group contributes to promoting dynamic charge injection and defect passivation, while the fluorine (‐F) group anchors the surface to enhance structural stability. Hence, the PhFA‐treated QDs exhibited a high photoluminescence quantum yield (PLQY), boosted efficiency, and observably improved stability. PeLEDs based on these optimized QDs show the pure‐red electroluminescence (EL) emission with a maximum EQE of 29.2% and an operational half‐lifetime surpassing 950 min at an initial luminance of 140 cd m −2 , which are among the highest reported to date for pure‐red PeLEDs.