ScholarWorks@동국대학교

초록

Quasi-two-dimensional (2D) perovskite light-emitting diodes (PeLEDs) exhibit high red-emission efficiency but poor stability due to defect-mediated recombination and ion migration in hybrid perovskite nanocrystals (NCs). Here, we present a solvent-free mechanochemical synthesis of red-emitting quasi-2D (OA)<inf>2</inf>(MA)<inf>2</inf>Pb<inf>2</inf>I<inf>8</inf>(PbSO<inf>4</inf>) NCs using dioctylammonium sulfate (DOS), guided by first-principles calculations. The DOS ligand promotes PbSO<inf>4</inf> layer formation, which passivates defects, suppresses ion migration, and enhances humidity resistance. Unlike iodide-based octylammonium iodide (OAI) devices that degrade rapidly and emit only at 763 nm, DOS-stabilized PeLEDs show dual emission at 651 and 763 nm, indicating improved phase stability. The devices achieve a peak luminance of 7,039 cd/cm2 and an external quantum efficiency of 9.76%, retaining over 60% of initial EQE after 100 days, markedly outperforming conventional OAI-MAPbI<inf>3</inf> PeLEDs (<20%). These results demonstrate that sulfate passivation provides a simple and scalable route to robust, durable red-emitting quasi-2D PeLEDs, offering a promising strategy for high-performance optoelectronic devices. © 2025 The Author(s).

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