Arginine-Mediated Buried-Interface Regulation Enables Efficient Air-Processed Green Perovskite Light-Emitting Diodes

Air-processed perovskite light-emitting diodes (PeLEDs) hold substantial promise for low-cost, scalable display and lighting technologies. However, ambient fabrication suffers from moisture and uncontrolled crystallization, leading to severe interfacial defects that limit device efficiency and stability. Herein, we report an interfacial engineering strategy utilizing l-arginine (l-Arg)-modified PEDOT:PSS as a hole transport layer to regulate the nucleation behavior of air-processed FAPbBr3 perovskite films. l-Arg incorporation simultaneously improves precursor wettability for uniform nucleation and enhances surface hydrophobicity to mitigate moisture ingress during growth, yielding dense, high-quality films. Furthermore, the guanidinium/amino and carboxylate moieties of l-Arg interact with bromide vacancies and undercoordinated Pb2+ ions, respectively, effectively passivating interfacial trap states and mitigating defect-assisted nonradiative recombination. As a result, the optimized air-processed FAPbBr3 PeLEDs deliver a maximum luminance of 47,100 cd m-2, a current efficiency of 24.9 cd A-1, and a peak external quantum efficiency of 6.62%, accompanied by substantially improved operational stability. This work establishes amino acid-mediated bottom-interface modulation as a facile and effective strategy for advancing ambient-processed PeLEDs toward practical optoelectronic applications.