Cluster-Free Intrinsic Assembly for Efficient and Stable Perovskite Light Emitting Diodes

Metal halide perovskites have emerged as transformative candidates for next-generation optoelectronic materials, yet their performance remains constrained by an inherently rapid and uncontrolled crystallization process driven by pre-aggregated clusters in precursors. While cluster-related challenges have been partially explored in perovskite photovoltaics, systematic investigations into their mechanisms and practical solutions for perovskite light-emitting diodes (PeLEDs) remain scarce. Herein, we introduce a cluster-free intrinsic assembly strategy to fundamentally reshape the crystallization dynamics of perovskites. By exploiting the diuretic furosemide (FRSM) as an ionic binder, we achieve simultaneous coordination of all ionic components within the perovskite precursor, effectively suppressing cluster formation and redirecting crystallization toward a cluster-free intrinsic assembly pathway. The resulting perovskite films exhibit homogeneous high-quality perovskite nanocrystal structure, with exceptional optoelectronic properties and remarkable ambient stability. These advancements enable PeLEDs with a record external quantum efficiency (EQE) of 31.0% alongside unprecedented operational stability (equivalent T₅₀ >310 000 h at 100 cd m^-2, T₉₀ > 1000 h at 1000 cd m^-2), establishing new performance benchmarks for PeLEDs. Our work establishes a paradigm linking precursor-state engineering to film-quality determinism, demonstrating that eliminating conventional cluster-dominated aggregation pathways can revolutionize the assembly process and unlock the potentials of perovskite optoelectronics.