Synergistic Enhancement of Blue Emission in Sb ³⁺ /Cl ⁻ Co‐Doped CsPbBr ₃ Nanocrystals for High‐Performance Light‐Emitting Diode Applications

Abstract Metal halide perovskites (MHPs) have emerged as promising candidates for optoelectronic applications, attributed to their remarkable optical and electrical properties. However, achieving stable and efficient blue emission from MHPs remains a significant challenge due to inherent defects, nonradiative recombination, and phase instability. In this study, a co‐doping strategy that integrates Sb ³⁺ and Cl ⁻ into CsPbBr ₃ nanocrystals (NCs) under ambient conditions is presented, yielding blue‐emitting CsPbBr ₃ :SbCl ₃ NCs with a high photoluminescence quantum yield (PLQY) of 95.9% at 466 nm. Structural and spectroscopic analyses reveal that the introduction of Cl ⁻ not only increases the bandgap of NC, leading to a blue‐shifted emission, but also modulates the rigidity of PbX ₆ ⁴⁻ octahedra, thereby facilitating the substitution of Sb ³⁺ for Pb ²⁺ . Meanwhile, Sb ³⁺ doping effectively suppresses Auger recombination and mitigates surface defects. The co‐doped NCs exhibit remarkable stability, maintaining over 80% of their PL intensity after prolonged exposure to elevated temperatures, as well as over 90% in aqueous environments or under ultraviolet irradiation. Density functional theory results further indicate a lower binding energy for the co‐doped NCs, suggesting enhanced lattice stability. Furthermore, a pure‐blue light‐emitting diode incorporating these NCs demonstrates stable luminescence performance under varying driving currents.