Dual-Carboxylate ligand engineering of CsPb(Br/I)3 perovskite nanocrystals for stable high-efficiency WLEDs

Perovskite light-emitting diodes (PeLEDs) employing CsPbX 3 nanocrystals (NCs) face persistent challenges in balancing emission efficiency and spectral stability due to surface halide vacancies, which trigger nonradiative recombination, halide phase segregation, and self-doping effects. In this work, we address these limitations by introducing 3,5-dicarboxyphenylboronic acid (3,5-DA) as a multifunctional bidentate ligand additive. The unique coordination architecture of 3,5-DA, featuring multiple chelating groups, enables strong binding affinity to perovskite NC surfaces. This interaction effectively passivates halide vacancies while suppressing ion migration and defect formation. The optimized CsPb(Br/I) 3  NCs exhibit enhanced stability and suppressed nonradiative losses, enabling high-performance white LEDs (WLEDs). At a driving current of 10 mA, the fabricated WLEDs demonstrate a luminous efficiency of 10.32 lm·W −1 , a CIE coordinate of (0.3379, 0.3391), a correlated color temperature (CCT) of 5260 K, and an external quantum efficiency (EQE) of 6.48 %. This work provides a ligand engineering strategy to concurrently resolve efficiency-stability trade-offs in PeLEDs.