Dual-Carboxylate Ligand Engineering of Cspb(Br/I)3 Perovskite Nanocrystals for Stable High-Efficiency Wleds

Abstract

Perovskite light-emitting diodes (PeLEDs) employing CsPbX3 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.

Keywords: CsPb(Br/I)3 perovskites, bidentate ligand, surface passivation, red light, WLEDs