Bi-Functional Chelating Ligand Enables Ultra-Stable Blue Emissive CsPbBr₃ Nanoplatelets Film

Quantum-confined perovskite CsPbBr₃ Nanoplatelets (NPLs) have recently emerged as promising blue-emitting materials for perovskite light-emitting diodes (PeLEDs). Yet, their susceptibility to optical instability in solid films under ambient conditions poses a significant hindrance. This study introduces a novel chelating strategy that utilizes metal manganese ions and multidentate ligands, markedly improving the structural stability, and emission efficiency of NPLs. The approach involves adding Diethylenetriaminepentaacetic acid (DTPA) to the perovskite precursor solution, which allows for strong coordination to surface [PbBr₆]⁴⁻ octahedrons via its multiple chelation sites. Ensuing metal manganese ion integration during the purification phase addresses Pb²⁺ and Br⁻ site vacancies, culminating in near-perfect octahedral structures with significantly fewer vacancies. These metal manganese ions are then further immobilized on the NPLs surface by the chelating effect of unbound DTPA functional groups. The resultant CsPbBr₃ NPLs films demonstrate an impressive PLQY of 66%, showcasing remarkable air stability with consistent blue emission for up to 5 days. The CsPbBr₃ NPLs-based PeLEDs show electroluminescence at 460 nm with a current efficiency of 1.07 cd A⁻¹ and a maximum luminance of 220 cd m⁻². The proposed chelating strategy positions perovskite NPLs as an extremely promising prospect in future applications of high-definition displays and high-quality lighting.