Enhancing luminescence efficiency of CdSe quantum dots through the amine-assisted Z-type ligand

Organic ligands play a key role in passivating quantum dots (QDs), facilitating their green production and large-scale synthesis. Alkyl- amines, in particular, significantly enhance the photoluminescence efficiency of CdSe QDs. However, the interaction mechanism between alkylamines and QDs remains unclear. In this study, we propose a mode of interaction between amines and QDs, referred to as Z* ligands, which are formed by the combination of alkylamines with Z-type cadmium carboxylate. Our findings demonstrate that, compared to traditional Z-type, L-type, and X-type ligands, the Z* ligand exhibits more pronounced fluorescence enhancement of QDs while minimizing the surface etching effect. Through density functional theory calculations, we further elucidate the mechanism by which the Z* ligand enhances the photoluminescence efficiency and stabilizes the QD surface. These insights deepen our understanding of organic ligand passivation on QDs and open new paths for the green synthesis of highly luminescent QDs.