Atomic-Level Insights into Manganese-Environment-Related Photophysical Properties of II-III-VI Quantum Dots Using Well-Defined Nanofragments

Gaining in-depth insights into the photophysical propertiesofdoped semiconductor nanocrystals or quantum dots (QDs, d-dots) isessential for controlling the dopant-mediated functionalities of QDs.However, the lack of an atomically precise local-coordination environmentat the doping sites renders atomic-scale investigation of the dopant-relatedphotophysical properties within d-dots considerably challenging. Instead,the current understanding is limited to the average number or relativepositions of dopants in a single d-dot. Structurally well-definedmetal chalcogenide supertetrahedral clusters, which conceptually areregular tetrahedral nanofragments of II-VI QDs and featureprecise manganese doping sites, were selected as ideal models to studythe local-manganese-environment-related photophysical properties.Herein, supertetrahedral clusters were released from the originalcrystal lattice into solution as surfactant-encapsulated complexes,providing a new perspective on external environments to explore theinfluence of superlattice confinement on photophysical properties.Photoluminescence characterization indicates that both local-dopantenvironments (i.e., local manganese concentration)and external environments (i.e., superlattice confinement)significantly affect the lattice strain within clusters, which inturn effectively alters the emission of manganese ions. Additionally,with highly local manganese concentration, energy transfer from thehost to the manganese dopant and Mn-Mn exchange coupling interactionswere directly observed using ultrafast spectroscopy. This study unravelsthe effects of the environments on the photoluminescence and excited-statedynamics of semiconductor clusters where manganese is located at theatomic level, providing an ideal reference model for subsequent studiesrelated to the precise nanochemistry of II-III-VI d-dots.

Automated summary

This study investigates the effects of the local manganese environment on the photophysical properties of II-VI quantum dots. Structurally well-defined metal chalcogenide supertetrahedral clusters are used as ideal models to explore the influence of external environments on photoluminescence and excited-state dynamics. The study provides insight into the precise nanochemistry of II-III-VI d-dots.