Correlated Incorporation and Structural Variability in Au-CdSe/CdS Plasmon-Exciton Hybrid Microspheres

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• The structural arrangement of semiconductor quantum dots (QDs) and plasmonic metal nanostructures in hybrid assemblies is critical for controlling light-matter interactions.
• Understanding the self-assembly of these nanomaterials is essential for designing advanced optical and electronic devices.

Purpose of the Study:

• To systematically investigate the structural aspects of self-assembly for thiol-capped gold nanoparticles (Au NPs) and CdSe/CdS QDs into hybrid microspheres.
• To analyze the composition-dependent morphology and spatial distribution of Au NPs and QDs within the hybrid structures.
• To provide a quantitative understanding of the statistical nature of nanocrystal incorporation during self-assembly.

Main Methods:

• Synthesis of hybrid microspheres using thiol-capped Au nanoparticles and CdSe/CdS quantum dots at varying component ratios.
• Characterization of hybrid microsphere morphology and composition using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS).
• Statistical analysis of EDS data, including Gini index and Moran's I, to quantify compositional heterogeneity and spatial clustering.

Main Results:

• Confirmed composition-dependent morphology of Au-QD hybrid microspheres via TEM and EDS.
• Statistical analysis of EDS data indicated that nanoparticle incorporation deviates from Poisson statistics, suggesting chemical and structural influences on assembly.
• Revealed uniform dispersion of Au nanoparticles, while CdSe/CdS quantum dots exhibited localized domain accumulation, as measured by Gini index and Moran's I.

Conclusions:

• The study provides a quantitative understanding of the statistical factors governing nanocrystal incorporation during self-assembly.
• Demonstrated that spatial distribution of QDs and Au NPs can be controlled, offering routes to structurally deterministic plasmon-exciton hybrid architectures.
• Highlights the importance of statistical analysis in characterizing heterogeneous nanomaterial assemblies for tailored optical properties.