Analysis of Giant‐Shell CdSe/CdS Quantum Dots via Analytical Ultracentrifugation Combined with Spectrally Resolved Photoluminescence

TL;DR

Researchers used a new method combining ultracentrifugation and light detection to study the size and light properties of CdSe/CdS quantum dots.

Contribution

The study introduces a novel method combining analytical ultracentrifugation with spectrally resolved photoluminescence for nanomaterial characterization.

Findings

The method revealed core size dispersity in quantum dots, causing emission band shifts and broadening.

Spectrally corrected photoluminescence spectra were obtained from a single experiment and compared to single-particle studies.

The technique was validated using certified fluorescence standards and showed potential for advanced nanomaterial analysis.

Abstract

Knowledge of the structure–property relationships of functional nanomaterials, including, for example, their size‐ and composition‐dependent photoluminescence (PL) and particle‐to‐particle variations, is crucial for their design and reproducibility. Herein, the Angstrom‐resolution capability of an analytical ultracentrifuge combined with an in‐line multiwavelength emission detection system (MWE‐AUC) for measuring the sedimentation coefficient‐resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant‐shell CdSe/CdS quantum dots (g‐QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands. The MWE‐AUC PL measurements are calibrated and validated with certified fluorescence standards. The spectrally corrected and size‐dependent PL spectra of the g‐QDs derived from a single MWE‐AUC experiment are then analyzed and compared with the results of single‐particle spectroscopic studies, yielding the PL spectra, decay kinetics, and blinking behavior of individual g‐QDs. This study underlines the vast potential of MWE‐AUC with in‐line optical detection for the characterization of advanced nanomaterials with a complex structure.

Analytical ultracentrifugation (AUC) is a powerful tool for studying the size–property relationships of nanomaterials in their native environment. A methodology based on AUC with in‐line multiwavelength emission detection is developed, enabling the measurement of the size‐resolved emission spectra of giant‐shell CdSe/CdS quantum dots. The results reveal core size dispersity, leading to the shifting and broadening of the emission band.

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