Time resolved confocal fluorescence microscopy has enabled the study of nanocrystal photophysics with single particle sensitivity. These measurements have shown that the emissive behavior of individual particles is heterogeneous within an ensemble colloidal solution. Combined with improved chemical control over precursor conversion – demonstrated recently by kinetic rate tuning of thio- and selenourea precursors – the role of composition and structure on core/shell nanocrystal luminescent properties becomes more clear. Time correlated single photon counting (TCSPC) was used to study biexciton quantum yields, photoluminescence lifetimes, and blinking behavior of CdSe/CdS heterostructures with varying gradation of Se/S alloyed interfaces. Time-gated photon antibunching analysis was used to ensure the data used in this study is based on single particles, both as dilute colloidal solutions and on solid substrates. Near unity ensemble quantum yields are seen by reducing the strain of the core/shell interface, suggesting a link between interfacial defects and non-radiative decay.

Single particle fluorescence studies of semiconductor nanoparticles alloyed by kinetic control

255th National Meeting (2018)

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