The surface treatment of thiol-capped CdTe quantum dots (QDs) was carried out with a small amount of sodium borohydride (NaBH4) in aqueous solution at room temperature. The treatment effectively enhanced the photostability of QDs and increased the photoluminescence (PL) efficiency by a factor of two as against the original ones. By measuring the PL trajectories of single QDs with a total internal reflection fluorescence microscope under the same irradiation density of 0.72νWνm-2 at 532nm, the photostable lifetimes were determined to be 15.2 5.9s for surface-treated QDs, and 5.8 1.9s for the original ones, respectively. Both the original and treated QDs could be ingested into human hepatocellular carcinoma cells (QGY) by incubation. The photobleaching of cellular QDs was measured with a confocal microscope. Remarkable enhancement was found for the photostability of the surface-treated QDs in QGY cells, demonstrating its advantage for cellular labelling applications.
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- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering