Photoluminescence of CdSe and CdSe/ZnS quantum dots: Modifications for making the invisible visible at ensemble and single-molecule levels

• Recent advancements in the optimization of quantum dot's photoluminescence quantum efficiency.
• Surface modification of quantum dots and its relation with blinking suppression.
• Quantum dots as energy donor for FRET-based bioanalysis.
• Quantum dots delivered in cells for bioimaging.

This thematic article is written with an intention to provide an overview of our recent research on the modulation of quantum dots photoluminescence and the applications of quantum dots to bioimaging. In particular, we summarize the physiochemical factors that affect the photoluminescence of CdSe or CdSe/ZnS quantum dots at ensemble and single-molecule levels, blinking and blinking suppression of quantum dots, bioconjugation of quantum dots, applications of bioconjugated quantum dots for analyzing some selected biophysical processes at single-molecule levels, and intracellular delivery of quantum dot bioconjugates. These research subjects are correlated with the state of the art accomplishments in the quantum dot field.