Development of highly luminescent and cytocompatible near-IR-emitting aqueous Ag2S quantum dots

Colloidally stable and highly luminescent near-IR emitting Ag2S quantum dots (NIRQDs) were prepared by a very simple aqueous method using 2-mercaptopropionic acid (2MPA) as a coating. Emission of Ag2S-2MPA NIRQDs can be tuned between 780 and 950 nm. These NIRQDs have photoluminescence quantum yields (PLQY) around 7-39% and exhibit excellent cytocompatibility even at 600 mu g mL(-1) in NIH/3T3 cells. With such improved properties, Ag2S-2MPA NIRQDs have a great potential in practical bio-applications.