Tunable ZnO quantum dots for bioimaging: synthesis and photoluminescence

Photoluminescent semiconductor quantum dots (QDs) are of significant interest for bioimaging and fluorescence labelling. In this regard, the design and synthesis using a chemical hydrolysis approach is described of high sensitivity and high specificity non-toxic ZnO QDs (similar to 5 nm). The ZnO QDs, with long term stability of up to 12 months, exhibited strong green yellow emission on doping with small concentration of manganese, which is tunable to the near infrared biological window (about 650-770 nm). Furthermore, the embedding of ZnO QDs on silica nanospheres led to a significant increase in photoluminescence intensity rendering them suitable for bright QD based probes.