title: Facile synthesis and characterization of highly fluorescent and biocompatible N-acetyl-L-cysteine capped CdTe/CdS/ZnS core/shell/shell quantum dots in aqueous phase.
abstract: The synthesis of water-soluble quantum dots (QDs) in aqueous phase has received much attention recently. To date various kinds of QDs such as CdTe, CdSe, CdTe/CdS and CdSe/ZnS have been synthesized by aqueous methods. However, generally poor-quality QDs (photoluminescent quantum yield (PLQY) lower than 30%) are obtained via this method and the 3-mercaptopropionic acid stabilizer is notorious for its toxicity and awful odor. Here we introduce a novel thiol ligand, N-acetyl-L-cysteine, as an ideal stabilizer that is successfully employed to synthesize high-quality CdTe/CdS/ZnS QDs via a simple aqueous phase. The core/shell/shell structures of the CdTe/CdS/ZnS QDs were verified by x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, x-ray powder diffraction and transmission electron microscopy. These QDs not only possess a high PLQY but also have excellent photostability and favorable biocompatibility, which is vital for many biological applications. This type of water-dispersed QD is a promising candidate for fluorescent probes in biological and medical fields.
authors.affiliation: College of Chemistry and Life Sciences, Guangxi Teachers Education University, Nanning 530001, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiao
authors.forename: Shan
authors.initials: S
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Su
authors.forename: W H
authors.initials: WH
authors.lastname: Chan
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis*; D019187:Cadmium Compounds / Q000737:chemistry* / Q000633:toxicity; D003460:Crystallization / Q000379:methods; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D008422:Materials Testing; D044367:Phase Transition; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry* / Q000633:toxicity; D013691:Tellurium / Q000737:chemistry* / Q000633:toxicity; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry* / Q000633:toxicity
chemical_list: D001672:Biocompatible Materials; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D018036:Selenium Compounds; D017967:Zinc Compounds; D014867:Water; C058667:cadmium selenide; D013691:Tellurium; C044696:zinc selenide; C028337:cadmium telluride