Hydrothermal synthesis for high-quality glutathione-capped Cd x Zn 1 - x Se and Cd x Zn 1 - x Se/ZnS alloyed quantum dots and its application in Hg(II) sensing

• Published in: Luminescence (Chichester, England) Vol. 32; no. 2; pp. 231 - 239
• Main Authors: Lai, Lu, Sheng, Si-Yu, Mei, Ping, Liu, Yi, Guo, Qing-Lian
• Format: Journal Article
• Language: English
• Published: England 01.03.2017
• Subjects: Cadmium - chemistry; Cadmium - pharmacology; Cell Survival - drug effects; Dose-Response Relationship, Drug; Glutathione - chemistry; Glutathione - pharmacology; HEK293 Cells; Humans; Mercury - analysis; Quantum Dots; Selenium - chemistry; Selenium - pharmacology; Structure-Activity Relationship; Sulfides - chemistry; Sulfides - pharmacology; Temperature; Zinc - chemistry; Zinc - pharmacology; Zinc Compounds - chemistry; Zinc Compounds - pharmacology; alloying mechanism; hydrothermal synthesis; alloyed quantum dots; cytotoxicity; fluorescent sensor
• ISSN: 1522-7235; 1522-7243
• DOI: 10.1002/bio.3174

High-quality Cd Zn Se and Cd Zn Se/ZnS core/shell quantum dots (QDs) emitting in the violet-green spectral range have been successfully prepared using hydrothermal methods. The obtained aqueous Cd Zn Se and Cd Zn Se/ZnS QDs exhibit a tunable photoluminescence (PL) emission (from 433.5 nm to 501.2 nm) and a favorable narrow photoluminescence bandwidth [full width at half maximum (FWHM): 30-42 nm]. After coating with a ZnS shell, the quantum yield increases from 40.2% to 48.1%. These Cd Zn Se and Cd Zn Se/ZnS QDs were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. To further understand the alloying mechanism, the growth kinetics of Cd Zn Se were investigated through measuring the fluorescence spectra and X-ray diffraction spectra at different growth intervals. The results demonstrate that the inverted ZnSe/CdSe core/shell structure is formed initially after the injection of Cd . With further heating, the core/shell structured ZnSe/CdSe is transformed into alloyed Cd Zn Se QDs with the diffusion of Cd into ZnSe matrices. With increasing the reaction temperature from 100 °C to 180 °C, the duration time of the alloying process decreases from 210 min to 20 min. In addition, the cytotoxicity of Cd Zn Se and Cd Zn Se/ZnS QDs were investigated. The results indicate that the as-prepared Cd Zn Se/ZnS QDs have low cytotoxicity, which makes them a promising probe for cell imaging. Finally, the as-prepared Cd Zn Se/ZnS QDs were utilized to ultrasensitively and selectively detect Hg ions with a low detection limit (1.8 nM).